View Full Version : 7320 kHz (BBC WS from Rampisham)
Simone wrote:
... did not notice it later today,
Sorry to say that three of these dropouts occured shortly after each other at around 12:40 UTC. So they were not limited to the first hour.
Roland
Hi Roland,
but none in the last hour that I listened, and I did not mean that this problem is solved, thatīs the third one ;)
73, Simone
Hi,
here is my report for today.
As always, there is a carrier on 7325 kHz during the last hour. But despite that, reception was good.
Roland
Hi all,
for four days in a row the datastream problems have not occured again, also a strong signal today, see first part of my report attached
73, Simone
... and good results continued later today, see attachment
73, Simone
Hi,
a very strong signal today.
Roland
Hi all,
also a strong signal in the last hour today, and no audio/ datastream problems at that time!
73, Simone
Hi all,
a very weak and unstable signal today, lower bitrate for audio because of an additional service (BBC WS AOD 3.4 kbps ) that could not be decoded, the deep dips about 1411 were caused by Tx problems ("exploding spectrum")
73, Simone
Hi,
I can confirm Simone's observations about the weak and unstable signal. I can't believe that it was just propagation that caused all that but who knows.
There was also a loss of sync at 10:08 UTC with a very strange spectrum. Simone described it as an "exploding spectrum", a description that fits very well.
I was unable to decode the data service with Dream.
Roland
andy.chance
02-09-2004, 15:13
A different antenna was used from about 13:00 Tuesday, bearing 120deg rather than the normal 105.
Andy.
Hi all,
again lots of dropouts with th weak signal, see attachment
73, Simone
Hi,
a weaker signal than usual because of the other beam today. No "exploding spectrum" as long as I listened.
Some strange carriers occupying a bandwidth of approx. 2.5 kHz just above the DRM signal for about 15 minutes after the start of transmission.
Roland
Hi,
again a weaker signal today with some dropouts. I don't quite understand, why there are more dropouts since the signal is not that weak. It seems however somewhat more unstable.
Does the other beam cause more scattering on the ionosphere towards my location and in a way that the channel estimation cannot cope with? Or is it just the lower signal strength?
I did not notice an "exploding spectrum" today.
Roland
Hi all,
signal was not so weak today in the first hour, normal bitrate and no AOD service as in the past days, if I may ask (and it is not a secret) what is the reason for using the 120deg beam?
73, Simone
Hi,
here is my report for today.
The skipping CD effect, already known from 1296 kHz, now appeared on this frequency as well.
Roland
Hi all,
signal got stronger after the first hour of todays transmission, a few dropouts, not caused by Tx problems, see attachment
no message text today
73, Simone
Hi all,
a weak and unstable signal today, especially in the second hour of the transmission (condititions improved later, better results in the last hour, not included in the log)
73, Simone
Hi,
here is my report for today. A rather weak signal.
Roland
Hi all,
agian a weak and unstable signal, lots of dropouts, see attachment
73, Simone
Hi,
here is my report for Sept. 6th.
Not a strong signal.
Roland
Hi all,
some dropouts because of a weak signal, improving after 1200, see attachment
73, Simone
Hi,
a little bit weaker than on the usual beam, but still quite good.
Roland
Hi all,
signal strength was again not great, but a very stable signal today, so results improved a lot, see attachment
As Roland mentioned the different beam yesterday, is it still not the regular beam (hope it will not be 120° during IBC)
73, Simone
Hi,
here is my report for Sept 8.
Not bad.
Roland
Hi,
Signal was rather weak and unstable. Not a good result.
See attached comparison report with both Dream and DRMSW.
Roland
Hi all,
does anyone know which beam is being used these days?
73, Simone
does anyone know which beam is being used these days?
Hi Simone,
looks as is if it is the standard central european beam, signal is quite strong and reception is excellent at this moment.
Roland
Hi,
as already mentioned, the signal was quite strong today and reception was excellent.
Here is a comparison report between both software decoders.
Roland
Hi,
here is a 4 hour report. I guess the spike at 12:53 was caused because some frames were wrongly attributed to the wrong minute.
I noticed an occurence of the skipping audio effect at about 13:32:15.
Roland
Hi all,
a long log today. Don't know what happened at 13:52. Very stable reception all the time.
Hi,
here is today's log.
Excellent.
Roland
Hi,
a very strong signal. 100% properly decoded.
Roland
Hi,
a weaker signal than yesterday.
Also interesting to see how the results from both decoding softwares differed. No idea why.
Roland
Hi all,
also good results last Sunday in the Netherlands (being 66° from Rampisham), about 150km from Amsterdam, see attachment
73, Simone
Hi all,
good results today, signal strength stable at about S9, see attachment
73, Simone
Hi,
not such a strong signal today as on other days.
I noticed the skipping audio effect again at 10:51 UTC.
Roland
Hi all,
good conditions today and big trouble at the Tx after 1206
73, Simone
Hi all,
it seems yesterdays problems have been solved and excellent reception today (continued in mobile reception), see attachment
73, Simone
Hi,
good reception today with a very strong signal. But not all problems seem to have been solved, since the skipping audio effect could again be heard twice at 11:02 during the news broadcast.
