[R-390] More R648

[Roy Morgan]

On Dec 15, 2015, at 10:24 AM, Richard Green via R-390 <r-390 at mailman.qth.net> wrote:

> another R648 s/n 926 here...the R648 has several "features" that are somewhat annoying: filter selection tied to the mode, and no convenient separation of the AF and RF gain control. It would be interesting to hear the rationale behind these "features". Skip

Skip,

I have no special knowledge about the design process, and can only guess as to why those “Features” were included:

Imagine being at 20,000 feet in a P-3 aircraft, with winter flight suit and gloves on, in the middle of the night somewhere over the mid-atlantic, and you have to get the radio onto some frequency for a new comm link.  You really don’t want extra knobs to twiddle to get the job done.  And the signal you are hunting comes from a communication station Stateside that is running plenty of power into big antennas, so digging a signal out of the noise is not needed.

By the way, the later 51S-1 is set up similarly.  Filters are selected by the mode switch, but it does have separate RF and AF gain controls and a rejection notch.  Otherwise, the thing is disappointingly simple to run, especially compared to the R-390 radios.

Roy



Roy Morgan
k1lky68 at gmail.com
K1LKY Since 1958

PO Box 101 Bernardston, MA 01337