[ARC5] Tuning Cable Question

[Mike Hanz]

On 5/30/2014 1:48 PM, Geoff wrote:

>> On 5/30/2014 1:04 PM, Robert Eleazer wrote:
>>> As we all know the tuning knobs for the earlier TRF radios like the 
>>> RU and SCR-283 are larger than the ones used for the SCR-274-N and 
>>> ARC-5 types.
>>> Is this because the TRF sets had more mechanical stuff to turn than 
>>> the superhets and thus needed cables capable of handling the extra 
>>> load?
>>
>> If it were a function of load, wouldn't the inner phosphor bronze 
>> flex drive cable be larger in diameter than the ones in the command 
>> set drives? (It's not...they are both ~.148"OD) What is somewhat 
>> inexplicable is why the earlier cables had a larger diameter sheath 
>> than those for the command sets, and thus needed a larger connecting 
>> nut, which forced the spinner knob to be larger, and the knee bone is 
>> connected to the thigh bone, and....
>>
>>  - Mike  KC4TOS
>
> Did they originally simply use what was on most auto radios thru to 
> the late 30's? A dashboard or steering column mounted tuning head with 
> 2 cables to the firewall mounted electronics box.

That's an insightful question, but most of the examples of auto radio 
remote drive cables from the 1930s that I have seen used the smaller 
diameter sheath, with a coarser sheath wrap that wasn't as flexible as 
the aircraft stuff.  Not sure it was exactly the same diameter as the 
ARC introduced cable, either.  Possibly the early days used an 
automotive speedometer cable from the late 1920s as a prototype and then 
it just stuck.  Stranger things have happened.

           73,
  - Mike  KC4TOS