Roland
Hi Roland,
you are right, the skipping audio effect is still there, I recorded another example yesterday during the 1200 news, just before the other problems started.
73, Simone
Hi,
a strong signal, but with problems, see attached screenshot. Also, the well known audio skipping could be heard several times.
Roland
Hi all,
good results during 4 hours today although the signal was weaker in the first half hour, see attachment
Great that the Tx problems have been solved within a few minutes today ;) !
73, Simone
Hi all,
strong signal and good results, see attachment.
Skipping audio effect occured several times.
73, Simone
Hi,
here is my report of today's reception.
As Simone already wrote, there were quite a few annoying audio skips.
Roland
Hi all,
good conditions today, two dips I think due to Tx problems, see attachment
73, Simone
Hi,
here is my report for Sept. 20.
Good signal.
Roland
Hi all,
good conditions continued today, Tx problems at 1200 and 1355 (and already a signal at 0926), see attachment
73, Simone
Hi,
quite good reception during my listening period. But of course, the audio could be heard skipping again. It seems to happen more often during the news, but why?
Roland
Hi Roland and Simone, The BBC are aware of the skipping audio, the problem is in the studio at the output of the audio switching matix. Therefore the problem could also affect analouge broadcasts. I hope it will be fixed soon.
James.
PS I also asked about the data on 1296 kHz, and recomended that it is removed or a decoder is made available
Hi all,
a few dropouts today, no problems besides the skipping audio, see attachment
@James: Thanks for contacting BBC, maybe they can make a decoder available at least for the bws, that would be great :)!
73, Simone
Hi all,
strong and stable signal, perfect reception (besides skipping audio), see attachment
73, Simone
Hi,
perfect reception albeit a few few audio skips could be heard.
Roland
Hi,
good reception again.
I noticed a new effect. There was an audible dropout albeit a good SNR of >21 dB (I checked in Dream's long logfile, which logs SNR every second) at 10:21 UTC. I conclude that it was encoder-related.
Roland
Hi,
good reception, some locally generated interference from my ADSL-modem.
I did not notice any recurrence of the skipping audio effect, but like the day before, there were some short dropouts instead. It seems that these have now replaced the audio skips.
Roland
Hi all,
signal got stronger after 45min, good conditions for during 4 hours, see attachment
73, Simone
Hi all,
a weaker signal today in the first 2 hours, see attachment
...but much stronger in the last hour of todays transmissio, see attachment
73, Simone
Hi,
a little bit of interference, probably originating locally, but still quite good.
Roland
Hi all,
looks like some Tx problems but I did not listen/ watch it at that time, see attachment
73, Simone
Hi,
here is my report for Sept. 27.
A strange dropout around 11:12 UTC. Perhaps it was transmitter related as it conforms with a similar dropout in Simone's report.
Roland
Hi all,
perfect results during the 5 hours of transmission today, see attachment
73, Simone
Very good today. Dream shows two straight lines in the graph, the DRM software shows some fluctuations, but both gave 100% perfect reception.
Roland
Hi all,
strong and stable signal today, but an intermittent Tx problem (the old data stream problem again?) from 1313, see attachment
73, Simone
Hi all,
the Tx problem just occured again today, see attachment
73, Simone
the Tx problem just occured again today, see attachment
Exactly, see attachment.
Roland
Hi all,
as already mentioned above, the Tx problems caused some dropouts, besides this pretty good results, see attachment
73, Simone
Hi,
Very good reception today. 100% properly decoded.
However, there were encoder or audio stream related dropouts at 10:32 UTC (two dropouts shortly after each other) and at 11:05 UTC. I did not notice any skipping audio effects today.
Roland
Hi,
very good reception today after a delayed start of transmission. Also a very strong signal today (like yesterday as well).
Roland
Hi all,
here is my report of 4 hours of reception in my car, some periods were mobile reception, overall about 1.5hours, but the graph would show no difference, also starting the engine etc. can not be seen.
73, Simone
Hi,
good reception, but several audio dropouts. I noticed a low volume background hiss during these dropouts.
Roland
Hi,
very good reception today.
Roland
Hi,
I'm clearly too far from the Tx. A QRG of 14 MHz would have been better. Anyway, this is one of the few times that I've got audio on this transmission. Time: 14:15 - 15:00 UTC. Result: 24 %....
Originally posted by Per
I'm clearly too far from the Tx.
Hi Per,
I don't think that this is the reason. You are far off the beam! They are transmitting with a highly directional antenna (in my direction :) ) and you get just a few watts of power transmitted into your direction.
Roland
Hi all,
perfect today, Tx problems did not occur again since last Friday, see attachment
73, Simone
As it should always be.
Roland
Hi all,
pretty good again today, the one dip in 4.5 hours should be neglected, see attachment
73, Simone
Hi,
a very strong signal, but some encoder problems today.
Roland
Hi all,
the Tx problem occured again a couple of times today (no sync although the signal was strong and the spectrum looked OK), see attachment
73, Simone
Originally posted by simone
... and the spectrum looked OK
Not quite. Immediately before the signal became decodeable again, it looked strange each time for a few seconds, see the attached screenshot taken yesterday.
