[EdHolland]

Arran - I bet you're right probably vinyl, there was no rubber smell when desoldering it, which you often get with the older stuff. I did start wiping it down with solvent, which worked well until one of the wires detached from inside the bulb holder... so I replaced.

The wires were black, and the insulation still flexible.

There is also clear vinyl tubing that covers the short length of FM balanced feeder. This was completely grey and dusty looking - I thought it was simply grey tubing, but it cleaned up rather well, and is now slightly yellowed, but transparent, and the red plastic of the feeder wire can be seen.

Most of all, I'm happy that something isn't on the fritz inside the radio, which I was utterly convinced was the case for a while. This one had such a catalogue of noises - Mrs H called it snap crackle and pop, LOL!

[David]

When dealing with noise on power lines, time to get my Jackery 240 out. Talk about clean can hold a portable am radio next to the thing and no buzz. Purchased the thing in 2019 for back up power during storm season hate running a gen set at night. One can never have to many of the things! Others on the market but have no idea how clean the power is they make. On the old engine form folks were talking about THD from there gen sets some starting checking grid power at there homes and reported low of 1.7 to a high of 3.9 would never guessed a high of 3.9. David

[EdHolland]

David - I think I understand but what units are you discussing (Low of 1.7, high of 3.9)?

Budget constraints for Ham Radio led me to a 25A power supply that is a switching design. The reviews were good, and I have found it to be almost perfectly quiet. It does have the odd harmonic audible on the lower bands, but very feint, and the PSU has an adjustment that allows you to shift the frequency to remove the interference. So far it has been great.

One of the worst offenders for QRN here are two items on my test bench - my soldering iron, which must have some really cheap triac temperature adjustment circuitry, and my digital signal generator, which spews out digital harmonics all over the place, and can make some adjustments difficult - in which case I bring out the old Heathkit tube generator. Should really go through the caps on that LOL!

On the Zenith, just waiting for my shipment of NE51 pilot bulbs, then it can all go back together.

[David]

1.7-3.9 %, a modified Sine wave inverter is around 25%. Most generators from big box stores run 10% at a 50% load. What is the distance from your HF rig to the power supply? Have a Zantrex (Pro-Watt) power inverter purchased in 2005 rated as one of the best NOT! If you get within 20 feet of the beast with a portable AM radio all you hear is BUZZ. If I run a 50 foot ext cord a tube radio radio on AM is happy. Run my 2 meter rig using a very old Aston power supply with a heavy transformer hope I never drop that thing on my foot . David

[EdHolland]

David - sorry, I reread your post and finally saw THD - now the % figures make sense. Thanks for explaining.

The PSU for my Kenwood is on the shelf above the rig (convenient setup, and length of wires from the radio). Antennas are all out doors, and any noise from the power supply is really minimal, just the odd "squiggly" on 80m. I could try making up a longer power lead, and adding more suppression on the DC and AC sides, but it really isn't problematic in use, especially as you can use the control to tune the harmonics away.

It's very similar to this one.

https://www.amazon.com/Regulated-Designe...ems&sr=1-1