Date
1 - 20 of 23
EUMETSAT transponder tests?
|
geojohnt@aol.com
Hello All,
Interesting(?) happenings this morning/afternoon with 11.263 V and H.
My SR1, 1 m dish, Inverto Black Ultra quad LNB under clear sky conditions up until the switching on of the V channel saw SNR of 13.6/.7/.8 dB and -18.0 dBm Power.
After the firing up of the V channel SNR appeared little effected - possibly 0.1 or 0.2 0.3 dB down at times.
It's difficult to say precisely as we all know 'the effect of the atmosphere' on signal propagation.
And I have to switch my single SR1 polarisation and wait a few seconds - so cannot view two readouts at the same time
Following yesterday's H and V comparison report, today saw some changes.
At 10:55 this morning clear sky conditions things were fairly usual - TP1 13.8/.9 dB SNR (a bit high) Power -18 dBm - as usual.
HVS-2 13.5/.6/.7 dB SNR Power -21 dBm (as usual).
13:50 today TP1 13.6/.5 dB SNR but Power now -21 dBm. HVS-2 13.5/.4/.7/.5 dB SNR and Power -21 dBm as usual.
13:52 - 13:53 TP1 SNR 13.7/.9/.6/.9/14.0/.8/14.0/13.9 then settling 13.8 - for a while with the odd 14.00 dB - Power back to -18 dBm.
14:25 - 14:26 TP1 13.8 - 14.00 dB SNR, Power -18 dBm. HVS-2 13.6/.7/.6/.4/.3/.6 dB SNR, Power -21 dBm.
Regards,
John.
|
|
|
|
On 16/11/2022 10:30, geojohnt via groups.io wrote:
The old adage - "if it aint broke, don't try to repair it" come to mind?Thanks for the reports, John. If it's working well now, leave it as it all changes in a few month's time when EUTELSAT 10B is launched. All being well, no adjustments will be needed, but... Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv |
|
|
|
geojohnt@aol.com
David,
Yes, perhaps 'wrong' was not the right word.
But it was a bit alarming to see the V channel higher than the H?
It would be interesting to be at the uplink station varying the levels of both channels to see the 'mutual effect/interaction' with all the technical readouts available?
It was good to see my TP 1 level jump back to normal at 14:43 yesterday and I've checked it every few hours since then.
At 19:04 yesterday TP 1 was 13.7 dB SNR, Power -18 dBm.
HVS-2 a healthy 13.3 dB SNR, Power -21 dBm.
So for me having the V channel in operation (at its current level) appears not to have made much difference to the H channel - possibly minus 0.2 dB in SNR?
I'm not going to try to tweak the skew - as Ernst said earlier, with the V channel off he, as I found, skew could be rotated several degrees either way from the 'location computed skew' before any change to the H channel SNR was noted.
However, Ernst reported with both V and H channels on, SNR changes were very sensitive to small skew adjustments away from the optimal.
The old adage - "if it aint broke, don't try to repair it" come to mind?
This morning 10:24 TP 1 SNR 13.8 dB, Power -18 dBm. HVS-2 SNR 13.3/4 dB, Power -21 dBm.
Clear sky between the gusty wind and heavy rain.
