Just got mine this week, testing it in the house, there is a hum when turned on, lessens when radio is warmed up, my first Galaxy, have it hooked to 120v-12v power supply, never had hum with my Cobra radios with same power supply, normal or is hum from supply and when hooked to battery hum will go away? Too cold to hook it up to truck this weekend.
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DX 979
- Thread starter dirtcrew51m
- Start date
Never had a hum. Is the ANL and or noise blanker on. Very nice radio. Did you get the new DX-979F with the freq counter. From what I see they have discontinued the 979 without.
DX 979. I dont care about the frequency counter. Hum is almost gone. might be from being new. ya I like it. Cant wait to put it in my Explorer. I love listening to ssb and its small size.
Hum and noise can be generated from your computer monitor, cell phone charger, fluorescent light fixtures, etc. You will need to hunt down the source cause by systematically unplugging anything plugged into the wall throughout your house. It has NOTHING to do with the fact that your radio is new . . .
Unplug the antenna. If the noise goes away, it's not coming from inside the radio.
The frequency-counter digits are being switched on and off a few hundred times a second, and if that switching waveform leaks into the radio's receiver audio, you'll hear that sound. Shutting off the display will make that noise go away, if that turns out to be the source of it.
73
The frequency-counter digits are being switched on and off a few hundred times a second, and if that switching waveform leaks into the radio's receiver audio, you'll hear that sound. Shutting off the display will make that noise go away, if that turns out to be the source of it.
73
As I said I was just curious, my first Galaxy, never had a Cobra do this, I have several old and new, even hooked to the same power source, the hum is almost gone, I am going to hook it up to my truck soon, so I will see.
I have an older radio shack power supply from about 1973 or so. it is a 2 or 3 amp and it puts static into the radios also. not filtered too good for the cheap one I have. a few radios it does not put noise into them due to the radio being filtered pretty well. it is really to small for most radios now days. back them most only drew about 1 1/2 watt when keyed.
I think I remember having one of those before. Don't remember seeing a regulator circuit in it either. Is that true?
I have not looked inside it for years but it does not have much inside it at all. it is very light when you pick it up. it still works . the 10 amp version they came out with years later seemed to work pretty good. but never did want to pay their price for one. it was like 99.00 for one of them.
The ones I have are just boxes with a transformer and a rectifier. Besides you got me thinking. I am trying to tune the radio in the house with it, limited power output, too cold here in Jersey to put the cb in my Explorer, I made a power supply from a 60 amp server power supply, I should use that to tune the radio.
You'll also need a 50ohm dummy load and a decent VSWR/power meter. Don't use your antenna to tune the radio. You most likely already know this. But it never hurts to remind. And don't use metal screwdriver in the radio. Soft plastic tip driver will work just fine as to not break the pots for adjusting things. JMHO's. Be safe and take your time.
