7320 kHz (BBC WS from Rampisham)

[jbriggs]

Hello DRM's
From today we are starting a new experiment. Single Frequency Network (SFN) tests. But this means the data transmission has stopped for a few weeks:(
Now we use 2 senders and 2 antennas to transmit on the same frequency (for some of the time, not all the time) from Rampisham.
Today the second antenna had a bearing of 61 degrees (Baltic/Norway/Sweeden). The original antenna points on 105 degrees (Austria)
Question, can anyone see the difference between using 1 Sender and the periods when 2 are used?
James

[dk8cb]

Hi,

I listened today for about 50 minutes from 10:00 UTC to 10:50 UTC and noticed two breaks in reception at around 10:40 (I don't have my log here at work, so I can only guess the precise time of the event), when the spectrum suddenly looked very strange as if there was additional noise on the signal but only within its own bandwidth. At first, I thought, that there were adjustments being made at the transmitter.
Dream lost sync during that time but recovered quickly.
During the rest of the time, reception was very good with 100 % correctly decoded audio at 20.96 kbit/s.

dk8cb

[dk8cb]

Hi,

here is the corresponding screenshot.

It would be interesting to know, if those breaks correspond to a change at the transmitter.

dk8cb

[jbriggs]

Hi dk8cb,
I think the change in reception was when we only had 1 transmitter working.
Today I will make some careful notes of the exact times we make changes and post them here.
James

[dk8cb]

Hi James,

here is today's first 55 minutes. Sorry, have to leave and must switch off.
Very bad at the beginning.
The missing station label in the screeenshot is due to the fact that I started logging before the broadcast actually began.

dk8cb

[jbriggs]

Thanks for the replies, here are the events this morning

0958 On air 61 degrees only
1019 SFN both Tx's on air, 61 and 105 degrees
1022 1 transmitter on air, 105 degrees only
1032 0 transmitters!
1033 1 transmitter, 105 degrees only
1041-1043 Tune up 61 degree transmitter giving interfering AM carrier
1044 SFN both transmitters on
1047-1048 adjust delay between transmitters by up to 3mS
1049 1 transmitter only on, 61 degrees
1050 SFN both transmitters on
1115 1 transmitter, 105 degrees only

James

[dk8cb]

Hi James,

thanks for the information,

0958 On air 61 degrees only

I already suspected that, because signal strength was a lot less than usual. My location should be almost in the centre of the other beam.

1041-1043 Tune up 61 degree transmitter giving interfering AM carrier

At that time, the carrier was clearly visible in the spectrum, but nevertheless reception continued.

When interpreting the screenshot, one should keep in mind, that the values shown are always delayed by one minute, i.e. the interval over which values are summed.
I clearly noticed the break at 10:32. The reason, why the SNR doesn't reflect that and doesn't go to zero (as does audio) might be due to the timeconstant involved in calculating this value.

dk8cb

[simone]

Hi all,
with my location (91° from Rampisham) being in between the 2 beams, results are not as I expected. On the 61° beam I only got a very weak signal, the 105° beam worked quite good but no improvement that I could see in the results at the times when both transmitters were used, see attachment
73, Simone

[simone]

Hi all,
... and the results later today, another SFN test at 14:05?
see attachment
73, Simone

[carknue]

Hi James,

here is my complete log.

Wouldn´t it make more sense to do SFN from two different sites? e.g. Rampisham and Juelich.

[simone]

...and here is today´s logfile, still wonder about the improvement in the last hour.
73, Simone

@Carsten: Transmissions from different sites beaming at the same target area would be interesting.

[dk8cb]

Hi,

here is my log of half an hour of today's transmission. (Sorry, I could not log for a longer period of time)

There was a carrier before DRM transmission began, but it was not visible any more in the spectrum after DRM transmission had begun.

dk8cb

[simone]

Hi all,
I could only do a logfile of the first 22min, good results, I can´t say if it is one or two transmitters, btw I often get red sync/data lights and never reach 150 sync frames, see logfile attached
73, Simone

@James: Will the SFN tests continue over the weekend?

[jbriggs]

Wouldn´t it make more sense to do SFN from two different sites? e.g. Rampisham and Juelich.
Hi Carsten
Yes you are correct. This is the intention, we may be able to do a SFN from Rampisham with RNW in Bonaire soon. But before we send the equipment to Bonaire, we thought it would be a good idea to test it first!
With some more development we can also start tests with modulator equipment from different manufacturers. Then a test with Rampisham and Sines or Rampisham and Juelich is possible.
This (in theory) could improve reception reliability.
However, I think same site SFN has a future as well.
James.
PS no SFN transmissions today, just 105 degrees.

[simone]

Hi all,
strong and stable signal this afternoon, see attachment
73, Simone

[lmaes]

An hour of perfect reception from Rampisham on 7320 kHz.

Ludo

[MarkT]

Reception report for today from Rampisham.

[simone]

Hi all,
good results again from Rampisham,
see attachment
73, Simone

[simone]

... and later a few dropouts using the portable Sony SW7600G, but still quite good, no problem for listening, see attachement
73, Simone

[simone]

Hi all,
maybe some problems at the Tx?, good results after 1338, see attachment
73, Simone

[dk8cb]

Hi,

here is my report about the first 80 minutes of today's transmission.

dk8cb

[dk8cb]

Hi,

here is my report about the first 70 minutes of today's transmission including a break with no DRM signal but an unmodulated carrier instead.
Excellent reception during the rest of the time.

dk8cb

[simone]

Hi all,
bad results except the last hour, see attachment (btw a break in audio decoding with the DRMSWR before 1200 because of CELP encoding)
73, Simone

@James: What beam was used today?

[dk8cb]

Hi,

here is my report about 70 minutes of almost perfect reception today. Only two short glitches in audio.

dk8cb

[simone]

Hi all,
here are my results of the transmission today, some bad periods especially at the beginning, better results at the end of the transmission (maybe I am out of the beam?), see attachment
73, Simone

[dk8cb]

Hi,

here is my report about 70 minutes of quite good reception for today.
I notice since yesterday that the text messages refer to the currently running programme, but for my taste they contain too many references to BBC webpages. This is an increasing tendency that is accompanied by many references to BBC web pages on the programme itself.

