[ARC5] R-23/ARC-5

[Robert Downs]

The 12SG7 (equivalent to a 12BA6 except for base and envelope) might have
helped the performance of the 10-meter conversion a little bit, but only if
some other component values were also changed.

Robert Downs


-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of Kenneth G. Gordon
Sent: Thursday, February 28, 2019 19:20
To: Arc5 at mailman.qth.net
Subject: Re: [ARC5] R-23/ARC-5

On 28 Feb 2019 at 20:01, Mike Morrow wrote:

>     current balancing resistor.  However, there should 
>     have been little motivation for increased RF stage 
>     gain in an R-23.

This is absolutely correct. My rebuilt BC-453B can "hear" a 0.1 microvolt CW
signal with all 
stock original tubes.

https://www.youtube.com/watch?v=vlz83QXM66A

I also have a BC-454 which someone attempted to modify, back in the 1950s,
to cover 10 
meters. After I did some work on it to finish the original owner's project,
with the original 
12SK7 RF amp, it easily copies a 1 microvolt CW signal.

I can think of no good reason to change the RF amp to any other tube.

Ken W7EKB
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