View Full Version : RTL on 1440 kHz
hello happy new year 2005,
what happen emmision drm ? i do not received today in my
digital radio mondiale coding technologies,
i have check any frecuencias 13620,7265, etc and not drm señal
will be my radio bad?
please tell me emision is operativas today thank very much
regard
pedro
granada
spain.
Hi Pedro,
all frequencies are on air, must be a local problem.
73, Klaus
radiomann
01-01-2005, 10:58
My results not to bad for me, good listening, fell asleep about 3 ish, no good for day time reception for me.
Paul
Absolute brilliant sound quality now with 23.6 kbps p-stereo. Actually my SNr still high enough with 18-19 dB. But every crackle sound on MW causes a short dropout. The signal is absolute stable between S8 and S9.
At 23.5 kbps here (near Cologne) the SNR is still 23 dB (upper limit for the WR-G303e).
The sound is better than on 6.095 kHz but female voices are still hissing.
I think this is a good bit rate, but I wonder what it would sound like at 31 kbps (mode A at lowest protection level)...
BTW: The receiver indicates radio text but it doesn't seem to be transmitted.
Regards - Jens
Hi all,
Firstly happy new year, hope there are not too many sore heads out there....
Wow` it`s like listening to a local FM stereo transmission just now, amazing audio quality considering the distance.
I suffer from slow cyclic fading from RTL around midday then improves as the afternoon goes on.
hi all,
First happy New Year to everybody.
Just want to inform that we are txing right now with the power of 240kW to the antenna beaming to Germany.
Thank you for all your reception reports and logs.
Originally posted by carknue
Absolute brilliant sound quality now with 23.6 kbps p-stereo. Actually my SNr still high enough with 18-19 dB. But every crackle sound on MW causes a short dropout. The signal is absolute stable between S8 and S9.
Can you or someone do a recording with this bit rate, reception is zero for me during the day
They've just switched back to 19.6 kbps...
Regards - Jens
Originally posted by DRM-Fan
Can you or someone do a recording with this bit rate, reception is zero for me during the day
Not with Dream running on my PC. The higher the bitrate, the higher is the CPU usage of Dream especially with SBR and p-stereo. But I will do it next time when DRM Software Radio is running.
SNR dropped down to 15-18 dB the last hour and I got more and more cracle on the airwaves here. It is really time for me to move away from here. Also my DVB-T reception suffers from this.
Originally posted by carknue
Not with Dream running on my PC. The higher the bitrate, the higher is the CPU usage of Dream especially with SBR and p-stereo. But I will do it next time when DRM Software Radio is running.
SNR dropped down to 15-18 dB the last hour and I got more and more cracle on the airwaves here. It is really time for me to move away from here. Also my DVB-T reception suffers from this.
Hmm did you read my reply about your pc problems ? I can record with Dream with bit rates of 30 kbps or more (SW) How much RAM do you have ?
Surely it is no problem on a 2.4 Ghz machine, but mine is a 0.933 Ghz system. That makes the differnce.
SNR is down to 14 dB now. I wonder why. Signal is still S8-S9.
Originally posted by carknue
Surely it is no problem on a 2.4 Ghz machine, but mine is a 0.933 Ghz system. That makes the differnce.
SNR is down to 14 dB now. I wonder why. Signal is still S8-S9.
Oh ok I thought I read you had 2.6ghz pc, the more RAM the better though
Yes, I also have a 2.6 PC, but I can't use that for DRM because of the QRM it produces.
Now RTL changed to Mode B, I think a bit too early. IR is still only groundwave. SNR climbed up to 16-17 dB.
Originally posted by carknue
Yes, I also have a 2.6 PC, but I can't use that for DRM because of the QRM it produces.
Now RTL changed to Mode B, I think a bit too early. IR is still only groundwave. SNR climbed up to 16-17 dB.
ok I have my Elektor right next to my TFT monitor, very low QRM with me anyway
Hi DRMs,
here are a 14 hour logfile from RTL on 1440 kHz.
Quite good results and a perfect sound with the high
bitrate (23,6 kbps). Actual they use 18,4.
In spite of the low SNR sometimes, there was no problem
during the high bitrate!
regards, Michael
---------------------------------------
FRG 100 + Sony AN1 wide range antenna
Hi,
Not bad considering 1282 km distance to Luxembourg and almost "daylight".
Time: 13:05 - 14:40 UTC. Max SNR:24.1 dB.
Still too weak in Munich now (15:00 UTC), although the interferer is slowly getting strength already, it seems to be somewhere in the East where darkness sets in earlier.
So far, only RTL's station label can be received at an SNR around 7 dB.
Roland
I think, that now we have quite a critical reception phase. The signal of RTL is still weak, because the skywave has not yet build up, but there are already strong signals from other parts of europe. I only have now 15 dB SNR with lots of dropouts, but mostly, they are produced locally, from electrical switches.
Now the first skywaves reaching Frankfurt. Signal strength increases, but selective fading begins. Overall SNR increased to over 20 dB now. But still dropouts.
Oh no, signal is now booming in with 28 dB and they lowered bitrate to 15.3 mono without SBR. I think that these mode changes must be recalculated. But that is the purpuse of these tests ;-).
Still a very low SNR with no audio in Munich, although it's dark already.
Roland
radiomann
01-01-2005, 16:09
I am now getting audio, now it's the last hour:(
See screenshot.
Paul
Nearly the whole afternoon I had only 15 dB and now 29 dB with just bad sound quality :(
Over here, the gain in signal strength due to better propagation at darkness is overcompensated by the fact that my neighbour has now switched his low voltage lighting on which causes noise that covers the signal.
Roland
It would be very interesting to see how the radiation patterns of Marnach's day- and nighttime antennas look like.
Any chance that these are to be published?
Roland
My neigbours have switched the whole day their electric devices on and off and caused dropouts in my RTL reception. Now the signal is too strong for them:D They can do what they want now.
Nearly perfect
S9 at 17:00 UT
Sorry forgot the log
Bernd, DF9RB
radiomann
01-01-2005, 16:58
The last hour.......
Paul
Hi,
very bad over here in Munich, even in AM the signal is very weak now, I guess that the daytime antenna is being used right now. The current local noise spike interference is also very annoying.
Roland
Ok, here comes my complete daytime log. 9 hours with more than 97 percent audio in a distance of nearly 200km and off the main beam of the antenna; I would call this perfect.
You can cleary see the six mode changes in the graph (deepest dropouts). The SNR slightly decreased over the day. It went down to 14-15 dB, but that was still enough for 23.6 kbps, because the groundwave signal was very stable at S8. Not comparable to shortwave reception. The many short dropouts between 11 and 15:50 UTC were all caused by local electric switching crackle noise. The signal strength and SNR were too low to compensate that. But all these dropouts were very short and hardly noticable, because these crackles only last for tens of seconds.
The SNR increased extremely in the last hour, when skywave propagation started. Bitrate could be higher for 28 dB.
Why are you stopping at 17:00 UTC?
Congratulation to all technical staff from RTL for this first and perfect daytime medium wave DRM transmission. 23.6 kbps p-stereo sounded absolute brilliant! Keep on the good work!
Originally posted by carknue
9 hours with more than 97 percent audio in a distance of nearly 200km and off the main beam of the antenna; I would call this perfect.
That's how it should work with groundwave propagation.
