[Heath] Heathkit SB-644A, Remote VFO Cables

[Bob G3OOU]

Hi Ken

RG62 is 93ohm coax with a much lower unit capacitance than RG58. I used 
RG62 coax on a low loss RF scope probe which is documented on my 
technical web site.

Heathkit used RG62 for the interconnections on the SB301/401.

73

Bob

Bob F Burns G3OOU, G-QRP 6907, @BobFBurns
Crystal Palace Radio & Electronics Club: http://cprec.btck.co.uk/
Admin/sales site: http://www.g3oou.co.uk/ Technical site: www.qsl.net/g3oou

On 09/10/2021 20:52, Kenneth G. Gordon wrote:
>> On 10/8/2021 2:54 PM, Steven Feinsmith wrote:
>>      coaxial cable. The original cable labeled as follows:
>>      
>>      300V  80 degree  FR-1  (UL)  AWN  STYLE  1436
>>      
>>      I searched for the specification for that cable. Unfortunately, there was almost no
>>      information such as 50-ohms?
> I will bet that is RG-62, which Heathkit used to interconnect different bits such as the SB-300
> to the SB-400, etc.
>
> I believe that stuff is 68 ohms.
>
> The reason Heathkit used it was because it shows very much less attenutation than RG-58,
> but as mentioned, the impedance is of no real concern.
>
> In your case, I would, like Chris, recommend that you simply use RG-58, although you
> COULD use RG-174 (50 ohms) if you wanted something far more flexible. The power levels
> are so low that using RG-174 wouldn't matter....although soldering it to an RCA connector
> would be more difficult.
>
> I would certainly not use RG-8X. It is not necessary, and is too hard to use for what you need
> it for.
>
> As for the RCA connectors, it turns out that Collins also used those extensively because they
> provide a much better match to 50 ohms than a PL-259/SO-239 does, and at power levels up
> to well over 100 watts, they work just fine. Of course, the ceramic-insulated ones are best.
>
> The so-called "UHF" connector, however, does hold onto each other better because they are
> screwed together.
>
> Ken W7EKB
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