Roland
Hi,
here is my report for today. Again a few encoder related dropouts with loss of sync.
Roland
Hi all,
the problem did not reoccur for the rest of the transmission after 1110, good results, see attachment
@Roland: The "weird spectrum" when gaining sync again is just the behaviour of the DRMSWR I think ( I know that it looks like this on the screen and have posted it before)
Originally posted by simone
@Roland: The "weird spectrum" when gaining sync again is just the behaviour of the DRMSWR I think
Hi Simone,
no, I don't think so. The spectrum display is not dependant on decoding, it is displayed anyway. It might shift a little on the frequency axis when sync is obtained, because the FFT bins are then aligned with the carriers, but this is by such a tiny amount that you will not normally notice it.
It also looks exactly the same on Dream.
The DRMSWR will also display any AM, FSK, noise or whatever other signal that lies within its limited bandwidth window like a normal spectrum analyzer on which resolution, bandwidth and scan time are set to equivalent values.
Of course, when looking at a modulated (especially wideband) waveform with any spectrum analyzer, one must be aware that the spectrum plot is always the result of the analyzer's response and is thus always dependant on scan speed, analyzer filters, frequency resolution, scan time and sequence. In this regard, the DRMSWR does not behave differently from any spectrum analyzer with the exception that it does not scan frequencies sequentially like a conventional analyzer does but that it obtains all frequency components simultaneously instead, as if it was using a filter bank.
Furthermore, sync is only regained a few seconds after the "weird spectrum" has disappeared, when everything looks (and is) normal again.
Roland
Reception quality today was again as it should be.
Roland
Hi,
here is my report on today's reception.
At 12:03 it looked like there was some interference from below, but it might also be a local problem.
Excellent for the rest of the time if one disregards the skipping audio effect, which is now to be heard on both 7320 kHz and 1296 kHz. In the past, it used to occur only on one of these frequencies, but now it's audible on both.
Roland
Hi all,
strong and stable signal, the bad results at the beginning were computer related, even better SNR using the loop antenna in the last hour (please ignore the break at 1400 for changing antennas), no Tx problems, see attachment
73, Simone
Hello,
very good reception today.
regards,
Arne
Good reception today.
Roland
Hi all,
a weaker signal at the beginning, getting stronger in the afternoon, perfect results, see attachment
73, Simone
Hi,
perfect reception.
Roland
Hi all,
pretty good results thgis afternoon, see attachment
73, Simone
Hi all,
very stable signal today, perfect results, see attachment
73, Simone
Hi,
also perfect in Munich today.
Roland
Hi all,
a weaker signal than usual with lower SNR, but improving during the course of transmission. A few dropouts as a result.
Roland
Hi all,
strong and very stable signal, excelllent results and it seems the Tx problem does not occur anymore, see attachment
73, Simone
Hi,
good reception today, here is my report in two parts. I interrupted logging, because I carried out some experiments on the receiving setup in between.
Roland
Hi,
perfect reception today.
Roland
Hi,
one of Rampisham's DRM transmitters currently seems to be down. So far, there is no transmission on 7320 kHz (10:00 - 10:35 UTC).
However, 9760 kHz from the same site is in operation, so I guess that the TX will be available for the BBC World Service after the end of that transmission.
Roland
And here is my report after the late start. The dropout at the beginning is a result of the DRM signal disappearing for about a second shortly after start. Perfect from then on.
Roland
Hi all,
some Tx problems this afternoon, besides this a strong and stable signal, see attachment
73, Simone
Hi,
transmisssion started with no audio but a slight hiss instead. Audio appeared after about 2 minutes, later there were periods with undecodeable signal as already mentioned by Simone. I can confirm a further undecodeable period at 11:22 UTC when I was still listening but had already stopped logging.
Roland
Hi,
today, at about 10:49 UTC, signal strength suddenly fell to such a low value, that both softwares lost lock. I increased RF Gain to its maximum value, but that didn't help. Signal strength recovered slowly after a while and reception improved until it was back to normal.
The only explanation I have is perhaps some kind of ionospheric storm caused by a solar flare or a similar event. I am interested to hear if someone else has made similar observations.
Roland
Hi all,
some problems at the beginning of the transmission today, also a strange period at 1033- 1043 with a limited SNR of 20dB, see attachment
73, Simone
Hi,
transmission started late, then the signal disappeared again and there were some tune-ups with carrier signal only.
My observations do confirm Simone's results of a lower SNR for about 10 minutes before 10:43 UTC. I first thought it was a result of local influences, but obviously, there was another reason for it.
Roland
Hi,
instead of the BBC, there is VT Digital with test tones on this frequency today.
Here is a screenshot.
Edit 10:08 UTC: Now, the proper programme came on.
Edit 11:02 UTC: Now, the TX completely went off the air. What's going on?
Edit 11:06 UTC: Back on air.
Roland
Hi,
and here is my report on this transmission.
When I started logging, the station label was "VT Digital", however it changed to the usual BBC WS label later.
Roland
Hi all,
pretty good results all day, I did not notice what was wrong at the beginning but there was a restart after 15min .
