[Boatanchors] Re SX-130 question

John Kolb jlkolb at jlkolb.cts.com
Wed Feb 1 03:05:39 EST 2012

This is common to most (all?) receivers which do not have a product 
detector for SSB but simply
add a BFO signal to the IF signal going into the AM detector.  This 
is true even of the R-390 receiver.

For the BFO signal to replace the missing carrier of the SSB signal, 
it needs to be much stronger than
the SSB signal components.  If the SSB signal is strong, the BFO may 
not be enough stronger to
serve as a carrier.  In this case, turning down the RF Gain reduces 
the SSB signal to a proper level
to work with the BFO signal.

With the RF gain turned down, the AGC will probably be less 
effective, so constant adjustments
of it may be necessary (riding the gain).


At 08:49 PM 1/31/2012, Ron Barlow wrote:
>Many thanks to all who replied to my request for info on the SX-130. 
>The owner (a member of the Hallicrafters mailing list) states that 
>the RF gain control must be reduced to obtain good copy on SSB. He 
>states that if the RF gain control is advanced, the audio distortion 
>becomes severe.
>  He asks if this situation, is normal, for this particular receiver.
>  He sent along a copy of the owners manual, which states that 
> "under certain conditions, it may be found advantageous to reduce 
> the RF GAIN setting for improved reception." Judging from the 
> owners description, his receiver seems to require a great deal more 
> attention, to the RF gain control, than the owners manual suggests.
>  Unfortunately, I do not have access to the receiver, and I have 
> never operated an SX-130. Therefore, I am not in a good position to 
> judge whether his receiver is operating normally. Any and all 
> advice is greatly appreciated, and I will forward it to the owner 
> of the receiver.
>                                        Many thanks & 73 de Ron  N4GJV

More information about the Boatanchors mailing list