Newsnet on Ka Band A

[dx qwer]

On again:

18511 V 3630 2/3 DVB-S2/HD 8PSK, SIS testcard

 

[tony smith]

Hi Folks
Astra 1L @19.2 east Ku band Vertical is still working via SIS for ITV both regions and ITN, SNG newsgathering, have opened up higher frequency section on the next transponder, operating at 18.584 Ghz V 3629 symbol rate,(downlinking) also have seen 18.708 V 3629 . This seems to be used if the lower lease 18.506 to 18.543 V is full.

One other interesting point is that they have been operating, using 18.506V to 18.543V Ghz from Paris France (Downlinking) , looking at the original transponder mapping this section was only for UK operations, this was when the satellite was to be used as a data link from low data uplinks to downlink into large hubs, as this is not the main operation for this satellite now, the goal posts have changed?

Looking at the variable downlink levels on what is K band, with SIS /ITV newsgathering, depending on weather(Like Rain etc etc.)apart from needing a good satellite receiver with narrow bandwiths(DVB2 S extensions) also a good operating RF threshold, it must be hit and miss as to getting a usable signal at the downlink sites.

I have seen some carriers down at -76 dBm my threshold is -72 to decode any thing, (Technomate 6902 and 1.8m Channel master dish, with rectangular K band feed, plus Norsat LNB local osc 17.250 Ghz) The receiver's AFC will show 1 high level channel across 3/4 down links if its carrier is high some come in at above -65dBm.

So I think this use of Ku band for uplinking with a 1.2 or 1.5 metre dish, to a 2.3 metre dish downlink at DVB S2 is not going to take off any time soon.

 

[Llew]

hi Tony
Yes, I've seen feeds in the 18.7xx region, especially links from Paris during the outrages there.

On my Triax 1.1M dish,I've used a Norsat 7000 Ka LNB with the XMW or with a 'borrowed' Inverto/Triax Saorsat feedhorn, also a DirecTV SL3, LNB.

My current LNB, a Hughes Band A LNB removed from a Hughes TX/RX assembly, coupled with the XMW feedhorn is proving to be much better at locking (and, more to the point, holding) a weak carrier than my other units showing similar dB levels.

 

[tony smith]

hi Tony
Yes, I've seen feeds in the 18.7xx region, especially links from Paris during the outrages there.

On my Triax 1.1M dish,I've used a Norsat 7000 Ka LNB with the XMW or with a 'borrowed' Inverto/Triax Saorsat feedhorn, also a DirecTV SL3, LNB.

My current LNB, a Hughes Band A LNB removed from a Hughes TX/RX assembly, coupled with the XMW feedhorn is proving to be much better at locking (and, more to the point, holding) a weak carrier than my other units showing similar dB levels.


View attachment 88402

Hi Llew
yes LNB set up looks good, will post one of mine when I get time.

 

[tony smith]

Hi Folks
Just a shot taken off the spectrum display screen, and two shots pics, in this the levels are all good, just before the largest one, Newsnet was -63dBm highest I have seen for a long time

 

[scopus]

Hi Folks
Just a shot taken off the spectrum display screen, and two shots pics, in this the levels are all good, just before the largest one, Newsnet was -63dBm highest I have seen for a long time[/QUOT

Hi Folks
Just a shot taken off the spectrum display screen, and two shots pics, in this the levels are all good, just before the largest one, Newsnet was -63dBm highest I have seen for a long time

It's been quite high for some time with me Tony. I'm using the same as Llew, but with the Hughes feedhorn on OMT

 

[tony smith]

Hi Scopus
Yes agreed they are higher than when the K band downlinks started 2014 by SIS/ITV on Astra 1L, but its the variations
in levels on their downlinks I was also commenting on. The lowest to the highest , across the 18.500 to 18.560 section
can be greater than 7/8 dBm, all using similar uplink kit, and the fluctuations in the carrier levels is also big ref to Ku downlinks, I know they are very much more affected by weather, but even so they do pulse about.