But if DRM should become more widespread, a lot of people will be unable to receive stations properly, because there will be local interference sources of the kind many of us are already suffering from.
When everybody was still listening on AM, these interference sources were quickly identified and "corrected" but nowadays with a much greater number of electronic devices in the home environment, this gets more and more complicated. Now, new equipment is often also not tested for interference generation or the measurements are performed only in a narrow frequency range. Producing devices that don't generate interference is usually cheaper than to produce such ones that do not generate interference.
Many owners of interference producing devices will show no insight in improving the situation, as long as they themselves are able to receive their favourite FM stations.
It's somewhat strange, but the only hope we can have, is that those interferences will also affect digital TV, because people will be much more sensitive about their own TV picture quality than about how their neighbour can receive radio. Perhaps it is more likely that interferences will then be looked after if TV reception suffers as well.
Roland
Here's my summary of today's first daytime transmission:
During daylight ground wave reception was perfect and local noise caused no problem.
I don't need to attach a report, because the SNR was stuck to 23 dB and there were no dropouts at all.
(Reception with my "Satellit 700" wasn't free of dropouts because the ferrite rod is not as insensitive to local noise as my loop antenna on the balcony.)
The results near and after sundown were less stable because ground and sky wave were "fighting" but I noticed only two short dropouts.
I think that a regular service won't need more than two mode changes: 23.5 kbps should work fine during daylight, 15.2 kbps during darkness.
Also congratulations to the technicians at Marnach: You are doing a good job!
Regards - Jens
PS
@Roland: Not every new electronic device will be a problem. If picture tubes are replaced by LCD screens it will have positive effects on the local noise level.
Hi all,
Here is my log from 11.30-17.00 hrs UTC. Apart from sight fading at the start and a local thunderstorm between 14.00-14.30 hrs I was very pleased with the results.
Yes` would agree also the folks at RTL have done a great job over the last few days.
This sort of stuff gives DRM a very bright future don`t you think.
Bring on more MW/LW tests......
Hi all,
thanks to German Telekom DSL is working again :)(although many phone lines are still not back)
Signal at daytime is far too weak in my location (for Carsten S0-S2 with a Welbrook), here is an example from this afternoon using the Sony SW7600G.
73, Simone
DVB-T reception suffers from this as well, that is why Philips designed a DVB-T Box with a so called "Pulse Killer Chip" Today I whished that my AOR had such a chip also ;-)
It is the part of the industry to design DRM Radios that come with a proper antenna and not only a piece of wire. BTW I couldn't receive anything from RTL today on 1440 with my DWT and the wire antenna. The industry needs to design Radios with diversity antennas to detect and automatically phase out local QRM. We can fly to the moon so that shouldn't be too difficult.
Hi all,
here is my report for the last hour, when skywave propagation had started, with pretty good results but low bitrate.
73, Simone
Hi DRMs,
here are the last 90 minutes from RTL on 1440 kHz.
BTW, -same as Simone and Carsten, - the daytime signal was
to weak for my several modified Sony receivers with
> build in antenna < ( Sony SW1, Pro 80/70, 7600G).
Also no chance for my small elektor rx!
Only the Yaesu FRG 100 and 8800 and my old modified
Blaupunkt carreiver did a good job ;-))
regards, Michael
Originally posted by DigiBC
@Roland: Not every new electronic device will be a problem. If picture tubes are replaced by LCD screens it will have positive effects on the local noise level.
That is true, but unfortunately the number of switch-mode power supplies increases all around. And those are not always properly designed.
Take e.g. my ADSL modem (Teledat 300), it does not radiate on the cables leading in and out because these are properly filtered, but it directly radiates harmonics of the switchmode supply's switching frequency on shortwave. The modem's case is not shielded properly enough. The fundamental switching frequency is not very stable (it doesn't have to) and if the signal on 7320 kHz is weak, one of the harmonics that is directly radiated from the modem may fall inside Rampisham's DRM bandwidth and cause considerable interference. No problem if the DRM signal is strong, but a big problem with a weak signal although I am receiving with a dipole antenna. It would be much worse if my antenna were to be just a wire or a telescopic antenna in the room here.
Roland
Originally posted by carknue
The industry needs to design Radios with diversity antennas to detect and automatically phase out local QRM. We can fly to the moon so that shouldn't be too difficult.
I guess it would be more important to erradicate interference at the source. That is going to be much more effective.
Roland
Originally posted by dk8cb
I guess it would be more important to erradicate interference at the source. That is going to be much more effective.
Roland
Sure, but what do you want to do against the already sold and used HF polluters? Just wait until they will be replaced in several years? You must do it on both sides.
But what I do not understand is that this polluters can freely be sold in the shops. We have the CE sign and the RegTP in Germany in order protect the airwaves from this QRM. They do nothing or not enough.
Originally posted by carknue
But what I do not understand is that this polluters can freely be sold in the shops. We have the CE sign and the RegTP in Germany in order protect the airwaves from this QRM. They do nothing or not enough.
Any manufacturer can put a CE sign on his equipment. In theory, the EU directives then have to be applied which in practice means that the basic standards have to be adhered to.
But not every manufacturer cares or does have the equipment for proper measurements.
As long as nobody complains, nothing will happen.
But if a certain device generates interference everywhere and there are a lot of complaints put to the attention of the regulators, the said equipment may be withdrawn from the market by the regulator. Unfortunately, so far this happens almost only in cases where user safety is questionable.
So complain and don't take it as it is!
Edit: But still there is one problem that is overlooked: If a device is defective, but only in a way, that the interference protection devices (e.g. line-voltage capacitors) do not function anymore, nobody will replace the device or have it repaired for an astronomical price because it is still working otherwise.
In some cases, devices are only tested for interference generation in certain modes but not in others. There was once a case in the house I'm living in, where a Hitachi TV set would generate extreme switching noise but only when in standby, which it was for most of the time all day long. If switched on, everything was ok.
Roland
Hi,
here the reception results from Luxembourg City. As before, strange dropout in the 16-QAM mode (although I cannot state if they are real or just miscalculations from the logging software - although I think to the last option is more plausible).
And here the first daytime reception report. I changed the antenna in ealy afternoon, causing a few dropouts. SNR was better with the AN-1 than with the loop antenna.
Regards,
Michel
Hi Michel,
using DRMSWR simultanously you will not get these dropouts with 16 QAM, seems to be a problem with DReaM.
73, Simone
Hi,
here is a plot of today's quite long impulse response in Munich.
Current SNR is around 21 dB.
Roland
I can't help believing that they are playing the same songs every night. Perhaps in another sequence but still the same songs...
Roland
Everything is fine in Frankfurt. 26-28 dB. Higher Bitrate would be possible but not Mode A.
Oh no, still 27 dB and bitrate now down to 15.2 kbps. That is too low for me, I'll go to bed now.
Hi,
signal strength has risen before the bitrate change and SNR has increased as well.
Bitrate is now 15.32 kbit/s, audio bandwidth is < 5 kHz, which really doesn't sound nice.
Roland
Conditions couldn't be any better, but bitrate could be much higher....
Originally posted by dk8cb
Hi,
signal strength has risen before the bitrate change and SNR has increased as well.
Bitrate is now 15.32 kbit/s, which really doesn't sound nice.
Roland
Just like analogue MW :-( Why the switch anyway I wonder ?
