i have a mfj supply for the 2970dx..its a 35 amper..on ssb the lites of the radio flicker a little..on am they flicker with anymore than a 25 watt dk..on am the amp meter on the supply swings backwards after a 25 watt dk..on ssb the amp meter swings forward all the way up to 40 amps but the lights flicker..could thier be a problem with the supply or isnt it big enough ?
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power for rci 2970dx..
- Thread starter Splash1
- Start date
Are the power wires between the supply and the radio getting warm to the touch after keying down? That would be a quick sign.
Can you turn down the power output and let it run a bit more idle and see if it is still doing the same thing? I'd do that.
You didn't say how much power out you were transmitting either. A 35 amp supply shoud be good for up to 250 watts. If you are using a 35 watt radio on top of the heater, then you might be pushing it a tad too much. If this is happening with just the radio alone; then something isn't right.
Also: does the power supply get hot to the touch?
Can you turn down the power output and let it run a bit more idle and see if it is still doing the same thing? I'd do that.
You didn't say how much power out you were transmitting either. A 35 amp supply shoud be good for up to 250 watts. If you are using a 35 watt radio on top of the heater, then you might be pushing it a tad too much. If this is happening with just the radio alone; then something isn't right.
Also: does the power supply get hot to the touch?
Rob..the wires dont get warm..if radio is warm or cold the lights still flicker..i run the radio at bout 110 ssb on a hard whistle and bout 90 am with a hard whistle..i dont use a heater but the 2970dx has a internal 100watt one built in..on am with under 25 watt dk the lights dont flicker and the amp meter on the supply doesnt swing backwards but on ssb no matter how low the wattage is set the lights flicker on the radio but the amp meter on the power supply swings forward..
Sounds like something is wrong with that power supply to me. A good rule of thumb is 20 amp supply for every 100 watts output. Or you can figure it out more precisely using ohm's law, taking the efficiency of the RF device into consideration. Do you still see full power output of the radio even though the lights are dimming? If so, I wouldn't worry about it all that much. If you can borrow a power supply from someone else to compare with, that would be helpful.
just out of interest how do these radios perform dp they have any problems i.e drifting of frequency while run on full output i am looking at one on ebay at the moment considering making a bid
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If you're seeing 100 watts of output, then you divide that rating by the voltage you're running at. Let's assume the voltage is 13.8 volts. 100/13.8 = 7.25 amps. Now you have to consider that the radio is not 100% efficient, meaning that some of the current it draws will be turned into heat, not power output. The typical radio is a class AB device (I seem to remember the built in amp in this radio is, too). A class AB device is about 50-55% efficient (nice round number for estimating, anyway). So now to figure out the needed power supply you take the 7.25 amps and divde by 50% efficiency = 7.25/.5=14.5 amps. Round up a little for the lights and other circuitry required in the radio. You should see current draw on your power supply around 15 amps or so at max output of the radio. If you're really seeing 40amps, you have a problem somewhere. Perhaps the problem is in the "built in amplifier" of the radio?
moleculo..after reading your earlier post ''20 amps for every 100 watts'' i guess the power supply might be ok..the radio is designed to put out round 175 pep plus it was peaked and tuned so that would be round 200 watts which would be 40 amp draw which is what its doin..when i turn the power all the way down it on draw 10 or so amps..the watt meter i have is a diamond 200 and says it only shows 70 percent of power so its hard to gauge on my meter..
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How far away from the radio is the supply. Sometimes if they are too close together RF gets in and they can do funny things. If the audio still sounds OK at full output and the supply isn't getting too warm I wouldn't worry about it too much.
IF the lights on the radio are dimming then you need more amps..
If the radio is doing 175 PEP then the supply maybe too small...not enough head room, it would be close to maxing out.
Buy another of the same supply and put them in parallel.
Should make it all work a lot better.
IF the lights on the radio are dimming then you need more amps..
If the radio is doing 175 PEP then the supply maybe too small...not enough head room, it would be close to maxing out.
Buy another of the same supply and put them in parallel.
Should make it all work a lot better.
the more i study it i think the supply might be ok..when i turn the power all the way down the lights still dim a little..the 2970n2 i have in the mobile wired straight to the battery with 8 gauge wire dims a little also on the lowest setting..so im thinkin it might just be the way these radios are..
I had used a 40 amp supply with my old 2970
Worked fine indeed
20 amp may be a bit too little for the 2970
I would not try using less then 40
even though typically 20 amp supply per 100 watts is fairly accurate for most radios
I simply found that my old 2970 was happiest when i went to a 40 am supply
Worked fine indeed
20 amp may be a bit too little for the 2970
I would not try using less then 40
even though typically 20 amp supply per 100 watts is fairly accurate for most radios
I simply found that my old 2970 was happiest when i went to a 40 am supply
DXman
Yes, that's 3100 degrees F. Nine yrs of hard work.
Tested my 2970N4 on full power momentarily for current draw, meter read 45A on SSB I think. Will run further tests on am and ssb again.
Mine also dims even on bare min rf power setting. 8 guage directly to battery tied to a 180a alternator.
One issue I've noticed is that two folks tell me they can't hear me well, that's with mic gain on 3 O'Clock, does the mic gain need to be on full max setting?
Heat wise, not that bad. No heat equals best obviously. The area that gets slightly warm is the area where the power cables enter the back of the amp. Not the cablw but the aluminum around the entrance to the power cable area.
Thinking about buying a crusty ( mr rivets )made 70A amp for home use.
Mine also dims even on bare min rf power setting. 8 guage directly to battery tied to a 180a alternator.
One issue I've noticed is that two folks tell me they can't hear me well, that's with mic gain on 3 O'Clock, does the mic gain need to be on full max setting?
Heat wise, not that bad. No heat equals best obviously. The area that gets slightly warm is the area where the power cables enter the back of the amp. Not the cablw but the aluminum around the entrance to the power cable area.
Thinking about buying a crusty ( mr rivets )made 70A amp for home use.