Regards,
John
++++++++++++++++++++++++++++++++++++
John,
I don't think anything is "wrong" but I do understand that tests may be carried out to understand how the new on=frequency transponder may be affecting the existing BAS/HVS-1 reception. Your reports, and others, to EUMETSAT will be very welcome. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv -----Original Message-----
From: David J Taylor GM8ARV 🏴 🇪🇺 via groups.io <david-taylor@...> To: MSG-1@groups.io Sent: Tue, 15 Nov 2022 15:54 Subject: Re: [MSG-1] EUMETSAT transponder tests? On 15/11/2022 13:09, geojohnt via groups.io wrote:
> David and All, > > The front has just cleared my location and I'm back to clear sky reception. > > BS/HVS-1 SNR 12.6 dB Power -18.0 dBm. > HVS-2 SNR 13.1 dB Power -21.0 dBm. > > Something is very wrong! > TP 1 SNR is 1 dB down on normal. > > My E 9-B reception on the same dish (aligned on E 10-A) is at the usual 'signal > values' so I do not believe my dish has become mis-aligned during the gales here. > > Regards, > John. |
|
|
|
On 15/11/2022 13:09, geojohnt via groups.io wrote:
David and All,John, I don't think anything is "wrong" but I do understand that tests may be carried out to understand how the new on=frequency transponder may be affecting the existing BAS/HVS-1 reception. Your reports, and others, to EUMETSAT will be very welcome. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv |
|
|
|
On 15/11/2022 12:36, Ernst Lobsiger via groups.io wrote:
David,Agreed. In a similar context, Wi-Fi signal strengths can be given in a 0..100 "quality" measure, which I understand to be dBm+110, so it's never negative! "70" is "good". https://www.satsignal.eu/mrtg/raspi23-wifi-dbm.html Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv |
|
|
|
On 15/11/2022 12:29, James Brown wrote:
Looking at your EUMETCast Europe pages. My web browsers show your page David stuck on Nov 12 for link margin and some of the others don’t seem to be updating.Yes, I've seen this happening as well, not only on my own data but others too. Usually a Ctrl-F5 will fix the problem. It could be something in the browser caching - I see that when you click on the graph to get the four-graph page the date and time is correct, but the image is not. I also recall from ages ago that Windows would not alter the modification date of a file if it was rewritten within a few seconds. That may not be relevant, and may no longer be Windows behaviour. If anyone knows a fix, I'd love to hear it! Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv |
|
|
|
geojohnt@aol.com
All,
My BS/HVS-1 SNR has just, 14:43, gone back to where it should be - 13.7 dB.
Regards,
John -----Original Message-----
From: geojohnt via groups.io <geojohnt@...> To: MSG-1@groups.io <MSG-1@groups.io> Sent: Tue, 15 Nov 2022 13:39 Subject: Re: [MSG-1] EUMETSAT transponder tests? All,
I've just reported these findings to Ops.
John
-----Original Message-----
From: geojohnt via groups.io <geojohnt@...> To: MSG-1@groups.io <MSG-1@groups.io> Sent: Tue, 15 Nov 2022 13:09 Subject: Re: [MSG-1] EUMETSAT transponder tests? David and All,
The front has just cleared my location and I'm back to clear sky reception.
BS/HVS-1 SNR 12.6 dB Power -18.0 dBm.
HVS-2 SNR 13.1 dB Power -21.0 dBm.
Something is very wrong!
TP 1 SNR is 1 dB down on normal.
My E 9-B reception on the same dish (aligned on E 10-A) is at the usual 'signal values' so I do not believe my dish has become mis-aligned during the gales here.
Regards,
John.
+++++++++++++++++++++++++
_._,_._,_
|
|
|
|
geojohnt@aol.com
Charlie,
Yes, sorry, I have never received HVS-2 so all my reports are on the 'new' HVS-2 channel 11.623 GHz V.
All I have to do is change the SR1 H/V switch.
Mind you, I'm not licensed for HVS-2 so I -
Oh my goodness!
My BS/HVS-1 SNR has just 14:43 gone up to where it should be 13.7 dB.
Regards,
John. -----Original Message-----
From: Charlie <charlie.johnson119@...> To: MSG-1@groups.io Sent: Tue, 15 Nov 2022 14:24 Subject: Re: [MSG-1] EUMETSAT transponder tests? Clear here in SE London now and getting approx 11.2 dB (varying a *lot* between 10.9 and 11.5, usually very consistent on this dish) on 11263 H and 11.2 dB on 11388 H. About normal for C10 but a solid 0.8 dB down right now on C4.
Definitely got an LNB fault with the V pol after the 90 degree test... so can't speak fully for performance on C3 11263 V beyond the x-pol noise it is(n't) causing me!
Is your reported SNR there for HVS-2 on the old or new transponder, John?
Charlie
|
|
|
|
Charlie
Clear here in SE London now and getting approx 11.2 dB (varying a *lot* between 10.9 and 11.5, usually very consistent on this dish) on 11263 H and 11.2 dB on 11388 H. About normal for C10 but a solid 0.8 dB down right now on C4. Definitely got an LNB fault with the V pol after the 90 degree test... so can't speak fully for performance on C3 11263 V beyond the x-pol noise it is(n't) causing me!
