[ARC5] Re: [Milsurplus] WWII Aircraft Antenna AN-104-series

[jcoward5452 at aol.com]

I start my next employment tomorrow and hopefully they will have a 
network analyzer available for "lunch time use".It'll take a bit of 
time until my new employer gets used to my eccentricities!I'll look at 
the VSWR over the frequency range 100 to 156 MHz (and further too) when 
I get a chance.
 Jay


-----Original Message-----
From: kk5f at earthlink.net
To: milsurplus at mailman.qth.net; arc5 at mailman.qth.net
Sent: Tue, 2 Jan 2007 6:05 PM
Subject: [ARC5] Re: [Milsurplus] WWII Aircraft Antenna AN-104-series

Clete wrote:

>The frequencies the USAF used for aircraft AM
>were between 116.1 and 140.58 MHz. That was
>the range from "A" to "D" when I used the SCR-522.

All of the "new from factory" R-28/ARC-5 and T-23/ARC-5 VHF sets that 
I've come
across had the same four frequencies, and I've been told that often 
SCR-522 sets
had the identical setup:

A - 116.1, B - 126.18, C - 140.58, D - 142.74 MHz

The last two frequencies were also standard on the "new from factory"
RT-19/ARC-4 USN VHF sets.

>The antenna protruded into the inside of the airframe.
>The oval clamp could be on the inside, and was
>adaptable to whatever shape the inside of the
>airframe was.

There would have to be some substantial mechanical anchoring and 
bracing at the
bottom under the skin of the airframe. That clamp with the six braided 
straps
could only serve for reliable electrical connection.

>The antenna matching was a technical wonder. It's all inside there.

It would be interesting to know just what is under the metal shell and 
in the
wooden base of this antenna. It certainly seems to flattens the SWR 
response
from 100 to 156 MHz.

Jay wrote:

>I have a AN-104-B and a AN-74A antenna(s). The -104- has a thin metal
>sheath painted silver and the -74A also has a metal sheath but painted
>O.D.The -104- has a hole in the tip of the mast whereas the -74A has a
>small flange(?) with the hole for securing the HF antenna.

I've seen the AN-74, and how similar to the later AN-104 that it 
appears. Yet,
the VHF AN/ARC-5 manuals explictly state that antennas earlier than the
AN-104-A, -AX, or AT-8/AR should not be used. That makes me wonder it 
there's
some subtle technical difference between the similar looking AN-74 and 
the
AN-104.

Have you ever measured the SWR response of the AN-74?

73,
Mike / KK5F

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