[Milsurplus] Radio pic and early FM

[Mike Feher]

Nick – 

 

You are addressing wide band FM. There I believe it. Never ran into it in narrow band. 73 – Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

 

From: milsurplus-bounces at mailman.qth.net <milsurplus-bounces at mailman.qth.net> On Behalf Of Nick England
Sent: Saturday, April 19, 2025 5:04 PM
To: Mike Feher <n4fs at eozinc.com>
Cc: Facility 406 <facility_406 at bruteforcedevelopment.com>; milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] Radio pic and early FM

 

Well with a limiter and discriminator as FM receiver, you do indeed get capture. The weaker signal gets limited out. Very common phenomenon on my car radio where I get the station east of me or the one west, but never both at the same time. 

 

This is a reasonable article 

https://en.m.wikipedia.org/wiki/Capture_effect

 






Nick England K4NYW
www.navy-radio.com <http://www.navy-radio.com> 

 

 

On Sat, Apr 19, 2025 at 4:47 PM Mike Feher <n4fs at eozinc.com <mailto:n4fs at eozinc.com> > wrote:

I agree, Kurt. I cannot see that being the reason for the military not using it back then. I got my ticket in '63 and started on 2M FM around '66. Used some modified GE units first then went solid state. Never experienced any so called "captured" effect.  73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
908-902-3831

-----Original Message-----
From: milsurplus-bounces at mailman.qth.net <mailto:milsurplus-bounces at mailman.qth.net>  <milsurplus-bounces at mailman.qth.net <mailto:milsurplus-bounces at mailman.qth.net> > On Behalf Of Facility 406
Sent: Saturday, April 19, 2025 3:37 PM
To: milsurplus at mailman.qth.net <mailto:milsurplus at mailman.qth.net> 
Subject: Re: [Milsurplus] Radio pic and early FM

> The aviation industry deliberately passed on FM because to the 
> "capture effect."  An FM set, stuck on transmit, can block an entire channel.
> This is bad news when your up in the air covering a large area.  On AM 
> you at least have a chance of hearing another weaker station.

I've heard this all my life.

And, living in Nevada, where stations are spread out, it's barely a thing.

My personal observations, across 2+ decades, many FM receivers/transceivers, it works like AM.  Hear one, hear two, or more, but, also like AM, when closer to a stronger one, the stronger seems to take over.

I can personally attest, for the FM broadcast band, 2m, and 440 MHz, there is little to no capture affect, just one station stronger than the other, and I observe it several times per week.

I also monitor airband comms, almost daily.  One can hear one, two, three, with varying levels of interference to each other, to completely blocking.  So, in this sense, AM will also "capture".

AM, FM, they work the same, strongest "captures", modulation doesn't matter.

Perhaps the "capture" thing was based on a particular model receiver, under certain conditions, and the notion stuck?

I tune AM/FM just the same, reception is just the same, and being in a sparse/rural area, it's a good thing, as I often listen to both AM and FM in the boonies, and on the fringe of reception.

Kurt



-- 
This email has been checked for viruses by Avast antivirus software.
www.avast.com <http://www.avast.com> 
______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Milsurplus at mailman.qth.net <mailto:Milsurplus at mailman.qth.net> 

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/milsurplus/attachments/20250419/a6923d72/attachment.html>