I really wonder whether there were changes in the configuration or maybe a different antenna was used, as I got my best SNR ever on this frequency (better 28dB) with the longwire! in the first 15min (at 1430 power outage around here as already mentioned), see attachment
73, Simone
Hi,
here is my report for today. During the dropout some tuning seemed to be carried out.
Roland
Really good today.
Roland
Hi all,
good results all day, very stable signal, see attachment
73, Simone
Hi,
very good reception and a stable signal.
Roland
Hi all,
great results, see attachment
73, Simone
Hi all,
again 5hours of perfect reception, see attachment
73, Simone
Hi,
very good reception. The dropout was caused by myself.
Roland
Hi,
a delayed start today, but good reception.
Roland
Hi all,
no idea what happened after 1330 as it was an unattended log at that time, see attachment
73, Simone
Originally posted by simone
...no idea what happened after 1330
Hi Simone,
I did not listen at that time, but I noticed earlier, that someone was testing on 7310 kHz for a long time, first with carrier only, then with a 1 kHz test tone in AM. In Dream's spectrum plot, the carrier peaked at about the same level as the flat top of the drm spectrum from Rampisham but my 15 kHz wide IF filter also attenuates frequencies that are 10 kHz away from its centre frequency somewhat. So, in reality, the signal must have been stronger.
Perhaps they put wide bandwidth AM modulation on afterwards. We have seen very wide AM modulated signals with +/- 8 kHz from CRI in the past, so who knows ...
Roland
And here is my report.
Roland
Hi all,
good results again, a break in transmission and it stopped an hour too early (maybe because of the transmission on 9770 kHz?), see attachment
73, Simone
Hi,
transmission stopped at 10:59 UTC as if the TX was needed for a more important transmission on another frequency.
Is Rampisham currently short of working transmitters?
Roland
Hi,
here is my report for today.
Some strange effects:
- suddenly a very weak signal for some time, such that both softwares lost sync.
- a strong carrier on 7320 kHz at 13:49 UTC, it looked as if this came from the Rampisham transmitter itself.
Roland
Hi all,
good results besides the two problems that Roland already mentioned, see attachment
73, Simone
Hi all,
here is my report of the first 3 hours today, quite good results
73, Simone
Hi,
here is my report for today. The little ripple in the frames plot versus the end was probably caused by local switching noise spikes. I could see their effect in the spectrum plot from time to time.
Roland
Hi all,
good results except the last 45min, probably a local problem, see attachment
73, Simone
Hi all,
perfect results for 3 hours today, see attachment
73, Simone
Hi,
here is my report, which I was unable to post on November 2nd, because it was impossible for me to connect to the forum server.
Roland
Hi,
and here is my report for November 3rd.
Roland
Hi,
here is my report for a little more than two hours of reception today. Quite good.
Roland
Hi all,
quite good results for more than 3hours, see attachment
73, Simone
Hi,
I don't know why it happened that the signal suddenly became so weak that both software receivers lost sync.
Perhaps the transmitter operators know.
It took quite some time for the signal to regain its original strength.
Roland
Very good today.
A very strong signal, with signal strength reaching its peak around the middle of my logging period.
Roland
Hi all,
since 1130 yesterday as Roland mentioned yesterday the signal is not as strong and stable anymore as it has been for weeks, (maybe a different antenna?) . Still good results only twice an extremely weak signal caused dropouts, see attachment
73, Simone
Hi all,
signal was not as strong as in the past 2 months (since last Fri), good results but a twice a Tx problem occured, dropouts due to the weaker signal after 1315, see attachment
73, Simone
Hi,
a much weaker and unstable signal than usual at the beginning, but it improved later.
Most probably a result of the ionospheric disturbances.
12095 kHz AM was also much weaker than usual.
Roland
Hi all,
as it turned out this was the only frequency working today, quite good in the first 2 hours, signal getting weaker later on, see attachment
73, Simone
Hi all,
again not as strong as it used to be for the last 2 months, see attachment
73, Simone
Hi,
much different from Simone's assertion, the signal was quite strong in Munich.
At one time, during the dropout that is visible in the plot, there was a short interruption and then the well known "weird spectrum" appeared for a second or so.
Roland
Hi all,
lots of dropouts due to a weaK signal, see attachment
73, Simone
Hi,
not a good result today. At first, the signal was weaker than usual, then there was interference from a signal on 7315 kHz. I could not figure out what it was, it appeared intermittently. There was also a broadcast in chinese language on 7330, which I have not noticed on earlier occasions. If it is CRI, it may well have a broad +/-8 kHz spectrum (as seen before) and might also have contributed to interference.
Signal strength later recovered, but only for a while.
All in all it was one of the worst days I have encountered on this frequency.
Roland
Hi all,
today, reception was back to normal again.
Roland
Hi all,
pretty good results today but still signal strength is not back to what it used to be in Sept./Oct., see attachment
73, Simone
Hi,
quite good today, however at 11:53 UTC, there was a complete loss of signal.
Also, the 'weird spectrum' has just (12:05 UTC, not in the log) appeared for a moment.
