[Lowfer] XKO WSPR-2 SNR at VE3IQB
Bill de Carle
ve2iq at magma.ca
Sat Feb 2 23:26:58 EST 2013
Thanks for the nice words and good signal Dex. My receive system
isn't all that great but this location in the sticks can be quiet at
times. I have a pair of orthogonal loops, each approximately 30'
horizontal by 20' vertical, supported by trees in the woods about 150
feet east of the house. For this evening's test I am using only the
N/S loop, which favors your direction and is relatively insensitive
to house noise. In the N/S directions there aren't any nearby homes
or electrical transmission lines. I tune the loop(s) with a bank of
switched capacitors plus a variable 1000 pF, about 0.1 to 16
nanoFarads altogether. There is a switch to select LF or VLF band -
it adds extra inductance in series with the loop(s) so I can use the
same capacitor box to tune the full range of either band. Tonight I
have the preamp enabled - it's just a battery-operated
instrumentation amplifier (TL074 IC) so I can look at the
parallel-resonant voltage output without loading down the Q. The
preamp's output is low-Z and drives a buried cable back to the
house. I can run without the pre-amp, in which case the (then
series-resonant) loop passes through the centre of a ferrite core and
there are 10 turns on the secondary, driving the 100-ohm twisted-pair
buried cable. Just outside the house there is an isolation
transformer 100:50 ohms; the signal comes into the shack via a short
run of coax. Rx is a Kenwood TS-850, audio output to a netbook
running WSPRX. When Bob Raide (just south of here) fires up his
monster transmitter on the band, I can't use the pre-amp because I
never expected to see a signal that strong, hi! When I switch the
pre-amp off I see the WSPR SNR immediately drop by 10 dB. That's
partly thanks to the pre-amp's 10 dB power gain which brings the
signal+noise environment from the woods into the shack at a high
enough level to overcome the computer noise, SMPS-noise etc in the
shack. One drawback of this arrangement is there are too many
connections and switch contacts exposed to the weather. Another is I
have to plod through the snow every day to bring in the 12-volt 1-Ah
Gel cell for recharging or to change the receive frequency. Upside:
I need the exercise :-)
73,
Bill VE2IQ / VE3IQB
At 09:16 PM 2/2/2013, Dex wrote:
>Bill's reports show some impressive SNR values receiving XKO
>considering the distance.
>Knowing Bill's capability I guess I shouldn't be surprised.
>Tell us about your receive system Bill.
>
>2013-02-03 01:54 WD2XKO 0.137502 -23 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 01:42 WD2XKO 0.137503 -26 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 01:26 WD2XKO 0.137503 -24 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 01:22 WD2XKO 0.137503 -25 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 01:18 WD2XKO 0.137502 -25 -1 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 01:06 WD2XKO 0.137503 -23 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 01:02 WD2XKO 0.137503 -19 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:58 WD2XKO 0.137503 -19 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:54 WD2XKO 0.137503 -17 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:50 WD2XKO 0.137503 -17 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:46 WD2XKO 0.137503 -17 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:42 WD2XKO 0.137503 -18 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:38 WD2XKO 0.137503 -15 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:34 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:30 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:26 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:22 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:18 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:14 WD2XKO 0.137503 -15 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:10 WD2XKO 0.137503 -15 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:06 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-03 00:02 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:58 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:54 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:50 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:46 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:42 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:38 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:34 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:30 WD2XKO 0.137503 -13 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:26 WD2XKO 0.137503 -14 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:22 WD2XKO 0.137503 -15 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
>2013-02-02 23:18 WD2XKO 0.137503 -17 0 EM95tg 0.1 VE3IQB FN15nt 1209 13
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