DATV ⁽²⁾

Yes, ok, this is still not about the transmission path! But I wanted to experiment a little more with the wideband part of the transponder and DATV signals. To that aim I press ganged the small HD screen from our NVR (which in turn will be wired to the large TV downstairs) and attached it the the Winterhill box. With 12V from the lab supply to the Winterhill and the 25MHz LO being fed from the diminutive Leo Bodnar mini GPS reference clock it all appears to be working as expected. This was covered in Part 2 already but today I managed to get a screenshot with four DATV feeds, although one had just dropped leaving the last image that was received. Now I need to decide whether to keep this small screen for Winterhill or swap screens with the one I use for Hamclock with the latter then on the smaller screen. I will probably do the latter as this small screen will run from USB C from the PC meaning one less socket.

The reason I moved the dish was, as explained in part 1 partyl due to me wanting to send and receive DATV. Having sorted out the receive parts for the narrowband transponder the next step was to set up to receive the wideband one. the LNB was originally a 4-port device which has been modified to take an external 25MHz sinewave input on one of the ports thus leaving three free. I ran three runs of RG59 from the shack, one for the 25MHz feed and two for reception. So it was relatively easy to use the second of these to receive DATV. I already had a Winterhill DATV receiver (see https://wiki.batc.org.uk/WinterHill_Receiver_Project ) and documentation for this shows how to configure it for QO100 use using two of its inputs, leaving the other two free for other purposes. A splitter combines the two 'top' ports, feeding power from the first port. With the Winterhill set up to send 18V it flips that LNB receiver to the right polarisation for the wideband transponder. QED. And it just works. I did have to fiddle with settings because when I got the Winterhill I experimented with remote access so when turned on it…