[Milsurplus] ARC-2: Smart People Needed

[Ray Fantini]

Not having a schematic am being at a disadvantage and just tossing up speculation at this point but isn't there a fixed frequency IF stage after the variable IF? Know all the Collins stuff of the late forties and fifties used a variable IF section and then a second converter to a fixed frequency IF on 455 KHz for civilian stuff and frequencies like 500 and 250 KHz for military radios. The filtering is always on the output of the second converter.
Now interested in seeing the schematic for the ARC-2 being that may be the first radio to use the double conversion system and the father of the 75A, R-388 and later S line radios.

Ray F


-----Original Message-----
From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of David Stinson
Sent: Wednesday, April 02, 2014 9:41 AM
To: milsurplus at mailman.qth.net
Subject: Re: [Milsurplus] ARC-2: Smart People Needed

"...effective IF filtering has to take place before the input to the first IF amplifier with a filter being between the output of the mixer and the first IF..."

Thank you kindly for writing, Ray.
The ARC-2 uses a tunable IF from 1.0-1.5 MC that closely tracks the RF tuning.  
Fixed filtering will not work in this IF design.

TNX OM ES 73 Dave AB5S