One gets the impression that the BBC World Service doesn't want to be seen as a shortwave broadcaster anymore, but more as a provider of internet news services. Is there an intention to slowly fade out shortwave services (at least to developed areas)?

Is broadcasting in DRM seen just as an intermediate stage in this process?

dk8cb

[simone]

Hi all,
instable signal fluctuating at S9, see attachment
73, Simone

[dk8cb]

Hi,

here is my report for today's first hour of transmission.

dk8cb

[simone]

Hi all,
today no audio, not even a label at 25 dB
from1310-1410, overall better condtitions than the last two days, except 1147-1212

73, Simone

[dk8cb]

Hi,

here is my report of my best DRM experience so far.

Three hours of perfect FM-like reception.

Congratulations!

dk8cb

[simone]

Hi all,
great conditions today, pretty stable reception (today in the car with a mix of mobile and stationary reception), high SNR, see complete log of todays
transmission attached (some dropouts at 1115 when the only parking spot available was behind a high building;( )
73, Simone

[simone]

Hi all,
a weaker signal today (maybe another beam or just propagation conditions?), causing several dropouts,see attachment
73, Simone

[dk8cb]

Hi,

I'm currently listening to the BBC on 7320 kHz and it was strange to note that today the 10:00 time signal was delayed by as much as 32 seconds.
I remember, that it used to be delayed by about 12 or 16 seconds.
So I reckon that the BBC is now using a much slower encoder.
Is that true?

dk8cb

[dk8cb]

Hi,

here is my report for today.

dk8cb

[simone]

Hi all,
similar results as yesterday, instable signal about S9, I´m not sure what caused these deep dips, see attachment
Any information on the beam that was used today?
73, Simone

[andy.chance]

Yesterday used the same TX / Ant setup as normal.
Beam 105 deg.


Andy.

[dk8cb]

Hi,

excellent reception again today.

dk8cb

[simone]

Hi all,
pretty stable reception all day, see attachment
73, Simone
@James or Andy: The schedule (since A04) reads 115° beam (S Europe) for 7320 kHz, I´ve been wondering about the results in the past weeks which were too good for my location on 115°, does it mean the "normal beam" that is used on this transmission is 105°?

[andy.chance]

105 degrees is normal for this transmission. and has been since the start of the A04 schedule.
The online schedule is currently incorrect. I'll ask James to post an update to fix this.

Andy.

[dk8cb]

Hi,

here is my report for today. Low SNR and a lot of glitches in audio.

Quite unlike the last few days.

Was that a result of changes at the transmitter?

dk8cb

[simone]

Hi all,
some periods with a slightly weaker signal but results as usual, SNR within normal values, see attachment

Thanks Andy for the information on the beam and I´ve seen the schedule has already been updated.

73, Simone

[dk8cb]

Hi,

here is my report for today. Forget about the dropout at the beginning, it was caused by me.


dk8cb

[simone]

Hi all,
good results today and a strong signal, see attachment
73, Simone

[iw0hk]

Hello,
here one of my first DRM reception, using a PCR-1000 (without modificaton) and Dream Software. The station was BBC on 7320 Khz. Audio was good with no drops.

Wishes, Andrea

[dk8cb]

Hi,

here is my report for today.

There was already an unmodulated carrier exactly on 7320 kHz when transmission began.
Experiments with the scandinavian beam?

dk8cb

[simone]

Hi all,
here are my results from this afternoon in the car, mix of mobile and stationary reception
73, Simone

[dk8cb]

Hi,

here is my report for today.

At 14:30 the DRM signal disappeared, leaving a momentarily clear frequency, then there was a carrier that went on and off. After a short while, the DRM signal returned.

What happened?

The second deep dip was caused by me starting another application (Aida32) on the PC. I think, if a higher priority would be assigned to the decoding process, such things should not happen again.

dk8cb

[dk8cb]

Hi,

excellent reception today (and still continuing this way unlogged).

dk8cb

[dk8cb]

Hi,

no signal here. :mad:

I guess that the transmitter is currrently being used for the 9760 kHz transmissions instead. :(

dk8cb

[dk8cb]

Hi,

again no signal today. :(

What's going on?

Edit 10:06: Back to AM again? But only for half a minute.

Edit 10:18: Aaah, there you are again in DRM after some tune-up.

Edit 10:31: The text window shows: "Reconciliation. 4/4" :confused:

dk8cb

[dk8cb]

Hi,

and here is my report on an hour of today's transmission.
Perfect.

dk8cb

[simone]

Hi all,
some dropouts when the signal strength got too weak today, see attachment
btw the signal was stronger than ever in the last hour (sorry no log of this period)
73, Simone

[dk8cb]

Hi,

start of transmission was two minutes late today. Very good reception.
At around 10:25 there was a loss of signal followed by a few seconds in CELP mode and a strange station label (P23S), then back to normal.

dk8cb

[simone]

Hi all,
good results in the first 3 hours today, see attachment
73, Simone

[simone]

... and later in the afternoon even more stable with a stronger signal about S9+20, see attachment
73, Simone

[simone]

Hi all,
a quite strong and stable signal right from the start, getting weaker later today, so my local interference caused some dropouts at 1200-1300, see attachment
73, Simone

[dk8cb]

Hi,

here is my report for yesterday.

dk8cb

[dk8cb]

Hi,

here is my report on the first 40 minutes of today's transmission.

dk8cb

[simone]

Hi all,
good results with a weak signal today, not much difference between stationary and mobile (interval starting 1205) reception, transmission ended early (because of 9770 kHz ?), see attachment
73, Simone

[dk8cb]

Good as (almost) ever.

dk8cb

[simone]

Hi all,
perfect results today from Rampisham on this frequency, about 1/2 hour was mobile reception in between, but obviously no difference in the results, see attachment
73, Simone

[dk8cb]

Hi,

perfect reception today, but not a perfect transmission. There was a complete loss of signal at around 13:02. Were there problems at the transmitter or is someone experimenting?

I also notice that the time pips on the hour now come with less delay than a few days ago. Now they are delayed by about 23 seconds, in comparison to 32 seconds before. Using a new encoder?

dk8cb

[simone]

Hi all,
here are my results from this afternoon, I tuned in exactly when the signal disappeared, but it came back soon.
@dk8cb: In general in transmissions everthing lasting less than a minute is not really a problem (as long as it is not repeatedly), and here we should be even more tolerant.

