[Elecraft] K3 - Power cable voltage drop

[K9MA]

There can be stability issues with remote sensing. Also RF susceptibility.  Take care!

73,
Scott K9MA 



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Scott Ellington

 --- via iPad

> On Dec 24, 2019, at 4:03 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:
> 
> That would be a neat thing to do, but DO NOT do that on a power supply that is connected to anything other than the rig you are sensing from.
> 
> The voltage on other devices connected to the power supply will increase when you transmit on the rig to which the sense wires are connected.
> 
> Use a separate power supply for accessories.
> 
> If you need to use the same supply, you can adjust the voltage upward - the SS30 sold by Elecraft already has an output voltage of 14.1 volts.
> Still use a separate power cable to the transceiver and another cable to any distribution box that you use for accessories for best results (lowest voltage drop when transmitting).
> 
> 73,
> Don W3FPR
> 
>> On 12/24/2019 4:23 PM, K4HYJ via Elecraft wrote:
>> I do use voltage sensing at the rear of the radio.  Astron supplies can be
>> modified easily to do this - they already have sense wires tied to the
>> voltage output terminals.  Basically you disconnect them there and run leads
>> (keep em short) to the radio.  On transmit, my K3s drops less than 1/10 a
>> volt.
>> There are a few write ups floating around on how to do this.  I installed a
>> switch (make before break type) on my RS-50M so I can return to "normal"
>> sensing.  ***WARNING*** If the external sense wires are not connected to
>> anything the crowbar circuit will fire!!!
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