Happy Holidays to all on the list,
I was working on a SX-130 last night and noticed that they put a 1K resistor
in series with the Band 1 (Brdcst Bnd) on the ant section of the bandswitch.
When I shorted it out the signal strength went up. Anyone know why they put
this resistor in and made the bdcst band less sensitive? I also noticed it on
the SX-99 schematic so it was probably part of their general circuit design in
8 tube rcvrs. Thanks in advance for responding. 73 Mike KF6KXG

TchrMe wrote:
Happy Holidays to all on the list,
I was working on a SX-130 last night and noticed that they put a 1K resistor
in series with the Band 1 (Brdcst Bnd) on the ant section of the bandswitch.
When I shorted it out the signal strength went up. Anyone know why they put
this resistor in and made the bdcst band less sensitive? I also noticed it on
the SX-99 schematic so it was probably part of their general circuit design in
8 tube rcvrs. Thanks in advance for responding. 73 Mike KF6KXG

A guess...to lower the Q and broaden the bandwidth? Try the same test
at band extremes.

-BM

- - Bill - - wrote:
TchrMe wrote:
. Anyone know why they put this resistor in and made the
bdcst band less sensitive? I also noticed it on the SX-99 schematic
so it was probably part of their general circuit design in 8 tube
rcvrs. Thanks in advance for responding. 73 Mike KF6KXG

A guess...to lower the Q and broaden the bandwidth? Try the same
test at band extremes.

-BM

Several receivers even today intentionally reduce the BCB sensitivity to
reduce images in the upper bands from very strong local stations. The
Kenwood R-5000 and the Ten-Tec RX-320 are examples.

--
Brian Denley
http://home.comcast.net/~b.denley/index.html

Thanks to all who responded to my question. I now know the reasoning behind the
resistor. Mike KF6KXG