Voice of Russia on 15780 kHz

[lmaes]

Reliable reception of the last hour of the 4 hour service from Voice of Russia on 15780 kHz.

Ludo

[MarkT]

Hi DRMers

Here is 30 minutes worth of 15780 kHz this afternoon.
Reception was quite good.

[FritzWue]

Good reception:

[carknue]

15780 is back with very high SNR values. But signal is not stable, often fades out. Sound quality has improved a bit.

[carknue]

Quite good today

[CT1ADT]

Hi all

Quite good today,also...

[simone]

Hi all,
not bad today, see attachment
73, Simone

[carknue]

Hi all,

indeed, quite good today.

[CT1ADT]

Hi all

Good condition from VOR but with interferences

14:30 to 15:30

[simone]

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

[CT1ADT]

Hi all

My report last hour..

[CT1ADT]

Hi all

My long log today report ...

[simone]

Hi all,
very instable signal, bad audio decoding even at 8kbps, see attachment
73, Simone

[Andrew]

Hi DRMs,

Sorry, I was absent some days at the transmitter site.
There was a disturbance of the DRM signal former (Thales encoder - modulator), and the alert staff has rebooted it, but has not installed the demanded configuration, now it has been already fixed.

Andrew.

[simone]

Hi Andrew and others,
reception not too bad when I started but later very instable signal, see attachment
73, Simone

[carknue]

And another comparision. Vor reception was much better last year....

[carknue]

Hi Andrew,

still bad results. I found two reasons for that.

1. very low signal strength Max. S7
2. Often a strong AM station on 15785 khz

Have you made some antenna or TX changes? I have the 15780 khz mutch stronger in my memories from last year.

[simone]

Hi Carsten and others,
the interference in the adjacent channel above caused big problems in my location, see attachment
73, Simone

[carknue]

Hi Andrew

Today, signal was back to normal for me. Very high peak SNR of 34.9 dB. Did you change someting?

[Andrew]

Hi Carsten and others,

nothing was changed with transmitter and antenna, probably there were bad propagation conditions and interferences?
What about AM-interference on 15785kHz and when has it appeared?

Regards,

Andrew.

[cesco]

never seen a snr of 27 before.

[dk8cb]

Hi,

I have just found out by listening in USB on 15785 kHz, that the interference on 15785 kHz is from KOL Israel. Their carrier signal is >20 dB stronger than the DRM signal from Taldom. It also sounds as if KOL Israel is somehow distorted or overmodulated.

There is also very strong interference from an AM station on 15775 kHz. I am unable to identify the station. The language seems to be some african or perhaps southern indian dialect, but this is only a guess. I have never heard that language before. It seems to be a religious programme, the only word I can understand is "Christo" appearing repeatedly.

Edit: Now, the DRM signal has completely disappeared here in Munich, most likely due to propagation conditions. The station on 15775 has just signed off and immediately before, an adress in Bangladesh was given twice, but it did not contain the word "Radio".

KOL Israel still sounds distorted here, even with no more trace of a DRM signal from Taldom.

dk8cb

[cesco]

>I have just found out by listening in USB on 15785 kHz,

positive. the carrier on 15785 is clearly visible in the drm spectrum of 15780, degrading snr 3 to 6 db.

the AM "schalom" modulation is not distorted here . it sounds
strange on usb because of the 9+20 drm signal a 100 hz lower,
and it is completely covered by the drm modulation on lsb.

[Andrew]

Hi dk8cb and cesco,

thanks for your info, I've transfered it to our administration. May be something will be changed.

Best regards
Andrew.

[carknue]

Hi Andrew,

a good, a bad and a medium part today.

[CT1ADT]

Hi all

My today report is medium and bad
because had interference in adjacent frequency

[carknue]

Hi Andrew,

I discovered a new transmission in the morning from 7 to 12 UTC.

[Baldo34]

Hi,
heard also on Monday morning. Is this a regular transmission?
73, Klaus

[Andrew]

Hi Carsten, Klaus and other DRMrs,


yes, you are right. The VOR daily transmissions from 2:00 till 12:00 UTC and from 13:00 till 17:00 UTC will be continued regularly. It was decided on June, 4 , when I was in Moscow on the conference devoted to the digital broadcasting and I couldn't notify you in time, as I arrived at the transmitter site on Monday.
Programs are in Russian till 6:00 UTC, from 6:0 till 9:00 - in English and from 9:00 till 12:00 - in German. The second part of the VOR transmission after one hour break is usual as earlier.

Best regards,

Andrew.

[Per]

Hi,

I took advantage of the new transmission hours. This is my first result from VoR at 07:30 until 08:50. The signal dropped at 08:33 - after that now more sync.

73's Per - SM0ITS

[CT1ADT]

Hi all

This is my first result from VoR in new time.

[simone]

Hi all,
my first results on the morning transmission, not great, see attachment
73, Simone

[Andrew]

Hi all,
hi Klaus,

there are new corrections in schedule of VOR DRM daily transmissions which will begin from 6:00 UTC (the program in Russian is removed from the schedule).

Andrew.

[lmaes]

Variable reception this morning of Voice of Russia in English.

Ludo

[4S7DRG]

Colombo 15.06.2004

Signal of VOR here in Colombo
unfortunatly with poor SNR and
heavy QRM from other stations.

