Re: [Elecraft] K3 Voltage on TX

In general, it would be ideal if there were zero voltage drop. This just won't be the case in the real world.The VFO-B voltage indication is reliable in terms of the voltage in receive vs. the voltage in transmit. I think it reasonable to accept < 0.5 volt drop or less between RX and TX

Re: [Elecraft] K3 Voltage on TX

Hi Jeff, many thanks for your post regarding the soldering Anderson Plug leads connections. It seems that I should check it too as I have 0.7V drop RX/TX on VFO-B line measurement. (even although I never had any problem regarding the low voltage...) It is good hint for my old timer K3 (#778)

Re: [Elecraft] K3 Voltage on TX

Rich, The first K3 I owned always showed a large voltage drop on TX that was pretty much incurable (as well as other issues), much to my (and others) consternation. I tried (In no particular order) Heavy gauge power cables, No fuses, Upping the power supply voltage, Re soldering the 30 Amp

Re: [Elecraft] K3 Voltage on TX

I gave up running my K3 through a RigRunner for just that reason. I put in a short lead directly to the battery bank APP junction strip and things got a lot better. They got even better with a N8XJK Boost Regulator between the K3 and the junction. (Tested with 100W into a dummy load.) 73

Re: [Elecraft] K3 Voltage on TX

It would be nice to have test point type jacks on the back of the K3 to test the voltage drop from the PS through the APP's entering the K3. This would check the accuracy of the K3 volt-meter as well. I don't remember what it looks like in the vicinity of the APP's. The next best thing we

Re: [Elecraft] K3 Voltage on TX

Forgot to mention: the RR runs everything else that needs 14v. On Mon, Oct 26, 2015 at 5:08 PM, Jim Miller wrote: > I was having too much drop with RR as well. I switched to a 1ft line > directly to my Samlex 1235M which has been jacked to 14.4v no load. It only > moves a few

Re: [Elecraft] K3 Voltage on TX

You don't happen to have anything else in line between the power supply and the K3 do you? I've found those DC distribution panels sold by certain companies are contributors to significant voltage drop. Your statement " With the radio connected directly to the PS. I am now seeing 14.1 VDC

Re: [Elecraft] K3 Voltage on TX

I just checked my radio. Receive shows 13.7 volts. At 100 watts CW key down transmit it shows 13.3 volts. The current indicated on the power supply is 18 amps. Power leads are about 2 ft in length being #10 stranded with connectors crimped and soldered at both ends. Also a #10 AWG ground

Re: [Elecraft] K3 Voltage on TX

Well my take.ANYTHING between the power source and radio has resistance, regardless of how small. Resistance with any amount of current equals voltage drop. Thus E = IR Where E is the voltage drop, I is the current and R is the resistance. I'm not sure what some of those thing are nor

Re: [Elecraft] K3 Voltage on TX

On Mon,10/26/2015 12:37 PM, Bob McGraw - K4TAX wrote: In fact, anything in line between the power supply and radio can contribute to this. Even fuses, switches, power connectors and such. Any connection that is loose or terminal that is loose will be a voltage drop point. They just add up.

Re: [Elecraft] K3 Voltage on TX

I was having too much drop with RR as well. I switched to a 1ft line directly to my Samlex 1235M which has been jacked to 14.4v no load. It only moves a few mV when loaded to 20A. IIRC, the cable is now AWG12. jim ab3cv __ Elecraft

Re: [Elecraft] K3 Voltage on TX

Perhaps it's vanity, but I like running my rig off solar power and batteries. Since I also take the rig out in the field somewhat frequently, battery power avoids noisy generators. (Besides, I own the panels and batteries, but don't own a generator.) In any case, floating batteries requires a

Re: [Elecraft] K3 Voltage on TX

craft@mailman.qth.net" <elecraft@mailman.qth.net> Subject: Re: [Elecraft] K3 Voltage on TX It would be nice to have test point type jacks on the back of the K3 to test the voltage drop from the PS through the APP's entering the K3. This would check the accuracy of the K3 volt-meter as well. I do

