[Collins] Collins ham gear redesign

[Carl]

> I've been hearing claims of running high power for a very long time yet I 
> never hear grumbles about burning connectors off ordinary ham sized coax 
> or needing large coaxes and connectors.

** RG-213 and the PL259 will easily handle 5KW at low HF and low duty cycle. 
Most serious QRO is 20-160M.

I know RG-14 warms up at 5
> KW on HF from dummy load experiments at Collins. Salt water in a tank can 
> make a high power dummy load, but it modulates the signal as bubbles form 
> on the inner electrode.

** Never used it but I did run almost new surplus RG-17 and 177 in the 
60-70's to lower loss. Switched to CATV hardline in 79 and use it almost 
exclusively to 1296 and up to 1".
The run to the top of the 180' Rohn 45G tower is 450' or so, the 432 and 6M 
tower is 150', 144 and 222 200'.

432 and up will be locating to a new 45G tower mounted on the 2nd story roof 
of the central part of the house and bracketed twice to the higher 3 story 
part which has a 12' peak. That is a walk up attic with exposed 2x6" framing 
(mandatory in NH since the mid 80's) which will have paired 2x8's across 
them and tied into the brackets by some mighty strong hardware. Until I 
start adding small dishes, 40' above the top bracket should be fine. This is 
all on top of the highest hill in 20 miles with a -3 degree horizon worst 
case.
The house is a combination of 1830's, 1930's, and 1989 construction.


** QRO hams have been using 1/2" and 7/8" Andrew or similar hardline and 
CATV equivalents for many decades at up to 20KW or so.
These days the 7/16 DIN connector is often preferred.

Tubes such as the 3CX3000A7 or F7, 3CX5000A7, YC-156, 3CX6000A7, 3CX10000A7, 
and higher are readily available and not that expensive if you know where to 
look. There are several tetrodes in the mix also.



> On 7/8/2014 11:00 AM, Carl wrote:
>> A pair of 4X1's isnt even entry level into the QRO club these days.
>>
>> BTW, is there any market for a large prop pitch these days?
>
> There might be for EME arrays or large dishes. But the read out for 
> direction that is needed can almost make a M2 rotor a reasonable purchase.

** I still use a vintage Orion 2800 (now M2) on the 180' tower and it 
survived a 4el KLM 40M for decades until the winds pretty much tore up the 
antenna. Hill effect is tremendous here above the 120' level. An earlier OR 
2400 is on a 100' tower


The bigger the dish, the more rotor power is needed, but the
> more critical the aiming. A 12' dish at 10 GHz doesn't uniformly 
> illuminate the moon so tracking has to be updated several times a minute 
> to keep the illumination on the best parts.


** I still remember working on the 28' Kennedy and drive system at 
W1BU/W1FZJ in the early 60's.

Carl
KM1H
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