Since we are just getting a side
loop from there antenna pattern,
no wonder.

[Per]

Hi,

At the start of my listening at 11:20 UTC the reception was very good. But just to vanish some 15 minutes later....

73's Per - SM0ITS

[tradio99]

20.06.2004 - reception results (9.14 - 10.19)

[CT1ADT]

Hi all,
my today results on the morning transmission,
see attachment

[Andrew]

Hi Wolfgang and others,

The reception of our signal in Colombo is the surprise for us, though I've heard one time that our signal was received in Shri Lanka but with very low level and without audio decoding in fact.
It is planning to organize DRM broadcasts to South-East Asia from Siberia.

Best regards,

Andrew.

[simone]

Hi all,
good start this morning, but bad results from 0620, see attachment
73, Simone

[Per]

Hi,

Two hours of VoR this morning; 8-10 UTC.
A SNR at maximum 28 dB produced a good signal at my location: 93 %.

73's Per - SM0ITS

[CT1ADT]

Hi all
This is long today log
no problem with TDF @ 15790 kHz but
bad results from 14.30 to 15.30,because other signal
interfere there, see attachment

[Andrew]

Hi Manuel,

is there an interference on 15785 or 15775 kHz in your location?
I 've got the information that SSB stations from Israel and from Iceland are audible in Germany on these frequencies. Are they interfere in our signal in Portugal too?

Best regards,

Andrew.

[CT1ADT]

Hi Andrew

Today, I heard 14.30 to 15.30 and i have
on 15775kHz one AM station ( 14.30 to 15.00 ) in chinese ! language and ( 15.00 to 15.30 ) afrikane language !
This, caused low SNR in Your´s DRM signal...

[Per]

Hi,

Good reception from VoR this morning despite TDF @ 15790 kHz. Both stations produce the same SNR at my location = 18-20 dB.

[Per]

Hi Andrew,

Are there any transmissions today, July 23, from VoR?
I'm checking right now at 14:05 UTC and no trace of any DRM at 15780 kHz? The same situation this morning.

[Andrew]

Hi Per and others,

Regarding to July 23 - the transmitter was in air, but a thunderstorm was in our location.

Perhaps someone could receive our transmissions on July 23 - let us know. It's interesting what was indeed.

Best regards,

Andrew

[Per]

Hi Andrew,

I think it's the "strange" propagation, still in excistance, that spoils the reception.
I've been checking this frequency both earlier today and yesterday.
At 16:10 until 17:00 UTC I did receive VoR. But not with the SNR usually found on your station.

[Andrew]

Hi Per and others,

yesterday we have changed some settings, so check the reception of our transmissions, please.

Best regards,
Andrew.

[Per]

Hi Andrew and all,

It looks like that the magnetic storm is gone. Today I listened to the Voice of Russia from 07:00 until 09:00 UTC, with good result. I think the sound quility is good at 17 kbps, this was noticed during "Jazz Time".

[Per]

Hi,

This is the latest report from IPS: "DEGRADED HF PROPAGATION CONDITIONS EXPECTED FROM 30-31 JULY 2004"

That seems to be correct, as today the SNR is some 8 dB lower than yesterday.
Listening time: 07:50 - 09:10 UTC.

[Per]

Hi,

Todays listening was between 14:00 and 14:40 UTC. SNR varied between zero and 27 dB!

[Andrew]

Hi Per,

thank you for your reports, unfortunately the propagation conditions were bad these days.

Best regards,
Andrew.

[CT1ADT]

Hi all


my today report from 15780 kHz...

[Andrew]

Hi Manuel,

thank you for your report, it seems to be interferences which prolong to influence on reception?
Are they on 15775 or 15785 kHz?

Best regards,
Andrew.

[dk8cb]

Hi,

here is my report on today's reception. There was a carrier on 15785 kHz, but still, reception was quite good.

dk8cb

[Andrew]

Hi all DRMrs,

we repeat our test with changed settings of antenna system since August 5 from 13:00 UTC.

We are waiting for your reports...

Thank you in advance,

Andrew.

[CT1ADT]

Hi Andrew
Hi all
yours has another station in 15785 kHZ ( see attach.) Or yours down for 15775 kHz or down bit rate ( 11 kbs )
I prefers one clear frequency and high bit rate ( > 17kbs)

[carknue]

Hi Andrew,

I didn't logged your transmissions for a long time, because the results were always very bad here. There is always the stronger AM station on 15785 khz and your signal is this year much weaker than last year. But I think that your antenna is not really designed to cover germany.

Today I logged. There was only a good period between 15:30 and 16:00 UTC. I don't know if you changed something in that period?

[Per]

Hi,

This my result from this morning, 07:50 - 09:00. The interference on + 5 kHz, is not a problem at my location. Often its not visiable. But there is still big variations in SNR, from 8 to 26 dB.

[simone]

Hi Andrew,
still bad results here this morning, last year I achieved the highest SNR of all transmissions on this one, and like Carsten I have not sent reports lately because it is impossible here to listen anymore.
73, Simone

[Andrew]

Hi Manuel, Carsten and Simone,

many thanks for your replies. I completely agree with you, I also prefer a clear frequency and high bitrate but not all depends on us, sorry. I have already spoken about the problem of interferences from AM-stations on a meeting of technical committee of DRM consortium, which was held in Moscow on June 17, 2004... It seems the interference is a main problem for DRM reception of our signal at the moment, isn't it?