Is your reported SNR there for HVS-2 on the old or new transponder, John?
Charlie |
|
|
|
geojohnt@aol.com
All,
I've just reported these findings to Ops.
John -----Original Message-----
From: geojohnt via groups.io <geojohnt@...> To: MSG-1@groups.io <MSG-1@groups.io> Sent: Tue, 15 Nov 2022 13:09 Subject: Re: [MSG-1] EUMETSAT transponder tests? David and All,
The front has just cleared my location and I'm back to clear sky reception.
BS/HVS-1 SNR 12.6 dB Power -18.0 dBm.
HVS-2 SNR 13.1 dB Power -21.0 dBm.
Something is very wrong!
TP 1 SNR is 1 dB down on normal.
My E 9-B reception on the same dish (aligned on E 10-A) is at the usual 'signal values' so I do not believe my dish has become mis-aligned during the gales here.
Regards,
John.
+++++++++++++++++++++++++
-----Original Message-----
From: geojohnt via groups.io <geojohnt@...> To: MSG-1@groups.io <MSG-1@groups.io> Sent: Tue, 15 Nov 2022 10:32 Subject: Re: [MSG-1] EUMETSAT transponder tests? David,
Yes, as just posted under another 'Subject,' my HVS-2 V SNR is higher this morning than TP 1 H.
Which has not been the case since Saturday.
[Both down due to bad weather]
Regards,
John.
-----Original Message-----
From: David J Taylor GM8ARV 🏴 🇪🇺 via groups.io <david-taylor@...> To: MSG-1@groups.io Sent: Tue, 15 Nov 2022 10:10 Subject: [MSG-1] EUMETSAT transponder tests? I'm seeing the level varying on TP1 (C4) across Europe, so I guess this is
EUMETSAT tests in relation to the new HVS-2 transponder C3.
If it's just a level change it confirms something I've suspected for a long
time, that what we are plotting is not actually SNR, but (signal+noise)/noise,
hence the limit of zero dB and the apparent non-linearity for those with weaker
signals.
Interesting times!
Cheers,
David
--
SatSignal Software - Quality software for you
Email: david-taylor@...
Twitter: @gm8arv
|
|
|
|
James Brown
My loss is increasing and not weather related. Now down about 1.4db on this time yesterday.
toggle quoted message
Show quoted text
James. On 15 Nov 2022, at 12:41, James Brown <satellite@...> wrote: |
|
|
|
geojohnt@aol.com
David and All,
The front has just cleared my location and I'm back to clear sky reception.
BS/HVS-1 SNR 12.6 dB Power -18.0 dBm.
HVS-2 SNR 13.1 dB Power -21.0 dBm.
Something is very wrong!
TP 1 SNR is 1 dB down on normal.
My E 9-B reception on the same dish (aligned on E 10-A) is at the usual 'signal values' so I do not believe my dish has become mis-aligned during the gales here.
Regards,
John.
+++++++++++++++++++++++++
-----Original Message-----
From: geojohnt via groups.io <geojohnt@...> To: MSG-1@groups.io <MSG-1@groups.io> Sent: Tue, 15 Nov 2022 10:32 Subject: Re: [MSG-1] EUMETSAT transponder tests? David,
Yes, as just posted under another 'Subject,' my HVS-2 V SNR is higher this morning than TP 1 H.
Which has not been the case since Saturday.
[Both down due to bad weather]
Regards,
John.
-----Original Message-----
From: David J Taylor GM8ARV 🏴 🇪🇺 via groups.io <david-taylor@...> To: MSG-1@groups.io Sent: Tue, 15 Nov 2022 10:10 Subject: [MSG-1] EUMETSAT transponder tests? I'm seeing the level varying on TP1 (C4) across Europe, so I guess this is
EUMETSAT tests in relation to the new HVS-2 transponder C3.
If it's just a level change it confirms something I've suspected for a long
time, that what we are plotting is not actually SNR, but (signal+noise)/noise,
hence the limit of zero dB and the apparent non-linearity for those with weaker
signals.
Interesting times!
Cheers,
David
--
SatSignal Software - Quality software for you
Email: david-taylor@...