Roland
Hi all,
the old Tx problem occured twice at the beginning of my log, as already mentioned by Roland; the dropouts in the last hour were caused by interference from the adjacent channel above, see attachment
73, Simone
Hi,
quite good today until someone in the house switched something on that completely ruined my reception.
In AM, it sounded like very intense sharp 50 Hz pulses, I have never observed it before, perhaps someone bought new junk today.
Roland
Hi,
after the interfering device had been switched off, I continued to log with good results as before.
Roland
Hi,
quite good today.
Roland
Hi all,
good results also yesterday near Bonn, see attachment
73, Simone
Hi,
today, signal was weaker than usual.
Even an ionospheric sounder that wandered across the band, as was easily visible from the spectrum, did produce some dropouts. On other days, there is not so much influence of such interference on the decoding results.
Roland
Hi all,
perfect results, except the last hour, due to a weaker signal, see attachment
73, Simone
Hi,
rather good again today.
Roland
Hi all,
again problems in the last hour, see attachment
73, Simone
Hi,
the P23S problem accompanied with the 'weird spectrum' appeared again for several times. I have not seen it for long, but obviously, it still exists.
Roland
Hi all,
like Roland already mentioned, the old problems were back, besides this quite good results, see attachment
73, Simone
Hi,
I did not notice any P23S problem during my logging period today.
There was an incident of skipping audio shortly after the start of transmission.
The signal was not very strong, it even became weaker during the last 10 minutes of my logging period.
Roland
Hi all,
bad results due to a very weak signal, see attachment
73, Simone
Hello Rampisham!
Can someone put proper modulation on?
The encoder has reverted to P23S again but this time in a permanent way!
Roland
Hi Roland,
it looks like they are already working on the problem! But after the carrier it came back again wiith the P23S problem.
73, Simone
Edit: It is fine now, since 1040UTC, thanks!
Edit 1206: Still problems, the "exploding" spectrum occured again several times.
Hi,
a lot of problems today as already mentioned. Many interruptions during the course of transmission after the initial problem but also an extraordinarily strong signal during the last hour. However there were still some problems with interference from a russian AM station, which always begins transmission on 7315 kHz at 14:00 UTC.
The incorrect station label in my report is a result of the problems at the start of transmission.
Roland
Hi all,
besides the trouble at the Tx, the signal was quite strong, no problems with the interference when using the loop antenna in the last half hour, see attachment
73, Simone
Hi all,
again some Tx problems, no sync for some time despite a good looking signal and before regaining sync the "exploding" spectrum occured several times, transmission stopped at 1258 UTC (because of vt digital?), see attachment
73, Simone
Hi,
a lot of problems today:
- transmission started with P23S
- after audio had appeared, the spectrum exploded again for a few seconds.
- everything was delayed by 2 minutes 36 seconds, the Greenwich time signal for 11:00 UTC appeared at 11:02:36 UTC
Roland
Hi all,
remarkably good in the last half hour today, see attachment
73, Simone
Hi all,
after all the trouble in the past days, things seemed to be back to normal today, see attachment
73, Simone
Originally posted by simone
... after all the trouble in the past days, things seemed to be back to normal today...
Not quite. There was a break in transmission at around 11:17 that is also visible in my log.
Roland
Hi,
perfect reception, but the start of transmission was delayed by half a minute or so.
Roland
Hi,
again a day with good reception, start of transmission was again delayed by half a minute or so.
Roland
Hi,
good reception, but a weaker signal than yesterday.
One dropout was caused by a signal that looked like an ionospheric sounder that wandered across the band.
Roland
Hi all,
bad results because of a weaker signal today, see attachment
73, Simone
Hi,
some local interference and the usual carrier after 14 h UTC.
Roland
Hi,
today I listened on this frequency at a later time than I usually do.
Signal was weaker than I'm used to. There was heavy interference from an 800 Hz shift FSK signal which could not be seen in the spectrum plot as long as the TX at Rampisham was running, but which was obvious from Dream's new WMER plot. See attachment.
There was also the usual AM signal on 7315 kHz and shortly before the end of the BBC transmission, an additional carrier came on on 7325 kHz.
After Rampisham had left the frequency, the FSK signal became visible in the spectrum plot as expected.
Roland
And here is my report.
Roland
Hi all,
yesterday at noon 92% correctly decoded audio and SNR 20 dB in the Swiss Alps
73,Simone
Hi,
quite good today, however, as I started writing this, there was just an incident about a second long, in which the spectrum looked very broad and nothing could be decoded. Now it's back to normal.
Roland
Hi all,
signal was too weak yesterday afternoon, only 57% correctly decoded audio
73,Simone
Hi,
today, the signal was rather weak and almost every local noise peak produced a short dropout.
Also, there was a strong AM modulated carrier that came up a few times on 7325 kHz for brief moments as if someone was testing a system.
Furthermore, shortly before 14:00 UTC, the usual AM signal on 7315 kHz plus the FSK interference appeared.
Using LSB, I managed to determine which broadcaster is using 7315 kHz. It is the Voice of Russia broadcasting in Russian ("Radiokampanje Golos Rossije"). Their signal sounded as if there was an additional crackling noise on it.
