Is this normal?

[friskidog]

I have a galaxy DX979 peaked and tuned, I get good reports, here's the question, I hooked up a RM Italy 203p (200 watt pep )amp and I noticed on SSB the needle only jumps up to maybe 12W whereas W/O the amp on my needle bounces all the way over when transmitting. I still get better reports with the amp on but wondering why the needle doesn't go all the way over. I'm thinking because I turn the power on the radio down to about 2W when using the amp, could that be the reason?
Thanks
73's

 

[Fast1eddie]

Very good Sparky, you have answered your own question. Now go play skipland or whatever you cb wizards call it.

 

[gewecke]

Very good Sparky, you have answered your own question. Now go play skipland or whatever you cb wizards call it.

Careful ... picking on the cb folks will anger the goderators! :wink: 73, n9zas

 

[mmckenna]

I'm thinking because I turn the power on the radio down to about 2W when using the amp, could that be the reason?
Thanks
73's

Yeah, seems like you are answering your own question here.

But, maybe not.
RF amplifiers are usually designed for a certain "drive power". That's the ideal power input to the amplifier from the radio that provides the best performance. The amplifier manufacturer should provide information about what a suitable input power is.

Also, you need to consider the match between the radio and the amplifier. Just like an antenna, the amp needs to provide a proper match to the radio, just like adjusting the length of your CB antenna to get the best performance/lowest SWR.
It might be worth putting an SWR meter in line between the radio and the amplifier and see if it's OK.

Some amateur radio operators will put an antenna tuner in between their radio and their linear amplifier to do this.

 

[friskidog]

It's all good thanks, I wasn't sure. I did have a couple of icons a few years a go with and amp and antenna tuner but could not remember what the power meter said I just play around with the mobile for now SWR's are spot on with the mobile for sure.. Oh one other thing I can't picked on I let my license no code tech expire, thought it was kind of boring, I like skip! 2 meter eh?

 

[gewecke]

Huh? 73, n9zas

 

[SpugEddy]

Also, on AM the carrier is driven by the dead key power.
On sideband the carrier is modulation driven.
Thats how it was explained to me

 

[robertmac]

Good old amps on the CB band. Can you hear me now?

 

[kayn1n32008]

Also, on AM the carrier is driven by the dead key power.
On sideband the carrier is modulation driven.
Thats how it was explained to me

On SSB the carrier is supressed...

 

[friskidog]

Thanks for all the advice people! On my RM Italy KL203P says you can use an input up to 20W on SSB, I would not do that, I've been putting 2W into it, how much more could I safely drive it with w/o frying it or would that be pointless?

 

[gewecke]

Thanks for all the advice people! On my RM Italy KL203P says you can use an input up to 20W on SSB, I would not do that, I've been putting 2W into it, how much more could I safely drive it with w/o frying it or would that be pointless?

Pointless. Ditch the amp, leave the radio at 4 watts and be happy. :wink: 73, n9zas

 

[TheSpaceMann]

Thanks for all the advice people! On my RM Italy KL203P says you can use an input up to 20W on SSB, I would not do that, I've been putting 2W into it, how much more could I safely drive it with w/o frying it or would that be pointless?

The output power of some amps increases with higher input power. I suggest you check with the manufacturer of the unit.

 

[JayMojave]

Hello Friskidog: Amps last a lot longer NOT being over driven.

If this is a typical 13 db gain amp it will more than double your range twice. It takes 6 dB gain to double your range, that is 6 dB = 4 times the power. So a 13 dB gain will more than double your range twice.
A 13 db gain with 2 watts in will produce just over 8 times 2 watts, close to 40 watts. Which is a good amount of gain as compared to 2 watts.

See: CBRadioMagazine.com - RM Italy KL203P CB Amplifier

KL 203

Good luck, enjoy.

Jay in the Great Mojave Desert

 

[K7MEM]

Oh one other thing I can't picked on I let my license no code tech expire, thought it was kind of boring, I like skip! 2 meter eh?

I kind of agree with 2 Meters being a little boring. But that's only if you stick to the repeaters. There is FM simplex, SSB, AM, and CW also available.

You should have renewed your Technician license. All the ham licenses are now no-code. If it is less than two years since it expired, you can get it back again, without testing. But even if you retest, its pretty easy to get your license back.

With a Technician class ham license, you would have 10 Meter SSB privileges. If there is good propagation on 11 Meters, there is also good propagation on 10 Meters. When the propagation is good, working cross country is pretty easy, with only 5 watts. I've done it with a mobile unit. Upgrading to General class you would provide even more privileges.