Twitter: @gm8arv
|
|
|
|
James Brown
Seems correct now.
toggle quoted message
Show quoted text
Cheers James. On 15 Nov 2022, at 12:29, James Brown <satellite@...> wrote: |
|
|
|
Ernst Lobsiger
David,
regarding negative SNR values IMHO this is an mrtg limitation (probably unless you use it in RRDtool mode): https://groups.google.com/g/comp.dcom.net-management/c/_wGrZVOVaO8 Ernst |
|
|
|
James Brown
Looking at your EUMETCast Europe pages. My web browsers show your page David stuck on Nov 12 for link margin and some of the others don’t seem to be updating.
toggle quoted message
Show quoted text
Tried on two devices so not sure what might be happening? Cheers, James. On 15 Nov 2022, at 10:37, James Brown <satellite@...> wrote: |
|
|
|
Charlie
Perpendicularity of the pins in the individual LNB will definitely be the strongest determining factor on that - on mine it seems to be very good (Inverto C120 White Tech quad) as the C/N appeared to peak in the same place on skew on both H and V... and the adjustment was *very* sharp compared to how much leeway there was with it with just H on. Often a lot of variance between units of the same model on that! Also the cross-polarisation isolation performance of both dish and feed/LNB will be in play here - definitely some better than others again, the Inverto BU 40mm LNBF models that people seem to like in this group are usually a good performer on that metric from what I gather. Unfortunately (as mentioned in another post) I'm actually quite a long way down on max C/N I could achieve on 11263 V compared to 11263 H, when it stops raining I will twist the whole thing 90 degrees and see if the lower strength follows. If it does like I expect that means the V circuit is faulty... more expenditure! My opinion on which to adjust for? I'd see what the compromise gives but if it is a big drop on BAS/HVS-1 I'd take that as the priority as I find it more volatile with packet loss on my DD receiver. YMMV etc.
Charlie |
|
|
|
On 15/11/2022 11:33, Charlie wrote:
I don't plot signal level still so can't speak for that, but the C/N out of my Digital Devices setup definitely can go negative too (seen it whilst doing dish alignment, thankfully not during service!).Delighted that your meter can measure S/N rather than S+N/N which can never be less than 1, of course. That's the best result I've heard so far. One question is whether the optimum skew to reject C3 is the same as that to reject C4 - given satellite and LNB tolerances. Which do you adjust for - on a weak system adjust for best BAS/HVS-1 and drop HVS-2, perhaps? And it all changes when the new satellite is launched and working - November 20 - fine tweaks could need re-doing. Cheers, David -- SatSignal Software - Quality software for you Web: https://www.satsignal.eu Email: david-taylor@... Twitter: @gm8arv |
|
|
|
Charlie
Dang and blast it - guess images don't work properly replying through Gmail?! Hopefully this works now, the two relevant charts out of eLuna. Charlie |
|
|
|
Charlie
I don't plot signal level still so can't speak for that, but the C/N out of my Digital Devices setup definitely can go negative too (seen it whilst doing dish alignment, thankfully not during service!). Definitely had a drop on Friday matching the C3 switchon but it was very small - post skew adjustment I think that has gone away but it's small so could be other factors. Seeing the same drop around 0920 UTC today on C1 - with rain fade on too for fun.On Tue, 15 Nov 2022 at 11:21, Ernst Lobsiger via groups.io <ernst.lobsiger=belponline.ch@groups.io> wrote: On Tue, Nov 15, 2022 at 02:10 AM, David J Taylor GM8ARV 🏴 🇪🇺 wrote: |
|
|
|
Ernst Lobsiger
On Tue, Nov 15, 2022 at 02:10 AM, David J Taylor GM8ARV 🏴 🇪🇺 wrote:
If it's just a level change it confirms something I've suspected for a long time, that what we are plotting is not actually SNR, but (signal+noise)/noise, hence the limit of zero dB and the apparent non-linearity for those with weaker signals.David, last Friday afternoon when EUMETSAT switched on HVS-2 on T1 (V) I saw NO degradation on T1 (H). Now I see T1 (H) SNR steps down 1dB while signal power does not change. I think SNR I plot is true SNR (ES/No): The 0dB limit in my eLuna plots is something I have added in the graph definition! Both my TBS SNRs and LMs can actually go negative ... Regards, Ernst 
|
|
|