73, Simone

[simone]

Hi all,
good results in the last hour of todays transmission, see attachment
73, Simone

[dk8cb]

Hi,

a good signal today, but Celp(8kHz) encoding and 'P23S' station label!

No resyncs of my receiver, but I guess the sync problem between studio and transmitter site has not been solved yet.


dk8cb

[dk8cb]

Hi,

and here is my report as recorded from the start of 'proper' transmission.

dk8cb

[carknue]

Hi Simone and others,

here is a comparision of our todays log.
First 40 minutes without audio decoding.

[dk8cb]

Hi,

here is my report for today. The DRM signal was switched off several times followed by, what seemed to be, tune-up procedures with carrier only.

The time signal on the hour was again delayed by 32 seconds.
On the 1296 kHz programme from Orfordness, the delay is only 16 seconds, so I guess that the BBC encoder used for the 7320 kHz transmitter is a bit 'slow'.

dk8cb

[carknue]

Hi all,

very equal results in this comparision with Simone. Some transmission breaks.

See the perfect synchronized log files. They are made with a new log timer Beta version that also supports the FRG100.

Also notice the dropouts between 10:10 and 10:14, dk8cb had the same in his log from Munich.

[simone]

Hi Carsten,
looks great, signal strength in my place was stable at S9+10, compared to unstable S7-S8 on 9410 kHz which is usually at S9+20
73, Simone

[simone]

Hi Carsten and others,
actually this is the frequency where our results match the best, signal strength was again stable at S9+10, and as yesterday a period with lower SNR (from 1100), see attachment
73, Simone

[simone]

Hi all,
here are my results, a mix of stationary and mobile. Sorry for the two breaks, (at 1200-1219 I tuned to 9410 kHz), back on 7320 kHz as in the past days a period of low SNR until 1245 (no idea), signal strength about S9, stable, see attachment
73, Simone

[simone]

Hi all,
a weak signal and a stable, but very low SNR today, the last days the low SNR was only for a short period not all the time, see attachment
73, Simone

[dk8cb]

Hi,

here is my report for today.

A much weaker signal than usual, also a low SNR and quite a few short dropouts.
I suspect that either the scandinavian beam has been used or more likely, that were there some problems at the tx.
There was also a wrong text message, it referred to some music programme. It didn't change at all during the whole time.

dk8cb

[simone]

Hi James and others,
today I had again about 16 dB SNR all day, signal strength was within normal range, I tried 2 receivers and 3 antennas, all the same, quite strange, just because of propagation conditions or would you know of any problems at the Tx?
Btw there was still only one static text, the same text as yesterday.
73, Simone

[dk8cb]

Hi,

reception today was the worst I have encountered on this frequency so far.
Low SNR, weak signal.
Only a few seconds of audio, so I tried only for a short time.

What's going wrong in Rampisham?

dk8cb

[carknue]

I had a strong signal S9+10dB but also a very low SNR with lots of dropouts. Also the TX made a lot of noise on the adjacent channels. :confused:

[simone]

Hi all,
great to see things are back to normal after a restart at 1100, including the text messages, good results today, see attachment
73, Simone

[dk8cb]

Hi,

here is my report on 20 minutes of normal transmission recorded after an hour of problems with the transmitter in Rampisham.

dk8cb

[dk8cb]

Hi,

good reception today. However, the message text was static and referred to a programme that was not currently running.

A very strong signal in the beginning, later becoming somewhat weaker, but still very good.

dk8cb

[carknue]

Hi Simone,

the 7320 khz still is the frequency with the smallest differences. How strong was the signal today? If it was very strong I need too to add another 10 dB attenuation, because with signals above S9+20 my AOR is limited to these 28.5 dB SNR.

[simone]

Hi Carsten,
thanks for the comparison, I guess the signal was at least S9+20 maybe even stronger at times (but I was not there to watch it), I would suggest to try 10dB attenuation
73, Simone

[dk8cb]

Hi,

here is my report for today.

Excellent reception up to the moment when encoder problems began and when the encoder's test sequence was transmitted instead of normal audio.

It occurs to me that this small, almost unnoticeable ripple in the blue (audio frames) graph is not a result of propagation conditions or interference but a premonition of what happened later...

dk8cb

[simone]

Hi Roland and others,
later in the afternoon I tuned in again, probably they were working on the problem, still alternating between normal signal and the default settings with label P23S

73, Simone

[carknue]

Hi all,

again these heavy problems in Rampisham. The dropouts are quite synchron between Simone and me, so it surely was a transmitter problem.

Today I had 10 dB more attenuation, but nothing changed.

[simone]

Hi all,
good reception from Rampisham today, they started with a lower bitrate (17.4kbps), later the usual 20.9kbps were used.
In the beginning the text referred to this transmission mentioning the frequency and transmitter site and despite all the trouble and some not so positive comments during the past week the text read ;):
please post feedback about this service on the forum at www.DRMrx.org
Interestingly the SNR was better than on 9410 kHz later (although that signal was stronger), earlier 9410 kHz had always been better, maybe something was changed at the Tx?

73, Simone

[dk8cb]

Hi,

here is my first report for today. Excellent reception.

I have received information from Rampisham that, because of problems with the stream from the studio, transmission started using the local Merlin (Fraunhofer) ContentServer in Rampisham to generate the MDI stream at lower than usual bitrate.

The problems were later resolved and the usual higher bitrate was used from then on.
A CD-ROM drive had caused interference on the IDE channel of the BBC-built content server.

dk8cb

[dk8cb]

Hi,

and here is the second part of my report.

I had listened on 9410 kHz in between, but I returned after Project Qosam had switched to about 9 kbit/s bitrate which didn't sound so well.

The short period of low SNR with a dropout was my fault, because I played with the RF gain control on the receiver...

dk8cb

[dk8cb]

Hi,

here is my report for today.

dk8cb

[dk8cb]

Hi,

some weak moments today, but otherwise as good as almost ever.

dk8cb

[simone]

Hi all,
good results today after a few days with a slightly weaker signal, see attachment
73, Simone

[dk8cb]

Hi,

good reception today, but not such a strong signal as last week. Propagation conditions seem to be changing as summer is coming.

dk8cb

[dk8cb]

Hi,

good reception as usual.

dk8cb

[dk8cb]

Hi,

again a not so strong signal today and a few strange dropouts, the last one seemed to be due to local interference, the first one may have been transmitter related.

