[Fwd: Re: [ARC5] Re: [Milsurplus] History of Ham Mods: Opinions?]

[J Forster]

The US used switched Yagis to do DFing in the Rebecca system at around 220
MCPS. There was one two element Yagi bore sighted to the left and one to the
right of the flight path. The L-R switch was in the BC-929 display. The
transmit antenna was an omni rod.

In the ASB-5 a pair of Yagis were also used at roughly 515 MCPS, but the same
antennas were used for Tx and Rx, alternately...  first Tx on L, Rx on right,
then swap over the antennas. The T-R switching was done with a transmission
line of precise length, but the L-R was again a motor driven switch.

Best,
-John

============

Marty Reynolds wrote:

> I never gesssed the need for 4 yagis.  Radar was a Fug something, right?
>
> We used a 200 mhz sperry homebuilt radar I've never seen pictured in '42.
> Put in nose of Loadstars to hunt subs.  Have parts to a nosecone fm
> father-in-law
>
> Marty aa4rm
>
> > de WB2CPN
> > Those "half folded dipoles" were quarter
> > wave, or odd multiple thereof, verticals.
> > As you said, they had one reflector element.
> > You see a lot of folded verticals on the
> > 50 MHz Commercial band.
> > The first Yagi arrays I ever saw were on a
> > German night fighter.  It had four on the
> > plane's nose. All it took was a simple antenna
> > switch and a synchronized CRT for the pilot.
> > 73  Clete
> >
> >
> >
> >
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