Digital decoding when interference is present

[g3pyb]

Hello DM,
During the DATV test with G8LES on 70cm today i had chance to try several satellite recivers at L band in terms of the recovery after an interfering interuption.
The Porty 2 were not bad, the Technomatic 1500 was excellent , and the 12V sl 1003 from MAPLINS was a real problem, a momentary loss of the incomming signal locked up the decoder. A reselection of the channel restored the decoding.
However the sensitivity was good on the Sl1003, poorest on the Porty2 and highest on the Technomatic but is was billed as a more sensitive L band Rx.
I was pleased to complete the two way with Mike, I needed all the power I could muster, the hill behind me is about 300ft and i amat the 200ft level, I estimate the scatter losses at 35db so not mich left for the remainder of the 30Km to Mike.
The good news is that it worked and the path appeared to be stable, just need to work out how to tilt the 15 element yagi up at 30deg!

Regards Peterb g3pyb

[Billbo]

Hi
where did you purchase your Technomatic 1500?
Goole retuns a lot on hiphop records
Cheers
Billbo(G4BID)

[M0DTS]

Hi Peter..

When i was trying with digital on 23cm at christmas we experienced the same thing with the Comag SL65/12 receiver from maplin.
When the radar bursts came through the video dropped but did not recover for some time unless the channel was re-selected, at the receiving end there was only one satellite receiver available so we could not test any others.

We found that if the receiver is selected so that you can see both picture and channel list at the same time the video recovered nearly instantly, this also happens if the info screen is up.
I hope someone finds that tip uesful!

I'm looking to try some 70cm datv soon with the 'Poor Man's Digital ATV Transmitter' using the SL65/12 receiver and one of the recently talked about Glencomm L-band converters - just waiting delivery now....!

Rob
M0DTS

[g3pyb]

To G4BID I bought the unit from http://www.satellites.co.uk by E mail delivery was good.
Regards Peter B g3pyb

[g3pyb]

To G0DTS ok thanks for the message...........I found that reselecting the info button after the unit locked up returned the unit to decode, the tunning indicator is quite useful on info I like the audio tunning tool.
OK on your 70cm upconvertor, my location at home is only good for 90deg through to 270deg but I do go portable from time to time withe 100W to a 46ele ok J beam, and i have some useful hill not far away, keep in touch and when you have your upconvertor we might try a contact. My next portable trip will probably be in a few weeks time to Walbury hill to work G8ADM on 70cm and look for the 3cm output of BH.
You might find you need so notches at 70cm, I thought the local 70cm voice repeater would be a problem but it the telemetry at 434.8Mhz which is a real problem, locally I think it is crane collision alarm and they run all the time during the day and they are buiding a new large hospital extension quite close to Portsdown Hill
I have some 3cm DATV as well but only a 1 w to a 90cm offset normally 4MS/s and FEC 3/4.

Regards PeterB

[G4EWJ]

Peter,

I've just acquired a TMS-1500 CI+ and I find it takes about 10 seconds to recover from an interruption. If I change channel and back again, it locks up straight away.

The system information gives SW version 1.96 (Aug 18 2010) and HW version 1.12. I updated the SW from their web site.

I wonder which version you have and do you have any downloads for it?

Brian