Martin - K7MEM

 

[KC2GIU]

Hello Friskidog: Amps last a lot longer NOT being over driven.

If this is a typical 13 db gain amp it will more than double your range twice. It takes 6 dB gain to double your range, that is 6 dB = 4 times the power. So a 13 dB gain will more than double your range twice.
A 13 db gain with 2 watts in will produce just over 8 times 2 watts, close to 40 watts. Which is a good amount of gain as compared to 2 watts.

See: CBRadioMagazine.com - RM Italy KL203P CB Amplifier

KL 203

Good luck, enjoy.

Jay in the Great Mojave Desert

Thanks Jay. That is a good review. The internals look professional vs. some of those backdoor amps with unknown brandings.

Good to hear the reviewer got good results on 10-meters too.

 

[AC9BX]

...my needle bounces all the way over...

What needle? The one on the radio. Of course, it's measuring the radio power. It cannot measure the amplifier power.

...how much more could I safely drive it with w/o frying it...

Disclaimer: Any such amplifier used in the CB service in the US (and many other places) is very illegal.

The RM Italy site says 10W in for 100W out for AM or FM, 20W in for 200W out PEP using SSB. That's 10dB power gain. Sounds about right for the size of the thing. That means it is made to deliver 200W PEP with 20W input. That's how hard you can drive it without frying it. But like anything else running at full blast all the time is not the best idea.

If you drive it with 2W AM carrier you should expect around 20W out. Gain may well be non-linear across it's range.

Keep in mind for *standard* AM the total power is 4 times the carrier power. Your 4W radio actually would make 16W of power for full modulation AM. However, US law restricts the average power dissipation of the output device to 10W. This is where we get to the difference between peak, peak envelope, and average power which I won't go in to; and distortion from over-modulation and the difference between consumer class equipment and amateur and professional.
Moreover, US law requires commercial amplifiers approved for sale in the amateur service to exhibit NO amplification for CB frequencies. I doubt this amplifier complies with said law.

If this is a typical 13 db gain amp it will more than double your range twice. It takes 6 dB gain to double your range,

Double range is subjective. Line of site transmissions which is what 27MHz CB is intended to be will not see a double of range as such once the signal is already beyond the radio horizon. This also assumes the antenna system gets all the power into the air.

You'll do much better with good audio, an efficient antenna system, and good height than just adding power. Most CB shop's *peaking* just makes a mess.

 

[wyShack]

Friskidog-

Get your Tech license back and get on ten and six meters. Ten meters is nearly identical to CB and six meters is often called the magic band. Two meter FM with repeaters is just the start even for a Technician class amateur. Flip through the Part 97 rules and see for yourself.

73

 

[KC2GIU]

Double range is subjective. Line of site transmissions which is what 27MHz CB is intended to be will not see a double of range as such once the signal is already beyond the radio horizon. This also assumes the antenna system gets all the power into the air.

You'll do much better with good audio, an efficient antenna system, and good height than just adding power. Most CB shop's *peaking* just makes a mess.

Good audio with a power mic often gets a boost to be heard further away. Turner made a few good desk mics that work really well. Mine is a Turner +3. These typically took 9V power. Astatic makes a few good ones as well.

The antenna is another good part of range distance too. The better the antenna cable keeps more power reaching the antenna with less losses.

On CB, those items above running a legal stock radio can reach 50 miles for line of sight conditions. That is of course when skip is not around on a nice cool night. I've done this time and time again reaching distances that great.

As for those peeked radios, I've heard some on the air that are done just right as to not knocking your speakers off and others that require my tuning to hear them using clarifier knob because of the over modulation and bleeding through a few channels.

 

[KC2GIU]

Friskidog-

Get your Tech license back and get on ten and six meters. Ten meters is nearly identical to CB and six meters is often called the magic band. Two meter FM with repeaters is just the start even for a Technician class amateur. Flip through the Part 97 rules and see for yourself.

73

I'm a Tech Plus and like 2M & 10M and even 11M communications.

Not everyone in the world has a HAM ticket, thus talking to many local people, CB 11M wins much of the time. In the Nashville area, CB has more people than all of the HAM bands combined talking. CB is very redneck because of it. It lives very strongly here in the mid and southern states. To tell a southerner to give up CB for Ham radio is like taking away the confederate flag. It just ain't gonna happen. 80% of pickup trucks down here have CB radios in them. So, why would I a Ham use Ham radios to talk to the local folks?

 

[gewecke]

I'm done with red necks lol. The only way I'd EVER use cb again would be split frequency and on ssb on oppoosite ends of the band. :twisted: 73, n9zas