Also interesting: Today, the 10 o'clock time signal was not delayed by more than 30 seconds any more. Now the delay amounts to about 24 seconds 'only'.

dk8cb

[dk8cb]

Hi,

quite good again today.

dk8cb

[simone]

Hi all,
strong signal and good results again today, see attachment
73, Simone

[simone]

Hi all,
quite instable conditions today, so results are not perfect but still pretty good, see attachment
73, Simone

[dk8cb]

Hi,

here is my report on the first 80 minutes of today's transmission.

dk8cb

[simone]

Hi all,
good conditions today, strong and stable signal, see attachment
73, Simone

[dk8cb]

Hi,

again a day with excellent reception as it should always be.

dk8cb

[simone]

Hi all,
good results today as most of the time was mobile reception, see attachment
73, Simone

[dk8cb]

Hi,

excellent again today.

dk8cb

[dk8cb]

Hi,

reliable service again.

dk8cb

[simone]

Hi all,
good conditions again today (a few dropouts because of too much multitasking), see attachment
73, Simone

[simone]

Hi all,
another perfect hour on this transmission, see attachment
73, Simone

[dk8cb]

Hi,

once again a reliable service yesterday.

dk8cb

[dk8cb]

Hi,

100% again yesterday.

dk8cb

[dk8cb]

Hi,

very good again today, albeit there was a single audible glitch.

Also again, the other encoder seems to be used, the time signal on the hour now lags 31 seconds behind again, recently it used to lag only 24 seconds behind.

dk8cb

[DigiBC]

Hi!

For the last days I've noticed such a stable reception on this frequency like never before. The audio quality is very good too.

Today I did parallel logs on my PC using DRM Software Radio 2.0.34 and DReaM 1.0.8cvs (latest version). The comparison is attached.

Regards - DigiBC

[simone]

Hi all,
good results again today, see attachment
73, Simone

[simone]

Hi all,
signal was more stable and stronger than yesterday, good results, see attachemnt
73, Simone

[simone]

Hi all,
good results, also a comparison of FhG and Dream, see attachment
73, Simone

[dk8cb]

Hi,

again very good today.

dk8cb

[dk8cb]

Hi,

good reception today, with the exception of some strange dropouts that were followed by sync losses. I suspect transmitter problems being the source of the problem.

dk8cb

[simone]

Hi Roland,
seems they were still working on it later today, see results of the last hour attached
73, Simone

[rad]

Hi guys. On the topic of a possible SFN test from Rampisham and from Bonaire, I wonder which way the signals would be directed. It occurs to me that there are 4 possibilities.

Possibility 1:

Rampisham points towards Bonaire across the Atlantic and Bonaire points back at Rampisham across the Atlantic (the short Atlantic path).

Possibility 2:

Rampisham points towards Bonaire across Asia and the Pacific and Bonaire points back towards Rampisham across the Pacific and Asia (the long Asia/Pacific path).

Possibility 3:

Rampisham points towards Bonaire across Asia and the Pacific and Bonaire points towards Rampisham across the Atlantic (looping around the world anti-clockwise if you were looking down on the world from above the north pole).

Possibility 4:

Rampisham points towards Bonaire across the Atlantic and Bonaire points towards Rampisham across the Pacific and Asia (looping around the world clockwise if you were looking down on the world from above the north pole).

It occurs to me that Jakarta is about in the middle of Possibility 2 which would be quite interesting. Last night (around 1am Jakarta time) Rampisham was booming into Jakarta (the BBC Russia service). It is also possible to receive the Bonaire transmissions in Jakarta (the ones to Australia and also the ones to Europe). Provided that a clear frequency is used (and perhaps some non-noisy time like 1am Jakarta time), this SFN could be a very interesting experiment.

In fact, each Possibility could be tried out togther with switching on and off either Rampisham and Bonaire so that the difference betwen having one broadcaster and having 2 broadcasters for each possibility can be assessed. We could have people around the world ready to monitor it eg: Chris in New Zealand, the guy in Melbourne Australia, Me up in Jakarta, someone in Trincomale in Sri Lanka, people in the USA, and all you guys in Europe. The question would be whether using a SFN on a clear channel with one signal coming from Europe and one coming from Bonaire, the whole globe could effectively be covered. If you really want to get tricky, you could even add an extra broadcaster or two into your SFN, eg Trincomale in Sri Lanka, or RCI.

I guess it depends a bit on guard intervals and stuff like that (ie whether signals can be received sufficiently synchronously in such a wide area), but I think the idea of a global SFN is pretty cool. International broadcasters could cooperate (pool their transmission resources) to establish a global SFN which takes turns in broadcasting the content of each broadcaster (a bit like the World Radio Network).

[dk8cb]

Hi,

here is my report for today.

dk8cb

[simone]

Hi all,
I only tuned in the last hour today, good results, see attachment
73, Simone

[dk8cb]

Hi,

here is my report on 4 hours of good reception today.

dk8cb

[simone]

Hi all,
good results again today, see attachment
73, Simone

[simone]

Hi all,
good reception, no idea what happened at 1410, see attachment
73, Simone

[dk8cb]

Hi Simone,

similar observations here in Munich yesterday.
See attachment.

dk8cb

[simone]

Hi all,
results not so good because of a thunderstorm, see attachment
73, Simone

[dk8cb]

Hi,

here is my result for yesterday.

dk8cb

[dk8cb]

And here is today's result.

dk8cb

[simone]

Hi all,
good results today, although SNR is not as stable as in Munich.
The message text was static (same as yesterday), reading:
Off the Shelf. Coming next - World News

73, Simone

[dk8cb]

Hi,

good result today.

