[Elecraft] K3/100 Voltage Drop when transmitting

[James Walker]

I have a K3 that behaves similarly to what Mike described. I switched from an Astron 25 amp (15 years or more old) power supply to a switching power supply. Problem solved. One would think the problem was my Astron power supply, but I don’t see any such power drop when I use my Astron with other 100 watt rigs. Very strange. 

Jimmy Walker, WA4ILO
Macon, GA


> On Feb 25, 2019, at 1:58 PM, donovanf at starpower.net wrote:
> 
> 
> Hi Mike, 
> 
> What are your voltage readings at the power supply end of your 
> six foot power cords? 
> 
> 
> None of my K3s do behave the way you describe. 
> 
> 
> 73 
> Frank 
> W3LPL 
> 
> 
> ----- Original Message -----
> 
> From: "mjpilgrim" <mpilgrim at bellsouth.net> 
> To: elecraft at mailman.qth.net 
> Sent: Monday, February 25, 2019 6:55:01 PM 
> Subject: [Elecraft] K3/100 Voltage Drop when transmitting 
> 
> At first i suspected my Solar power system which was installed a year ago, 
> but now I plugged my K3 S/N 7317 directly into my 25A switching DC power 
> supply, and when key down, 100W in CW, on the internal K3 Power Meter i see 
> a voltage drop from 13.6 to 12.0VDC. My power cord is a 6', 10ga stranded 
> copper wire pair with Andersen Power Pole connectors. I have tried three 
> separate power cords, all 10ga with power pole connectors, but with no 
> change in the voltage drop scenario. If anyone has suggestions of where the 
> problem lies, I am all ears. Obviously, when operating SSB the drop is 
> present but not as severe. What am i dealing with? Better yet, how do i 
> fix it? Thanks in advance. 
> Cheers, 
> Mike, K5MP 
> 
> 
> 
> -- 
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