Thanks to dk8cb for your nice report, probably the reception in the morning is better (without interferences?). I have got the the similar information from Munich and from Rostock with about 100% audio decoding, but for the periods of 7:50 - 10:58 UTC.

Hi Per,
I think the SNR in Sweden has so big variations because our radiation sector direction is south-west (the edge of a zone covered and, in addition, unstable ionosphere). And the interference "cuts" our signal as "she wants".

And what are your opinions?

At the moment we prolong our test with changed settings for weekend.

Kind regards,

Andrew.

[CT1ADT]

Hi Andrew.
Hi all

I listened DRM about two years ago and I think that big
problem off DRM are the interferences that caused down
SNR --> dropouts.
For low bit rate < 17 kbs, i like more AM mode !
at the moment this is your´s bigger problem on 15780 kHz in my location.
"tacitus-ms" made a realistic exposition about this on
http://www.drmrx.org/forum/showthread.php?threadid=785
and I am in agreement one hundred percent.

[simone]

Hi Andrew,
in my location the problem is not only the interference, it is just that the DRM signal is so much weaker than last year.
73, Simone

[carknue]

Hi Andrew,

I totally agree with Simone. The main problem on 15780 khz this year is the very weak and unstable signal. It is mostly just around S5.

[Per]

Originally posted by Andrew


Hi Per,
I think the SNR in Sweden has so big variations because our radiation sector direction is south-west (the edge of a zone covered and, in addition, unstable ionosphere). And the interference "cuts" our signal as "she wants".

And what are your opinions?

Kind regards,

Andrew.

Hi Andrew + all,

Yes, if I look at the coverage map I'm clearly not in the target area. So I persume that the signal in my location is much weaker than in beam center.
Today provided a similar result as previous days: 70%. Listening time: 08:00 - 09:10 UTC.

[simone]

Hi Andrew,
I tuned in again this morning, better than last time, at least I could listen to the German service in the last 15min, see attachment
73, Simone

[lmaes]

The big variations are also present here in Belgium, and we think we are in the main transmission lobe.

Reception of signals from Portugal in the 15 MHz band are much more stable and the distance is comparable to Taldom.

Is the performance of the transmitter stable or are there perhaps variations in power, SWR or other factors? Is a different type of transmitter in use compared to the transmitters in Portugal. Might that be the reason?

In our opinion, if the performance of transmitter and antenna is more constant and less variable, then reception would be much better. We do not think that propagation is the main factor that causes not so good reception.

It would be good if Andrew and his team could work out a step by step analysis of the complete chain to determine the weak part and trying to fix that.

Ludo

[simone]

Hi Ludo,
I don´t know when you started listening to the transmissions from VOR, but if I compare with last year: I always had a very strong signal S9+20 and more, it never was as stable as the transmissions from Sines, the situation concerning interferences is comparable to last year, here in Germany we had the best SNR of all transmissions back then, the main problem now is definitely that signal strength is way too low compared to last year.
73, Simone

[Andrew]

Hi all DRMrs,

Thank you for your replies.

Ludo and Simone, the modern transmitter from Sines is significantly more powerful, than our one, so I think their transmissions must be received better almost in all cases when the distance is comparable. We try to use existing SSB transmitters with some modernisation in DRM mode, while another DRM transmitters are preparing.

This year the output power was a little less than in June-August of last year, but almost the same one as in October-December. The mode of operations of our transmitter during transmission sessions were stable.
Of course, we are analyzing what takes place actually in complete chain and what is the most significant for reception. Today we have returned the output power up to earlier level and with antenna settings as last days.
Let's see, what it gives.


Best regards

Andrew.

[simone]

Hi Andrew,
unfortunately no improvement of the results, see attachment
73, Simone

[lmaes]

Hi Andrew,

We did not read your message earlier, so we only tuned in the last half hour today. And the result is much better then it has been these past few weeks. If you look at the SNR you will see that it reaches almost 32!

Ludo

[dk8cb]

Hi Andrew,

here is a spectrum plot showing the heavy interference from 15785 kHz at 08:15 UTC today.

Very bad reception as a result.

Even the new bandpass filter in Dream does not help.

dk8cb

[lmaes]

Hi Andrew,

We had our receiver monitor your frequency a full 12 hours and enclosed is the result.

During the period 0814-1200 UTC the signal was quite acceptable with a 71% audio, but during other times, reception was nil, also in the afternoon transmission. A big difference to yesterday's early evening reception.

Hope the log is of some use.

Ludo

[CT4RK]

Hi all


About Taldom signal streng, and to compare it with Sines signal, First we can look to the slow go down into 11 years minimum sun spot number, and efecttively last year the propagation conditions was much better than now. What will do happen in the next 2 or 3 years, when the propagation will be praticlly closed? Second, Taldom are in hight latitude and in this latitude, the disturbances F/F2 layer during the day light and F during the night are more sensitive to the solar wind, and this year the sun have a great activity, with a big flares (remember that Taldom is in the auroras area). About the power Idont see a big diference between 35Kw and 80Kw, because it is more or less ...only 3dBs in the signal streng!! And of course 3 dBs is absolutly nothing in short wave. Much more diference have we with the fading that some times go up to 40dB, and 40dB is from 80kw to...8watts. Finally I can`t beleave that Andrew can`t see any trouble in the transmitter / antenna, that cause the great changes we can see in the signal streng in the receiver side.

