I've got a ICOM 2730 that I've used for approx a year now with no problems. Love the radio. I recently had the MARS-CAP mod done on it as I have an elderly lady in my area that we needed a reliable radio for emergency contacts using MURS frequencies. The radio worked flawlessly until I had the mod done and last night while conducting our local net the power started flickering off and on while I was transmitting. My power source is solar/battery. Like I said this radio has never acted up until now. Would the mod cause any issues like this? I can't imagine that it would. Any ideas why the power would flicker off and then right back on while transmitting? Thank you.
Icom: ICOM2730 powering off and on
- Thread starter KO4PIO
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mmckenna
I ♥ Ø
Does the power on/off trick only happen on the MURS frequencies, or does it do it on amateur frequencies also?
Generally, there are two reasons why a radio shuts itself off when transmitting:
1. Low voltage. The current draw when transmitting (as much as 12 amps with a 50-watt VHF radio) causes the power supply, whatever it might be, to sag or the power wiring has high resistance which causes a voltage drop at high current.
2. Mis-matched antenna. If the SWR is too high, the radio may detect it and shut off to protect the radio. If RF is getting back into the radio, that may also cause the radio to shut off.
1. Low voltage. The current draw when transmitting (as much as 12 amps with a 50-watt VHF radio) causes the power supply, whatever it might be, to sag or the power wiring has high resistance which causes a voltage drop at high current.
2. Mis-matched antenna. If the SWR is too high, the radio may detect it and shut off to protect the radio. If RF is getting back into the radio, that may also cause the radio to shut off.
MTS2000des
5B2_BEE00 Czar
It can also be that operating the radio outside of it's intended bandsplit is causing the PA bias to be wild and excessive current draw and/or hi reflected power causing the radio to reset. Does it happen on the ham bands? Awaiting the O/Ps response.
I'm going to take the battery tomorrow and have it tested. I noticed that my voltage meter reads 13.8 during the day but when transmitting it drops down to like 11.6 and if I talk a lil longer it drops to 10.8 or lower. The radio has an automatic cutoff at 10. something so I'm guessing that the battery is not holding a charge and the radio is shutting off when the voltage drops and when I let off the ptt mic the voltage goes up and the radio kicks back on. All speculation though.
mmckenna
I ♥ Ø
Classic signs of voltage starvation. It's either your battery or one of the connectors.
devicelab
Whacker Extraordinaire
Yeah, I tend to favor a voltage/current issue; however, definitely make sure the antenna is under 2:1 SWR at your transmit frequency. The transceiver's PA *should* be able to easily handle the frequency difference but perhaps not at a higher SWR. Ideally, I would want it < 1.5 which shouldn't be an issue with a matched antenna.
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