[DCASAZZA]

I have been enjoying my restored chassis from my 650, noodling around the bands trying to copy the worst signals to be found, that is untill night. What the blazes is the rythmic noise I find from one end of the dial to the other (with few exeptions). Only good signals over-come this constant drone. I have gone so far as to kill every circuit in the house to rule out anything with a 'chip' , battery chargers, tv's and such. No Joy. My ICOM-701 picks it up on 80-15 as well to varing degrees.
I remember a time I could listen to NY City AM stations at night from south Florida with a TRF or car radio.
Ive heard BPL samples and this too rythmic and steady. I cant help but feel this is some type of data sourced interference.

It only comes out at night... any ideas?

[AI2V]

I've got the same problem here especially below 1 megacycle. The noise also appears in the 75 meter ham bands between 3.5 and 3.7 megacycles. It could be anything electrical in the neighborhood- a motor, vapor light, controller, or anything that uses power; the higher the power the more noise. I gave up trying to find it.

[DCASAZZA]

Pete,
Thanks for your thought about my problem. As it happened your mention of a 'controler' sparked my recall of a power pack for the decorative lights at my walkway to my front door. On at dusk, off at dawn. Ding Ding Ding Ding That was it! It is a switching power supply providing 12.5 v AC and enough noise to drown out the entire band and it's on the same breaker ckt my radio was using. I have tried filtering input and out put to no avail so it will be replaced with a DC type.
By the way, in a true twist of irony, when I opened it up I discovered it to be encapsulated in a black tar-like substance much like our beloved capacitor blocks.

[Texasrocker]

... to filter any AC outlet to rid AC line noise (line hash), this idea works. I isolated my vintage radio repair bench from incoming ac-line hash by doing this yrs ago. Its simple too!
* Take (2) .1 uf/ 600 v bypass ( orange drop caps), Lay them side by side. (parallel). Twist the ends together on one-end only. Solder a green colored single (ground wire) to those twisted caps ends. Attach that 1 ground-wire to outside grounding rod near your workbench.
*Attach a old 2-prong type AC cable with (male AC plug), (solder independant 2 wires) to other 2 caps wire-leads from the capacitors making sure they cant short together. Use good electrical tape or heat-shrink to these 2 separate capacitors connections opposite end of the ground wire twist.
* plug the male end of the AC cord you soldered to the caps directly into your service-bench power strip, or other female connection of your house plug that you are using for testing your old radios.AC line hash gone!!Any other noises would be nearby florescent lights transformers,etc that can be turned-off to isolate those type interferences.
My neighbor runs a "cracker-box" electric welder down the street sometimes.I can see him in his driveway when he works on his welding projects from my vintage radio repair bench. I fully "isolated",.. and got rid of his AC line hash noise by installing the 2 caps (parallel) suggestion above.