[Per]

Hi,

Also at my location I can see the changes in SNR. Listening time today: 07:30 until 08:30 UTC. Result: 61 %.

[simone]

Hi all,
the SNR has improved a lot compared to the past days, but still not great, see attachment
73, Simone

[lmaes]

Hi Andrew,

Today's reception picture is very different from yesterday. We made another log from 0500-1700 UTC. We are curious to know what different settings were in use today compared to yesterday.

Ludo

[lmaes]

Hi Andrew,

Today's reception picture is very different from yesterday. We made another log from 0500-1700 UTC. We are curious to know what different settings were in use today compared to yesterday.

Ludo

PS : attachement enclosed this time

[lmaes]

Hi Andrew,

Another 12 hour reception log of your broadcast on 15780 kHz today. It seems reception improves day after day, but there remain many differences on the different days.

Overall average decoded audio was 23.2% on Tuesday, 34.8% on Wednesday and 41.9% on Thursday.

Ludo

[VE3MEO]

Hi Ludo,

32dB SNR is very impressive! It's rare to see reports so high and must be an indication of receiver/converter quality. What are you using?

Tom

Originally posted by lmaes
Hi Andrew,

We did not read your message earlier, so we only tuned in the last half hour today. And the result is much better then it has been these past few weeks. If you look at the SNR you will see that it reaches almost 32!

Ludo

[Andrew]

Hi all DRMrs,

thanks for your reports and opinions.

Ludo, we do not see any trouble in our equipment, but we inspect actions of an operating personal more carefully regarding the output power. The Thales reference receiver doesn't display something "criminal" like jumping SNR value or signal level.

Carlos is right, the difference of fadings can be much greater than difference of output power, and there are different characteristics of a path compared to Sines.


Kind regards,
Andrew.

[lmaes]

Hi Andrew,

Today's reception was very comparable to that of yesterday. Overall audio decoded today is 41.7%.

Ludo

[simone]

Hi Andrew,
today the best results within months! This looks more like the results we used to get last year, see attachment
73, Simone

[carknue]

Hi Simone and Andrew,

very unstable and weak around midday.

[simone]

Hi Andrew,
good results in the late afternoon again, any changes lately?
73, Simone

[DL1HTF]

Hi,

Here my report VOR radio program German language.

Regards -- Thomas, DL1HTF

[DL1HTF]

compare yesterday -- today radio program german language.

Today was very very bad condition.

Regards Thomas -- DL1HTF

[simone]

Hi all,
some periods with great results, others with a really poor signal, see attachment
73, Simone

[carknue]

Really great results in the last 15 minutes

[Andrew]

Hi Simone, Carsten and Thomas and other DRMrs,

the settings were not changed last 2 weeks.

It is planned to change our frequency to 9480 kHz for second part of broadcast from 13:00 till 17:00 UTC since August 23-rd.
Other part of broadcast is left without changes - on 15780.


Best regards,

Andrew.

[DL1HTF]

Hi Andrew,

First, today the receipt of the radio program German language was well in. The reception suddenly then got bad. Have you experimented? I have checked my antenna. The antenna works excellent.

Greeting Thomas, DL1HTF

[carknue]

Hi Andrew,

very strange. Reception now seems to be as good as last year. Quite strong signal and a extreme high SNR, that we know only from your transmissions. The signal completly faded out between 15:37 and 16:01 UTC.

[DL1HTF]

Hi,

Here is my reception report on about three hours. It is the complete German language radio program in today's morning.

Altogether, the reception was good. I have enjoyed listening:)

Greetings Thomas, DL1HTF

[Andrew]

Hi Carsten and Thomas,

It is pleasant to hear about improvement of reception, but these settings were kept for 2 last weeks and nobody experimented at the time that you pointed (15:30-16:00 UTC on August 20-th). It seems to be variations of propagation conditions - short waves...

I am already in holiday, I have to leave for a couple of weeks, therefore a break in my replies at the forum is probable.

Best regards

Andrew

[DL1HTF]

Hi Andrew,

I also think that this was due to the propagation conditions. You are right -- short wave ...

I wish you a restful vacation.

Best regards
Thomas, DL1HTF

[Jos]

Hi Andrew,

Now is it your turn for holiday.

We will read you back in about three weeks .

Kind regards and a nice holiday.

In attachment the last 45 min.before your holiday.

Jos

[Andrew]

Hi Thomas and Jos,

thanks for your kind wishes. Glad to meet you, Jos, after your holiday. I see the reseption in Belgium is not bad in the evening.

Let's see what it will be on 9480 kHz since August 23-rd (look at my declaration above). There will be another antenna compared to 15780 used last 2 weeks.

See you later and 73s for all DRMrs

Andrew.

[carknue]

Hi,

here is my report from yesterday. Quite unstable if you look at the SNR graph, but it was on a high level, so mostly no problems. There was a break between 12 and 13 UTC.

[Owdjim]

First time ever I've seen signs of this frequency here in NZ. Is there something new with the antenna or transmitter, or is it just favourable reception?

Still far too poor for any decoding.

