[R-390] R-390/URR heater circuits.

[Jordan Arndt]

I think that hits the nail on the head...!

73...Jordan VE6ZT

----- Original Message ----- 
From: "Renee K6FSB via R-390" <r-390 at mailman.qth.net>
To: "Jim Shorney" <jimnu0c at gmail.com>; <r-390 at mailman.qth.net>
Sent: Tuesday, August 11, 2026 1:03 PM
Subject: Re: [R-390] R-390/URR heater circuits.


> Bingo....helps mitigate AC Hum due the high impedance of AC fil especially 
> on the limiters.
> thanks Jim S.
> Renée
>
> On 8/11/26 11:34 AM, Jim Shorney via R-390 wrote:
>> Maybe this is relevant.
>>
>> https://www.wb4hfn.com/DRAKE/DrakeArticles/Why_8BN8-2B.htm
>>
>> On Tue, 11 Aug 2026 18:13:00 +0000 (UTC)
>> Jim Whartenby via R-390 <r-390 at mailman.qth.net> wrote:
>>
>>> Fred and Renée Well yes and no WRT answering my question. It is now my 
>>> understanding that the heater power reduction was done to improve some 
>>> aspect of using a triode as a diode. I am not sure what circuit function 
>>> is actually benefiting from this. The noise aspect is a reasonable 
>>> explanation for reduced heater power.
>
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html