Message-ID: <39244D9A.DAF70832@freesurf.ch>
Date: Thu, 18 May 2000 22:07:54 +0200
From: "Toni" <hb9asb@freesurf.ch>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re: LF receivers
References: <2000051810113968199@zetnet.co.uk>
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Hello Peter,
I'm using a Harris RF590 for LF reception, followed by a Timewave
DSP-599zx. The Harris tunes from 10KHz up to 30MHz and is available on
the surplus market. It was in widespread use in many US civil and
military services and was made in the USA from 1982-1998.

What I like is 
- the 1 Hz read out
- the very good stability with the built in Oven (still within 1Hz after
2 years of service, without adjustment)
- the slow tuning rate of 100 Hz for 1 turn of the VFO knob
- the synthesized BFO tuning in 10Hz steps
- the (adjustable) line out for the PC sound card

The receiver is fitted with the automatic preselector option and has
outstanding IMD and cross modulation immunity. There are  different AGC
settings (incl. OFF).

Problems are:
- IF blow by, due to insufficient blocking of the filter control circuit
(can be modified)
- Too large cw filter. Originally it was equipped with a 300 Hz filter -
but at -3db! and this corresponds to a 500Hz -6dB filter as it is used
in amateur transceivers
(I have replaced it by an ICOM FL 53A (250Hz at -6dB))
- uncomfortable VFO knob (replaced by one of a WJ8888)

The Timewave determines the audio BW and I'm using 35Hz most of time.
The built in noise reduction algorithm works quite well and attenuates
the worst static noise (no NB option in the Harris).

As back up receiver I'm using an ICOM IC765. All what I hear on the
Harris I can hear also with the ICOM. The ICOM has a very good NB but it
is useless together with the narrow CW filters (250 Hz in both IF's).
I'm using it also together with the Timewave DSP. 

73 de Toni, HB2ASB  
 

Peter Dodd schrieb:
> 
> I am working on the Receiver chapter for the LF book. I have a good
> introduction written by John 4GVC (with a description of the TS850,
> which caused many of us, including myself, to go this route) but
> would like to bring it up to date in the light of your collective
> experience. While I was up at Crawley I found that Derek was using
> the 990 to good effect.
> What is your favorite receiver and how does it compare with others
> that you might have tried?
> 
> --
> Regards, Peter, G3LDO
> 
> <g3ldo@zetnet.co.uk>