Can someone tell me what's happening :?: :?: when I dead key on channel 1. My SWR is 1.4:1 when I modulate the SWR goes down to 1.2:1. Can someone explain whats happening.
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SWRs
- Thread starter Drifter
- Start date
When checking swr there should only be a carrier and no audio or modulated signals at all thats why the Standing Wave Ratial (SWR) should be checked on AM mode because there is a carrier I turn mic gain all the way down and go from there. Also be aware that if there is to little of a carrier the SWR meter will not calibrate on some meters....
Barefoot I do not have the problem with the SWR back swinging with modulation. 1.2:1 CH1, CH20 1.1:1, CH40 1.0:1. With Power that's whe the back swinging with modulation occurs. CH1 1.4:1 back swings with modulation to 1.2:1, CH20 1.3:1 back swings with mod to 1.2:1 and CH40 is flat 1.1:1..... To be honest my SWRs are not bad but I wanted to know what was going on with SWR dropping with modulation.paws264 said:
The SWR itself isn't changing, but what comes out of your radio IS, when the power level changes.
Extra, unwanted "harmonic" frequencies will fool a SWR meter, and cause it to read high. This is because the antenna is not built to accept those extra frequencies. As a result, they "bounce" back down from the antenna, driving up the "reflected" or "SWR" reading. The meter can't tell how many frequencies are passing through it, just the sum total of the power they all represent, added together.
Your amplifier is simply putting out more harmonic energy on a dead carrier than it is when you modulate. When the extra harmonic content of your wattage falls off, the bogus "SWR" reading that they cause falls off with it.
Apparently, the barefoot radio alone doesn't have this bad "harmonic" habit.
On the other hand, if you had a handy, five-thousand buck instrument called a Spectrum Analyzer handy, it would tell you this at a glance. The list of things that a SWR meter CAN'T tell you is a lot longer than the list of things that it CAN tell you.
73
Extra, unwanted "harmonic" frequencies will fool a SWR meter, and cause it to read high. This is because the antenna is not built to accept those extra frequencies. As a result, they "bounce" back down from the antenna, driving up the "reflected" or "SWR" reading. The meter can't tell how many frequencies are passing through it, just the sum total of the power they all represent, added together.
Your amplifier is simply putting out more harmonic energy on a dead carrier than it is when you modulate. When the extra harmonic content of your wattage falls off, the bogus "SWR" reading that they cause falls off with it.
Apparently, the barefoot radio alone doesn't have this bad "harmonic" habit.
On the other hand, if you had a handy, five-thousand buck instrument called a Spectrum Analyzer handy, it would tell you this at a glance. The list of things that a SWR meter CAN'T tell you is a lot longer than the list of things that it CAN tell you.
73
Mr Drifter ? Your fine dude !! Just use the thing !! Sometimes Einstiens theroy of relativity will drive a dude nuts !! As long as your meter aint in the red and your around the 1.5 or so give or take a mark either way ......start modulating and enjoy. It's sometimes when we start turning this stuff into rocket science it tend to make perfectionists out of us when in reality it truly doesn't have to be that way.
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