Cheers, Chris

[dk8cb]

Hi,

today, I tried to listen to the german programme of VoR. But unfortunately, despite good signal strength, a perfect spectrum and a perfect impulse response, I got only a very low SNR. It improved a bit later, but it was not as it should be expected.
I would like to know why this was so. Are there any ionospheric effects the software is unable to compensate for? Is the signal already bad at the transmitter or does something happen at the antenna?

My report is attached.

Roland

[Owdjim]

Finally I was able to decode a little bit of Voice of Russia audio here in NZ today :-)

It was not a lot - bit's of the Russian National Orchestra & VoR English programme - but it is the first time I've been able to get any audio here.

What I could decode seemed to be very good audio quality.

Cheers, Chris

[Owdjim]

How is this log for DRM listening frustration - I have a nice audio recording of several minutes of test tones! By 06:00 it had faded completely.

Cheers, Chris

[Andrew]

Hi Chris,

probably it was the successful confluence of circumstances that the reception in New Zealand was possible. Central and West Europe was officially assigned as the target, though our antenna used at the moment for these transmissions has beam direction 240 degrees.

Best regards and 73,

Andrew.

[Owdjim]

Hi

Managed to decode some snippets of a Russian language lesson today.

Cheers, Chris

[Owdjim]

My best yet reception of Voice of Russia at 06:00 today. I could actually listen to the programming :-)

Cheers, Chris

[midre]

Hi DRMs,

here are a 4 hour logfile from VOR on 15780 kHz.
Up and downs the whole time, a lot of interferences
disturb the listening...

regards, Michael

[carknue]

Good reception this morning.

[simone]

Hi all,
again a very unstable signal this morning but also SNR peaking at 30dB, see attachment
73, Simone

[Owdjim]

Some good reception on 15780 for a while here today - normally this signal has been too poor to decode anything.

Cheers, Chris

[Andrew]

Hi all DRMrs,

since October 31 the VOR daily broadcasts on 15780 kHz will be transmitted from 7:00 till 11:00 UTC.


Best regards,

Andrew

[df9rb]

Hi all,

perfect today...

[df8uo]

Good result here today

Daniel


FT757GX + Dipole + Sat Schneider Module + Dream SW

[radiol]

This morning results (during geomagnetic storm)

[df8uo]

Today again nearly perfect reception over 1h and 15 min.

Daniel

[Per]

Hi,

Big variations in readability today.
Time 8:05 - 8:45 UTC.
Result: 57 %.

[dk8cb]

Hi,

a few short dropouts as a result of interference from a carrier on 15785 kHz but quite good otherwise.

Roland

[FritzWue]

Sometimes interference from +/-5kHz.

[radiomann]

This mornings log.

[simone]

Hi all,
too much fading this morning in Switzerland, see attachment
73, Simone

[dk8cb]

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.

A slightly better percentage of properly decoded audio with "Mod. Metric" activated, however, there was only very light interference from a carrier on 15775 kHz.

Roland

[CT1ADT]

Hi all

My today results on this frequency.

[df8uo]

Quite good results today.

Daniel

[carknue]

Quite good results yesterday.

[Per]

Hi,

It's a couple of days since I was able to receive anything on this frequency from Russia. Todays listening was between 10:04 and 10:58 UTC. Result: 50%.

[df8uo]

Perfect reception today SNR max 34 dB 100% audio till end of transmission

73

Daniel

[simone]

Hi all,
an unstable signal but not too bad overall, see attachment
73, Simone

[df9rb]

Hi all,

optimal conditions today. SNR up to 39,2 dB!

Bernd, DF9RB

[Andrew]

Hi Bernd,

congratulations to you! This seems to be the highest SNR value at a reception of our signal, almost the same value as at the transmitter site (40-42 dB)!

Best regards,

Andrew

[df9rb]

Hi Andrew,

tnx for the congratulations and thanks for the informations about the SNR at the transmitter site. I myself and others asked themselves quite often what is the SNR at the transmitter site.
Now we know from at least one. During this sunday morning I tried DW from Sines and VoR. Both stations where 59+40 but the
signal from Sines had much more fading, two imuplses in impulse response and the signal did not get better than 36 dB. VoR was very stable (less than 10 dB fading), the impulse response was one single very small impulse (less than 1 ms) with a hight of more than 50 dB.

Bernd , DF9RB

[Rene Schmitz]

HI Bernd, Andrew and all,

First of all, Congratulations!

It seems as if for the highest SNRs, you need a very stable signal. I have made some experiments by modulating the output of dream -t to RF with a DBM, and when I changed the audio levels, the SNR did instantly drop. Also it drops much more rapidly that it raises afterwards.

2-3dB difference over a tx distance of 2100km is really not bad!!

Cheers,
René

[df9rb]

Hello Rene,

yes, I made the same experience. A changing input level
decreases the SNR rapid, the recovery needs time. Thats why I had the idea why not to implement a smooth AGC to the DRM decoding software (see my post http://sourceforge.net/forum/forum.php?forum_id=242204 , AGC for DREAM). By the way there has been also a long time discussion about the optimal filter band width for DRM.
During logging VoR I changed the band width several time between 8 and 12 kHz (I have no 10 kHz filter) and there was no influence on the SNR (exept a decrease in the moment of switching). This test is under less stable conditions more difficult because of the influence of changing conditions.

