Re: Voltage drop in DX Power to K3

Posted by George Danner-2 on Apr 26, 2020; 4:28pm
URL: http://elecraft.85.s1.nabble.com/Voltage-drop-in-DX-Power-to-K3-tp7660188p7660195.html

A couple of solutions used in TV Broadcasting, especially in ENG & Satellite
mobile units.

1) Use a short jumper from the large conductor the the connector. I solder
the 2 wires together (inline) and cover the connection with shrink tubing.
This helps when you want flexibility between the large connector and the
equipment (think mobile vibration).
2)If the large conductor is stranded then remove strands until it fits the
connector.

Another solutions would be to keep what you have and remote the power supply
sense to the destination.
The advantage of this solution is that you have a large voltage swing with a
varying load.
The disadvantage is the power supply has to be capable of supplying all the
current needed at maximum load and the time constant has to be considerable
shorter than the load variation time constant.
Another disadvantage is that any other equipment on the power supply line
will "see" a varying power supply.
This solution is used in many different pieces of equipment in broadcasting.

73
George AI4VZ

-----Original Message-----
From: David Herring
Sent: Sunday, April 26, 2020 11:08 AM
To: N4ZR
Cc: Elecraft List
Subject: Re: [Elecraft] Voltage drop in DX Power to K3

I’m late in coming to this thread, so sorry if I missed the answer to this
question, but what is the voltage drop between the power supply and the
4005i?

73, David N5DCH

> On Apr 26, 2020, at 8:46 AM, N4ZR <[hidden email]> wrote:
>
> I've had an e-mail exchange with West Mountain Radio.  Measured the
> voltage drop inside the 4005i at only .08 volts at 100 watts key down.  My
> power cable from the 4500i to the K3 measures 0.3 ohms on each conductor,
> which at 20 amps should only yield a 1.2 volt drop, right?  I don't know
> where the other volt plus of drop is coming from.  The cable is 40 inches
> long, and only minor shortening is possible.  It is about the largest wire
> that will fit in the Powerpoles on both the K3 and the 4005i.
>
> Suggestions welcome
>
> --
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
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