[Collins] Collins Digest, 51J et al

[Dr. Gerald N. Johnson]

On 4/18/2010 12:26 PM, G3OOU at aol.com wrote:
>
>
> In a message dated 18/04/2010 16:01:05 GMT Standard Time,
> collins-request at mailman.qth.net writes:
>
> I'm  always interested in good receiver designs, I'd not know of the
> AR8516L  before.
>
> 73, Jerry, K0CQ, Technical Adviser to the Collins Radio  Association.
>
>
>
>
>
> Hi Jerry
>
> Thanks for your comments. I have very little information on the AR8516L but
>   I do have an operators manual on what appears to be the marine version
> called  the CRM-R6A but I cannot find a print or copyright date. The AR8516L
> that I saw  in the UK was well before 1965.

The AR8516L manual that I found indicates its primarily a marine radio 
made to operate from 110 volts DC, though the manual does show a 120/240 
optional AC input supply to give the 110 volts DC. Some comments I saw 
while searching for information indicated the AR8516L used small 
dimension hardware in places that tended to not survive shock and 
vibration well, so it didn't have a long life. I suppose its probably 
mentioned in some other reference books that I have that cover shipboard 
radios, but I've not hunted them in my book piles and shelves since I'm 
trying to move the whole collection to another location. It may be years 
before they pop up out of the moving boxes.
>
> Are you aware of the Squires Sanders SS1R design? Another interesting
> design of a 'certain age'.
>
Yes, I've know of that one since it was first publicized. The beam 
switching tube mixer was its main claim to fame and was a far better 
tube mixer than any of the usually pentode or pentagrid tubes for 
dynamic range. My 75S-3B uses a 6688 for the second mixer which really 
cut its noise and improved its dynamic range.

> Apologies for being a bit off topic.
>
> I am looking for a copy of the Collins 62S-1 PA schematic to study as I am
> interested in the multiband concepts and techniques of valve rigs.

http://www.collinsmuseum.com/62s1.html
Says:
> Transmitter Circuits
>
> The net inductance of L1 in series with L2 is parallel tuned to the 6-meter band
by the combination of C1, C2, and circuit capacitance. Tuning within the 
band is
done by varying the inductance of L2 which consists of a circular ring 
with a
rotating wiper arm. When operating on 2 meters, C2 is switched out of 
the circuit,
L3 is switched in parallel with L1, and L4 is switched in parallel with L2.
This reduces the net inductance of the circuit and the inductance range 
of L2
to provide the proper LC ratio and tuning range for 2-meter operation. 
The PA
plate circuits operate on the same principle with slight differences to
accommodate PA operating parameters. The PA tank circuit is resonated on 2
meters by the output capacitance of V5, the PA tube. A trimmer to provide
additional capacitance is switched into the circuit on 6 meters. Double
contacts are used on the PA bandswitch wafer to reduce inductive effects
and to handle the circulating r-f current. Link output coupling is used
with a series variable capacitor for loading adjustments.

http://www.algra-funkarchiv.de/manuals/005.htm has a beschreibung for 9 
Euro.

Several places in the US want a lot more for the manual.

I suspect its a series tuned output using mostly the tube capacitance 
for one side, link at the middle and tuning cap on the other end of the 
coil. That description says it switches out some C and shunts inductance 
to move from 6m to 2m.

One published design in Ham Radio Magazine used two 4CX150 or 250 in 
push pull on 2m and in parallel on 6m where the 6m tank was the 
isolating RF choke for 2m operation and the 2m tank made up leads from 
the tubes to the 6m parallel tuned output. And so had separate output 
connectors. I've not been into a 62S-1 and my search in the past few 
minutes showed the usual sources of Collins manuals didn't have it, 
though the commercial sources nearly all offer it for a price.
>
> 73
>
> Bob
>
> Bob F Burns
> Amateur  Radio Callsign: G3OOU
> G-QRP Member No: 6907; QRA: IO91WH; WAB: TQ25
> Joint  web site with Crystal Palace Radio&  Electronics Club:
> _www.g3oou.co.uk_ (http://www.g3oou.co.uk/)
> Technical web site: _www.qsl.net/g3oou _ (http://www.qsl.net/g3oou)
> ______________________________________________________________
>
73, Jerry, K0CQ