Bernd, DF9RB

[Rene Schmitz]

Hi Bernd,

I think with a very strong signal such as this, the filter BW is less of concern. Your 8Khz filter will have a -40dB BW of more than 10kHz, I would guess, so that the channel estimation does compensate for that, since the attenuated part is still strong enough (and noise from preceding stages is attenuated along.) It becomes problematic when the signal is weak, and the edges become attenuated, possibly beyond the noise floor of following stages (sound card).

I personally use a nominally 12kHz wide Filter (SFH450F) its a type that has a maximally flat group delay. I have the impression the filter is a lot wider though. Maybe its maximally flat over 12kHz.
(But I just had these, so why not use em...)

As for AGC, I'm thinking for DRM it would be good to use a simple feed forward scheme. And just compress the dynamics somewhat, say 1:2-4, other than trying to keep the input level constant.

Cheers,
René

[df8uo]

Strong and stable signal. However far away from Bernd's top SNR.
73
Daniel

[df9rb]

Hi all,

today the signal was quite strong but more fading. Therefore the SNR only reached 36.6 dB.

Bernd, DF9RB

[df9rb]

Hi all,

VoR exceeded the 40 dB hurdle! I think VoR has the best aligned transmitter for DRM worldwide!!!!! Dream logged 41.2 dB
Receiver TS850, 3 Element HAM-Yagi 15 m high, Signal about 9+ 20 dB, manual gain control


Bernd

[dk8cb]

Originally posted by df9rb
I think VoR has the best aligned transmitter for DRM worldwide!!!!! Dream logged 41.2 dB ...

But one should not forget that this transmitter is an SSB transmitter with a linear power amplifier, whereas many other transmitters with the exception of the newer pulse-width modulated types, are just linearity-corrected AM transmitters with class-C power amplifiers.

Also, I guess, you would not get such a good result using a non-directional antenna that receives everything of Taldom's signal that is bounced back by the ionosphere.

Roland

[df9rb]

Hi Roland,

I think the reason for this high SNR is the linear transmitter (I did not know that they use a SSB transmitter).
My beam for amteur radio helps only on weak signals on higher frequencies (i. e. DW from Trincomale or RTRN from Novosibirsk)
On frequencies above 12 MHz I see a F/B ratio of about 10 dB on the S-Meter but no impressive influence on the SNR if the signal is strong. Today I tried this again with DW from Sines. The attached screenshots showing the SNR and Delay dont show an influence of the antenna direction or the EWE antenna. From minute 12 to 8 backside of the beam, 8 to 4 beam directed to Sines, 4 to 0 EWE antenna. The delay from the minutes 12 to 8 could be a little higher (back side of the beam) but I am not sure that this would be reproduceable

BErnd, DF9RB

[Per]

Hi,

Max SNR here was 27.6 dB. Overall good result today from VoR; CDA: 93 %. Time: 10:05-11:00 UTC. The last 20 minutes before close down gave the best reception.

[df9rb]

Hi all,

perfect the last 50 minutes.

Bernd, DF9RB

[simone]

Hi all,
good results this morning, more stable signal than most days, see attachment
73, Simone

[df9rb]

Hi all,

100 % audio

Bernd, Df9RB

[Jos]

Hi all,

Today I got 94% of audio.

Jos

[Jos]

Hi all,

The reslts of today.OK!

Kind regards.

Jos

[df8uo]

Hi all,

almost perfect today for more than 3 hours (as usual)

73

Daniel

[Andrew]

Hi all,

Since March 27, 2005 a schedule of our daily DRM transmissions of VoR will be as shown below:

- 15780 kHz at 6:00 - 9:00 (in English),
- 15780 kHz at 9:00 - 12:00 (in German)
- 9480 kHz at 13:00 – 14:00 (in Russian)
- 9480 kHz at 14:00 – 15:00 (in English)
- 9480 kHz at 15:00 – 16:00 (in German)
- 9480 kHz at 16:00 – 17:00 (in French)

All times are UTC.

Great thanks for your reports and notes.

Best regards,

Andrew

[simone]

Hi all,
my first results since the A05 schedule, no interferences but some dropouts due to deep fading, see attachment
73, Simone

[4S7DRG]

Colombo
05-04-02

Hi all DRM´s,

Today a weak signal from Taldom at this end.
see attached log.

[df8uo]

Hi all,

find attached my log from today. Strong signal with some fading.

73

Daniel

[df9rb]

Hi all,

very high SNR today. Max SNR above 40 dB.

Bernd, DF9RB

[Jos]

Hi all,

My results are not good today!

Kind regards .

Jos

[carknue]

Quite good this morning.

[Jos]

Hi all,

In attachment my results of 6 hours listening.

Kind regards.

Jos

[Andrew]

Hi Jos,

it seems some magnetic storms have place, as our transmitter was on air at the time. It was paused only on 11-th of April for some hours in the morning for planned preventive jobs. It's interesting how about another transmissions on close frequencies in the morning and with similar paths?..

Kind regards,

Andrew

[simone]

Hi Andrew,
signal was very weak, that´s all I could get this morning, see attachment
73, Simone

[dk8cb]

Hi,

not so bad in Munich.

