[Collins] Mech filters in 75A3 - mechanical Filters

[Rodney Bunt]

Guy,

The 75A-3 was a 75A-2 with mechanical filters, it came out in abouot 1954, there was a retrofit to
the 75A-2 called the 75A-2a it was the same performance as the 75A-3.

There was story on how to add mechanical filters in QST in the 1954 year, can't remember which one
(I won a bunch of QST on eBay and am in the process of reading them all, I haven't read Oct, Nov,
Dec 1954 so it is earlier).

It is an interesting mod, in that that it was a plug and play mod.

The First IF tube was removed (unplugged) and a box with an Octal plug on the bottom inserted, and
it had two minature tubes and a crystal filter installed.

If you wanted to go back to 6kHz just plug in the Old Tube.

Rodney
VK2KTZ

--- "Guy Olinger, K2AV" <k2av@contesting.com> wrote:
> I note that some 75A3's have a pair of mechanical filters selectable
> from a lever behind one of the front panel knobs.
> 
> Where can I find out the filters that are used for this setup. Was
> this a factory mod or what?
> 
> Many thanks,
> 
> Guy, K2AV
> 
> 
> 
> 
> Sponsored by the Collins Radio Association
> http://www.collinsra.com


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