@Simone: My setup is limited to an SNR of just 23 dB, which may be partly due to my onboard sound chip on the K7S8XE motherboard and partly due to phasenoise of the ATS-803-A. So any ripples on the SNR may be masked by my receiving setup. Nevertheless everything works absolutely fine and I can't imagine that a higher SNR limit would improve things notably.

dk8cb

[simone]

Hi Roland,
it is probably the ATS 803A that limits the SNR in your configuration , last year I modified that type of receiver for a friend and did not achieve a higher SNR, and I remember I also had to be careful about adjusting the AGC, but as long as audio decoding is perfect you don´t need to bother about a higher SNR. But nevertheless I have interferences from the neighbourhood, so compared to 9410 kHz it is always a bit instable.
73, Simone

[simone]

Hi all,
about 4 hours of good reception today, see attachment
text was still the same as the past days( Off the Shelf. Coming next - World News)
73, Simone

[dk8cb]

Hi Simone,

a bit off topic :-)

the key to success with the ATS-803-A is to keep it on all day, so that the frequency becomes stable enough for DRM reception. If the audio is set to zero, it will not draw much current from the power supply, so that doesn't matter.
When I had my ATS-803-A off and only switched it on when I wanted to receive DRM, reception was good in the beginning for a very short time, but then the set started to drift at a speed which could not be tracked by the software. However, it will be stable after about half an hour...
So I now have it on all day. The results are known on this forum and I'm very pleased with them.
But anyway, I once pulled this receiver out of the plastics recycling container, so I have no reason to complain about frequency stability.

Next thing I will try though, is to screen the VCO tuning line which runs around unshielded inside the set for quite some distance.

Also, it's time to put my good old Siemens E411 to DRM still ... (after repairing it first)

I had a chance to see the Mayah 2010 today at HAM Radio Friedrichshafen, but reception in the hall was bad, 7320 kHz only gave an SNR of 16 dB at about 14:45 UTC.
I was told that the receiver aquires DRM very fast, i.e in about 1.5 seconds, much faster than our software solutions.
But it carries a price tag of about 800 EUR and has a mediocre speaker...

Regards,

Roland, dk8cb

[corrados]

> I was told that the receiver aquires DRM very fast, i.e in about
> 1.5 seconds, much faster than our software solutions.

I'm just wondering how they can play audio after 1.5 seconds while most DRM transmissions use a 2 seconds interleaver on the main data channel ;-)

[dk8cb]

@corrados

Hi Volker,

you are right of course. I only repeated the words of Charly Hardt, who had the Mayah 2010 on his booth at the exhibition... He had also only estimated the time after I had asked. ;-)

But still, he said, if they tune the Mayah and a software receiver to the same station, then the Mayah will always be the first that produces audio. Something I expected.

Another info: On the flea market at Friedrichshafen, a guy from the Netherlands was selling (and will still do so today) complete Elektor DRM kits for 70 EUR and the naked PCBs as well.

There was also a demonstration of the Thales OFDM Ham radio software, which has somewhere else been termed "vapourware" . Unfortunately, the people giving the demonstration were not there at the time when I was there and also not, when I returned later. So I could only see the screen on the two PCs.

dk8cb

[dk8cb]

Hi,

and here is today's report. A little worse than usually.

dk8cb

[simone]

Hi Roland,
that´s interesting as my results have improved today (but I had worked on the antenna this morning, maybe this helped), see attachment
(btw text unchanged:" Off the Shelf. Coming next - World News")
73, Simone

[simone]

Hi all,
looks like this morning they were already preparing for the transmissions to Lyon (QoSAM) but still using the regular beam, unstable SNR in my place but OK for audio decoding in mode A at low bitrate of 14.67kbps anyway. (Bitrate was never altered when I looked at it.)
73, Simone

[simone]

Hi all,
here are some results from this afternoon (rel.frames!), about 1400 UTC it was impossible to listen as the bitrate was changed too frequently, especially when switching between 750 and 1500 frames, so I never got audio decoding with 17.4 kbps, I wonder if the new receivers could cope with these changes. I also expect it was meant as a test for the equipment and not for listening, but anyway interesting to see how the software decoder reacts ;)
73, Simone

[simone]

Hi all,
I wonder if till 0855 the regular beam was used, as a had a strong signal and high SNR. Also in the afternoon about 1620 I had a quite strong signal again, see results for 0830-1000 attached
73, Simone

[dk8cb]

Hi,

here is my report on today's QoSAM Test.

A lot of dropouts due to rapid changes of the mode of transmission.
Mode A did not give good results. Also 11 kbit/s didn't really sound nice.

dk8cb

[simone]

Hi Roland,
I just realized that we both recorded the same period of this transmission today, so here is my logfile for comparison.
73, Simone

[dk8cb]

Hi,

thanks, Simone.

So here is my comparison report between Simone (near Frankfurt) and me (Munich).

dk8cb

P.S. no time to change the text in the graph. I have to leave for a business trip.

[simone]

Hi all,
some results from todays QoSAM tests, sometimes bitrate changed too fast for the DRMSWR, see attachment
73, Simone

[jbriggs]

Hi Simone, at times today the bitrate was changed every 30 seconds, which makes for a good demo, but is not something we would normally do. After each change, our Rx locked up after a few seconds, (5-6 for robustness mode change, less for code rate change). Is this what you observed?

Greetings from Lyon
James

[simone]

Hi James,
it was about the same for me, some code rate changes were hardly noticeable, but after robustness mode changes it takes a few seconds till you get audio decoding again, I think DreaM is a bit faster than the FhG software, but I expect you are using a professional receiver, not the software radios.
Btw signal strength and SNR (max. 25dB) on the beam to Lyon are much better here near Frankfurt than I had expected, ( of course the logfile analysis would not show this because of the tests).
Simone

[simone]

Hi all,
again the SNR was higher in the first 30min, which was mode A (I think, not B as the logfile shows), see attachment
Too bad the mode is not recorded in the logfile.
Interesting text:
Today is the final test transmission for Project QoSAM funded by the EU. From 1/7/04: 1000-1500;7320kHz;BBC WS, 9410kHz ceases.

73, Simone

PS: What was reception of this transmission like in Lyon (SNR?)?