Roland

[Andrew]

Hi Simone and Roland,

it's a great difference in your results at the same time, though the distance is almost the same. What only doesn't happen on the SW... :-)


thanks and kind regards,

Andrew

[dk8cb]

Hi Andrew,

here is today's result. Quality of reception was similar during the 30 minutes previous to the time shown in the log, but I couldn't log because I accidentally had Carsten's DRMcalc still open which unfortunately prevents data from being written to the log file.

Interference from KOL Israel on 15785 kHz.

Roland

[Andrew]

Hi Roland,

thank you for the information.
Has only interference disturbed the reception? We are reported that our signal is weak near Bonn today, but it seems to be better in your location.

Andrew

[simone]

Hi Andrew,
in my location it was not a matter of interference, most of the time the signal was so weak that I could not even see the DRM signal in the spectrum plot.
Btw I also have a similar problem on 6095 kHz in the morning all week.
73, Simone

[dk8cb]

Originally posted by Andrew
Has only interference disturbed the reception? We are reported that our signal is weak near Bonn today, but it seems to be better in your location.


Your signal was not very strong on my dipole, however it would have been sufficiently strong if there wouldn't have been interference. The spectrum plot shows that the carrier on 15785 kHz is sometimes 20 dB stronger than your signal and their modulation extends 5 kHz into your DRM spectrum. Using Dream's AM mode and LSB, I can even sometimes hear KOL Israel's modulation in your DRM signal.
But sometimes, the signal from Taldom is also stronger ...

Roland

[dk8cb]

Originally posted by simone
Btw I also have a similar problem on 6095 kHz in the morning

So did I today. The signal comes out of the noise very slowly, however stations that are further away are received well.
It is just the influence of normal shortwave propagation.

Roland

[df9rb]

Hi all,

conditons recovered (at least into South East Germany).
Signal came out of noise quite quick. Before a station
on 15785 caused S4 splatter but this signal was inaudible
within minutes after the band towards Taldom opened.
(see attachment)

Bernd, DF9RB

[simone]

Hi Andrew and all,
a very weak signal again today (as on some other transmissions), see attachment
73, Simone

[Jos]

Hi all,

No audio mod.during the first 90 min.

Last 90 min. acceptable signal.

Kind regards.

Jos.

[dk8cb]

Hi,

here is a short log.

Perfect reception.

Roland

[df9rb]

Hi,

here a comparison Saturday/Sunday.

Bernd, DF9RB

[Jos]

Hi all,

Results for today.(poor)

Kind regards.

Jos

[df9rb]

Very good today. VoR on 15780 is always good for
extreme high SNR

Bernd, DF9RB

[Jos]

Hi all,

Results of one hour listening(0800 - 0900 utc)

Kind regards.

Jos.

[hsseppo]

Hi all,

Strong signal today SNR max. 37.6 dB. At 6:14 - 6:58 UTC

Seppo

[dk8cb]

Hi,

not a strong signal today. At times, there was heavy interference from KOL Israel on 15785 kHz.

Roland

[dk8cb]

Hi,

signal strength increased a lot over the course of my logging period.

Roland

[df9rb]

Hi,

again very high SNR. Two interruption were caused by
swichting Bandpass Filter OFF a little later ON. The
high SNR was higher with Bandpass Filter.

Bernd, DF9RB

[FritzWue]

Signal rising slowly in the morning:

[df9rb]

Stable signal for 4 hours

Bernd, DF9RB

[df9rb]

And here the log ... sorry

Bernd, DF9RB

[Janucha]

raport from 2005.08.05

[simone]

Hi all,
not so bad today, see attachment
73, Simone

[dk8cb]

A bit of interference today.

Roland

[df9rb]

Super condx this morning. SNR several minutes above 40 dB

Bernd, DF9RB

[Per]

Hi,

Very peculiar reception this morning from VoR. Time 07:30 - 08:00.

[dk8cb]

Hi,

strong interference from an AM signal 4 kHz (!) higher. Identification of the AM signal was difficult because of the DRM signal but I think they were broadcasting in hebrew.

Roland

[Andreas]

Hi,

In my recent edition of Siebel's "Sender und Frequenzen" it reads that Israelian military broadcast station Galei Zahal is on air with 10 kW on 15785 so I bet you were right with hebrew.....

73, Andreas

[dk8cb]

Hi Andreas,

that's actually the station I thought of, but about I was not sure, so I did not post my assumption.
In the past, because of it being a military station, it has sometimes used off-channel and out-of-band frequencies. So 15784 kHz is quite possible.

Roland

[Andreas]

Hi Roland,

Now I'm exactly tuned on 15780kHz.

The DRM signal of VoR is gone, although they are still scheduled to be on air :confused:

On the right is Galei Zahal, exactly 5 kHz above, and 10 kHz on the left is, what I guess to be AIR Delhi.

Mysteries of propagation...........

73 and 51, Andreas

[dk8cb]

Hi Andreas,

that's strange, because before, the carrier was 1 kHz within the DRM spectrum. Perhaps deliberately!?

If you switch to input spectrum instead of input PSD, you will see a lot more!

Roland

[df9rb]

Hi all,

here a 3 hours log. I used two receivers on the same antenna and two PCs. The DRT1 from SAT-Schneider is a little better than the TS850. The DRT1 has an excellent AGC, the TS850 has been running with manual gain control. I did not readjust the gain during the 3 hours and the drop outs were caused by deep fadings whereas the AGC of the DRT1 corrected these fadings.

