[Milsurplus] Radio pic and early FM

[Facility 406]

On 4/19/2025 13:37, Hubert Miller wrote:
> I do a fair amount of "DX listening" and i note that when driving, a 
> stronger FM broadcaster will "pop in" even if for just a couple minutes 
> and then gone. On 2M hamband the strongest station wins, with just a 
> growl heard underneath. On MW AM band, i can so often hear audio from 2 
> stations

Most of my FM is mobile, and one fixed desktop receiver, originally a 
Tivoli Model 1, currently, a Realistic Chronomatic-230.  Mobile, a 2003 
Ford Taurus, 2011, and 2013 Toyota Tacoma, 2006 Chrysler 300, prior to 
those, a 1990, and 1991 Toyota 4Runner.  I am in a rural, and fringe 
area, often doing runs from Minder/Gardnerville to the south, to Reno in 
the North, and Fallon in the east.  It is not uncommon to hear a station 
fade, and another come in, especially along highway 50, east of Dayton, 
and west of Silver Springs.  I will change frequencies to listen to 
something else when I can no longer pick what I want to listen to out of 
the garble of 2-3 stations.

I think the whole capture affect idea is based on urban areas, with 
strong stations.  I have never noted it outside of large cities, in 
rural areas, everything is comparably weak, so they come in all the 
same, no different than AM.

> It kind of still bewonders me that this inches long antenna on top my 
> van does so well for AM DX.

Amplifier.  Sometimes they are built into the OEM radio, sometimes in 
the base of the antenna, sometimes a separate module.  In my Chrysler, 
it's separate module in the upper end of the c-pillar, passenger side. 
The antenna itself is about 2'x6', made up of several runs of copper 
trace with a matching network, printed onto the rear window, in between 
the defrosting elements.

Here's a scary thought....

The "shark fin" antenna, seen on so many vehicles, IS an antenna, but 
not for what you think.  It is the telemetry, and telematics antenna. 
There is a pair of 4/5G antennas in there to relay location, parameters 
of the vehicle, and any parameter that can be measured of any person, in 
any seat.  The secondary antenna is top-dead-center of the dashboard. 
Owners manuals often warn not to place items on the dashboard.  In the 
past, this was for safety, to keep things from sliding about, nowadays, 
it's to not block the telematics, and at times GPS antenna hidden under 
there.

Kurt