[Hallicrafters] SR-150 Tuning

[Ronald Oberloh]

I am in the process of restoring an SR-400 and have noticed the same 
thing.  Is this normal for the Hallicrafter transceivers?  If is is has 
anyone modified the circuit to correct the problem or know what might be 
causing this. If it was a little off it would not bother me but it  is a 
long way off.  If this is not normal then what might be the problem?   I 
have not checked the schematices but knowing a little bit about other 
Hallicrafter products I expect the SR-150 and SR-400 might have a lot of 
circuit in common.

Thanks
Ron   WA0KDS



John N. Schwartzberg wrote:

>
>> Hey Gang -
>>
>> I dusted off my radio bench, then the SR-150, to warm up the shack.  
>> I noticed the following while tuning it up on both 20 and 40 meters:
>>
>> With a resonant antenna load, peaking both the pre-selector tuning 
>> and the final output tuning for maximum indication on either an 
>> external watt-meter or the internal meter results in relatively low 
>> receiver sensitivity.  I can then increase the receiver sensitivity 
>> with the pre-selector tuning, but at the expense of output.  The 
>> manual includes the following tuning instructions:
>>
>> "Adjust the RF Level control until a small indication is seen on the 
>> S-meter.  In the transmit mode, the S-meter indicates the relative RF 
>> voltage.  Adjust the FINAL TUNING control for maximum output and then 
>> adjust the PRESELECTOR for maximum output indication.  Adjust the RF 
>> LEVEL control as required to keep the S-meter below S9, while tuning 
>> the PRESELECTOR."
>>
>> Is it "normal" to then be able to peak up the received signal using 
>> the PRESELECTOR control after this tuning procedure?  I don't recall 
>> that being the case in the past, but I can't honestly say that I've 
>> ever checked it.  I follow the prescribed tuning procedure, and go.  
>> For some reason today, I adjusted the preselector some time after 
>> tuning thinking the received signals were kind of low, and discovered 
>> that I could peak them up, but lost about 1/4 to 1/3 of the output 
>> indication.
>>
>> Has anyone else observed this on their SR-150, or does the collective 
>> brain trust have any thoughts?
>>
>> Thanks... and Happy New Year (or is that Hallicrafter's New Year?)
>>
>> 73,
>>
>> John
>>
>> N0GII
>>
>> Denver, CO
>
>
>
> _______________________________________________
> List Administrator: Duane Fischer, W8DBF **for assistance**
> dfischer at usol.com
> ----
> Hallicrafters Collectors International: http://www.w9wze.org
> ----
> http://mailman.qth.net/mailman/listinfo/hallicrafters
>