[Milsurplus] Think MAB, DAV and DAV-1

[Mike Morrow]

David wrote:

>Think the MAB Marine corps HF portable, one of the answers
>to the Army BC-611:

But a wrong answer, I'm afraid.  I suspect the the MAB post-dates the BC-611, which makes one wonder why a set like the MAB/DAV would see the light of day when something much less awkward and higher performing like the BC-611 was available.  Walt Hudgins speculated that the BC-611 design was the first military use of some of the 7-pin miniature tubes that were first introduced in 1939.  He cites a patent (without number) on the BC-611 design held by one Donald H. Mitchell.  I'd sure like to know what the patent number was so I could look it up on the US Patent Office website.

The MAB uses about the same tubes as the BC-611.  The MAB receiver has no RF stage and uses seven tubes to do the almost same thing as the BC-611.  Except that the BC-611 uses only five tubes, incorporates a receiver RF stage, and cleverly lights only half the filaments of the two 3S4 tubes on receive to save A-battery current drain.  Even compared to the BC-745 pogo-stick radio, the BC-611 is one heck of an efficient design.  Admittedly, the 14-pole PTT switch was essential to such efficiency.  About the only things I don't like about the BC-611 are the telescoping antenna and the use of only one screw to hold the case and chassis together.

>When this adaptor was fitted and a different radio chassis
>was installed, the MAB became a DAV (no suffix) direction finder.

Interesting info.  I had thought all the DAV-series were made that way from the start.

>The radio chassis for these three iterations looks the same
>at first glance, but they are not. The single connector on the
>MAB chassis has one center pin.  The DAV chassis has *two*
>connectors, a six-pin round being used to bring out the antenna
>connections. The DAV-1 and -2 chassis goes back to one connector
>that has five center pins.

I was wondering why the chassis for my DAV-2 had a different CCI-430xx number than my MAB, which I just noticed a few days ago.  I hadn't yet gotten around to comparing the two side by side.

Mike / KK5F