I thought they could try 23kbps even nightime
I think RTL should erect some kind of QoSAM system with receiving stations at a number of RTL-owned local stations and should adjust bitrate and mode according to propagation requirements. There may be some days when a low birate such as the current one is required but often more is possible and would be much better.
Roland
Maybe someone could record the IF signal of the following QAM 16 part for Volker. So he can investigate the Dream problem with that. For me it will be too late.
Reception report for tonight, things were more stable here when bitrate was lowered to 15.2 kbps.
Good night all.
Signal strength seems to vary now, the IR is rather long now and even at this low bitrate, occasional though very brief dropouts may be observed.
Roland
I think that an old rule is not observed by many DRM stations when bitrate and audio bandwidth are reduced.
This old rule states that, in order for the sound to still sound balanced and not dull, there also has to be some attenuation of lower bassy frequencies when the upper frequency limit is lowered.
In DRM this necessity seems to be disregarded and it is just the upper cutoff frequency that is lowered.
This makes the sound at low audio bandwidth even worse than on AM.
Roland
When the impulse response is chaotic as it now starts to become more and more often, audio dropouts will not be prevented by the low bitrate chosen.
Roland
I don't have audio any more, neither on Dream nor on DRM software.
The impulse response has become too chaotic, see screenshot. The receivers are unable to determine the proper start positions of data in the stream.
Roland
Hi,
and here is tonight's report.
Good night.
Roland
radiomann
02-01-2005, 07:28
Pleased I went to bed, pretty bad, it's a shame there is no DRM transmission between 17.00 - 0.00 that would be ideal for me, I will get very little logged on this frequency now back to work Tuesday and daytime is a no no anyway.
Paul
Hi all,
here is my complete log for last night, good results in the first hour and at the end using the frg100 and loop antenna, see attachment
73, Simone
... and here is the last hour with the portable Sony/ferrite antenna, bitrate only 12 kbps when I started but was increased in the last half hour, which gave better results, see attachment
73, Simone
... and here is a screenshot, showing the long IR at 0330 this morning.
73, Simone
Here are my night results. Perfect begining with 28 dB. Complete chaos after 1 hour. Last 30 minutes improved.
This moning it started with a lower SNR than yesterday. Now only 15 dB but still perfect decoding at 19.6 kbps.
Hi all,
at the start this morning I got 20dB SNR for 3min, then it dropped to 8-9 dB, now with the Sony outside I get audio decoding at 14 dB SNR again :)
73, Simone
Bad results today. SNR around 13 dB, lots of dropouts. Signalstrenght is the same as yesterday but there seems to be more local QRM.
No problems here with 23.6 kbps. S 8-9, SNR between 19 and 22 dB.
73, Klaus
tacitus-ms
02-01-2005, 12:16
RTL started a little bit later than usual, before they started DRM they used AM, and I could hear that there was strong fading in the AM signal. The AM signal was quite strong, but the sound spectrum had deep nulls because of the fading and using the Dream-AM (SSB) mode worked much better than the decoder of the FRG-100 receiver, because often the main AM carrier was deleted by the fading. Then DRM started with 18,4 kbit/sec with a very good sound quality. Only a few dropouts could be heared, but every time I had a dropout it was obviously caused by a quite long impulse response. If you look at the attachment you will see two screenshots of the impuls response windows, the first is made about 0:45 GMT, the last, when the problem became much worse, at 03:00 GMT. RTL switched from 18,4 to 15 kbit/sec at 01:00. Between 1:30 and 4:00 often the peak at + 6 ms in the impulrs response windows became higher than all the other peaks. The signal itself was as strong as erlear, but no reception was possible any more. At 4:00 GMT the impulse response became better and the reception was possible again until they stopped DRM. If I compare RTL 1440 with BBC 1226, the impulse response of RTL is very nervous and changes from one second to the next. At 9:00 I tried to receive RTL, but I got only 13 dB, mostly no audio, but a impulse response of only one peak (Mode A could be used to improve the 15 kBit/sec!)
Concerning BBC. Since I have been using the magnetic loop on the rotor and I can eleminate the spanisch interferor, usually I have no (0!) dropouts all the time and 20-30 dB S/N. I hope once it will be possible in case of RTL too :-)
Hi all,
here is a report from this morning, where the difference in reception between indoors and outdoors can be seen, from 1000 I put the Sony radio outside.
73, Simone
radiomann
02-01-2005, 13:57
I know there is a logical answer to this but why can't the UK beam be used during the day?
Paul
Paul, the answer to your question is simple. Because the target is north Germany.
But what I wonder is, why can't the german beam not be used during the night?
radiomann
02-01-2005, 14:10
Originally posted by carknue
Paul, the answer to your question is simple. Because the target is north Germany.
But what I wonder is, why can't the german beam not be used during the night?
Good question Carsten, as 1440 is to be used for Germany then surly the German beam could be used, I've just often wondered if the UK beam would work here as well as the night time signal during daylight, at night Germany gets 1440 well with the UK beam, I think it's 18.00 the UK beam comes on?
Paul
N_Scheer
02-01-2005, 14:18
Hi Carsten,
Why can the german antenna not be used during nighttime?
The german antenna is a 3 tower half wave antenna. The half wave antenna is better for the ground wave (during daylight time).
Transmitting with that antenna during nighttime may result in a greater fading area where the ground wave and the reflected wave make a clear reception impossible.
Regards
Nico
N_Scheer
02-01-2005, 14:23
Here is my one hour log from this morning
(Distance from transmitter aprox. 5km (only) , receiver: Panasonic RF-B33 with built-in antenna, external selfmade 12kHz mixer.
Nico
Originally posted by N_Scheer
Transmitting with that antenna during nighttime may result in a greater fading area where the ground wave and the reflected wave make a clear reception impossible.
This is true for classical AM, but with DRM's capability to withstand some multipath reception, at least as long as it doesn't result in a too long IR, the above may not be true any longer.
One should give it a try.
A question: How does the current nighttime antenna's radiation pattern look like?
Does it have some attenuation towards the southeast? I'm asking because the signal is not strong here in Munich, it is much weaker than Orfordness' signal on 1296 kHz. Or is this just a result of the Orfordness beam being much narrower and the resulting higher gain compared with your broad pattern?
Roland
The skywave brought back the reception. 27 dB now! Over the day it was terrible today. SNR down to 10 dB.
Hi,
the signal is still too weak over here to ensure an SNR that is high enough for continuous decoding. Even the low bitrate of 15.32 kbit/s doesn't help.
SNR is around 13 dB but there is also some local noise.
Roland
its a wrong world. the whole day i had only 13 db and bitrate was 23.6 kbps. now i have constant 27 db and bitrate is only 15.3 kbps :-(
Hi,
currently, the impulse response is quite ok. Signal strength in Munich has now improved, so has SNR. No need for the low bitrate used.
I think, on the long run, transmission parameters will really have to be adjusted not according to a static scheme but rather dynamically with respect to current conditions.
Establish a QoSAM system!
Roland
I forgot to attach the current IR plot.
Here it is.
Roland
Hi,
what happened at 16:23 UTC? Did they increase power?
Did the ionosphere change? Did someone switch off an interference source?
No idea what happened.
Roland
radiomann
02-01-2005, 17:01
My report from 15.24 - 17.00...
oh and I was the antenna.....
