[ARC5] Receiver Sensitivity - Power Supplies

[John Hutchins]

Scott -

I always thought, that I was imagining that I was hearing things 
better,  with the BFO on!

Turn on the BFO;  and throttle back on the RF gain when dealing with an 
AM station/contact.

On the BC-348 with the BFO on; it only drops the HV rail ~200 V by  < 1 
volt but it surly enhances the reception.

Thanks for the proof.

Hutch


On 4/26/2018 12:57 PM, Kenneth G. Gordon wrote:
> On 25 Apr 2018 at 23:11, Scott Robinson wrote:
>
>> Hi Bill,
>>
>> I'm curious: how did you measure the sensitivity? Wat do you mean by 'CW
>> sensitivity'?
> I suspect he means with the BFO on. When I measured the sensitivity of my own restored
> receivers, there was a considerable improvement in sensitivity when the BFO was on when
> compared with it off.
>
> For a BC-453B, AM sensitivity was 1 microvolt, and with the BFO on it was 0.3 microvolt,
> although MDS sensistivity was 0.1 microvolt.
>
> See this youtube video:
>
> https://www.youtube.com/watch?v=vlz83QXM66A
>
> The main thing that low (and very low) plate voltage does is reduce the audio power output
> level very significantly.
>
> The RF levels are not effected to the same extent.
>
> Ken W7EKB
>
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