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

Fri Nov 21 17:59:33 EST 2025

Mark – Indeed, that I understand. But what can YOU hear in a 10 Hz bandwidth that is intelligible? Or, is it just a matter of being able to discern that there are multiple stations there for a visual display? 73 – Mike 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

From: Mark K3MSB <mark.k3msb at gmail.com> 
Sent: Friday, November 21, 2025 5:51 PM
To: Mike Feher <n4fs at eozinc.com>
Cc: ARC5 <arc5 at mailman.qth.net>; Milsurplus at mailman.qth.net; Military Radio Collectors Association <mrca at mailman.qth.net>
Subject: Re: [MRCA] [ARC5] [Milsurplus] Vintage LF/MF Fun with my BC-453B

Hi MIke

Here's a screen capture from my SDR from 17 Nov 2025  0200 EST:

It shows the USB for VQK and HK, both on 332 Kc 

VQK is in Washington DC and HK is in Hickory NC.

The USB Frequencies are: 

HK 333.018 Kc
VQK 333.028 Kc

That's a difference of 10 Hz.  

At my QTH,  VQK is a boomer,  and HK is weak.   Without a very narrow filter, I cannot clearly hear HK.

73 Mark K3MSB

On Fri, Nov 21, 2025 at 4:07 PM Mike Feher <n4fs at eozinc.com <mailto:n4fs at eozinc.com> > wrote:

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 <mailto:mrca-bounces at mailman.qth.net>  <mrca-bounces at mailman.qth.net <mailto: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 <mailto:kargo_cult at msn.com> >
Cc: ARC5 <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net> >; Milsurplus at mailman.qth.net <mailto:Milsurplus at mailman.qth.net> ; Military Radio Collectors Association (mrca at mailman.qth.net <mailto:mrca at mailman.qth.net> ) <mrca at mailman.qth.net <mailto: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

 <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> 

 <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient> Virus-free.www.avast.com

 <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>  

-- 
This email has been checked for viruses by Avast antivirus software.
www.avast.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20251121/c3342960/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 27475 bytes
Desc: not available
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20251121/c3342960/attachment-0001.png>