Paul
Hi all,
Here is my log for today, on/off reception during daylight hours but conditions down compared with yesterday. Things got better when skywave kicked in. Must admit there were a few extra audio dropouts in there due to other activity on the PC, dial up etc. What a difference when they switched back to AM after 17.00 UTC. The mutipath distortion quite evident and some fading. I am still on the learning curve with DRM technology but would like to say the bitrate change to 15.3 kbps is quite listenable to my ears. Certainly better than hearing a distorted signal from my location anyway.
Hi all,
here are my daytime results. Only 85 percent today. I think my neighbours were more alive than yesterday and entertained themselves with some high tech equipment. Of course with a CE sign on it :D
I wonder that 23.6 kbps in Mode A can be decoded with a SNR down to 13-14 dB. Between 13:50 and 14:58 no decoded audio.
radiomann
02-01-2005, 17:58
Can't it stay as DRM until 18.00? No religious shows on until after that time, CRI starts at 19.00.
Paul
FritzWue
02-01-2005, 18:16
RTL started with very low bitrate 15kbps.
I do not like it as the audio is not better than with am.
A megawatt am transmitter and a wide modulation probably give better results.
I stopped logging after a hour because I had on channel interference caused by my low cost 12V power supply for the receiver.
FritzWue
02-01-2005, 18:16
...after replacing the power supply there was a long period of very stable reception and band conditions. I stopped recording later because I thought there was a problem with the snr display, as I still had 100% sound with displayed snr values around 12dB. Obviously there was no problem, just stable conditions.
FritzWue
02-01-2005, 18:17
Later in the afternoon the impulse response started hopping a lot and the delays looked very crazy.
24kbps with p-stereo was too much, I often had problems with sbr+stereo switching on and off.
FritzWue
02-01-2005, 18:18
I think 19.68 kbps sbr p-stereo was the best compromise today.
(pictures: 15, 19, 24 kbps)
Originally posted by carknue
... and entertained themselves with some high tech equipment. Of course with a CE sign on it :D
Of course. According to law, anything else may - in theory - no longer be sold in European Community countries and in some others such as Switzerland as well.
Roland
FritzWue
02-01-2005, 19:40
I finally found the source for my noise problem on 1440kHz. It is the power supply of my worldspace radio when it runs without load and one of my two monitors, even when it is switched off, has no real line switch. :mad:
Guess what labels are on there? :rolleyes:
Hi all,
somehow the impulse response currently looks as if trouble lies ahead, there are already quite a few dropouts ...
Roland
radiomann
03-01-2005, 00:30
I was just about to post saying seems very bad at the moment, I will leave it logging and go to bed, good night all.
Paul
Here is my results just after midnight. The impulse response was rather "wild" here also then calmed down at the end.
Good night folks.
Too many dropouts with bad IR, often with an otherwise good signal at the same time.
Roland
Hi all,
here is my report. Not a good result.
But I also had the impression that 5 kHz bandwidth sounded a bit better than yesterday.
Roland
Hi all,
bad results last night, good decoding and higher SNR only in the last hour this morning, but that did not sound good at 12.7 kbps and only 3.5 kHz audio bandwidth.
73, Simone
Hi all,
perfect reception only the last 1.5 h. As I see, Dream seems to have a serious problem with the QAM16 mode.
RTL needs to improve their nighttime antenna for DRM.
Hi,
It's getting brighter... that's why RTL is vanishing in the noise. But until 08:30 UTC it was perfect.
radiomann
03-01-2005, 09:19
89% for the first hour this morning, 74% for the hours 01.10 - 03.50.
Paul
As expected, here in Munich, there is only a faint trace of a signal this morning, sometimes not even enough for the station label to be decoded.
Roland
Quite good here, even with a bitrate of 27.8 kbps!
See screenshot.
73, Klaus
Oh dear! A lot of testing going on at the moment! Recorded my all time high a few minutes ago, S/N 25,4dB on my DWT. Is it my reception or are there some testing going on regarding audio output level?
BR, Carl.
Audio quality much better today in the last hour of the transmission. Excellent signal!
See screenshot.
73, Klaus
Perfect during the last 30 minutes
Bernd, DF9RB
FritzWue
03-01-2005, 17:02
Good results today.
I was near the receiver except from 13:15 to 14:45 UTC, so I don't know what happened then.
When I came back the fieldstrength was a lot higher than before and my receiver if was overloaded, so maybe at least a part of the missing audio is because of a receiver problem.
I lost the mail address for direct DRM reception reports to RTL. Does anybody remember?
Hi, email is drm@rtl.com. We changed and experimented some DRM settings this afternoon, causing some short interruptions. We also changed the modulation source which might result in a somewhat different sound level and quality. Transmitter power remained the same all over the day.
Regards,
Michel
radiomann
03-01-2005, 17:37
My last hour or so, I think 6095 is my best bet, shame no RTL transmissions can be picked up after 17.00 (UTC).:(
Paul
Hi all,
that´s all I could get at daytime :(, see attachment
73, Simone
FritzWue
03-01-2005, 17:58
Originally posted by lx1nw
Hi, email is drm@rtl.com.
Regards,
Michel
Thank you Michel,
will send several Dream screenshots from today.
Yesterday the conditons were much more difficult/ interesting, but I was still fighting with my local noise. These problems are solved now.
Hi all,
here is my daytime report. Looks better than yesterday. When the SNR is only around 16 dB, the fieldstrength is also low S8-S9. Even light local interferences always cause a short dropout, as you can see. The settings between 13:30 and 14:40 were not good for my reception.
You should not switch too early to Mode B, because Mode B requires a higher SNR. Normal skywave propagation in the early morning and evening could be handled quite good with Mode A. That shows every night the BBC on 1296 khz.
Question: What is the gain and the horizontal 3dB and 6dB opening angle of the daytime antenna?
Hi all,
Here is my daytime report. Things improved from 13.00 hrs onwards.
Hello Michel,
Mostly good SNR while you were changing bitrate from 14-15 hrs Monday. I was able to compare 12.6-23.6 and to compare 23.6 with 17.12 on 6095khz. 21.7 and 23.6 were both good, 12.6 inferior to AM.
I did not receive anything higher than 23.6. Audio not possible at higher bitrates anyway. A good winter opening.
Hi,
is it just my impression or is the stereo balance not correct and doesn't it emphasize the left channel? Could left and right channel have different tonal characteristics ie a different audio frequency response?
I'm currently listening on headphones but I also got the same impression when listening on speakers.
I can't help but it somehow sounds as if it would come out of a pot. Is it just the low bitrate that's to be blamed?
Roland
Here is today's impulse response. Already a bit long, but no big problems so far.
Roland
Hi all,
pretty good tonight, the new loop antenna that I just built gives 4dB better SNR, although it is still indoors, no dropouts so far, see screenshot.
Poor sound quality now with only 5 kHz audio bandwidth and no stereo anymore, higher bitrate would be possible with the current conditions.
73, Simone
tacitus-ms
04-01-2005, 01:11
The night testtransmission of RTL started just like yesterday, that means strong signal, often very good S/N but a very long impulse response, so that there were a lot of dropouts in the first 3/4 hour of the test. The impulse response has often its highest peak at + 6 ms and looks nearly like known from DW 3995 kHz. Then the S/N decreases and then there is no audio any more. I am sorry that I have forgotten to start the logging.
regards tacitus-ms
Hello again,
Log up to 0100 improving. 15.32kps from 0058 not good!
Compared my audio files from 14-15 hrs Monday and both channels have different audio... 1 side is muddy. Bit rates were 23.6 on 1440 and 17.1 on 6095 (mono I know). Must be me!
