[Milsurplus] Antenna Question

[WA5CAB at cs.com]

The manuals says that the AN-147-B was modified with struts and stiffener 
plates and that there was a modification kit to convert the -A essentially to 
a -B to prevent damage to the antenna and aircraft due to parts falling off 
in flight.  The -B and/or kit are not shown in the 3/44 Operator's Manual 
and are in the 9/44 edition.

In a message dated 8/2/2009 1:28:00 PM Central Daylight Time, jfor at quik.com 
writes: 
> There are two Yagi antennas listed for the SCR-729-A and AN/APN-2
> (Rebecca) systems. They are the AN-148-A and AN-148-B.
> 
> I believe they are essentially identical, except the -B version has
> diagonal Bakelite struts to mechanically stiffen the Yagi elements.
> 
> Does anyone know if that is the reason for the struts and if so, when and
> why it was done? Was it because of elements breaking off on higher speed
> aircraft later in the war? I can see that the elements could well fail
> because of metal fatigue, excited by airflow. The elements are airfoil
> shaped as I remember.
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480