Re: [Elecraft] K3 Voltage on TX

If voltage is being checked via the K3 display, I believe there is a series diode before the internal metering that adds a 0.6V drop in TX?   73, Mike  AC5P On Monday, October 26, 2015 5:08 PM, Bill Frantz wrote: Perhaps it's vanity, but I like running my

Re: [Elecraft] K3 Voltage on TX

...@mailman.qth.net] On Behalf Of Jim Miller Sent: Monday, October 26, 2015 5:09 PM To: Bill Frantz Cc: Elecraft Reflector Subject: Re: [Elecraft] K3 Voltage on TX I was having too much drop with RR as well. I switched to a 1ft line directly to my Samlex 1235M which has been jacked to 14.4v no load

Re: [Elecraft] K3 Voltage on TX

Dick, If the main interest is the drop in voltage, the 12V jack will work fine, no matter how many diodes are in series with it. So you get 10 volts during RX and 9 volts during TX, that is a 1 volt drop (OK, that is extreme, but hopefully makes the point). If you are instead looking for the

Re: [Elecraft] K3 Voltage on TX

Seems to me the display on VFO B is accurate enough for this purpose. Now to make sure of the accuracy along with voltage drop, measure the voltage at the power supply terminals. I would expect the voltage at the power supply terminals and the VFO B display in receive mode to be identical,

Re: [Elecraft] K3 Voltage on TX

If the wire gauge is OK and the supply regulation is not at fault, give some attention to the connectors at each end of the cable, too. A drop of 2.8 Volts points to some sort of issue. 73, Phil W7OX On 10/26/15 9:02 AM, Jim Brown wrote: On Mon,10/26/2015 8:48 AM, Rich wrote: My K3 shows

Re: [Elecraft] K3 Voltage on TX

On Mon,10/26/2015 8:48 AM, Rich wrote: My K3 shows 13.7VDC on RX. When I TX that reading drops to 10.9VDC. Is that a normal drop? It's not good. Two possible reasons -- poor regulation of the power supply and IR drop in the power cable. How long is the power cable between the K3 and power

Re: [Elecraft] K3 Voltage on TX

Rich, Yes, that is abnormal. Either your power supply is sagging or there is too much voltage drop in the power cable. To figure out which it is, measure the power supply voltage at its terminals during transmit. If it is staying "right up there" as it should, then the problem is in the

Re: [Elecraft] K3 Voltage on TX

That's still too much. Last time I measured my K3, the drop was 0.6 V on TX at 100W. Cartridge type [AGC] fuses and the holders are common culprits. I've replaced all of my fuses with the automotive fuses with the blade type contacts. They present a large contact area, are very tight, and

Re: [Elecraft] K3 Voltage on TX

Thanks to all. I have check my PS and it does not fluctuate even a tenth of a volt on TX.With the radio connected directly to the PS. I am now seeing 14.1 VDC and 12.0 VDC on TX. So I need to look closer at the wire gauge and connectors. That is still about 2VDC drop. Thanks for the

Re: [Elecraft] K3 Voltage on TX

That's way more drop than I experience with a 4S1P LiFePO4. Things to check: Length and gauge of wire [remember to double the length when calculating resistance, it's a round trip for the electrons]. Poor regulation in the power supply or depleted battery or battery at the end of useful

Re: [Elecraft] K3 Voltage on TX

Guess I'm more empirically than theoretically oriented, but my first act would be to touch and feel the cable and connectors after allowing the K3 to draw full current for a minute or two. Even 2 volts at 10 amps is 20 watts. That's enough to cause heating you should feel very quickly if it's

Re: [Elecraft] K3 Voltage on TX

mean lots of wasted power. 73 Fred, AE6QL -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Rich Sent: Monday, October 26, 2015 10:05 AM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] K3 Voltage on TX Thanks to all. I have check my PS