Originally posted by simone ... higher bitrate would be possible with the current conditions.
Hi Simone,
same impression here. SNR is currently 23...24 dB with almost no dropouts today. But ionospheric conditions seem to be also quite favourable today as I had already noticed on 1296 kHz a while ago.
BTW There are also text messages today.
Roland
Originally posted by simone
... the new loop antenna that I just built gives 4dB better SNR
Is it tuned or broadband? Which size? Any amplifiers attached? Inductive coupling?
So many questions, so much curiosity ...
Roland
Hi Roland,
I will post some details and maybe a photo tomorrow, have to go to bed now, sorry :)
I also would like to put the antenna outside but it is not waterproof yet.
73, Simone
Hi,
here is a 1 hour report. Quite good conditions today. The dropout is a result of the bitrate change.
Good night everybody, I'm heading for the bed now.
Roland
Hi all,
my best results so far, using the newly built antenna indoors, see attachment
73, Simone
Here are my results from South West France today (sry raw data for now).
Eric
Nr Bordeaux, France
Sangean ATS909 + built-in ant - on batteries
IBM Thinkpad + external mixer
Hi all,
Results from last night, short log this time.
FritzWue
04-01-2005, 16:56
No comment :D
Will log with WinRadio tomorrow.
Hi folks,
Here is my report for this afternoon. Don`t know what happened
between 14.45 to 15.00 hrs, I suspect a very bad fade. Dropout at 16.25 hrs was caused by PC re-dialing.
Hi all,
here are todays results, conditions improved at 1510, dropouts at 1550 caused by myself.
73, Simone
Very good reception this afternoon between 4 - 5pm with SNR of over 25db often..
Hi DRMs,
my today >daylight < reception logfile.
Nearly perfect conditions ( except between 1100-1200)!
regards Michael
--------------------------------------------------
FRG 100 + Sony AN1 wide range antenna
remark:
Sorry, a mistake by myself! I just noticed, the daytime results taken by :
FRG 100 + long wire
Michael
Hi all,
here are the resuls from last night. I wonder why it cannot beginn more close to 0:00 UTC?
As you see, the DRM Software Radio had no problems with the QAM16 part in the last hour.
Good reception with mor than 97 percent.
And here are my daytime results. Higher snr than the last days, but today I used the DRM Software Radio instead of Dream. Reception really improved after 15:00 UTC.
For a better Daytime reception, RTL needs more power with a non directional antenna. In direction north east it goes better than in south east.
Hi,
I think we can expect a long impulse response today. There were already such problems on Orfordness' 1296 kHz transmission that has just ended.
We shall see.
But why does it always take that long until transmission starts? What are these short AM periods good for?
Roland
Hi,
here is a sample of today's impulse response. It changes rapidly.
Currently, SNR on Dream is 22dB, 1 to 2 dB more than on the DRM software.
Roland
Hi,
here is another sample of an impulse response during a dropout. Dropouts seem to occur mostly when peaks with long delay have substantial amplitude and often when the first few peaks are momentarily weak.
Roland
Hi all,
and here is my report.
Many dropouts, despite almost no interference. Too many ionospheric paths.
Good night. Not worth listening any longer anyway.
Roland
Hi all,
not as good as the night before, due to a too long IR and higher bitrate, see attachment
73, Simone
Here are my results from last night.
Eric
Nr Bordeaux, France
Sangean ATS909 + built-in ant
IBM Thinkpad, external mixer
Hi all,
Are conditions really bad this morning. Have listened on/off all morning and picked up nothing via ground wave.
Can anyone confirm this also.
Hi all,
Just starting to get "bits" of signal now. Going to do some loging
now.
FritzWue
05-01-2005, 17:02
Today's unattended log with WinRadio G303i.
The last dropout was homemade. I touched the wrong switch on the antenna attenuator when coming home.
Hi again,
Here is my log for this afternoon, things got better from 14.00 hrs.
Back to work tomorrow so may catch the last hour or so in the afternoons after early shift. It is a pitty tests can not be done after 17.00 hrs up to midnight.
Hi Mark,
could you please put your coordinates into the dream.ini file? Would be interesting to see your distance from the tx.
Here is my automatic nighttime log.
And here is my automatic daytime log.
Hi Carsten,
I had noticed the Tx distance error some time ago. I was a regular DRMSWL user and thought I would try the Dream receiver for a change. Thanks for the info and will try to input my coordinates later tonight.
Regards
Mark
Hi all,
Some 'gaps' of today's reception due to reconfiguration of DRM exciter, changing power settings and small AM tests.
Many thanks for your efforts & stay tuned
73,
Eugène
radiomann
05-01-2005, 20:25
Originally posted by MarkT
Hi again,
Here is my log for this afternoon, things got better from 14.00 hrs.
Back to work tomorrow so may catch the last hour or so in the afternoons after early shift. It is a pitty tests can not be done after 17.00 hrs up to midnight.
Hi Mark
Got to agree 17.00 to midnight would suit me, daytime no good for me anyway and Midnight start not really much hope now I'm back at work:(
Got to say you do very well on 1440.
Paul
Originally posted by radiomann
Hi Mark
Got to agree 17.00 to midnight would suit me, daytime no good for me anyway and Midnight start not really much hope now I'm back at work:(
Got to say you do very well on 1440.
Paul
Hi Paul,
Talking of early shifts, I had developed a bad habit of staying up to late and regretting it at 6 am in the morning, LOL.
Up here the reception from Luxembourg has always been quite good. I remember listening to the Fab208 in the late seventies and eighties on a transistor radio and could always "find" it on the dial.
I think my success with DRM on 1440 is maybe due to the Wellbrook ALA1530 loop antenna. The aerial is mounted at the top of my garden roughly 20 meters from the "noise zone".
I have used dipoles, long wire with bauln and nothing comes close to this aerial in performance, especially SNR.
Regards
Mark
radiomann
05-01-2005, 22:43
Hi Mark,
Well I had 10 days off over the holidays and since RTL started DRM at Midnight, LOL, 00.30 then, I've sat up until 4am, boy am I feeling it now, I'm getting to old for this, I too listened to 208 from 1982 till closedown 92, shame at the time but I think RTL had very little choice it was losing too many listeners, many rumours going around again, maybe one day.
When I lived on Merseyside 208 came in fairly well, now I'm in Kent a little worse but not much to be honest, they always said the further North the better, seems so, well and a good anntena.
I wonder what would happen if I attached my 1m motorised satellite dish to my Winradio:D
Paul
I would buy one of these Wellbrook 1530 antennas but the price seems expensive for what they are £150 plus £10 postage. Is there another place selling them cheaper I wonder ?
Also is it really nessasary to have one at least 6 meatres from the house, what about the loft how would that do ?
Originally posted by radiomann
I wonder what would happen if I attached my 1m motorised satellite dish to my Winradio:D
Do not connect the dish, but the screen of the cable leading to it!
Depending on how long it is and where it is grounded, your antenna cable that runs to the dish might constitute a not so bad antenna if you connect the outer shield to your receiver input as if it were a wire antenna.
The only problem might arise from the fact, that the antenna needs a counterpoise somewhere and that it will use the mains wiring as such by coupling to it through the power supply. This might then introduce noise travelling around on the mains wiring into your antenna system.
Roland
Hi all,
quite good today with a stronger signal than on previous days.