Roland
Hi,
again a day with a very weak signal as if the wrong beam is used.
Hardly listenable to because of too many dropouts.
Roland
Hi all,
it seems the signal gets weaker every day, today I had my worst results ever on this transmission, see attachment
I really wonder if the reason is just propagation :confused:
73, Simone
Hi,
there were some tune-ups today with short intervals of carrier and DRM signal, regular transmission only started after the news.
Still a weak signal and many dropouts.
Roland
Hi all,
today the signal was much stronger than the past days, quite good results but the old transmitter/ data stream problem (P23S label) occured again at 1145-1200, see attachment
73, Simone
Hi all,
as Simone has already mentioned, signal strength was much better than during the past few days. I still wonder if that was just a matter of bad propagation.
I could only listen for a short period, no problems during that time.
Roland
Hi all,
automated log today. Signal looks very strong. Break between 11:45 and 12 UTC.
And I'm not happy to see that my local killer noise happend quite often during the day. This noise also kills DAB and DVB-T for half a minute. I think it is caused by the heating system. But soon I will move and hope that this terrible noise will not follow me.
Hi all,
only an unattended log of the first hour, looks like a strong signal today, see attachment
73, Simone
Hi,
here is a comparison report using the penultimate and the ultimate CVS-version of Dream with Mod. Metric activated on the latter.
This feature is supposed to improve decoding in the presence of interference, but with almost no interference on this signal, except from a weak AM station on 7315 towards the end of my logging period, there is no difference.
Signal was quite strong today.
Roland
Hi all,
looked like they were using the regular beam today, strong signal ( some of the dips were caused by myself), see attachment
73, Simone
Hi,
a strong signal again.
Roland
Hi,
excellent reception with the exception of the first minute, when the well known P23S problem with no audio occured. OK after that.
Roland
Very good reception today.
Roland
Hi all,
not so good in my location, see attachment
73, Simone
100%, as it should always be.
Roland
Hi all,
pretty good results today, see attachment
73, Simone
Simone, Roland, notice anything different today? Have a close look at your attachments.
Roland, I am interested to see the difference between DReaM & DRM in your file: a bug?
James
Hi James,
the bitrate was different to normal, but there is always the difference between DReaM and DRM thatīs the bitrate (80bps) for the text.
73, Simone
Hi Simone, I did not know about the 80 bps difference: thanks. The reduction in bitrate is due to the use of UEP, so I am really interested to hear comments on any differences you can see/hear.
James
Hi James,
for a discussion of the difference in indicated bitrate have a look here (http://sourceforge.net/forum/message.php?msg_id=2524277).
It is difficult to judge the effect of UEP under nearly perfect reception conditions such as today. I did not notice any dropouts or moments with reduced audio quality today.
This UEP test might have been interesting a few days ago, when quality of reception was among the worst ever encountered on this frequency. (But I rather prefer it the way it is now.) There are rumours that a different antenna was used for a few days. Can you give us some enlightenment on that?
Roland
corrados
09-12-2004, 08:39
Originally posted by jbriggs
...The reduction in bitrate is due to the use of UEP, so I am really interested to hear comments on any differences you can see/hear.
James
Hi James,
I was listening to your UEP tests yesterday. I had a lot of dropouts so that the effect of "graceful degradation" should be clearly noticable. But it wasn't the case... The dropout behaviour was just the same as using EEP.
The reason for that could be that the length of the higher protected part of the audio block is too short so that it does not completely cover the block where the 8-bit CRC is calculated (unfortunately, this length varies with time depending on the audio material and AAC encoder algorithm but the length for UEP in DRM is fixed. So a certain "headroom" should be considered when setting the length).
Another thing might be that the difference in protection level was too little. You set the higher protected part to a rate of 0.5 and the lower protected part to a rate of 0.6 (correct me if I'm wrong...). It would be very interesting to see how the system performs if you would choose a rate of 0.5 for the higher protected part and a rate of 0.78 for the lower protected part so that the difference is larger.
I put a recording from yesterday on our homepage so you can try it out yourself. Since the file size is approx. 30 MB, I'll remove the file soon (it will be available at least until next weekend). Here is the direct link:
http://www.tu-darmstadt.de/fb/et/uet/fguet/mitarbeiter/vf/DRM/download/UEP_BBC_B10kHz_20_14kbps.wav
Volker
Hi, Ollie here from BBC R&D. (My first ever posting).
Thanks for the responses so far to our UEP tests, and please keep them coming!
We did some laboratory tests of UEP, and found that we could get a modest improvement in degradation behaviour by protecting 20% of the audio data at the stronger rate, a parameter suggested by the audio coding experts.
It gets better if you protect more at the stronger rate, but then there is a significant reduction in the bit-rate, and so the audio quality is sacrificed for the listeners who have a good signal.
However, I'm aware that the proportion needing higher protection is programme-dependent, and it might be that the BBC World Service material would benefit from different settings to the material we used in our lab tests.
I suggest that we keep the parameters the same over the weekend, and then try increasing the part A length next week, to see if that improves things.