[simone]

Hi all,
good results as usual, back on the regular beam for this transmission, see attachment

[dk8cb]

Hi,

here is my report for today. A short dropout around 10:11.

dk8cb

[dk8cb]

Hi,

here is my report for yesterday.

dk8cb

[dk8cb]

And here is my report for today.

dk8cb

[simone]

Hi all,
it didn´t look so good at the beginning of the transmission with some (old) problems, but later perfect transmission with pretty high and stable SNR, better than usual, maybe some changes at the TX?
(Btw the BBC text did not change all day.)
73, Simone

[simone]

Hi all,
again a strong signal this morning and the SNR reached the same high values as yesterday, see attachment (please ignore the two dropouts)
73, Simone

[simone]

...but after a restart in the afternoon for some reason the SNR dropped about 4dB, but still perfect audio decoding, see attachment
btw the text was working again and great coverage of Wimbledon!
73, Simone

[carknue]

Hi all,

still a lot of problems in Rampisham. Several tx shutdowns. I think there was a tx change. Low SNR in the last part.

[simone]

Hi all,
quite good results today, see attachment
73, Simone

[simone]

Hi all,
a few dropouts today, no idea what happened around 1320, see attachment
73, Simone

[dk8cb]

Hi,

some dropouts yesterday. During one these dropouts, I could see how the signal disappeared.

dk8cb

[simone]

Hi all,
not too bad after a very strange beginning, see attachment
73, Simone

[dk8cb]

Back to normal again today.

dk8cb

[simone]

Hi all,
back to pretty good results today after yesterdays problems, see attachment
73, Simone

[simone]

Hi all,
good results again today, see attachment
73, Simone

[dk8cb]

Hi,

before start of transmissions on 7320 kHz I can usually observe a noise peak at 7320 kHz +/- 10 kHz. It is not very strong and its frequency is not fixed, it moves around slowly. I have no idea, where it comes from. It looks like some pseudo-noise modulated psk signal. It might also be something originating locally.
Normally, this signal is about 20 to 30 dB weaker than the DRM signal from Rampisham. But yesterday, it was quite strong and it moved slowly into the DRM spectrum from an initially lower frequency and it then completely ruined my reception.

Does anyone else have this noise signal?

Edit: Today, the noise peak is there again on 7313 kHz. Wonder what it is.

dk8cb

[dk8cb]

Hi,

I just determined the source of the interference. It originated locally from my DSL modem. Pulling the power cord removed the noise peak. I think, a ferrite in the power cord will remove it completely.
Will try out later.

dk8cb

[simone]

Hi all,
some problems today, good results from1225, see attachment
73, Simone

[dk8cb]

Hi,

no problems in Munich.

dk8cb

[simone]

Hi all,
some problems in Rampisham today, very weak signal after the restart, results improved after 1230, see attachment
73, Simone

[simone]

Hi all,
good results at the beginning, later bad conditions because of thunderstorms until logfile ended abruptly because of power outage, see attachment
73, Simone

[simone]

Hi all,
good results, high and stable SNR for this transmission (with a break at 1148-1153), see attachment
73, Simone

[dk8cb]

Hi,

here is my report on today's reception. Bad reception at the end of my listening period. I don't know if this is due to local interference, but it looked more like a sudden drop in signal strength.

dk8cb

[simone]

Hi Roland,
also bad results in my location later today, see attachment
73, Simone

[simone]

Hi all,
again a very weak and unstable signal from Rampisham today, (just bad propagation conditions?) see attachment
73, Simone

[simone]

Hi all,
the bad conditions and a very weak and unstable signal continued today; or have there been any changes at Rampisham that would explain these results?
73, Simone

[dk8cb]

Hi,

also a very unstable signal in Munich. Is something wrong at the TX? Is the noise level on 7320 kHz too high? There is no interference, but still reception is sometimes bad.
But today it looks more like a sudden TX fault.

Are there any effects that are beyond the WSSUS propagation model, which the decoding software cannot deal with, such as Ionospheric intermodulation (the famous "Luxemburg Effect")?

Or does the summer heat cause antenna wiring to heat up, elongate and come too close to each other such that sparking may happen?
I Know that under certain conditions, corona discharge may occur in antennas. Has anybody ever determined how such highly nonlinear phenomena will affect a DRM signal?

dk8cb

[jbriggs]

No known changes at the Tx station. I don't have any explanation.

It is possible to get a sustained corona on the Tx antenna, however, UV detectors near the antennas detect the discharge and action is taken to identify the faulty antenna within minutes. A sustained corona will cause a lot of damage to the feeder or antenna, melting aluminium or steel, they are most common in the spring or fall, when there is a large temperature difference between day and night.

With an AM transmission, usualy the demodulated audio is heard quite loudly from the corona: quite an interesting and strange effect! With DRM I guess there will just be "white noise", but I don't plan any experiments.


James

[dk8cb]

Originally posted by jbriggs
With an AM transmission, usualy the demodulated audio is heard quite loudly from the corona: quite an interesting and strange effect!


Hi James,

I was told that once, when visiting the Wertachtal site many years ago. Unfortunately, there was no opportunity to witness it myself. ;-(

Such a discharge with its highly nonlinear and even negative dynamic resistance will produce a lot of distortion and harmonics as well.

dk8cb

[simone]

Hi James,
interesting start today, at the beginning again a weak signal (carrier only) after adjustments about 1006 UTC the signal increased a lot within a few seconds, after that strong signal with AM and later also improved DRM signal, better results and higher S/N than the past days (although it was mobile reception) until 1145 (then it looked more like a lot of trouble;)), perfect results in the last half hour before transmission stopped at 1400, see attachment
73, Simone

[dk8cb]

Hi,

as Simone already pointed out, an interesting mix of DRM, carrier and AM in the beginning of yesterday's transmission.

However, quite a solid signal after that.

dk8cb

[simone]

Hi all,
signal is still very unstable and weak most of the time, but also periods with really high SNR (like 1350-1400 SNR>27dB, max. 27.7dB), see attachment
also problems with the dynamic text, which read "World Football. Coming next - World News" all day
73, Simone

[DRM-Fan]

I was going to ask about this freq. I am not getting a trace of anything. I was hoping to listen to RNZ and Australia yesterday. Was anything broadcast at all ?

[simone]

Hi Dave,
RNZI and Radio Australia is not on 7320kHz (that´s BBC WS), they are Saturdays on 9770 kHz ("VT digital"), see my results from yesterday on the other thread, concerning these transmissions you are probably too close to Rampisham to receive anything.
73, Simone

[simone]

Hi all,
this afternoon 15min with a very weak signal, see attachment
73, Simone

[simone]

... and earlier today also not what it was like in the past but not really a problem for listening, see attachment
73, Simone

PS: Again problems with dynamic lablels from BBC WS.

