Question SB303

[George T. Baker]

Don, the RF ATTEN control is just a 600 ohm pot connected between the
antenna receptacle and the first stage r-f input. As I recall, the
attenuation action is very smooth and operates over the entire range of
rotation of the control. Possibly your pot has gotten dirty, etc. and
would respond to having some cleaner squirted into it. Do that and move
the wiper around a few times and then let it dry out.

I copied that circuit with a separate pot in a small metal box and used
it for years with my Drake C-Line - worked great!

In return for the tender front-end, as I recall the 303 had some of the
best-sounding SSB of any receiver of any price. I guess I need to get
mine out of the closet and go through it and see how it still works!
;^) Hasn't been used for about 20 years so I guess some electrolytics
could stand replacement.

72/73, George
Fairview, TX   30 mi NE Dallas in Collin county
Amateur Radio W5YR, in the 54th year and it just keeps getting better!
R/C since 1964 - AMA 98452   RVing since 1972       Kachina #91900556


Dan Pividal N4VET wrote:
>
> I also have an SB303 and since we are on the subject I have a question.
> My SB303 has the RF ATTEN and not a noise blanker on the front panel.
> However, my RF ATTEN never seemed to work right to me.
> I get full audio on an S9 signal and if I turn the knob only about 1/4 inch
> my audio drops to nothing.
> Is this pot working the way it is meant to?
> I would think it should be a gradual drop through the range of the knob.
> I will be going back into this radio soon and would like to know if I need to
> fix this.
> If your SB303's work the same I wont waste my time in trying to put a meter
> to the pot.
> And yes, the SB303 is very prone front end overload. Anything over S9 seems
> to do it. It helps if you switch to fast AGC so that the first letter of a
> word does not spike.
> Waiting to hear from you guys,
> Dan N4VET

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