Here is a sample of today's impulse response.
Roland
Hi,
a little shaky tonight but a lot better than on previous days.
As always on this transmission, dropouts were not a result of a weak signal but more of a long impulse response.
Reception was best during the high bitrate period before 01:00 UTC.
Roland
Hi all,
quite good results for the first 1.5 hours, then conditions got worse, see attachement
73, Simone
Here are my results here.
Eric
Hi,
over here, the signal is rising out of the noise for about half an hour now. Still a lot of fading resulting in many dropouts.
The impulse response is quite nice, see attachment.
Roland
Hi,
good reception for the last hour.
Today I changed every 15 minutes the receiving antenna:
16:00 to 16:15 30 m wire
16:15 to 16:30 Loop
16:30 to 16:45 30 m wire
16:45 to the end Loop
With the wire the signal is approx 15 dB stronger but
no influence on the SNR. Also the impulse response don t change.
For Eugène, LX1RR:
The audio level is some dBs lower than RTL on 6095
(and most other DRM stations). You should adjust!
Bernd, DF9RB
Hi all,
here are my results for the daytime transmission
73, Simone
Hi all,
here are the last 2 hours from today. Again very stable.
Strong fading in the last 30 min. which has no effect at all. :)
73, Klaus
Hi all,
Here is my report for the last hour this afternoon.
Hi DRMs,
here are my today results. Still perfect.
In opposite to the day before this logfile was taken by:
FRG 100 + Sony AN1 wide range antenna
regards, Michael
FritzWue
06-01-2005, 17:11
Today a part is missing in my unattended log.
When I came back the winradio application had closed itself without win xp rebooting, I started it again and it ran through to the end...very strange. Still wondering if this is a software problem or a problem with my revised pc setup.
I don't know what caused the longer dropout in the afternoon.
Hi,
many dropouts over here. I guess, I am located just too much south for Marnach's daytime antenna.
I moved windows around a lot on Dream during reception. This sometimes causes a QT library error on Dream, and a minute change is lost in the log. This must have caused the shape of both plots to shift against each other beginning from about the centre of the plot.
Roland
FritzWue
06-01-2005, 17:18
Originally posted by dk8cb
Hi,
many dropouts over here. I guess, I am located just too much south for Marnach's daytime antenna.
Roland
Hi Roland,
wrong direction and twice my distance!
That's a big difference during daytime!
Originally posted by FritzWue
wrong direction and twice my distance!
That's a big difference during daytime!
Hi Fritz,
but it was already dark during my logging period. Before, there was just a faint trace of a signal with often no lock or just 6 dB of SNR.
Roland
Hi there,
here is my automatic nighttime log.
...and here it follows with todays daytime log. SNR was a bit higher but still too weak for my crackle interferece on medium wave. I think without these crackles, I would be close to 100 percent.
xfielder
06-01-2005, 22:17
Hello Everyone !
This is my first ever posting. As it happens I have the data
of the antenna patterns of the Geneva plan of 1975.
I made the enclosed picture as a guide to those that have
expressed interest of how the antenna on 1440 radiates.
This is the daytime pattern; I plan to do something similar for
the nighttime pattern later.
The red line is a rough estimation of the 0.7mV/m FS contour
as is a rule of thumb for the range of a MW station using AM.
I do not know the corresponding value for a DRM signal. I
assumed a ground conductivity of 10mS/m.
All the Best – Hakan
Hi Hakan,
VERY INTERESTING, thanks a lot!
Now I know that I am located almost exactly (116°) at the minimum.
Roland
Hi,
quite good today, but I already expected that because Orfordness on 1296 kHz was also very good.
It was interesting to see that the impulse response didn't change as fast as it did on other days.
Roland
Something else:
The impulse response on this frequency always shows MANY different paths with a considerable total delay. I wonder if this is a result of the broad radiation pattern of the transmitting antenna.
I believe that I get reflections not only from ionospheric layers directly over a line Marnach - Munich but also stray signals from ionospheric layers over areas much further afield, perhaps even from above northern Germany.
Roland
Richard Beales
07-01-2005, 04:06
Hi all!
My first MW DRM log - my Sony suffered the famous blown FET problem a few months ago and I only got the replacement part today.
Anyway, very good results tonight. The 15.32kbps bitrate between 0100 and 0300 sounded OK for background listening. The graph shows two big dropouts in the final hour, but I only heard a few short glitches.
Hello Hakan,
thanks for the interesting diagram. My direction is
fortunately only somewere between 3 and 6 dB attenuated
Bernd, DF9RB
Here my morning log from start until the signal
disappears in the background noise.
Bernd, DF9RB
FritzWue
07-01-2005, 17:17
Today's daytime log.
At noon higher Bitrates would have been possible with me.
The later decrease in SNR was partly caused by receiver fm if overload here.
radiomann
07-01-2005, 17:57
Wow now that's how it should be.
Paul
Originally posted by FritzWue
Today's daytime log.
At noon higher Bitrates would have been possible with me.
The later decrease in SNR was partly caused by receiver fm if overload here.
tacitus-ms
07-01-2005, 17:59
Hi, Hakan,
thanks for the antenna diagram. And its true, my hometown is almost in the direction of the maximum. I have mostly a very strong signal, but after nightfall the impulse response becomes too bad to receive RTL any more (with the strongest peak at 6 ms, less than 50 % audio!). I wonder what kind of antenna BBC 1296 is using, because they are able to use mode A at night! Here in Münster BBC is much weaker than RTL 1440 , but after nightfall nearly as stabile as a local FM station. The impulse response of BBC has always 2 strong peaks, but normally the limit of the maximum of the delay of mode A is not violated.
FritzWue
07-01-2005, 18:46
Pulse response seems to be a real problem.
Attached is a row of five screenshot I took today on 1440kHz at
UTC:
08:04
09:03
13:45
16:10
16:43
No problem at daylight, but when the transmission starts in the morning it is still rather wide and really bad when it is getting dark in the afternoon. These are the same times when I heard this terrible selective fading on the a.m. signal last year.
Hi all,
here are my automatic nighttime results. Not usable I would say :-(
But as I see in the different reports here, nightime reception seems to be very good if you are more than 600 km away from TX. We have perfect results in the north of England and in France. Remember, Orfordness is also more than 600 km away for most of us and also gave mostly good results. It becomes more and more a rule, that the more far away, the better the DRM reception is. Also the Vatican state is more than 600 km away and has no problem with a too long IR. So the German RTL Radio will not be receivable during nightime in Germany. My suggestion for RTL is to rent a DRM TX in Sines and do a DRM SFN on 6095 khz. DW does the same on 6075 khz (AM) wich works perfect. The 1440 khz may be better for an english service at nightime. But we surely need 24 h DRM transmissions on this frequency to see, if it is only a problem in the late night.
And here are my automatic daytime results. SNR looks quite good today. Better than the days before. But as it is a goal for RTL to cover whole Germany, they must think about more power and a differnent antenna pattern, that gives better coverage to the east and south. In Frankfurt we are often in the dead zone of 6095 in summer month and need a reliable medium wave coverage, that is strong enough to beat the big city QRM. Remember, the millions of potential RTL listeners will not have a Wellbrook on the balcony.
