I am looking for a schematic for a Collins 18 S-4. It is apparently a 10
channel 100 Watt tranceiver that was used in aircraft. I have two of them
that have had the dyno's removed. They look pretty hefty with an 813
modulated for AM by a pair of 811A's. They have a removable cover on the
front to manually change channels. It is simply a rotary switch with a
screwdriver slot.


The only source I found wants $75.00 for a manual for what is probably a
$10.00 radio.

Thanks all

Fair Radio has repros


"Fred W4JLE" wrote in message
...
I am looking for a schematic for a Collins 18 S-4. It is apparently a 10
channel 100 Watt tranceiver that was used in aircraft. I have two of them
that have had the dyno's removed. They look pretty hefty with an 813
modulated for AM by a pair of 811A's. They have a removable cover on the
front to manually change channels. It is simply a rotary switch with a
screwdriver slot.


The only source I found wants $75.00 for a manual for what is probably a
$10.00 radio.

Thanks all

Fred,
Maybe I can help. My father was a field engineer for Collins Radio
from 1952 to 1955 and worked with the 18 S transmitter/receiver and 180
L antenna tuner.

I have saved things from those days for sentimental reasons. Turns out,
I have two copies of the 18S-4 instruction book. I thought it was just
an operators manual, but it's almost a half inch thick, and does have a
schematic of the set and parts list and pretty good pictures. It's a
second revision dated November 1953.

I don't need two copies, so I'll bet we can make a deal that will at
least give you some place to start without you spending your life's
savings. I'll bet Art Collins would turn over in his grave if he heard
you call his 18S-4 a "ten dollar radio".

Of interest is where did you acquire these units?

John

Fred, Looks like you're covered. If you need more info, perhaps I
could help. I have the AF training pack for the unit as well as the
original Collins book. As one who's gotten one on the air (sic), I can
tell you that there are a few points to ponder. Hopefully you have at
least one tuner. If there are no tuner, you can build an external
network. The big thing for most of us was/were the L/C tuning elements
for the receiver and transmitter. The rx requires two elements (mixer
and RF)and the transmitter one (driver). They plug into the boxes in
the middle of the unit and screw down to a horizontal bars. Originally,
the tuning elements came in a large kit and are set up for chunks of the
HF band. I was unable to find any elements, whatsoever, over about a
year's worth of looking. I ended up putting three together for just 80
meters. As you may have gleaned, the 18-S is pretty much an ART-13 and
simple receiver, sans the VFO and ability to variably tune either the tx
or rx.
Racks are unobtainium (unless, again, you got one with yours). The rear
connectors can be had from the Wm Perry Co. for about $20-$25 each. I
do wish you good fortune with the project. FWIW, I can tell you that,
although they did work OK when properly set-up, the AF techs cursed the
radio set and were pleased when the ARC-38 and the 618S equipment came
into the inventory. The 18S is said to be a stop-gap to provide for
compliance with the emerging ICAO requirements. Interestingly, I have
copies of the Proceedings which address the HF aeronautical spectrum in
the early 50's and the recommendations and requirements made back then.
Regards Jeep/K3HVG

I should proof-read my posts better, too!!

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

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

Thanks for the great tips. I guess I will nail down a manual/schematic and lay down a battle plan from then on. I like the VFO/RF section idea.

73,

Mark


[quote=K3HVG]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!

I have a manual coming, if you have any particular areas you need info on
let me know.

If the copyright has expired, I will scan it an publish it on LuLu press.

I have two and I am awaiting the manual to see what goes in the rear of the
chasis that seems to be missing from both of mine.

There is a cradle that goes across the back and nothing occupies the space
on either of mine.

"MilRad" wrote in message
...

Thanks for the great tips. I guess I will nail down a manual/schematic
and lay down a battle plan from then on. I like the VFO/RF section
idea.

73,

Mark


K3HVG Wrote:
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

Unless I'm missing something, I think you'll find that's where the
dynamotor goes. And... BTW, the ART-13 dynamotor is the exact one that
goes there, sans the mount, of course, and the bolt holes match up 100%.