Message-ID: <003401bf0e92$982c08e0$f0d225c3@194.95.193.10.fen.baynet.de>
From: "Walter Staubach" <ba338@fen.baynet.de>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Receivers
Date: Mon, 4 Oct 1999 17:50:42 +0100
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Hallo to You all from DJ2LF
About receivers/transceivers for lf: I use the the IC729 (=IC728+6m) with
500Hz filter. I think it`s rather good for big antenna, not for loops.
My location in a small village has less man-made-noise, no Loran. So-as we
say in German- I "hear the grass growing",hi.  73 Walter DJ2LF

-----Ursprüngliche Nachricht-----
Von: Peter Dodd <g3ldo@zetnet.co.uk>
An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Datum: Sonntag, 3. Oktober 1999 10:35
Betreff: Re: LF: Receivers


>
>> There's been some discussion about filters etc recently which reminded me
of
>> a question I wanted to ask the group...
>> What receivers/tranceivers work well on LF? and possibly..
>> What receivers or transceivers don't work very well?
>
>> All I need is something like this:
>
>> IC735; rather deaf, needs external preamp/filter.
>> TS850; excellent, especially with two CW filters.
>
>The receiver itself in not the whole story.
>In the early days of 73kHz experiments I used an old IC-707 with a
>Datong converter. I found its performance was very poor with lots of
>birdies and breakthrough. On a visit to Mike, G3XDV, I listened to
>his 73kHz setup, which comprised the same Daytong converter but with
>an IC 706 as the tunable IF. His receive setup sounded totally
>different with nice crisp sound and the occasional 'gunshot' static.
>The difference in performance was the result of Mike using a tuned
>circuit preselector and a carefully adjusted variable attenuator.
>
>Much of my early work on 73kHz and 136kHz was done using a Drake 4C
>with 1500, 500 and 200Hz Sherwood filters and first IF roofing filter
>- with a double-tuned circuit preselector and a variable attentuator
>(potentiometer). and I was happy with this (except for poor frequency
readout).
>
>When 136kHz became available my main problem was Loran. This holds
>the S-meter at S6 at 1.5kHz bandwidth and at narrower bandwidths the
>filter rings due to the Loran. John, G4GVC, was having more success
>on receive than most and after hearing John's TS-850 receiver setup,
>I bought a second-hand TS-850. The filters and bandwidth control,
>plus 3+OFF AGC setting make this the best receiver I have ever used
>in  over 40 years of Ham Radio. But it still needs a preselector and
>variable attenuator to get the best out of it.
>
>My feeling is that if Loran is not a problem at your QTH then any
>modern transceiver that has good sensitivity at LF and has a CW
>filter will work provided that the gain distribution throughout the
>receive system (antenna, converter, receiver front-end, audio) is
>under control. The component between the headphones also contributes
>to receiver efficiency. I find that a 500kHz filter is the best in
>the presence of Loran.
>
>However, I recently asked if anyone knew of a Level Meter D2155 made
>by Siemens that I recently aquired. I got no response so I assume
>that no one knows about it. So I decided to try it as a very good
>receiver, and it seems very good except that the bandwidths of 3.7kHz
>and 20Hz are a bit strange. With the narrow filter on I do not hear
>Loran and it converts all signals and noise to a single note but it
>does not ring. A normal CW signal stands out but is rather 'soft'.
>I used it for the first time this morning, 3/10/99, and the fist
>signal received was (I think) DL calling CQ on 136.54. The D2155 was
>not tuned quite onto him before he went over. The next signal was
>G4GVC and we had a QSO. John's signal was -80dBm. G3BDQ called me but
>I had to go QRT. His signal was -78dBm. You may all be getting a
>different type of report from me in the future!
>
>Next Tuesday morning I will be running tests on 72.1kHz on Slow CW
>and listening/looking on that band and on the 136kHz  band for
>replies. If you want a sked let me know.
>
>
>
>--
>Regards, Peter, G3LDO
>
><g3ldo@zetnet.co.uk>
>
>
>