Hi all,
Managed to do some logging this afternoon. Results not to bad, some fading after 14.00 hrs.
tacitus-ms
07-01-2005, 20:33
Originally posted by carknue
Hi all,
here are my automatic nighttime results. Not usable I would say :-(
But as I see in the different reports here, nightime reception seems to be very good if you are more than 600 km away from TX. We have perfect results in the north of England and in France. Remember, Orfordness is also more than 600 km away for most of us and also gave mostly good results. It becomes more and more a rule, that the more far away, the better the DRM reception is. Also the Vatican state is more than 600 km away and has no problem with a too long IR. So the German RTL Radio will not be receivable during nightime in Germany. My suggestion for RTL is to rent a DRM TX in Sines and do a DRM SFN on 6095 khz. DW does the same on 6075 khz (AM) wich works perfect. The 1440 khz may be better for an english service at nightime. But we surely need 24 h DRM transmissions on this frequency to see, if it is only a problem in the late night.
Yes, I am also afraid that the distance is the problem. SFN of RTL 6095 LUX and Sines would really be a good idea! But I do not want to abandon hope that 1440 khz could work here because of this I observed:
Here my distances to the stations and the results:
Often I am in Amsterdam. Of course, I test DRM there too:
The configuration: FRG 7700 and Dream-SW, long wire, loop not neccesary, because BBC is much stronger than the Spanish interferer.
Amsterdam-Orfordness: 195 km --> no IR problems and reception stronger than in MS.
Configuration at my home: FRG 100 with ALA 1530 (you know, the spanish station :-) ) and Dream SW:
MS-Orfordness: 435 km --> no IR problems
MS-Marnach: 242 km --> IR very long, big problems at night.
Could the good results of BBC in Amsterdam be caused by the sea between Amsterdam and England? If not then the antenna diagram of BBC must be the reason and then maybe RTL could improve the results by modification of the antenna.
regards tacitus-ms.
Hi DRMs,
again a >daytime result< but today with a changed
equipment. Quite good for this kind of configuration.
regards, Michael
radiomann
07-01-2005, 22:50
The 1440 khz may be better for an english service at nightime. But we surely need 24 h DRM transmissions on this frequency to see, if it is only a problem in the late night.
Sorry Carsten I don't think 1440 is much good for the UK either, we had it long enough time for something new for the UK, they should of kept 252LW for the UK, though the South-East suffered in parts.
Paul
radiomann
08-01-2005, 00:37
Well I tried , too many dropouts though, plus another late start:
S metre 9 + 10 - 9 +20
SNR 13 average
Goodnight, I will go to bed with 1548 Capital Gold Analogue, at least I can hear them.
Paul
[i]Goodnight, I will go to bed with 1548 Capital Gold Analogue, at least I can hear them.
Paul [/B]
Not listening to it via DAB though ? 128k stereo has to better than 4.5khz AM mono !
Richard Beales
08-01-2005, 02:47
Hi all,
Very good results up here again tonight. The impulse response looked terrible at times, but Dream does an amazing job!
Hi all,
thats what I said before, 641 km from Richard seems to be the right distance for this nighttime transmission.
In Frankfurt Dream failed again completely last night.
Mode A is doing very well this morning!
Hi,
Good result here in Stockholm this morning, until fade out at 08:30 UTC. Strong interference from Radio France International in St Petersburg (10 kW).
Thanks Hakan, the antenna diagrams are very good!
Hi,
her my "morning report". Signal faded out out 8:50
Bernd, DF9RB
Hi,
although dusk is just at the brink of setting in, RTL's transmission using mode A, may already be received quite well in Munich. Still a very nice impulse response. However, the fact that the IR moves around in time and also changes shape constantly, is an indication that the signal is already received via an ionospheric path.
Roland
Hi,
45 minutes later with it being almost completely dark outside and after the change to mode B, the impulse response has lengthened a bit and now shows a few more peaks.
When comparing this to the previous IR, note that the time scale has changed due to mode B and its longer guard interval.
Roland
Hi,
the IR of the daytime antenna looks nicer than with the nightime antenna. But maybe it is just a question of time. But RTL really should try the daytime antenna at night. I also think, that mode A would work nice at this time right now. And with mode A we would have a higher bitrate with more error protection.
Hi,
now at complete darkness, shortly before DRM is switched off, here is what it currently looks like.
Reception is still quite good.
Roland
Hi all,
just before the end of the transmission the IR is still great here, but it never looks like that at nighttime.
73, Simone
Hi all,
and here is my report. Mode A was only used until the large dropout when mode was changed to mode B.
Roland
Hi all,
no drop outs during the last hour. The drop out
in the beginning is the mode change from A to B.
FritzWue
08-01-2005, 17:06
I was late today. The big SNR variations in the afternoon are partly caused by my insufficient receiver agc not compensating enough when there is strong fading.
FritzWue
08-01-2005, 17:08
To the end there was much less degradation in pulse response, very different from yesterday.
Hi all,
good results in the last hour today, using the portableSony/ ferrite rod and DRMSWR, see attachment
73, Simone
And here are my daytime results. I would be really interested in knowíng how the reception would continue after 17:00 UTC with the daytime antenna. It really looks very promising.
Richard Beales
08-01-2005, 18:10
Hi,
My graph is like the reverse of the last two hours of Carsten's...
Almost perfect between 1500-1600, then after the mode change at 1600, suddenly reception became much more unstable, with quite a few dropouts in the final hour.
Hi Richard,
really interesting. Looks like you get in UK the same trouble with the german beam, as we have here in the late night with the UK beam. I suppose that we would have a better nighttime reception with the german beam in the RTL Radio main target area. I cannot see a problem caused by a too strong groundwave interfering with the skywaves here, as mentioned here before. Let's give it a try, it cannot get worse.
Originally posted by carknue
I would be really interested in knowíng how the reception would continue after 17:00 UTC with the daytime antenna. It really looks very promising.
Hi all,
the question is, whether they did not use the nighttime antenna already after the mode change. Perhaps someone from Marnach can give us some information on that.
Roland
Hi all,
Here is my log for this afternoon. Daytime reception was poor today here but things improved.
radiomann
08-01-2005, 23:32
I only have DAB downstairs which sounds great. 1548am sounds poor but at least I can hear it more than 1440, why are RTL's frequencies so bad, 1440. 234, 6095, 5990 even 252 was poor, come to think of it Five TV is poor, a trend going on here I think.
Originally posted by DRM-Fan
Not listening to it via DAB though ? 128k stereo has to better than 4.5khz AM mono !
Hi,
RTL, thou art early!:cool:
But thy right sound channel is missing!:mad:
Roland
Hi,
quite a nice impulse response tonight.
Roland
The sound is really bad, even with 18.4 kbps. But reception is perfect.
Originally posted and later deleted by tacitus-ms
... But terrible sound and the right channel has nearly no audio.
It sounds as if they capture the sound input for the modulator from the speaker of an old and very cheap FM Radio through a microphone.
Roland
tacitus-ms
09-01-2005, 00:36
Very good impulse response tonight, and a good signal. (In Germany we wold call it "geil :-) ). But terrible sound and the right channel has neary no audio. Don`'t they test themselves their transmissions in Marnach? It seems to be a problem with the coder.
This post should be part of "RTL 1440", but the stupid forum software does not allow to delete your own post, if it starts a new thread.
regards
tacitus-ms
Edit by Simone: Moved your post to this thread.
Excellent reception and an SNR of 24 dB but such an awful sound! Very low volume after the mode change.
