BATC Forum

I've got my DTX1 working nicely on 24cms with my sat rx - just set it to the correct freq (its lo is 9.75GHz), set the FEC and bit rate - job done nice video.

Thought 70cms would be just as easy - I know the output freq of the sup-2400 for 437MHz in and sure enough nice strong signal being passed to the sat rx at1963MHz
Sat rx tuned to 11713MHz and correct settings but no decode.

Running out of ideas as to what maybe wrong - the sup2400 inverts the spectrum, might this be a problem ?

Any ideas ?

Sat tuner is a Samsung, but can be tuned / set to anything.

73 Tim

Hi Tim,

Couple of thoughts - presume you did modify the SUP2400 as per the CQ-TV article.

Was the LO frequency the same for 70cms? They default to 9750 or 10600 and you may need to set it up again for a second satellite / transponder.

73

Noel - G8GTZ

Tim,
I assume that you have set your satellite receiver up for a Universal LNB, which has local oscillator frequencies of 9750 & 10600MHz. The frequency to tune is 2400-437=1963MHz. However, this puts it in the upper tuning range of the LNB where the 10600MHz local oscillator is used. You need to tune the receiver to 10600+1963=12563MHz, 2000ks/s, and it should be there.
73 de Shaun G8VPG.

Well that was easy ! rx is working fine now, just had to tune the sat rx to the correct freq as you mentioned above.

Thanks guys

While I was at it I measured the rx sensitivity - starts to decode at -106dBm which doesn't seem too bad given that I have no idea of the noise bandwidth on the sat rx.

How does this compare to others rx sensitivity ?

FYI I measured the output of the DTX1 at -9.5dBm and fed it into the rx via a precision stepped attenuator. The RX itself is very well screened so I don't think the -106dBm figure is too far off the mark.

I modified the SUP 2400 as per the article and also fitted SMA's to it at both ends so making a neater 'plumbing' job.

Now if I can just find someone within range of IO83LR on either 70cms or 24cms.....

73 Tim