On Sun, Nov 29, 2009 at 8:02 PM, Michael Tondee mat_62@netcommander.com wrote:
I've been trying to get my receive setup going the last few days but I'm having horrible results. I have my 11 element 70cm "cheap yagi" back up on the mast and my homebrew SaebrTrack and OR-360 AZ/EL TV rotator system interfaced to SatPC32. I have an ARR preamp mounted at the mast fed with a seperate 12VDC feed and about a 40 foot run of JEFA brand LMR 400. Once I get into the shack there is a bit of patchwork to the cables. I'm using a Yaesu VX3 to receive and due to the SMA connector on the HT and not wanting to strain it I have a 4 foot adapter cable of LMR 100 that goes from an SMA to a SO-239. I then have to use a short length of coax with a PL-259 to N male to mate up with a N barrel connector connected to my LMR 400 coming from outside. Now obviously, I know this isn't optimum and eats up valuable RF and I intend to change it ASAP but I'm hearing absolutely nothing on AO-51 passes. Not even the hint of signals. I'm thinking with that preamp in the line I should at lest hear something discernible besides noise regardless of the patchwork of cables. Am I off base in thinking this? I did catch just a bit of discernible signal off SO-50 last night but it was almost overhead. I'm not a beginner at this but I'm frustrated. Perhaps I'm putting too much faith in the preamp to push the signals through my hodgepodge of adapters and cables? Any thoughts are appreciated. 73, Michael, W4HIJ
Michael --
I think something is quite amiss here, perhaps a connector is bad or a bad joint in one of the cables. I bet a couple of hours with a volt-ohmmeter will find the guilty party. Alternatively, you could be in a bad noise situation.
By way of comparison, because of my digital project right now I have a very minimal station, with a 70cm vertical antenna soldered directly onto a N-connector. About 10' of LMR400 goes to the preamp, which then has another 100' of cable to my FT-817. AO-51 is not great copy, but I know it is there. Similarly, all the usual cubesats in CW mode, and SEEDS (CO-66) with its fine FM signal of cheering Japanese school-children.
(Actually, this got me thinking that SEEDS would make a pretty good way of evaluating two side-by-side receiving systems. Pass the resulting wav files through a SSTV decoder, and the one with the better picture wins!)
You might consider making a very simple vertical antenna, attaching it to one end of the preamp with a very small patch cord between it and the radio, and using that as a kind of baseline.
73, Bruce