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

[Glen Zook]

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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