Simple QRP projects, 10m, 8m, 6m, 4m, FT8, 160m, WSPR, LF/MF, sub-9kHz, nanowaves and other random stuff, some not related to amateur radio.
7 Feb 2015
FT817 sensitivity
Today I checked the sensitivities of my FT817 and FT817ND using a loaned signal generator. Although about 10dB deaf at 472kHz (expected) both were easily able to copy down to -127dBm on CW on all bands to 70cms. -127dBm is as low as the generator would go. I could have added a 10dB attenuator, but did not. I also managed easy access of GB3PY and GB3OV 70cms repeaters at the 500mW level into the V2000 vertical. My conclusion is things are OK at my end and I wonder if G6ALB has some additional cable loss at 70cms at his end (water in the feeder?). My antenna has been up for about 2 years whereas his has been up for around 20 years.
I had a good one some years ago on 2m. I could hear them, but some over a few miles couldn't hear me? SWR measurements were bang on the nail?
ReplyDeleteFor a while I put it to the back of my mind but when I was getting Xmas trees out of the loft one year, I opened the little door where the Coax was terminated on the Slim Jim just really for curosity at the time I suppose, and there it was the braid had come disconnected!
It always pays to look twice at a problem even though SWR meters give the right indication and you might not think its your fault?
73 G1KQH
At least I've eliminated the FT817s and the quick 70cms repeater test suggests the antenna and cable are fine too. When fitter I want to put good low loss cable up to the V2000. This should gain me 1-2dB on 70cms both RX and TX, which would be useful. However between G6ALB and me we need to find out where our losses have increased.
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