Our current feeling is that we would be reluctant to go any higher than 0.6 for part B in a shortwave channel. Going to 0.71 would mean that the audio would start to fail earlier, albeit with a wider region of "graceful degradation".
Thanks again for your helpful feedback.
Originally posted by ollieh
It gets better if you protect more at the stronger rate, but then there is a significant reduction in the bit-rate, and so the audio quality is sacrificed for the listeners who have a good signal.
Hi Ollie,
to be able to contribute anything to these tests, I should perhaps sacrifice my good reception on the dipole antenna by using a small telescopic arial instead. Perhaps I'll do that tomorrow.
Today, I have perfect reception again.
But, all in all, I have to point out, that reception on this frequency is usually very good if there are no problems originating from the transmitting site, something I do notice much too often. The overall decoding result, when summed over many days could be much improved not so much by UEP but rather a lot more by putting out a PERFECT SIGNAL! This means that one should concentrate on efforts to solve the occasional transmitter audio feed dropout problems, problems of sometimes inaccurate transmitter tuning(?), and the old problem of skipping audio. Has the BBC already looked into the question, why the audio on this frequency is always delayed by half a minute, something that cannot be noticed on any other frequency of any other broadcaster, not even on Orfordness' 1296 kHz transmissions? Imagine someone setting his clock according to the GMT time signal.
All these problems have been there for a long time now and albeit occuring not as often as they used to, these are the problems that still limit the overall result (when integrated over a month or so) at least for my location and my equipment.
I'd really like to see more efforts in trying to get rid of these "old" but still unsolved problems.
It doesn't help, if reception quality could in theory be perfect but when the practical application of this theory fails.
Roland
Hi,
again perfect today.
Has the encoder software been udated? My subjective impression is that the SBR on the "Lily Bolero" shortly before the news sounds a bit better, but perhaps I still have the sound from 1296 kHz in my ears...
Roland
corrados
09-12-2004, 12:56
Originally posted by ollieh
...We did some laboratory tests of UEP, and found that we could get a modest improvement in degradation behaviour by protecting 20% of the audio data at the stronger rate, a parameter suggested by the audio coding experts...
I have attached a figure showing the number of CRC protected bytes in the AAC stream used in your UEP transmission on 7320. As you can see, a value of approx. 40 bytes for the higher protected part should be ok. How many bytes did you use?
...It gets better if you protect more at the stronger rate, but then there is a significant reduction in the bit-rate, and so the audio quality is sacrificed for the listeners who have a good signal...Our current feeling is that we would be reluctant to go any higher than 0.6 for part B in a shortwave channel. Going to 0.71 would mean that the audio would start to fail earlier, albeit with a wider region of "graceful degradation"...
Ok, lengthening the higher protected part will decrease the bit rate but increasing the rate in the lower protected part will increase the overall bit-rate. So if one has a very good reception he will have the benefit of high quality audio. The one who has bad reception can still hear something (which might be still ok to listen to).
I would really like to hear how it sounds if UEP protection is used with a large difference between the higher and lower protected part rate in the case when reception is not so good.
Volker
Hi all,
today there were some dropouts in the last 15min of the transmission, that I tried to listen to. I think the dropouts sounded pretty much the same as with EEP, but I will listen more carefully the next days. Also I think it is great that they started tests with UEP, maybe with other settings it really should improve the results.
73, Simone
Hi all,
perfect reception today. The dropouts were caused by my local terro noise. For this noise does not help any error protection.
Hi all,
good conditions today for testing UEP ;) (looked like something had been changed intentionally in order to provoke more dropouts )
I will upload some audio samples later.(see General Topics/UEP)
73, Simone
Hi all,
perfect results today, (looks like a winradio but 2dB better ;)), what a strong and stable signal compared to yesterday! Any changes at the Tx, a different beam yesterday? No comment on UEP as I could not notice any audible dropouts.
73, Simone
Hi,
on Dec. 10, signal was rather weak. I suppose that something had been changed deliberately to provoke dropouts and test UEP. But still, reception was good at the beginning. Initially, I also tried with a telescopic aerial to provoke some interferences, but reception was impossible on the telescopic aerial, both decoding softwares would not even synchronize.
Later, I deliberately introduced local interference to see how UEP works, so my report is not representative for the reception that would have been encountered normally.
Roland
Hi,
today, signal was rather strong and it got even stronger towards the end of transmission.
During the last two hours, there was interference from the well known FSK signal with a center frequency about half a kHz below 7320 kHz.
Dream - with 'Modified Metric' switched on - could cope quite well, however there were some dropouts on the DRMSWR.
Attached is a screenshot of the new WMER plot showing the interference at the two carrier frequencies of the FSK signal. I wonder where this signal originates from.
Roland
And here is today's report.
Roland
Hi all,
again a strong and stable signal, perfect decoding, so no comment on UEP, see attachment
73, Simone
Hi,
perfect reception today, signal got stronger during the course of transmission, even the FSK signal did no harm at least not for Dream. 'Mod. Metric' was on.
Roland
Originally posted by dk8cb
Hi,
perfect reception today, signal got
Roland
Hi,
It's a pity that the antenna is so highly directional. Today I can 'see' the signal, but SNR is just around 6 dB, hence no audio at 11:15 UTC.