The impulse response slowly begins to lengthen, see attachment, however reception is still very good if one disregards audio quality.
Roland
Hi all,
quite good conditions last night, see comparison of DRMSWR and DReaM attached
73, Simone
... and similar results using the SW7600G/ ferrite rod
73, Simone
Very good reception results last night.
Hi all,
A short report from last night. Some audio dropouts caused by other PC activity.
Sorry I have no screenshots (I have left the software decoder front ends at work for some experiments) but I feel this is well worth reporting - my experience here in Eastbourne, England.
At home I have a Coding Technologies "black cab" prototype portable (the discontinued one) which has only a telescopic whip (not ferrite rod even) for MW - these are well know for their problems, including interference from the PSU, and sensitivity issues among others. The only thing it has previously provided a 'service' on (and by service, I mean not dropped out at all during a listening session) is DW out of Sines on 15MHz. I believe it is important not to produce reception logs from serious receivers with huge aerials, but to experience what performance a 'consumer' can expect from a cheap DRM portable - admittedly I would hope better performace from an eventual production model than can be expected from the 'concept' radio I am using - more suited to demonstrations at exhibitions than real world listening!
Anyway, imagine my astonishment last week when I decided to stay up to see how 1440kHz was doing - it came up without the whip extended, and remained stable! After 10 mins or so I decided to continue listening until the first dropout - anyway by about 3am I admited defeat and went to sleep - it did not drop out at all! It was also the reason that I was late for work the following day!
As I type this at 12:45UTC, I am listening to 1440kHz again! The sun is in the sky and I do need that whip extended, but is it still a 'consumer grade' service!!! I.E - no fiddling about or positioning for reception and no drop outs! Talk about proof for me at least that DRM really seriously works on MW!
Can't wait for some LW tests to happen - groundwave is going to be a winner.
As for the programme content, the music mix is ok - but why does the audio always seem a little over-cooked on RTL's DRM services? Do they have mpeg playout in the studio, or lossy STL's? Or is it being mangled by a cranked audio processor?
Kind Regards,
Rash.
Hi,
I gave RTL a try at 12:50 today. Broad daylight and still a good signal. Well, at least for 15 minutes, then the signal became weaker.
Hi all,
one hour of good listening at daytime with the SW7600G/ ferrite antenna, see attachment
73, Simone
Hi,
last night, reception was rather good, but only of course, if one disregards the awful audio quality and Dream's repetitive errors at the low bitrate.
Roland
Here are my daytime results. Quite good, except between 12:10 and 12:30 when SNR was extremely low.
FritzWue
09-01-2005, 17:01
Only 99.9% audio....not my fault! :D
FritzWue
09-01-2005, 17:40
During the first hour and sometime between noon and 15:00 UTC there was a carrier on frequency. Did anybody else notice it, or was it a local problem here?
Good reception between 1400-1600 UTC although I prefer a higher bitrate.
Ludo
Can anyone tell me why prior to 4pm (UK time) when 19.68kbps was being used I was getting good reception with SNR's around 8 - 12db where as with a lower bit rate of 18.40kbps no audio was heard until SNR was 15db or more which is what I'm use to. I have never had any audio with such low SNR's which is why I am asking...
FritzWue
09-01-2005, 21:41
"I have never had any audio with such low SNR's which is why I am asking..."
Yes, I have also seen that before:
http://www.drmrx.org/forum/attachment.php?s=&postid=13897
100% audio after RTL switched from 18.40 to 19,68 kbps at 10:00 UTC although snr was only 11 to 13 dB.
Hi,
a strange minimum in SNR and percentage of decoded audio around the time of sunset, most likely because of interference from the east, where it gets dark earlier and from where propagation is already better.
Roland
Hi,
do they expect us to report on the AM transmission today or what is going on?
Roland
tacitus-ms
10-01-2005, 00:57
RTL starts perfect this night. A little bit late as usual :-). But perfect IR and only 1 ! dropout caused by my light switch within 35minutes. And they solved their sound problems we heard yesterday. Already yesterday most of us had perfect reception. DID TEY MODIFY THEIR ANTENNA?????? Or do they use the day-antenna as discussed before in this forum. It is very sad that at 01:00 GMT they started with the stupid 15,32 kbit/mode.
regards
tacitus-ms
Richard Beales
10-01-2005, 10:26
Hi,
Very good results last night again.
(I saw the strange low-SNR effect yesterday afternoon too - good solid 19.68kbps audio with only 10db SNR.)
Attached my today's results.
Eric, Nr Bordeaux (France)
Sangean ATS 909 built-in ant
Solid reception of today's last hour.
Ludo
Here is a sample of last night's quite nice impulse response.
I was unable to post it this morning because of a DSL access problem.
Roland
Quite good reception this morning. I really wonder, which antenna was used. I'd like to read some information from Marnach about this.
Roland
xfielder
10-01-2005, 23:45
Hello Everyone,
The question about the vertical antenna diagram is interesting and me too would
find it interesting to know about this. Also old time medium wave AM needs anti
fading antennas with low radiation.
The day-time antenna system of the 1440 transmission for the German audience is
build up from HALF wave vertical radiators. Those have 50% of the power radiated
under 25° of vertical take off angle. Radiation under 25° reaches receivers at distance
more then 435 km on average via the sky wave.
The night-time antenna system for the British audience is build up from QUARTER
wave vertical radiators. Those have 50% of the power radiated under 40° of vertical
take off angle. Radiation at 40° reaches receivers at distance more then 225 km on
average via the sky wave. So it has not that good anti fading characteristics as the
day time antenna.
I think they can achieve better with lower radiation also on the night-time antenna
system as there seems to be problem with the high radiation bumping up and down
between the ionosphere and the earth. Distinct propagation seems to be an important
parameter for good performance.
I hope this is of interest.
All the Best -- Hakan
PS.
Hello Roland
– I could not figure out were to find ° on my keyboard so I copied
from your posting and it worked out fine. Thanks for the help!
Hi,
what kind of strange 5 kHz bandwidth mode is this?
(The noise peak at 7.5 kHz IF is most likely interference from my neighbour's low voltage lighting system.)
Roland
tacitus-ms
11-01-2005, 00:35
What's that: Today (11.05.2004, 00:39) RTL DRM only with 5 kHz bandwidth. But Dream displays "9KHz, Mode B and 19 dB S/N". Of course, no Audio possible. See Screenshot
regards
tacitus-ms
Hi,
now, after the mode change to 18.4 kbit/s P-Stereo there is audio with dropouts, but here, signal is now much weaker than it usual is. I have also got some interference.
Now, there's again another mode change to 15.32 kbit/s.
Roland
Hi all,
here are my results for last night, no decoding with the 5kHz wide spectrum at the beginning. I had not updated DReaM yesterday, so there are these dips in the last hour.
73, Simone
Hi,
a much weaker signal than usual last night.
Roland
I also noted a weaker signal here last night.
Eric, Nr Bordeaux, France
ATS909 + built-in ant
cc: DRM-Fan Dave yr mailbox is full, it says. Infos about my ATS909 mod can be found at:
http://www.f5nsl.org >> DRM >> my rx logs
3 hours of perfect reception, as usual.
73, Klaus
Hi,
here is today's impulse response during a dropout.
Roland
Very bad reception today.
Roland
Richard Beales
12-01-2005, 02:02
Hi,
Very poor here too.
Hi all,
here is my report for last night
73, Simone
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