The AM Forum

Hello All,
I thought I had this one nailed but I am still having a problem with one or more street lights cycling on-off, making intereference on 75 and 160.

My first shot at this was to drive around with my Sangean portable tuned to 1885. I lucked out and an overhead light went out as I drove by and less than a minute later it made its signature sound in my receiver trying to start up. The problem was I had to be almost under the light to receive the interference. There were numerous  street lamps in less than a mile cycling, but none, except this one, had that nasty start-up sound to them.

The power company fixed the one bad one that I turned in. That got rid of the worst interfernce,  BUT NOW there's another one in there that's not so offensive.

Could I use the MFJ powwer line sniffer? It's just an A.M. receiver in the 150 mhz band and has a pretty good track record for finding arcing insulators.

Or do I conintue with the first method looking and hoping to see a street light go out and wait for it to start back up with it's interference??

Thanks

Fred

Have you considered standing off at a distance with a rifle and scope attached?

Hi Fred,

Over the last few years I've identified and reported at least 50 high pressure sodium lights that were cycling off/on in my area.  I've never used anything other than the broadcast AM radio in the vehicle tuned to the high-end of the band (on a frequency thats not occupied by a local).
You don't need to do much more than drive around your area in an every growing circle and you should be able to correlate the the audio with a visual observation.  Some lights are noiser than others but they all seem to cycle at fairly regular intervals.



Sam / KS2AM

I don't know what the problem is  with those damned things, but they are constantly crapping out and cycling on and off.  Within a radius of a quarter mile from here right now, I am observing at least four that each cycle on and off at about 1 1/2 minute intervals from dusk to daylight.  None of them seem to be generating any audible interference here at present, but last year there was one, about a half mile away, that made 75 and 160m unusable.  They are a low priority with the power company, so whenever I have reported one they say they will have it fixed within five days.  At their observed failure rate, those things must be a considerable expense and constant PITA for the power company line crew to maintain.  Round here, most of the POS's are located on private property, and the landowner pays a monthly flat rate fee.  Nearly everybody has one, so there are plenty of lamps to potentially be causing interference at any given time.

If I can get my 2m CB rig running again, I am going to look for a cheap used shack-on-a-belt, or a portable VHF scanner to use to help identify the street lamp or power line problem that is actually causing the interference.  My plan is to patch audio from the HF receiver directly into the 2m CB base station, lock it key-down, and use the shack-on-a-belt to allow me to remotely monitor the noise on my receiver as I roam the area looking for the problem, comparing the noise pattern heard on my receiver to what I hear on the portable radio at the scene.  Many times I have discovered severe noise sources only to find, after the power company fixed it, that it wasn't the one causing the offending noise at my station.

Any of the HT's that receive the VHF aircraft band, if it has an AM detector, are useful for this.