Hi Ian, I made some measurements with my rather older TF2002B, on a GII I
borrowed from a friend to check for LF performance. My results sound similar
to yours....I reckoned it would need between 20 and 40 dB of pre-amp at 136
to give the 100nV sensitivity I get on the AOR 7030. I did not bother with
73k at the time. If you have a very big aerial like Mal's I suppose you get
such a lot of signal (and noise!) that you couldn't use much more gain. For
us lesser mortals it is barely adequate. I was also quite taken aback by the
"chunder" that could be heard with no signal at 136k, this is probably the
PLL reference. It is something I do not hear on the 7030 (even at the 10nV
level) despite DDS LOs not being famed for their quietness.
Stick with it, we look forward to hearing another station from your region
(particularly on 73!!) Finbar is keeping the flag flying on 136k at the
moment. He is consistantly heard here on the East Coast (Nr Woodbridge,
Suffolk) at about 579 these days, and is now working into Germany.
Cheers de Alan G3NYK
[email protected]
-----Original Message-----
From: Ian Kyle <[email protected]>
To: [email protected] <[email protected]>
Date: 24 September 2001 17:12
Subject: LF: Re: IC-706 on LF
Re 706s,
I have found my nice new IC 706GII to be a dead duck for 73 KHz receive.
I agree with Mike that it is usable on 136 with a bit of assistance, but
not
on the lower band.
Not hearing much on one band and *!*!*! all in the other, I decided to do a
proper test. If anyone is interested, the CW 10dB S+N/N in the narrow
filter
(270Hz) checked using a TF2008 sig.gen. (admittedly not recently calibrated
but within a dB or so against a known source) at the two frequencies was -
136 KHz 10uV p.d.
73 KHz 83uV p.d.
Now unless I happen to have a particularly dud sample, it would seem that
there is a pretty good HPF in there.
Due to circumstances beyond my control (building works to provide a 'boys
dorm' for visiting grandsons and a home for the dispossessed shack/computer
suite/workshop in a new 'west wing') it will be at least November before
regular transmissions can be made on LF, but I do intend to keep the
promise
I made earlier this year. The only good thing to come out of all the
excavation and general flapdoodle is that I got a five leg earth mat down
under the founds of the extension.
73 de,
Ian
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