Digital rxrs and PIDs

Ideas, technical topics, help and discussion for ATV repeater builders
g8gtz
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Digital rxrs and PIDs

Postby g8gtz » Sun Jun 09, 2013 10:03 pm

Hi

There seems to be a recurring issue with the consumer STB type receivers not reliably decoding different PIDs. Up until recently the Comaq SL30 in use at GB3HV didn't seem to suffer a problem but now refuses to accept any signal unless it uses the PIDs that were used for the first transmission when the channel info was setup.

This is not a problem for the normal home station where you can simply do a rescan and lock to new PIDs - however at remote repeaters we need to guarantee access from any station, so we either need a receiver which will reliably decode any PID or we all need to use the same PIDs.

As far as I know, only the Tutioune software and professional receivers such as those from NDS / Tandberg seem to decode any PID reliably, however unless you have the latest 1260 model, these receivers will not auto detect FEC.

Stations using a couple of the repeaters "down south" have adopted the PID values which the NDS encoders use as default and it seems to cure the problem - these are as follows:

Video PID=308,
Audio PID=256
PMTPID=258

So does anyone know of another receiver which doesn't have these problems, does auto FEC and is reasonably priced or are there any objections to us adopting the above PIDs as a standard for UK DATV stations?

73 - Noel G8GTZ

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G8LES
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Re: Digital rxrs and PIDs

Postby G8LES » Sun Jun 16, 2013 8:00 pm

I can also specify PCR PID do we have a setting for that is it the same as video?

G4KLB
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Re: Digital rxrs and PIDs

Postby G4KLB » Sun Jun 16, 2013 9:01 pm

I am using

Video PID= 0X100 = 256
Audio PID= 0X101 = 257
PMTPID= 0X800 = 2048

Which are the default SR Systems settings.


Default DigiLite settings are

Video PID= 0X100 = 256
Audio PID= 0X101 = 257
PMTPID= 0XFFF = 4095

I have never had to change the PMT PID for any receiver so far, so left them as they were.

What are others using?


Colin G4KLB

G8DKC
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Re: Digital rxrs and PIDs

Postby G8DKC » Mon Jun 17, 2013 8:12 am

Hi All,

I'm happy to stick with DigiLite settings V 256 A 257, and PMTPID 4095 unless advised.

73

Peter

G8DKC

g8gtz
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Re: Digital rxrs and PIDs

Postby g8gtz » Sun Jun 23, 2013 5:09 pm

Hi

It would seem to make a lot of sense if we all went with the default digilite settings:

Video PID= 0X100 = 256
Audio PID= 0X101 = 257
PMTPID= 0XFFF = 4095

This means some of us will need to delete any memory / channel settings we have stored in the rxrs at repeater sites and then get a station with these PID settings to transmit and be accepted as the default.

Once this is done, then you will have to tell your users of the new settings.

I will changeover HV on the next visit to site.

73

Noel - G8GTZ

g4wvu
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Location: Colkirk, North Norfolk, UK

Re: Digital rxrs and PIDs

Postby g4wvu » Fri Aug 16, 2013 9:39 am

Hi all.

I will also change GB3TN's 437 input to v 256/a 257/p 4095 next visit, as we seem to be agreed on a standard now.

Mark G4WVU

g4wvu
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Location: Colkirk, North Norfolk, UK

Re: Digital rxrs and PIDs

Postby g4wvu » Sat Aug 24, 2013 9:58 pm

For info:
GB3TN

437 mhz input DVB-S PIDS now reset to general standard :

Video : HEX 100 / 256
Audio : HEX 101 / 257
PMT : HEX FFF / 4095

The receiver (Fortec Star FS 4000 II ) will lock to any valid PIDS on SCPC (within reason) but the signal has to be present for about 5 minutes before it will RE-STORE other PIDS as the default. .....use above! :-)

Mark

G4wvu

g8gtz
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Re: Digital rxrs and PIDs

Postby g8gtz » Fri Sep 20, 2013 3:53 pm

Today I have changed the GB3HV rxr PIDs to the new adopted UK DATV standard – namely:

Video PID= 0X100 = 256
Audio PID= 0X101 = 257
PMTPID= 0XFFF = 4095

You will need to change to these values to be able to access GB3HV DATV on 70 and 23cms.

Please pass on to anyone else who needs to know.

Regards

Noel

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G8ADM
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Re: Digital rxrs and PIDs

Postby G8ADM » Mon Oct 07, 2013 11:20 pm

Peter B sent me details of the Big Sat, Golden 1 satellite receiver as a possible solution to the PID problem.
This receiver will work on any PID.
Peter has written an article for the next CQ-TV #242
I have tested it with different PID's and it works fine.
I have changed the Audio, Video and PMT pid's.
When I change the PID there is a still image for a few seconds and then it locks up ok.
So like Professional receivers this receiver is definitely an answer to the PID problem.
Also it will receive Symbol Rates down to 1 MS/sec. The lowest I can go is 1.133 MS/sec and it worked fine.
It also has a locked LED, the volts from this are useful for controlling repeater logic.

The cost from this link is £35 but they may be cheaper on EBay. It was delivered next day.

See: http://www.microxpress.co.uk/sd-satelli ... eiver.html

Dave. G8adm

g8gtz
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Joined: Wed Apr 07, 2010 6:26 pm

Big Sat 1CR lock detect modifications

Postby g8gtz » Wed Oct 30, 2013 9:15 pm

Robin G8DRK, keeper for GB3UT sent me the following:

The BigSAT Golden 1CR receiver has a Lock-LED that shares its strobing with the LED display. So to successfully "decode" the Lock-LED status for Repeater-switching purposes, it is necessary to employ a little interface circuit that samples both sides of the Lock-LED and produces a ripple-free output that is referenced to chassis.

You need 2 transistors, TR1 is NPN (BC548 or similar). TR2 is PNP (BC558 or similar). Both types are very uncritical.
You need 5 resistors (2x 47K, 2x 10K, and 1x 1K).
You need 1 capacitor (10uF electrolytic or tant).
You will need to make use of the +5 volt supply - not available on the front panel itself, but present on the card module and main PCB.

________________________________________
Draw out your circuit from the following description:

Connect emitter of TR1 to cathode of the green Lock-LED (that's the end of the green LED nearest to the red power LED).
Connect base of TR1 via a 47K to anode of green Lock-LED (that's the end of the green LED furthest from the red power LED).
Connect collector of TR1 via a second 47K to +5 volt line (+5 volt is available on the card module - it is labelled underneath).
Connect a 10uF capacitor across this second 47K (pos end to the +5 volt line, neg end to TR1 collector).
Connect a 10K from TR1 collector to TR2 base.
Connect TR2 emitter to the +5 volt line.
Connect TR2 collector via another 10K to chassis.
Take your switching volts output from TR2 collector via a 1K.

________________________________________
Output will follow state of Lock-LED (Extinguished = 0 volts, Illuminated = almost 5 volts with no strobe ripple). There are spare pins on the serial port you can use to feed the switching volts out to the world. It can be easily removed (two screws) to allow easier access for soldering to the lower row of pins. I suggest using pin-9 (Ring Indicator) as the output. Pin-5 is already a convenient chassis/ground. There is no appreciable "hang" delay built into the circuit - I prefer to do that operation within the switching unit itself.

If you are removing the card module (to improve micro's ventilation and free some space), then the +5 volts line can be found on LH pin of its socket on main PCB (viewed from above, front), also on the LH connection of Q3 in front of that socket, and on R13 (not fitted) close by - take your pick. On my receiver the 5 volt rail was somewhat low at 4.77 volts, but that just affects the maximum output available.
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