[Milsurplus] information on RT-7/APN-1

[jmfranke]

It is a 400 MHz FM radio altimeter. There is a wobbulator inside that is 
best described as a speaker driving a small variable capacitor to FM the 
transmitter. The acorn tubes form a balanced detector. The return wave is 
delayed from the transmitter. The difference in the transmitted wave and the 
received wave is an audio frequency that increases with altitude.

John  WA4WDL

--------------------------------------------------
From: "Phil Lewton" <lewton_eng at clear.net.nz>
Sent: Monday, June 06, 2011 5:10 PM
To: <Milsurplus at mailman.qth.net>
Subject: [Milsurplus] information on  RT-7/APN-1

> Hi I have an RT-7/APN-1
>
> Can any one identify this item it appears to be aircraft may be radar but
> not sure
>
> free to good home cost only postage.
>
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