Dave Haupt wrote:
>The original reason that hams preferred the P version of the tube was
>the same reason for most of our preferences: price and availability.
>The tube was used in relatively high quantities in MRI equipment. Users
>of MRI equipment routinely replace tubes as a preventive measure, and
>there were literally thousands of "P" type tubes made avaialable as
>full-output pulls for a fraction of the price of a non-P tube.
>Since the non-P version of the tube was predominantly used in ham amps,
>when you did find a rare used one, it was generally used up.
>For any ham application I know of, there's no technical reason to
>choose one over the other.
There are definite advantages in using the 3CPX at 432MHz, as identified
However, most of these factors apply *only* at UHF where gain and
efficiency at beginning to fall. At HF these factors do not apply, so it
comes back to price and availability.
Let's hope there will still be enough 3CPX800A7s available for the
432MHz amps that can really benefit from them.
73 from Ian GM3SEK
Amps mailing list