Adjusting SWR with amp

[W5LZ]

...and to take that explanation just a tiny bit further...

The least amount of 'coil'/inductance used is always the best way of adjusting a tuner. And to take that little chunk of information just a tiny bit further, the least amount of 'coil'/inductance necessary thingy is also true for an antenna.

And from personal experience, if a 'Dentron' tuner can't find a match for an antenna, there's something not 'right' about the antenna! They were built very nicely, as in rugged. Their 'biggest' fault is with the meter switching buttons, push buttons, plastic 'doogies' that hold the button 'in', they get worn, don't want to stay 'in' anymore. The meter stays switched, but the indicators on the buttons don't work anymore. RATS! But very nice tuners.
- 'Doc

 

[pro151]

Wow!

 

[steved]

OK, a lot of differing input here...

I'm having the same issue...antenna is tune to an almost flat 1:1, flip the amp on and the SWR goes into the red (not pegged)...

Is this something to worry about, or should I not worry since the antenna is tuned correctly?

I should also note the amp is not being over driven, 13.8VDC, and getting good reports...radio is not clipped.

 

[freecell]

"I guess all of the hams that wrote those articles were wrong...."

if anything written in "those articles" indicated that SWR increases with applied power then they were wrong.

the RATIO between maximum and minimum voltage (or current) doesn't change with the amount of power applied.

note to steved:

a gayboy 1X2 is a class c pos.. 300W out of 2X2SC2879's is all that's real and the other 200W is all crap. ask lazybones, he can tell you all about it. no one in that other vbulletin forum has a clue.

in the meantime, if you're tired of switching equipment in and out i suggest that you observe the maximum output ratings of the number and type of devices used in the last stage of the amplifier and restrict your swr measurements in the following manner. USE ONLY THE MINIMUM AMOUNT OF POWER NECESSARY TO OBTAIN A SET (CALIBRATION) READING when making swr measurements. 2X2SC2879's don't produce 500W @ 27Mhz..

 

[steved]

So I probably should look for a straight 4-pill, if anything? I thought long and hard about a Texas Star for just this reason. This is exactly what I was trying to avoid.

I assume by your comment, that it is the 2290 *overdriving* the 2879s that's causing my headache?

I have a 2-pill (2@2879s) also, but I was going to install it in the car. I wonder if it would do any better?

I'm using a PC76XL that is unclipped with a variable...

Ohh, and thanks for the input...it is greatly appreciated.

 

[freecell]

just ask yourself a simple question. what is a 60W transistor doing ahead of a pair of 2879's that are rated at 10W MAX drive each? it's there to drive the 2879's into saturation and beyond so you can get that fuzzy feeling when you look at your wattmeter.

 

[steved]

Yeah, I answered my own question after I thought it through...the amp itself is the problem, not the rest of my setup. I should have research the 1x2 better before I bought it...I had something similar before, never had problems. Hind sight is 20/20...

 

[BOOTY MONSTER]

I've seen and heard the term harmonics before. What is it? Feedback, distortion or what? Would I hear it in my "talkback"?
Thanks

http://www.dxing.com/radterms.htm[/QUOTE]

this is weird ! i dont recall making this post . i certianly know what harmonics are . maybe i was having too much fun ? guess ill go change my password to be on the safe side .

 

[BOOTY MONSTER]

just ask yourself a simple question. what is a 60W transistor doing ahead of a pair of 2879's that are rated at 10W MAX drive each? it's there to drive the 2879's into saturation and beyond so you can get that fuzzy feeling when you look at your wattmeter.

dont forget the fuzzy sound in your transmission aka harmonics/distortion .

 

[steved]

http://www.dxing.com/radterms.htm

this is weird ! i dont recall making this post . i certianly know what harmonics are . maybe i was having too much fun ? guess ill go change my password to be on the safe side .[/QUOTE]



You do realize I dug this post up from like this past December??

 

[BOOTY MONSTER]

yep . i looked at the date but cant understand why i would have asked that question . hey steve , did you decide to go with the 102 the fatboy or the 5000 ? just curious .

 

[hotrod]

Hey T-bone !! You still with us ? !! How much more deeper you think they can get ? They can feed you a smorgasbord of information , How perfect does it have to be for anybody ? IM just glad it wasn't required to know all of this to get across the street with my cb radio / given coax / amp and my back pocket SWR meter . I feel after 20 sum years the basics have gotten me by and I personally didn't have to go to college to get deeper then I personally needed to be. Wow ! It's looking more and more I have lived a antenna coax SWR lie my whole radio life :roll: all because I kept it simple and it always seemed to work so well for me ?. It must have been the RF God's watching over me ? No burnt up radios / amps / antenna's or feedlines !! Trust me here , IM not knocking the knowledge , IM just saying I would have been gone decades ago if I personally would have had to gotten so deep into it.(it would have more then likely taken the fun out of it for me) But I'd be one of the first ones to admit , that it just don't have to be perfect to work and to work well. It just doesn't have to get so deep for the average Joe's of the CB world . How hard does it have to be ? It don't !! Buy a decent well made talked about antenna and follow the freak'in instructions ! drill the hole in the roof , run the line and chances are , with your little back pocket SWR meter , you will see 1.1 / 1.2 / 1.3 / 1.4 / 1.5 or maybe even a little more , now follow the instructions on how to tune it lower if possible , slide the stinger up and down from channnels 1/20/40 Dah Da !! your lower then 1.5 around the band on both ends !! You the man !! Now get that amp in line and check things out , 9 times out of 10 your false reading of maybe going from 1.1 to 1.3 will be totally Bob Bitch'in !! you are good to go Joe !! Now enjoy your radio and power and let them know who's the boss,but most of all , HAVE FUN !

i know this is a old post but gotta say i also agree with switchkit.keep it simple
it will work.

 

[mackmobile43]

i know this is a old post but gotta say i also agree with switchkit.keep it simple
it will work.

Now if he would only learn punctuation.

 

[freecell]

yeah i read it before, once was enough.
there, now it's gone.

 

[steved]

yep . i looked at the date but cant understand why i would have asked that question . hey steve , did you decide to go with the 102 the fatboy or the 5000 ? just curious .

I haven't had time to play with it...for the time being, I'm going to hook my 2-pill up...clean signal into a even a class C should give me clean signal out as long as I don't over drive it...at least enough to see if it is the amp or not.

I'm not sure on the antenna yet...the 5000 is less obtrusive, but I haven't had the 102 long enough to see if it works as well...I sorta like the 102.