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The NX7U AO-40 portable setup Mk II



I'm baaaaaacccccccckkkkkkkkk..............
Today was the maiden voyage of the "new" portable AO-40 setup.  I had been using a 38"x26" BBQ, AIDC3733, and Kenwood TM-255A for the downlink; and a 9 element yagi, FT-100 (20W) for the U-band uplink (actually the semi-famous M2 440-18 yagi broken in half).
Now I have a 76cm offset dish with 6T helix feed, DEMI 2400-144RX (the one recently repaired), and same TM-255A for downlink; uplink is a 6-turn helix and same FT-100/20W on U-band.  The 6-turn helix is just a 1/2 length version of my home station 12-turn, using two closed loops for reflectors instead of a solid/grid sheet.
The results exceeded expectations.  This morning I had a pleasant CW QSO with W3STW.  Range=57k-km and squint~4 deg.  The MB was S7-S8 and the background noise was <S0.  This is by far the largest MB SNR I have ever personally experienced!
On the home front (60cm prime focus with same DEMI d/c and FT-726R) I could get at best S3.5 on the MB for roughly the same attitude.  The old portable stn could get about the same S3-S4 MB.
I need to do some verification, but I have a suspicion that in repairing the DEMI d/c I may have improved it significantly.  It sounded "crisper" than it ever had before.  Those with long detailed memories will recall that I couldn't account for about 9dB of system loss in my AO-40 beginning.  Plus, it always took about 30-45 seconds for the noise rise to gradually build up on the RX when I switched on the DEMI.   Now the rise is immediate and complete (not building over time) and the beacon drift during warm-up is much smaller.  I recall another reader with a DEMI d/c who had to do some minor frequency tweaking to get the d/c system to work right.  I have a feeling that my d/c was sub-specification to begin with, and my messing with it has put it back on track.  More on that after further testing (need to put it back on the same home system to compare). 
Anyhow, glad to be back on the bird...I have a 95cm offset waiting in the wings for the home station; I should be in decent shape for the winter!
73,

Scott Townley NX7U
Gilbert, AZ  DM43di

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