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				 Collins 18 S-4 
 
			
			Mark,  I built a control head.  No big thing.  Also, AM is the deafult.All you really need do is plug in a mic on the front panel.  RF and AF
 gain must be controlled externally, of course.  The crystals you have
 won't do you much good but you can have a set cut for.. say 3885, or
 such.  That's what I did.  I hooked a Heath VFO up to the transmitter
 and it worked OK.  The 18-S4A receiver is much better than the straight
 unit inasmuch as it has a mech filter installed.  The straight unit is
 as broad as a TCS!  Also, I did not use the fixed elements in the TX
 tank circuit.  I brought out the "untuned" RF into an external
 PI-network (instead of the tuner) for 80 meters.  That way, I could tune
 wherever needed and not worry about the fixed freq. tank components.  I
 have both original Collins 18-S4 and 18-S4A manuals.  Unfortunately, I
 no longer have "unlimited copy capability"...hi!
 
 MilRad wrote:
 Great topic here as I recently decided to try and get my 18S-4 on the
 air. I am looking for the 314S-4 control head if anyone out there has
 one. I'm not sure how to change from CW/AM without it. I have the rack
 and tuner.
 
 I'd like to get the schematic and manual also but don't want the large
 investment in case this doesn't get off the ground. I have the small
 handbook but that was a bit of a dissapointment as it doesn't have tech
 data in there. I believe my unit is complete as it has most of the
 crystals. Not Ham band but close. I'll have to check what tuning units
 are in there.
 
 73,
 
 Mark
 
 
 
 
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