[TowerTalk] Siamese type Coaxial Cable with /4 wire needed.

[Joe Subich, W4TV]

Don,

On 1/7/2016 9:53 AM, n8de at thepoint.net wrote:
 > Why the 4-wire control cable?

The question specifically stated the need to control an Icom AH-4
tuner.  The Icom tuners require +13.8V and ground (which can be
supplied via a bias T) but they also require control lines "start"
and "key" which can not be multiplexed onto the coaxial cable.

One could possible use "siamese" coax plus single pair with a
bias-T but the Icom tuners still require some individual control
lines.  *Unfortunately*, most siamese cable is 75 Ohm, not 50 Ohm.

73,

    ... Joe, W4TV


On 1/7/2016 9:53 AM, n8de at thepoint.net wrote:
> Why the 4-wire control cable?
>
> You can use the coax for switching ... I invented the idea in the
> 70's... it's very much like what is in the ARRL Antenna Handbook (and
> the ARRL Handbook) ...
> similar switching is available from MFJ/Ameritron .. and was used by
> Drake and Heathkit years ago.
>
> Just need to build a small blocking circuit at each end of the coax.
>
> 73
> Don
> N8DE
>
>
> Quoting jimlux <jimlux at earthlink.net>:
>
>> On 1/7/16 4:23 AM, John K0CQW wrote:
>>> Looking for 8X type coax with 20 ga / 4 wire control Siamese together.
>>> approximately 50 feet.(OR variations)
>>>
>>
>> You might find some 75 ohm coax with wires as used in security/video/
>> ENG systems.
>>
>> Belden 9265 is RG59 + a shielded twisted pair. 9165 has 3 pairs.
>> http://www.belden.com/techdatas/english/9265.pdf
>> 1dB/100ft loss at 10 MHz
>>
>> There's also Belden CCTV cable RG6 + 18/2
>>
>>
>>
>>
>> For only 50 ft, I'd get some black heat shrink and use it to bundle
>> your coax and control cable. something like a half inch of heat shrink
>> every foot.
>>
>> Or, depending on the environment, just spiral black tape the length of
>> it.
>>
>>
>>>  Any sources ?
>>>
>>> Looking to get a OM on the the air in a assisted living.
>>>
>>>  Working with a Icom AH-4.
>>
>> Are you fixed on the AH4?  There are other remote tuners that can be
>> powered/controlled via the coax.
>>
>>
>>
>>>
>>> HAVE to make this a "CLEAN" installation.
>>>
>>>  Specifically looking for the coax and control wire together.
>>>
>>> Thanks de John KØCQW
>>> _______________________________________________
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>>>
>>>
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