[DRM-Fan]

Originally posted by simone
Hi Dave,
RNZI and Radio Australia is not on 7320kHz (that´s BBC WS), they are Saturdays on 9770 kHz ("VT digital"), see my results from yesterday on the other thread, concerning these transmissions you are probably too close to Rampisham to receive anything.
73, Simone

OK but also 7320 as well as 9770 is non existant with me, no signal I'm in East Sussex so should get something

[dk8cb]

Hi,

not so good today.

dk8cb

[simone]

Hi all,
bad propagation conditions resulting in a weak and instable signal all day, improving a bit after 1340, see attachment
73, Simone

[dk8cb]

Hi,

first a weak signal, then a loss of the data stream (CELP, P23S station label) in Rampisham today.

dk8cb

[simone]

Hi all,
reception improved after 1230, SNR stable at 24 dB in the last hour (not included in the log), also as Roland mentioned for some periods the test signal was transmitted instead of the regular datastream, see attachment
73, Simone

[dk8cb]

Hi,

a lot of interruptions today with the test sequence and P23S station label.
Also one interruption caused by myself changing the antenna cable.

dk8cb

[simone]

Hi Roland,
what about signal strength, was that back to normal yesterday?
I tuned in here in Switzerland (111° from Rampisham) in the last minutes and had an even weaker signal than at home, also interruption of thedatastream occured.
Greetings from Switzerland
Simone

[dk8cb]

Hi Simone,

signal strength was quite good, perhaps a little less than what we have witnessed some weeks ago, but quite good. So the dropouts were all caused by data stream losses.
But the guys in Rampisham are already investigating, so let's see what comes out.

Any running competition in Switzerland?

73, Roland

[simone]

Hi Roland,
signal here in the Swiss Alps this afternoon instable, between S1 and S7, short periods with good S/N (25dB), also looked like they are still investigating.
PS: You are right (concerning running, good detective work!), hopefully results will better than on DRM :) but for me the race is just to prepare for the next big event.
73,Simone

[dk8cb]

Hi,

here is my report on today's reception.

The TX lost its data stream three times and reverted to its default test stream with the infamous 'P23S' station label.

dk8cb

[carknue]

Hmm, still a lot of problems... Signal was strong and stable.

[simone]

Hi all,
yesterday the signal was much stronger here in Switzerland than the days before, S9+20, no problems concerning the datastream in the last 30min
73,Simone

[simone]

.. and here is an example of the results I had with the weak signal the days before yesterday
73, Simone

[simone]

Hi all,
strong and stable signal about S9+10-20 today, good SNR
73, Simone

[dk8cb]

Hi,

a strong and stable signal, but many incidents of stream loss and the infamous P23S station label.
No fun to listen.

dk8cb

[simone]

Hi all,
strong and stable signal again, strange behaviour of the DRM SWR, whenever the datastream problem occured, the MMplayer started on its own, never noticed this before, see attachment
73, Simone

[jbriggs]

We suspect that a satellite Rx/Router is causing the "P23S" problem. I hope this will be fixed soon.
James

[dk8cb]

Hi,

here is my report on an hour of good reception today. No 'P23S' incident so far.

dk8cb

[simone]

Hi all,
good results, stronger signal in the last hour as on many days before, see attachment
and more important: all problems solved, no more "P23S" label today :)
73, Simone

[dk8cb]

Hi,

unfortunately, no problems solved. Transmission started with the 'P23S' station label, audio appeared after some time, but P23S returned several times afterwards.
Also P23S at the moment (11:08 UTC).

BTW: The forum clock seems to have drifted away again.

See attachment.

dk8cb

[simone]

Hi all,
no more "P23S" today, strong signal and good results using the old FRG8800, see attachment
73, Simone

[dk8cb]

> no more "P23S" today

No Simone, quite the opposite. It started at 09:59 UTC with the 'P23S' label and audio came on late.

But you were only logging after that.

dk8cb

[simone]

...just happy nobody is watching my work so closely :)

you are right Roland, but it is nearly 3 hours which I logged without any interruption, so quite good compared to the past
73, Simone

[dk8cb]

Hi,

and here is proof of the 'P23S' station label. Quite good after that.

dk8cb

[carknue]

Hi all,

perfect today. Much stronger and more stable than the 9770 khz.

[dk8cb]

Hi,

a late start with a lot of tune-ups and also AM for a while, then some shaky periods and good reception versus the end. A little bit strange.

No 'P23S' today, hopefully the problem has been fixed now.

dk8cb

[simone]

Hi all,
as Roland mentioned some adjustments in the first minutes, after that excellent reception in my location, strong signal (S9+20), see attachment
73, Simone

[dk8cb]

Very good reception today. Also quite interesting reports on the programme itself.

dk8cb

[simone]

Hi all,
again perfect reception like yesterday, see attachment
73, Simone

[simone]

Hi all,
here is what the so stable looking S/N was really like, when recording every second, see comparison attached
73, Simone

[carknue]

Strong and stable. Perfect reception. Now I prefer this frequency from Rampisham.

[simone]

Hi all,
good results continued today, see later also thread mobile reception
73, Simone

[dk8cb]

Hi,

also good reception in Munich today.

dk8cb

[dk8cb]

Hi,

today's transmission started again with the infamous 'P23S' station label. Later, the proper audio stream came on, but several more 'P23S' sequences followed.

The first dropout (pink marker) was caused by myself.

dk8cb

[simone]

Hi all,
besides the `P23S` problem that reoccured a few times, good results, great signal after 1310, see attachment
73, Simone

[jbriggs]

Problems yesterday were caused by the MDI generation/encoding equipment at the studio. Cure (for now) is to reboot the PC generating the stream.
James

[simone]

Hi all,
a weaker signal today causing some dropouts, in addition to the breaks in audio decoding ( I assume the same problem as yesterday, btw also no text messages since yesterday), but good to read it is a different problem now than last time, so that one has been solved successfully. Signal strength improved towards the end, see attachment
73, Simone

[dk8cb]

Hi,

also a weaker signal in Munich today and a few droputs as a result.

dk8cb

[dk8cb]

Hi all,

does anyone else also notice these strange occasional clicks on the audio on this frequency today?