Bernd, DF9RB

[Janucha]

raport from yesterday

[df9rb]

Hi all,

100 % audio for 260 minutes, max SNR=43.6 dB!

Bernd, DF9RB

[FritzWue]

No good results on that ferquency at my location. Probably I am too far in the northwest.

[df8uo]

Excellent this morning. Got my highest SNR of 38.7 dB.
73, Daniel

[df9rb]

Very good today. SNR > 43 dB. 1st graph DRT1, 2n TS850, both sharing the same antenna (3 ele Ham Yagi).

Bernd, DF9RB

[df9rb]

Excellent conditions this morning. SNR not below 41 dB now for 30 minutes!!!!

Bernd, DF9RB

[df9rb]

Hi all,

VoR booming in today like a lokal FM-station
Under todays excellent conditions only short SNR peaks are visible in DRMCalc.

Bernd, DF9RB

[FritzWue]

Jesus! :eek:

Here in northwestern Germany no such signal like in lucky Bavaria!
carknue will have to modify his DRMcalc 3.2. :D

[df8uo]

Hi all,
also here very good signal. After changing the modification of my FT757 i could today get 40 dB SNR for the first time. The 9 kHz AM filter is a little too small (advantage in case of interference), limiting the max SNR to 38 dB. Now i can also use the 455 kHz IF at the input of the AM filter, improving the max SNR in case of no adjacent channel signals.
73, Daniel

[Digger]

Hi,
Some of your reports about >40 dB SNR made me curious and I logged this frequency for an hour in the morning, 3rd of October. Unfortunately, I cannot agree with this at all.... Will keep an eye on it for a while though.


Terje

[df9rb]

Hi all,

log from this morning (scaled now for SNR up to 44 dB! - TNX to Carsten) . Today I observed a double pulse with only 0.6 ms time difference (see attachment). Normally the time difference between pulses is 2 ms which results from additiional hops between the F-layer in approx. 300 km height and ground. The only explanation I have for 0.6 ms (180 km) is that the signal was also (or the 2nd hop) was reflected on the E-layer in approx. 90 km height.
Does anyone have a good explanation for this double pulse?

Bernd, DF9RB

[df9rb]

Hi,

excellent condx this morning! SNR> 42 dB for minutes.

Bernd, DF9RB

[carknue]

Good reception here, but not a strong signal max. S9. So no chance of SNR highscores at the moment

[df9rb]

Best reception was in the beginning of the transmission.
Max SNR 44.5 dB! (Carsten scaling up to 44 dB is not really
enough but I would leave it)
BTW the digital part from VoR is excellent but analogue volume
is changing up and down and I always have to readjust volume control on my speakers!!!!


Bernd, DF9RB

[df9rb]

During the German program SNR 45.1 dB.


Bernd, DF9RB

[carknue]

Quite unstable here.

[Per]

Hi,

Very good reception at my site.
But what happend at 10:42 UTC? The transmission was supposed to stop at 12 UTC.

[FritzWue]

Here in the northwest of Germany no chance getting the same strong signals like Bernd DF9RB has in the southeast.

[df9rb]

The differnence is dramatically. 1st graph 3 ele ham yagi 15 m up, 2nd Degen indoor loop at the window. I think the indoor antenna is more standard for SW-listeners - some improvements are necessary.

Bernd, Df9RB

[Andreas]

Sorry but I can only get frustrating results like this over here


:confused:

[Andrew]

Hi all,

since 30-th of October 2005 till 4-th of March 2006 the VOR daily programs will be transmitted on 12060 kHz at 08:00-13:00 UTC and on 5810 at 14:00-17:00 UTC.

Thanks for your monitoring and reports.

Andrew

[Jos]

Hi all,

For the last time on 7515 my results.

Kind regards.

Jos.

[df8uo]

Hi Andrew and all,
quite good result today.
73, Daniel

[FritzWue]

Driving from Duessledorf to 48712 Gescher via A46, A3, A2, A31.
The first big dropout were autobahn tunnels.
There was a lot of fading on the signal and later it got weaker when driving north.
There also was a strong interfering signal/carrier 5kHz up.

[df9rb]

Hi all,

VoR on 15780 back with record-breaking SNR!

Bernd, DF9RB

[Digger]

Hi,

Got interested in the high SNR and logged VoR today with a very disappointing result. Max 20 dB or so and plagued from 15.785 MHz AM during the entire transmission. :eek:


Terje

OK, I suspect the Long Wire antenna is out in this case in my location... :mad:

[df9rb]

Hi,

the station 5 kHz up (I think from Israel) is much weaker here in South East Germany but also observeable in PSD even with the HAMYagi. SNR today again close to 40 dB.

Bernd, DF9RB

[Janucha]

In summer first wave-jump on ionosphere is shorter than winter and I may hear VOR in my home. Normaly I was into silent zone.

[Sixten]

Hi all.

35 min. of solid reception from VoR. Very strong only slow QSB.
My QTH is not in beam direction.

[mitajohn]

Hi all,

This is my first report on this frequency. Not a bad result from a rather weak and unstable signal.

John.

[mitajohn]

Hi all,

A nearly excellent result today for 40 mins.

John.

[mitajohn]

Hi all,

Not bad from this weak station.

John.

[df9rb]

Up and down. Fieldstrtength mostly below 100 µV.

Bernd, DF9RB