[ARC5] [MRCA] [Milsurplus] Vintage LF/MF Fun with my BC-453B

[Mike Feher]

Hi Mark – I am curious, what can you possibly hear thru a 7Hz or even a 20 Hz audio filter? Thanks & 73 – Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

 

From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> On Behalf Of Mark K3MSB
Sent: Friday, November 21, 2025 3:28 PM
To: Hubert Miller <kargo_cult at msn.com>
Cc: ARC5 <arc5 at mailman.qth.net>; Milsurplus at mailman.qth.net; Military Radio Collectors Association (mrca at mailman.qth.net) <mrca at mailman.qth.net>
Subject: Re: [MRCA] [ARC5] [Milsurplus] Vintage LF/MF Fun with my BC-453B

 

HI Hue

 

Sorry for the late reply.

 

I'm blessed to have some friends that keep their eyes out for tuning knobs!

 

The HP-23 provides 250V B+.  For my full up SCR-274N setup, I use the same HP-23 but have a 1K 10W resistor in line to drop the voltage to about 190 to 200V.   I'll do that for this setup when I find some time.

 

The Blue Box under the HP-23 is my 28V supply.   I got it at an estate sale for $20. It was originally a 12V supply, but it was nicely constructed and had dual metering.   I replaced the 12V transformer with a 28V transformer and added a regulator and pass transistor. I think I can source 5A from it, but in any case it is more than sufficient for any ARC-5 (generically speaking) receiver.   I have the output filtered, and it's pretty clean.

 

The box under the headphones is a Timewave DSP-599zx noise filter / audio processor.  I"ve done what I call "iron man" listening -- no external audio processing -- and after doing it a few times I find it's much easier on the ears to be able to adjust the audio bandwidth down to 20 Hz.  By the way, the little blue box to its left is a Ratzlaff 7 Hz audio filter!    I've had to use it many times with my SDR or modern receivers.

 

73 Mark K3MSB

 



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