New Sirio Gain-Master installed but poor TX

[cmdrwill]

OP stated he's using a Magnum 257HP, which runs 80 watts. That'll easily outpace a 7-10 amp power supply.

A 80 watt transmitter on CB?

 

[mmckenna]

A 80 watt transmitter on CB?

Import/10 meter/etc radio.

I'm not judging, just trying to help out the guy.

 

[mmckenna]

I should add "Up to 80 watts" variations of the radio seem to range from 25-80 watts.

 

[BloodandRoses]

Legally 4 watts AM 12 Watts SSB.. Which hardly anyone does that these days...........

 

[mmckenna]

Legally 4 watts AM 12 Watts SSB.. Which hardly anyone does that these days...........

Agreed, but I'll leave that battle up to someone else.

 

[stlouisx50]

This is what I found on Cb magazine for the Magnum..... "When running these radios as a base unit Magnum recommends the Astron 20 amp power supply."

You think 20 amp is enough? I think the 36 amp definitely sounds like a good idea to cover any extra if and or buts, per your suggestion.

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[mmckenna]

Amateur HF radios that cover 10 meter band with 100 watts will often pull a bit more than 20 amps.

Not sure of the efficiency of your radio, you'd have to test with an ammeter to see how much it pulls on transmit.

Unless it's doing something really stupid, 30 amp power supply should be more than enough. Not sure I'd trust 20 amps.

 

[cmdrwill]

Import/10 meter/etc radio.

just trying to help out the guy.

Well the power supply listed back in this thread probably will not provide the current for that transmitter. This answers why the radio does not 'get out'.

Mmc is on target, need more Amps.

 

[stlouisx50]

Well the power supply listed back in this thread probably will not provide the current for that transmitter. This answers why the radio does not 'get out'.

Mmc is on target, need more Amps.

This one should do the trick yes? MegaWatt[emoji768] S-400-12x 36 Amps 430 Watts 9.5 to 15 Volts Adjustable Ham CB Radio Power Supply 13.8V 12V Not a China Clone Real MegaWatt MW https://www.amazon.com/dp/B00LIBRKQM/ref=cm_sw_r_other_apa_mOhkAbBNMAN0Z

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[alcahuete]

7 amp power supply wont work on high wattage radios....................

Yes...I understand that. But it isn't the high wattage radio he is having trouble with, unless I'm reading his post wrong.

The OP said his 257 is working fine, but it's the Galaxy DX-44 that isn't. The DX-44 draws 2.2 amps. We'll call it 3 just to be safe, for mods and such.

 

[alcahuete]

Yep, just read it again, and it seems his problem is with the Galaxy. The 257 (his mobile radio) is working just fine, but the DX-44 is not.

Like I said on Page 1, if it's the DX-44 having issues, this is NOT a power supply issue. It's draws 2.2 amps, per the manufacturer specs, unless it's the HP model, which the OP really didn't say.

He talks of a 2 S-unit difference between the 2 radios. Makes sense as well. You're looking at 7W on the DX-44, vs. 80 watts on the 257. That's going to be close enough to a 2 S-Unit difference. A little less, but close.

It all adds up, as far as I'm concerned. You can't expect the same performance on a 7W radio that you can on a 80W radio.

 

[mmckenna]

This one should do the trick yes? MegaWatt[emoji768] S-400-12x 36 Amps 430 Watts 9.5 to 15 Volts Adjustable Ham CB Radio Power Supply 13.8V 12V Not a China Clone Real MegaWatt MW https://www.amazon.com/dp/B00LIBRKQM/ref=cm_sw_r_other_apa_mOhkAbBNMAN0Z

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By the specification, it'll work.

As for how well it's built, I have no idea. Never used that brand.

 

[stlouisx50]

I didn't have the wattage up to 80 when the Magnum was turned on. There's no way possible to do that with a 7 amp power supply. So having 2 more bars of sig strength is an indication something is still wrong.

 

[Michael-SATX]

Try undoing or eliminating that 25ft coil by radio !!!

The cable just under 200 feet. I have about 25 extra feet, coiled up inside near the radio. I did a horrible job installing the connectors onto the coax. Hope this makes sense.
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When I read the part about you saying that you had 25ft coiled up behind the radio I threw up a red flag !
Describe that to us ... roughly how tight of diameter coil are we talking about and is it tie wrapped all tight ?
It brought me back to a lesson learned installing a CB and having approx 10~15ft antenna coax tightly
wrapped up causing very high SWR with poor TX/RX. Eliminated the excess/coil and SWR/TX then good.
I read that you said your SWR was low but I would loose that coil and like others said use far less coax.

