[Hallicrafters] SX-28A "deaf" on higher bands

[Roger Basford]

Hi Glen,

Could be a valid point you have, I have a double antenna fed by 450 Ohm twin 
so I could try that direct onto the SX-28. Have been using a commercial 
active loop fed with coax for the tests, it favours the lower bands but 
works fine up to 29 Mc on my other boatanchors.

73 and thanks for the response!

Roger/G3VKM


----- Original Message ----- 
From: "Glen Zook" <gzook at yahoo.com>
To: "Roger Basford" <roger at new-gate.co.uk>; <hallicrafters at mailman.qth.net>
Sent: Friday, April 14, 2006 10:21 PM
Subject: Re: [Hallicrafters] SX-28A "deaf" on higher bands


> Before doing anything else I would try a television
> type balun (one from the USA).  Hook the 300 ohm
> output to the 2 antenna terminals (removing the ground
> between A-2 and G).  Then hook the coaxial cable into
> the "normal" input.
>
> I don't know if television baluns are available in the
> U.K. and if they have the same characteristics as
> those in the United States.  But, the older receivers
> are set up to use balanced fairly high impedance
> feedlines and many don't work that well with a direct
> coaxial feed.
>
> For the article that appeared in Electric Radio a
> while back on use of these baluns go to either of my
> websites the URL of which is listed at the end of this
> message.  The article is available on both websites.
>
> I had to install one just last night in an RME-50 that
> had the antenna terminal strip removed and an SO-239
> connector installed.  This one had to go internally to
> the receiver.  It made up to over a 20 dB improvement
> in the sensitivity depending on the band.
>
> Glen, K9STH
>
>
> --- Roger Basford <roger at new-gate.co.uk> wrote:
>
> I have fired it up and it works, but I think there is
> a problem with the RF preselector stage, as there is
> loads of gain and good S meter readings on the 550kc
> to 3.0Mc bands but things are very quiet on the HF
> bands, falling away to very little on 20 metres.
> Before I start ripping out the RF section (!) has
> anyone come across this problem?
>
>
>
>
>
>
>
>
>
> Glen, K9STH
>
> Web sites
>
> http://home.comcast.net/~k9sth
> http://home.comcast.net/~zcomco
>
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