[Elecraft] Regarding KAT500 current drain

[Joe Subich, W4TV]

> However one way is to get the "rigrunner" 12v strip that has a
> current sensor in one of the ports which turns on the rest of the
> ports...and plug the K3 into that current sensing port.

If you do that, *do not* power any accessory that handles audio going
to the transceiver mic or line inputs from the "auxiliary" power strip.
Doing so will result in "RFI" as transceiver return current finds its
way back to the power strip through the accessories and in turn pumps
the ground (power supply) reference for those accessories.

When using an auxiliary power strip it is absolutely impossible to
provide a zero Ohm return for the transceiver's primary power supply
and return current *will* divide among the multiple returns (some
via accessories).

If one has "12V" accessories and a "12V" transceiver, the accessories
should always be powered from an auxiliary output on the transceiver
*or* from a *completely isolated* power supply.  *Never* connect
accessories to the same supply as the transceiver.   Kenwood have
recognized this issue for years; all of the instruction manuals for
their 12V transceivers recommends using a separate power supply for
TNCs and Terminal Units.  While Kenwood references "noise pickup"
the real reason is to avoid "noise" coupling via the power supply
return.

73,

    ... Joe, W4TV


On 4/25/2012 1:00 PM, hawley, charles j jr wrote:
> I think we need a device that powers a number of 12 vdc devices
> triggered by the 12 v coming out of the K3. However one way is to get
> the "rigrunner" 12v strip that has a current sensor in one of the
> ports which turns on the rest of the ports...and plug the K3 into
> that current sensing port.
>
> Sent from my iPad
>
> On Apr 25, 2012, at 11:52 AM, "Eric Swartz - WA6HHQ,
> Elecraft"<eric at elecraft.com>  wrote:
>
>> No. We do not recommend powering this number of devices form the K3
>> AUX 12v conn.
>>
>> Eric --- www.elecraft.com
>>
>>