6400 Voltage Drop During TX

Yeah, I think this is about right … I went through similar investigation a while ago, and improved things a bit, but there seems to always be some drop and I think yours is not unusual.

What I did:

• turned up the voltage from my Astron power supply, such that the power-supply puts out 14.1V and FRStack shows me 13.8V internally. Truly, this is not hugely different from what you see, on RX.
• Tune: I have 13.5V (FRStack) with 10W output
• TX: 12.9V (FRStack) at 100W (20m) output. This differs notably from yours, but there is still voltage drop.

I use a West Mountain Radio RigRunner 4008H for distributing my shack power. When I dove into my own voltage drop concerns, I got out my tiny tub of MG Chemicals' Conductive Grease and went to town:

• I lightly scratch-cleaned every connection within my Astron (using a fiberglass "pen" designed for this purpose), and at the output of my Astron RS-35. Followed by De-Oxit spray-wash. Then conductive grease as I reassembled. The capacitor s.crew-terminals, the output bolts/washers/nuts, transformer and diode all got this, and whatever else I could find. I have two Astrons, so I could take one out-of-service for a week or more, and do this job right.
• I cleaned all PowerPoles associated with my RigRunner. Generally this meant spraying DeOxit into the "mouth" of each, then using a toothpick to introduce a small bit of conductive grease onto the out-facing "slope" of each PowerPole terminal. Then mate/unmate a few times to spread grease around. BTW - all my PowerPoles are crimped with the proper crimper, then soldered; terminals are positioned before crimping so that they are "relaxed" in a horizontal plane and shouldn't try to turn or twist when mated (to maximize conducting cross-sectional area).
• I pulled each and every fuse on my RigRunner, used the fiberglass-scratch-pen lightly, then sprayed DeOxit, and toothpick-coated each side of each blade with conductive grease.
• Lastly, I re-arranged my RigRunner connections, such that the incoming Astron power was right next to my FlexRadio connection. Lower-draw accessories are farther away.

I measured voltages at each connection along the path. I came to conclusions. My RigRunner and power distribution is best I can make it, but there seems to be some small amount of voltage-drop I cannot remove. My notes remind me that, for TX:

• I achieved 0V drop from inside Astron to the input of the RigRunner, both TX and RX. Before cleaning, this was a low 0.05V anyway.
• the RigRunner alone drops 0.25V internally, between connectors and fuses. Before cleaning contacts and fuses, this RigRunner drop was 0.5V (so, nice improvement).
• From RigRunner to FlexRadio, my 10ga soldered PowerPole cable and the mating connectors (ie including the other half of each PowerPole on the RigRunner and Flex) have 0.37V drop on TX. Before cleaning and re-arranging RigRunner, this drop was 0.94V (thus, link to Flex was the biggest "win").
• FlexRadio internally has 0.2V drop between terminal and wherever FRStack measures internally. I cannot change this.

Summary: by thorough and diligent attention to every aspect of your DC path, you may be able to lower your 2V drop to something like 1.2V or so. Helpful, to be sure, but not earth-shattering. And I found it satisfying to do the work and think about each step, despite the modest result.

Suggestion: quick and effective step: simply turn up your Astron output voltage. I researched all my other Astron-connected gear (TS-850, Antenna switch, LP-700 SWR, 2m Transverter, VHF amp, etc), and determined I must not exceed 14.2 volts. So, I dialled my Astron up to just below this point.

Note: the MG Chemicals' Conductive Grease is carbon-loaded for conductivity, and can make a spectacular mess. I highly recommend wearing nitrile gloves, and apply sparingly.

I similarly dove into, and pre-prepared my second Astron in the same way as the first. My first Astron is meter-less and required internal adjustment; Astron #2 has meters and external adjustment-knobs.

HTH!

I would look at the Power cable and the Anderson Power Pole connectors as Power Pole's have a tendency of loss under loads. This starts at the Power Supply, then if you have a Rig Runner with or with out a fuse in circuit and of course the Radio Cable needs #10 wire with 45 Amp Power Poles.

At the factory the Radios where calibrated with a Power supply voltage of 14.2Volts if I remember right.

The internal Ethernet port are for the M version front Panel model of the Radio to plug into.

Here is some interesting information regarding DeOxit. It also mentions silver dip which I have found to be very effective for severe cases. Note that silver sulfide is the predominant salt that forms on silver. It is not conductive. Sometimes just making and breaking the contacts a few times will remove the thin layers of silver sulfice and silver oxide.

Len…13.70 V - 12.83 V = 0.87…Yes?

I'm a bit confused as to where he is measuring the voltages. The last message states he is measuring at the Power Pole connectors. If that is the case then all the drop is between the power supply and the rear of the radio, so that eliminates anyrhing internal to the radio. The drop is still about 0.045 Ohms

What gauge wire are you using when you make this measurement? And how long is it?

And do as Mike suggested to see the actual voltage drop:

Per Mike…

Another way to test this is to measure the voltage drop across the cable with the VOM. Put one meter lead on the + of the power supply and the other end on the plus of the radio. This will measure voltage drop.

Next, so the same for the Negative lead. You might be surprised what you find.