My radio meter is acting strang.

[Moleculo]

I bet you have an impedence mismatch between the radio and the amp. What length of coax jumper are you using? Try a longer jumper and see if that helps. Sometimes that's the only way you can correct things without having the amp worked on.



Moleculo


</p>Edited by: <A HREF=http://p067.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=moleculocdx363>MoleculoCDX363</A> at: 5/31/04 2:33 pm

 

[Moleculo]

Yes, the Coax's impedence is 50 ohms. But the amp's input impedence could be off. Sometimes varying the length of coax will "present" a different impedence to the amp, much like using an antenna tuner. You shouldn't really have to use either a tuner or mess with the coax length, but sometimes with CB amps, it's all you can do unless you feel like sending the amp to a tech to correct. Most of the better Ham amps have an adjustment on the back so you can make the adjustment yourself.



Moleculo


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[Big Nasty Trucker]

My Galaxy 45MP meter is acting strange. When I am running it barefoot the meter shows plenty of swing and acts normal. When I turn my amp on, the meter doesn't act nearly as agile and doesn't show the forward swing that it does when barefooting.



Is this normal or do I have problems somewhere?


Galaxy DX44V

Galaxy DX45 MP

Galaxy DX73V

Gray 300 AB Biased

2X4 HomeBrew

RK 56 Astatic 636L

MonkeyMade Antenna

Capacity Hat

140 Leece Neville

4X750 Batteries

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[JustinDePolis2]

Hey there,



Moleculo is 100% correct, in stating that the amplifier's input impedance is probably off. One way to check is to inser an SWR bridge in between the radio and amplifier with the amplifier on, and simply check it. This is one cheap way. It still won't tell you weather it's a reactive load or resistive, although for a CB amplifier it's not important. If you notice that the SWR into the amplifier is high, set up all of the equipment like you normally would, except, have the amplifier going into a dummy load, and an SWR bridge in between the radio and amplifier. On the input circuit of the amplifier, typically near the input combiner, there will be probably a small 68-150 pf silver mica capacitor, by changing that value up or down, it will lower the input SWR. You can also play with the capacitance on the input transformers, although I would not do this unless you know exactly what you are doing, know the size of the transformers, turns, etc.



Justin



http://www.fgbestcommunications.com


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