Thanks for the tip on the loop tuning, will try that out tomorrow and
see the difference it shows.
The mixer and amp is just a temporary setup to see if i would be lucky
enough to see any signals....hmm
As in the other post i am receiving with my ic-706IIG now and seems a
bit better for spurious than the wideband mixer!
I'l make a crude filter tomorrow for the input and hopefully cure the
main breakthrough probs but i am now hearing things...
I'l try Rik's site sometime when qsl.net actually responds.. anyone else
notice it is really slow these days?!
I'm using spectrum lab for the monitoring, have used it as a general
monitor for all souncard stuff for a while now and very impressed., i
also use winrad for sdr and weak sigs etc..
Are there any other forums on the net for LF and VLF, seem very hard to
find any meeting place for common interest in 136KHz like the handy
on4kst setup for eme/vhf and up skeds etc..
Thanks for your web link too Alan, will have a look through later.....
Rob
Alan Melia wrote:
Hi Rob as dave said it is quiet at the moment. I found attaching a gen to a
loop can give silly answers, and you can finish off far enough off resonance
to seriously affect the signal levels. I connect my generator to a small
coil about 8in diam with about 8 turns or any-old-wire. Set the two loops in
the same plane with the exciter look a couple of diameters of the big loo
along the axis. Then peak the main loop. I get quite a bit signal from DCF39
on 138.83 here the field strength is about 1mV/meter and that vives me an
S9+32dB signal from a 12m high Inverted L.. You will get a little less on a
loop but not that much less with a large one.
Most of the "accumulated wisdom" is summerised on a couple of big tutorials
on Rik Stobbe's web site, and he has lots of links to other projects
information
http://www.qsl.net/on7yd/136khz.htm
It occurs to me that depending on your location you may need a low-pass
filter between your loop and the rx to keep out MW BC stations, the 612 is
not the best intermod performer, but is adequate if protected sufficiently.
The use of a PC "waterfall" program (ARGO is popular, free, and easy to use,
and works with most on-board sound cards I think) is very useful for
identifying QRM and also spotting weak signals.
Welcome to LF ( which stands for Lotsa Fun !!)
Alan G3NYK
http://www.btinternet.com/~alan.melia/index.htm
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