Besides, very bad propagation conditions today, a very weak signal on 7320 kHz in the beginning, I was unable to get sync at 10:00 UTC, this continued for quite some time, but now conditions seem to recover all of a sudden.

dk8cb

[dk8cb]

Hi,

really strange conditions today. See attachment.

P.S. The strange clicks dissapeared after my last post, they were probably a result of the bad propagation conditions.

Edit: I have just noticed (Aug, 15th) that I had attached the wrong file, but here is the proper one.

dk8cb

[carknue]

Originally posted by dk8cb

P.S. The strange clicks dissapeared after my last post, they were probably a result of the bad propagation conditions.


dk8cb

That's the way how Dream handles droputs, it produces click sounds. Not nice indeed.

[carknue]

Very weak condition on most bands yesterday.

[simone]

Hi all,
strange conditions today, pretty good results until 1130, then I hardly got sync, see attachment

[simone]

...but after 1400 reception was quite good again.
Btw the bitrate today was 18.24 kbps (default settings with this configuration?), at least that´s what the DRM SWR showed, the other days it had been corrected in the first minutes.
73, Simone

[simone]

Hi all,
weak and instable signal, nearly no audio decoding at 1335-1415, see attachment
Bitrate again 18.24kb/s
73, Simone

[dk8cb]

Hi,

here is my report for today.

Signal strength varied widely.

dk8cb

[simone]

Hi all,
the signal was much stronger and more stable than yesterday, also bitrate was back to the normal 20.88kb/s, see attachment
73, Simone

[dk8cb]

Hi,

once again a signal with widely varying field strength. Very pronounced fading of the whole signal at the beginning but a more stable signal later.

Also, audio was missing at the start of transmission.

dk8cb

[simone]

Hi all,
quite good results today, see attachment
73, Simone

[dk8cb]

Hi,

quite good today.

Roland, dk8cb

[simone]

Hi all,
quite good between 1000-1300 today, see attachment
(@Roland: bitrate was increased after the first minutes),
no reception (or transmission?) later this afternoon in the last hour of the transmission
73, Simone

[dk8cb]

Hi,

here is my report for today.
There were some instances, when the signal disappeared completely, not as a result of propagation but obviously because of work at the TX.

dk8cb

[simone]

Hi all,
no such breaks later today, but again the signal was not very strong, see attachment
73, Simone

[dk8cb]

Hi,

very good today. I noticed the following:

- it seems that the local encoder was used, because the time signal was only delayed by 5 seconds, compared to over 30 seconds on other days

- the encoder sometimes produces very slight clicks that are only audible when one listens carefully, but they are not a permanent phenomenon

- there was a loss of audio for a few seconds at 12:11 UTC, however MSC decoding was ok, so audio must have been missing already at the input of the encoder. This short period was preceded by some short, audible distortions.

dk8cb

[simone]

Hi all,
signal not as strong and stable as on 9 MHz but quite good results, except 10min about 1115 (maybe a local problem), see attachment
@Roland: Looking at my results, I think the same equipment at Rampisham has been used today as on all transmissions this past week.
73, Simone

[simone]

Hi all,
strange results today, despite a strong and stable signal a somehow low and limited SNR, according to logfile no audio decoding but I can hear some audio, see attachment
73, Simone

I tuned in again, still the same 1230-1300.

[dk8cb]

Hi,

no audio and low SNR around 14 dB as well here.

Has the Thales encoder gone haywire?

dk8cb

[simone]

Hi all,
strong signal in the last hour, unfortunately still only intermittent audio decoding and limited SNR, no fun for listening, see attachment
Is there no alarm from the control receiver in such a case?
73, Simone

[dk8cb]

Hi Simone,

according to James, the problem is, that there is no monitoring receiver yet.

dk8cb

[dk8cb]

Hi,

here is my report for today. A somewhat shaky start, but quite good afterwards.

I noticed that, with the Thales encoder that was used today, the audio bandwidth amounts to only about 9.3 kHz. I don't remember what is was when the other encoder was still used.
But nevertheless, aside from a few occasional clicks that seem to appear in clusters very seldomly, the audio quality was very good.

Roland

[simone]

Hi all,
a few dropouts because the signal was not that strong today, see attachment
@ Roland: I have noticed on many BBC WS broadcasts that the audio bandwidth varies, depending on the programming or whatever, so it is not necessarily a matter of the encoder (but it was the Thales as I can see a difference in my results ;) )
73, Simone

[dk8cb]

Originally posted by simone
... it was the Thales as I can see a difference in my results ;)

It can also be heard. There is more bass with the Thales encoder.
Also, the time signal on the hour is only delayed by 5...6 seconds when the Thales encoder is used. But that requires real listening to find out, not just logging.

But most important, it doesn't cause 'P23S' incidents, which I think is the reason for it being used.

Roland

[dk8cb]

Hi,

here is my report for today.

For some reason only known in Rampisham (or not even there ;-) ), a lower bitrate was used.

Roland

[simone]

Hi all,
strong and stable signal today, bitrate was back to normal but it was one of the days with only 9.5 kHz audio bandwidth (according to DReaM), see attachment
73, Simone

[simone]

Hi all,
it looks like the equipment at Rampisham has been changed again, good results and no more P23S ;) see attachment
73, Simone

[dk8cb]

Hi,

not a strong signal in the beginning but improving later. I had some local interference which seems to have been caused by someone else inside the house here.

Roland

[dk8cb]

Hi,

here is my report for today. Some TX tune-up in the beginning, quite good later.

Again, as on 1269 kHz yesterday, a short loss of audio of less than a second duration at approximately 11:00:20 UTC, shortly before the time signal.

Roland

[simone]

Hi all,
good results again and more important no MDI stream problems for nearly 3 hours that I recorded the logfile, see attachment
(dropouts at the beginning caused by too much multitasking, sorry)

[dk8cb]

Hi,

quite good today.

However some very short audio dropouts with correctly received frames, so they were already there at the transmitter.

Roland

[simone]

Hi all,
pretty good conditions today (except 5min with a local interference), see attachment
A few interruptions of audio (muting less than a second) in the first hour, did not notice it later today, no datastream problems, so maybe both problems are solved now!
73, Simone