Hi,
an extremely strong signal today, I had to turn down all controls to their minimum settings. :)
The tuning that was carried out 10 minutes before transmission started, seems to pay off.
Roland
Hi all,
again a quite strong signal as in the past two days, for testing UEP last Fridayīs beam was more suitable in my location, see attachment
73, Simone
Hi,
again a perfect result.
I really wonder if this is a result of more data being properly decoded because of UEP.
Of course, the data decoded at the fallback bitrate will show up as properly decoded data.
But signal is also very strong today.
Roland
Hi all,
again a pretty strong signal and good results, too good for testing UEP, see attachment
@Roland: The good results lately are just due to a much stronger signal since Saturday and a high SNR (today>30dB, my best ever on this transmission I think), and not caused by the use of UEP. Last Friday (Dec 10th) I had bad results when UEP had also been used.
Hi,
very good but not 100%.
Roland
Hi,
quite good with the exception of some dropouts shortly after 12:00 UTC which also gave an opportunity for the effect of the UEP bitrate fallback to be heard.
Roland
Hi all,
some dropouts after 1245, where the advantages from using UEP could be heard, see attachment
73, Simone
Hi all,
a weaker and instable signal and lots of dropouts today (looks like a special beam for Fridays ;)), see attachment. Effects from using UEP could be heard quite often, but also many times audio was lost completely.
73, Simone
Hi,
also a weaker signal in Munich but still quite a good result.
Roland
Hi,
it really seems that a somewhat different beam is used on Fridays and Saturdays (and perhaps Sundays) compared to other weekdays. Again not a strong signal today.
The influence of the AM station with a 20dB stronger carrier than the DRM signal that came on at 13:54 UTC on 7315 kHz is clearly visible from the report. The usual afternoon FSK signal was also there and took its occasional share, though it was much weaker than the AM station.
Roland
Hi all,
quite good again today, (except a local problem at 1230), see attachment
73, Simone
Hi all,
nearly perfect today, see attachment
73, Simone
tradio99
19-12-2004, 19:13
frequency is blocked here by analog broadcasting on 7315 and 7325 kHz, time of screenshot is 15.45 UTC
Hi,
rather good today at least on Dream.
Also a strong signal.
Roland
Not a strong signal today but quite good nevertheless.
Roland
Hi all,
a weak signal, but good results, good audio decoding even at times of lower SNR except the last hour with the interference from 7315kHz, see attachment
73, Simone
Hi,
again a weak signal today. Given that, the interference from harmonics generated by my ADSL modem's power supply caused a lot of dropouts.
Sudden jumps in SNR and the percentage of properly decoded audio are the result of my attempts to make this interference harmonic move away from the DRM spectrum by putting mechanical strain on the modem's case and thus trying to cause a slight frequency change. Sometimes this does work, but not always. Guess, I have to put it in a metal box some day.
Roland
Hi all
also a weak signal in my location, many dropouts, see attachment
73, Simone
Hi all,
again a weak signal today, see attachment
73, Simone
Hi,
also again a weaker signal than usual and problems with local interference which wouldn't have been noticed if signal strength would have been better.
Roland
Hi all,
quite good today with a stronger signal than yesterday.
Roland
Hi all,
although signal strength is still not back to what it used to be, results were not so bad today, see attachment
73, Simone
Hi all,
good conditions today, very stable signal, perfect decoding, see attachment
Merry Christmas to all!
Simone
Hi all,
very stable signal. Nearly perfect reception over 1.5 h
Merry Christmas to all
Daniel
Hi all,
perfect reception today, see attachment
73, Simone
Hi all,
like in the past days, strong and stable signal, perfect decoding, see attachment
73, Simone
Hi,
quite good on Dream, not so good on the DRMSWR due to some interference. Dream's "Mod. Metric" did help.
Roland
Hi all,
bad results today, interferences in the last hour, before due to too much fading (signal varying from S3- S9+20), see attachment
73, Simone
Hi,
a delayed start of transmission, but very good reception.
Roland
Hi all,
bad results on the tests earlier this morning, did these tests use a different beam/ antenna or was propagation that bad at that time? Anyway, good results when the regular transmission started (a bit late). Similar results concerning audio decoding using DReaM and DRMSWR, but 2 dB better SNR with DRMSWR, see attachment
73, Simone
Hi all,
an excellent result today. That's how I like it.
Roland
Good and stable signal today, only few droputs.
73
Daniel
Hi all,
stable signal, perfect decoding today, see attachment
73, Simone
Hi all,
very strong and stable signal. But you can clearly see the 9 teeth of horror. I wonder if our heating system is powered by an atomic reactor?!?
Strong and stable signal today
73
Daniel
Hi all,
pretty good results until 1330, see attachment
73, Simone
Hi,
perfect during my listening period.
Roland
Hi,
quite good today.
Roland
Hi all,
perfect decoding for nearly 4 hours, see attachment
73, Simone
Hi,
some interference after 14:00UTC.
Had to stop listening, too much soccer for me.
Roland
vBulletin v3.5.3, Copyright ©2000-2012, Jelsoft Enterprises Ltd.