wattage problem

bayfire300 · Post by **bayfire300** » Fri Dec 02, 2005 12:55 pm

hi guys maybe you can answer me this ,,i know it has me puzzled

i have a maxtrac 45 watt .....when i take a short piece of rg8u w/ n connectors to watt-meter it reads 20 watts....when i change cable to rg213 w/ pl239's it reads 45watts.............now i use the rg 213 to duplexer and rg213 or rg8u from dupleaxer to wat-meter it reads 20 watts........i changed duplexers (from another repeater that putts out 45 watts no matter what cable i use) and still reads 20 watts

how can that be?

thanks
otto

kb0nly · Post by **kb0nly** » Fri Dec 02, 2005 1:12 pm

Bad coax, bad connectors, many possibles here.

You mentioned that you get 45w out of the transmitter then connect that same piece of coax to the duplexer and your only seeing 20w out the duplexer, have you checked the tuning and loss through the duplexer? Are you using the same suspect piece of RG8U from the output of the duplexer to the wattmeter?

bayfire300 · Post by **bayfire300** » Fri Dec 02, 2005 1:17 pm

i connect the radio to the watmetter w/ rg213 pl239's and get 45w....i disconnect from watmeter and put it to duplexer....take another piece of 213 from duplexer to watmeter and it reads 20w just saying that would seem the duplexer is out of tune .......but...............i took another duplexer from a diff repeater i have which it always reads 45w and tried it on this repeater in question and it also reads 20w so it cant be the duplexer

otto

kb0nly · Post by **kb0nly** » Fri Dec 02, 2005 2:25 pm

Are you saying that the other repeater shows 45w after the duplexer? I highly doubt your getting the same power out of the duplexer that you are seeing on the output of the transmitter, your going to have loss through the duplexer regardless of how well it is tuned, but the goal is to make sure your not loosing too much!

bayfire300 · Post by **bayfire300** » Fri Dec 02, 2005 2:29 pm

yes the other repeater reads 45w after duplexer ..i never tried what it does before the duplexer......so i knopw that duplexer is good.......when i hoo it up to the repeater or transmitter in question it either duplexer reads 20 watts......i know it sounds weird....i cant figure it out
otto

kb0nly · Post by **kb0nly** » Fri Dec 02, 2005 2:31 pm

How about trying the cables from the other repeater to, have you tried that?

I still think it must be a bad connection or cable somewhere.

bayfire300 · Post by **bayfire300** » Fri Dec 02, 2005 3:02 pm

yes i even tried the new duplexer to old repeater and everything was fine........somehow i think it might be the tramsmitter ot maxtrac.....i even went as far as changing the mini uhf to so 239's to new ones
i am so lost lol....
otto

440roadrunner · Post by **440roadrunner** » Fri Dec 02, 2005 3:26 pm

Not knowing the "real" situation, some comments:

For the most reliable reading on what a transmitter is outputting, us a dummy load/wattmeter.

Coax cables, and connectors can cause problems, but.......

If there is some reactance in the system, changing the LENGTH of a cable, all other things being equal, can cause the INDICATED power/ swr/ reflected to change.

I'd start by running down a good reliable dummy load---not a cantenna!!!! and read the wattmeter----if possible---with a good dummy load connected RIGHT TO the wattmeter

bayfire300 · Post by **bayfire300** » Fri Dec 02, 2005 4:10 pm

ok i found it .....your not gonna believe this ....on each duplexer antenna port i have a "N" to so239connector cus my feed lines are pl259's....the when i disconnected the duplexer from good working repeater to put on other repeater i left the connector on the feed line ( i have 2 antennas up on the roof)......the problem was the center pin on the adapter for the repeater not working so well was shorter than the other one....i changed the n to so239 adaptor and wah la!! 40w out of the duplexer........ok now i need a drink

thanks for all your input i really appreciate it

otto

kb0nly · Post by **kb0nly** » Fri Dec 02, 2005 5:06 pm

Another one of those, "this is gonna drive me nuts" problems.. LOL

At least you found it. First thing i go after with a problem like that is cables, connectors, and adapters if any.

And not all adapters are created equal!

440roadrunner · Post by **440roadrunner** » Fri Dec 02, 2005 11:11 pm

Coaxial adaptors are ALWAYS suspect in this day and age---especially since Radio Sh.. decided to sell poorly made adaptors that used

SPRINGS

for internal connections. Can you spell inductance? Can you spell reactance? Can you spell reflected power?

kb0nly · Post by **kb0nly** » Fri Dec 02, 2005 11:21 pm

Yep, your a lot better off changing to the correct connector on the coax to begin with. Adapters are ok if you buy good quality ones though, but probably not something you want to rely on for years to come, etc.

bayfire300 · Post by **bayfire300** » Sun Dec 04, 2005 5:13 pm

yea i plan to in the spring when i put up my tower........also i got the adaptors from an electronics place online ...not radio shack...i learned that lesson b4 lol
thanks again for all your help
otto