 

[Llew]

Hi Folks
Just a shot taken off the spectrum display screen, and two shots pics, in this the levels are all good, just before the largest one, Newsnet was -63dBm highest I have seen for a long time

Yes, very good conditions tonight. Many Regionals up. Sometimes for me when it's busy, 18557V, the Newsnet HQ TP, drops down to an unlockable signal here, 3.4dB against 6-9 dB with the others.

 

[scopus]

Hi Scopus
Yes agreed they are higher than when the K band downlinks started 2014 by SIS/ITV on Astra 1L, but its the variations
in levels on their downlinks I was also commenting on. The lowest to the highest , across the 18.500 to 18.560 section
can be greater than 7/8 dBm, all using similar uplink kit, and the fluctuations in the carrier levels is also big ref to Ku downlinks, I know they are very much more affected by weather, but even so they do pulse about.

Agreed Tony, the levels vary such a lot, some feeds can be as high as 15dB and some as low as 7dB with me at any rate.
The Hughes is quite robust in bad weather, much better than the SL3 I had.

 

[tony smith]

Hi
interesting point about the Newsnet ITN's output, if the reason maybe when the satellite ITV regionals are all busy up/down linking maybe to reduce any crosstalk or just to reduce the satellite's power buss loading they reduce their
HPA gain, must check more

 

[Llew]

An Xmas party going on at Newsnet HQ. Or was, soon back to their desks.

 

[tony smith]

Hi Yes hope all at Grays Inn Road HQ had a good Christmas working, have been there, and done that , much nicer not to have to work Christmas.
Looking today at adown link 18.515 Ghz which is having a hard time of it, not sure if the wind , rain or both thats the problem, but the downlink levels are jumping up and down from nothing to +6 dBm then down to +4 dBm, and sometimes +2dBm unable to lock to signal, just seen Bristol down link 18.538 Ghz at +10dBm, so it must be local to them problem.

 

[Llew]

18515V, usual parameters for Newsnet feeds.

Fixed OB camera on Abergeldie Castle in Scotland, waiting for it to fall into the River Dee. Heavy rain at present, so stay tuned...

This 'castle' looks more like a Folly to me

 

[Archive-8]

18515V, usual parameters for Newsnet feeds.

Fixed OB camera on Abergeldie Castle in Scotland, waiting for it to fall into the River Dee. Heavy rain at present, so stay tuned...

This 'castle' looks more like a Folly to me


View attachment 89463

Is the feed still going ? Please llew?

 

[Llew]

Yes, it went to SIS card for a while when he moved the camera to a different angle.

 

[Archive-8]

Yes, it went to SIS card for a while when he moved the camera to a different angle.

Thanks for your reply, looks like my lnb has some sort of problem:-(

All other lnb's are working properly with the Dr HD d15, TM5302 & Tbs Sat Card, but not the hugehes.

Been out and checked the coax, and still nothing:-(

Any ideas please?

 

[Llew]

When did you last use the Hughes on these feeds?
We've had some wet weather of course - maybe some water ingress ? What feedhorn do you use?

 

[Archive-8]

The last time I watched newsnet was Christmas Eve, the feed is one from my 20ghz hughesnet lnb.



Looks like I will have to take it all apart and check. Just as soon as I get a chance.

 

[Llew]

OK Chris, Usual water entry point would be feedhorn to LNB or LNB to cable, but you will have made a good seal there, no doubt.

A presenter's turned up. Company for the cameraman, must be lonely there waiting...and waiting...

 

[Archive-8]

OK Chris, Usual water entry point would be feedhorn to LNB or LNB to cable, but you will have made a good seal there, no doubt.

The coax has amalgam tape on it, tanken that off already and checked, that's dry, put new tape on.

The feedhorn had a rubber o ring between them.

But I will check the top as that hasn't been checked!

Just as soon as Tesco's have dropped off my shopping I will go and check.