[Hallicrafters] SX-28 sensitivity on 10-15 meters?

[Glen Zook]

I guess it depends on the TV balun.  According to an
amateur friend of mine who was in the CATV business
for many years, most TV baluns make it all the way
down to the broadcast band without any problems.  He
said that there is certain signalling that takes place
below 5 MHz and that is why the baluns usually make it
down to the BC band.

I do know that the one's I have checked have improved
the sensitivity of my Collins 51J2 all the way down to
the BC band as well as several locals have used them
on their Collins 75A1 receivers and have been very
pleased with the improvement on all bands.  Now the
improvement with the 51J2 was only like about 6 dB
from a direct 50 ohm cable input on the broadcast band
(.5 to 1.5 MHz).  The improvement differed from band
to band and ranged from this 6 dB to well over 20 dB
on the high end.  For those who are not familar with
the 51J2, it covers 0.5 to 30.5 MHz in 30 ranges of 1
MHz.

Of course, like most consumer items you "takes your
chances"!  However, even the fact that they match the
unbalanced to balanced may be a definite factor in
them working below 5 MHz.  The ones that I have been
using are blue in color, about 2 inches long, have a
type "F" female connector on one end and twin lead on
the other.  These were obtained from my friend.  He
gets about 25, or so, at a time as "free samples" from
his old CATV suppliers.  It seems that the cost of
these to the cable companies is well under 25 cents
each, approaching 10 cents for many of them.  We pay
like 3 dollars or more from Radio Shack!

I do use a commercial coax adapter that converts the
type "F connector on the balun to a BNC.  

Glen, K9STH


--- "Roger D. Johnson" <n1rj at pivot.net> wrote:

I checked out a TV balun on a network analyzer at
work. It was pretty sorry below 5 MHz!

=====
Glen, K9STH

Web sites

http://home.attbi.com/~k9sth
http://home.attbi.com/~zcomco

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