Hello, I'm new at the HAM radio thing, but I just put me up my antennas and
I have a power supply out of a old pop up camper that was only putting out
12.3 volts, with no load out of it, I can receive signals very clear, but
cannot transmit signals, my strength meter goes full scale, but no one can
hear me, and I know that a few friends should have been able to hear me. My
question is if I have a power supply that is not putting enough voltage will
that effect my radio where I cannot transmit, my friends say all they get on
the other end is a buzz noise, and I notice that the lights on my display go
dim when I transmit. Thanks in advance.

Dustin Kellogg
KC8ZEM

My
question is if I have a power supply that is not putting enough voltage will
that effect my radio where I cannot transmit, my friends say all they get on
the other end is a buzz noise, and I notice that the lights on my display go
dim when I transmit.

Dustin, this should have been covered in the theory which you studied for your
exam. The radio requires a certain voltage (most likely 12.9 to 13.5 VDC) and
CURRENT. If you have a radio which is supposed to output 25 watts, an easy
rule of thumb is to triple the amount of watts (75) and divide it with the
input voltage. For example, the old RatShak I used mobile for some years was
25W out..divide 75 with 13.5 VDC gives me approx. 5.5 amps needed for xmit.
Now, as the rest of the circuitry, lamps, etc draw some current, lets round it
up to 6 amps. The supply would have to output around 6 amps with no "sag" in
voltage to properly run the rig and give some leeway.

This is very simplistic...and only a quick "SWAG" method of looking at current
requirements. Your manual should give exact specs on your rig.

I'd bet (esp. with the "buzzing noise"....60 cycle noise due to poor regulation
in the power supply) that the P/S is either too low wattage, in need of new
filter caps, or both.

To get on the air, try a 10 to 17 aH 12V GelCell and use the P/S to charge the
battery. The GelCell will output enough current to run the rig, and the "power
supply" can charge it. Don't leave it connected all the time to the power
supply, though. Overcharging can damage the battery. A better solution is to
either rebuild the power supply (if the transformer can output enough current
to run the rig) or buy a commercial unit, such as an Astron RS20. WATCH OUT
FOR POLARITY!!! It is painful to watch smoke come out of your radio.....

I think you have a chance to get some "hands-on" time here, and maybe even
build your own power supply! It is fun, and then you have the right to say
that you're using something you built with your own hands....very satisfying,
at least to me. Today, so few folks can say that they even know what goes on
inside the "boxes" they own.....personally, I enjoy tinkering. Lots cheaper
than therapy, and I get new toys when I do it right......!

Cheers;
A

My
question is if I have a power supply that is not putting enough voltage will
that effect my radio where I cannot transmit, my friends say all they get on
the other end is a buzz noise, and I notice that the lights on my display go
dim when I transmit.

Dustin, this should have been covered in the theory which you studied for your
exam. The radio requires a certain voltage (most likely 12.9 to 13.5 VDC) and
CURRENT. If you have a radio which is supposed to output 25 watts, an easy
rule of thumb is to triple the amount of watts (75) and divide it with the
input voltage. For example, the old RatShak I used mobile for some years was
25W out..divide 75 with 13.5 VDC gives me approx. 5.5 amps needed for xmit.
Now, as the rest of the circuitry, lamps, etc draw some current, lets round it
up to 6 amps. The supply would have to output around 6 amps with no "sag" in
voltage to properly run the rig and give some leeway.

This is very simplistic...and only a quick "SWAG" method of looking at current
requirements. Your manual should give exact specs on your rig.

I'd bet (esp. with the "buzzing noise"....60 cycle noise due to poor regulation
in the power supply) that the P/S is either too low wattage, in need of new
filter caps, or both.

To get on the air, try a 10 to 17 aH 12V GelCell and use the P/S to charge the
battery. The GelCell will output enough current to run the rig, and the "power
supply" can charge it. Don't leave it connected all the time to the power
supply, though. Overcharging can damage the battery. A better solution is to
either rebuild the power supply (if the transformer can output enough current
to run the rig) or buy a commercial unit, such as an Astron RS20. WATCH OUT
FOR POLARITY!!! It is painful to watch smoke come out of your radio.....

I think you have a chance to get some "hands-on" time here, and maybe even
build your own power supply! It is fun, and then you have the right to say
that you're using something you built with your own hands....very satisfying,
at least to me. Today, so few folks can say that they even know what goes on
inside the "boxes" they own.....personally, I enjoy tinkering. Lots cheaper
than therapy, and I get new toys when I do it right......!

Cheers;
A

"AA" wrote in message
...

snipped

I'd bet (esp. with the "buzzing noise"....60 cycle noise due to poor
regulation
in the power supply) that the P/S is either too low wattage, in need of
new
filter caps, or both.

Cheers;
A

I'm not familiar with the rig that is being discussed to go into much detail
nor am I going to disagree with your suggestions as they may be on target as
well, however... the buzzing sound could also be caused by the Antenna being
too close to the PS or the RF getting into the Power Supply, regardless how
well regulated it may be. The loop that is formed, will create a buzzing.
Been there done that! I helped out another fella not too awfully long ago
with the same problem in one of these radio groups. CL

"AA" wrote in message
...

snipped

I'd bet (esp. with the "buzzing noise"....60 cycle noise due to poor
regulation
in the power supply) that the P/S is either too low wattage, in need of
new
filter caps, or both.

Cheers;
A

I'm not familiar with the rig that is being discussed to go into much detail
nor am I going to disagree with your suggestions as they may be on target as
well, however... the buzzing sound could also be caused by the Antenna being
too close to the PS or the RF getting into the Power Supply, regardless how
well regulated it may be. The loop that is formed, will create a buzzing.
Been there done that! I helped out another fella not too awfully long ago
with the same problem in one of these radio groups. CL

If I remember correctly this (power supply) was salvaged from a mobil home. If
so it was probably a float charger for storage batteries and has neither filter
caps or regulating circuit.
I hope the radio still works when you get it on some clean DC power.
good luck
Don

If I remember correctly this (power supply) was salvaged from a mobil home. If
so it was probably a float charger for storage batteries and has neither filter
caps or regulating circuit.
I hope the radio still works when you get it on some clean DC power.
good luck
Don

Well, that certainly would put a different spin on things! Hard to diagnose
a problem with some facts missing! CL

"N0DG" wrote in message
...
If I remember correctly this (power supply) was salvaged from a mobil
home. If
so it was probably a float charger for storage batteries and has neither
filter
caps or regulating circuit.
I hope the radio still works when you get it on some clean DC power.
good luck
Don

Well, that certainly would put a different spin on things! Hard to diagnose
a problem with some facts missing! CL

"N0DG" wrote in message
...
If I remember correctly this (power supply) was salvaged from a mobil
home. If
so it was probably a float charger for storage batteries and has neither
filter
caps or regulating circuit.
I hope the radio still works when you get it on some clean DC power.
good luck
Don