 

[stlouisx50]

When I read the part about you saying that you had 25ft coiled up behind the radio I threw up a red flag !
Describe that to us ... roughly how tight of diameter coil are we talking about and is it tie wrapped all tight ?
It brought me back to a lesson learned installing a CB and having approx 10~15ft antenna coax tightly
wrapped up causing very high SWR with poor TX/RX. Eliminated the excess/coil and SWR/TX then good.
I read that you said your SWR was low but I would loose that coil and like others said use far less coax.

I did cut off an excess amount of coax and still had the issue. The coil is fairly loose. I too know about a tight coil and tried unwinding it and laying it 15 feet out and back w/ no difference.

But to describe the coil size, I'd say about the roundness of a 55gal drum.

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[stlouisx50]

So the symptoms I have now are I can almost hear someone keying up and then nothing. I also was doing fine using the Magnum in my car going to work and then coming home I was told my radio was making a strange sound. I thought they were joking. So I got home and tested my sound output and would hear a loud hum off and on at various mic settings (built in) the same with wattage adjustments. If I turned the radio off it would work fine, but then go through the same symptoms.


I'm guessing the low amperage of the power supply when I did the test messed up the radio(s).

I'm extremely upset right now $600 down the drain, now a $400 radio that has preformed extremely well has bit the dust.

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[mmckenna]

I'm guessing the low amperage of the power supply when I did the test messed up the radio(s).

I'm extremely upset right now $600 down the drain, now a $400 radio that has preformed extremely well has bit the dust.

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Unlikely a low voltage/current starved situation would damage a radio like that. It would take a high voltage condition to really do damage.

Even high SWR won't immediately damage your radio. It will cause some heat build up, but not what you are describing.

It sounds more like a grounding/electrical issues, or RF somehow getting back into your audio. If it was me, I'd go through and check all your connections, make sure the radio is properly grounded (NOT relying on the negative power lead or antenna ground, but an actual short ground from the radio direct to the vehicle body). I'd also check the SWR in your car to make sure it's not too high. High SWR can reflect power and that can get into the audio stream.


As for the $600, playing radio ain't a poor man's game. On the commercial side for a base/repeater type install, it's not unheard of to spend as much money on the antenna system as you do on the radio. For what you've described, the cost sounds about right, but I totally understand your frustration.

To loop back on this, I really think you need to fix your coax connections, clear the branches back from your antenna, make sure -everything- is grounded, shorten your coax, and address the power supply issue. You are on the right track.

 

[stlouisx50]

Thanks, I'll check those out.

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[stlouisx50]

Unlikely a low voltage/current starved situation would damage a radio like that. It would take a high voltage condition to really do damage.

Even high SWR won't immediately damage your radio. It will cause some heat build up, but not what you are describing.

It sounds more like a grounding/electrical issues, or RF somehow getting back into your audio. If it was me, I'd go through and check all your connections, make sure the radio is properly grounded (NOT relying on the negative power lead or antenna ground, but an actual short ground from the radio direct to the vehicle body). I'd also check the SWR in your car to make sure it's not too high. High SWR can reflect power and that can get into the audio stream.


As for the $600, playing radio ain't a poor man's game. On the commercial side for a base/repeater type install, it's not unheard of to spend as much money on the antenna system as you do on the radio. For what you've described, the cost sounds about right, but I totally understand your frustration.

To loop back on this, I really think you need to fix your coax connections, clear the branches back from your antenna, make sure -everything- is grounded, shorten your coax, and address the power supply issue. You are on the right track.

So I was able to make sure the power connections on the radio were reconnected securely like they were before. I transmitted to a few people near and far and they told me I sounded really good. Then seconds later I sounded very muffled. He thought, definite problem. It would come and go apparently. He indicated like like the sound of pushing too much power. However I was not. Another guy, who I always chat with said, I sounded as if I had a very stuffy nose.

I'll see how the drive home in the morning goes.

I did set the mic gain down a bit more, however in the past I was always able to have it turned all the up with no issues. Maybe disconnecting the radio from power and reconncting the power reset something in the digital realm of the radio? Who knows.

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[mmckenna]

SSB or AM?