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How important is SWR?


The antenna is to long,need to shorten it up a bit,with VHF it doesnt take much cutting on an antenna to make a huge difference .

And yes SWR can make a difference .When a signal is reflected back into a radio ,the radio gets rid of the reflected signal in the form of heat ,as you know heat is a radios enemy .If the SWR is high enough it can simply cause parts to fail when you key the mic..

.It would be well worth the time to tune the antenna for where you plan on operating at.Your radio will thank you in the long run
 
The antenna is to long,need to shorten it up a bit,with VHF it doesnt take much cutting on an antenna to make a huge difference .

And yes SWR can make a difference .When a signal is reflected back into a radio ,the radio gets rid of the reflected signal in the form of heat ,as you know heat is a radios enemy .If the SWR is high enough it can simply cause parts to fail when you key the mic..

.It would be well worth the time to tune the antenna for where you plan on operating at.Your radio will thank you in the long run

Thank you for the reply. It's much appreciated. Should I be cutting in half inch increments?
 
The higher you go in frequency the more critical antenna length becomes so cutting in small increments is important. Don't push the antenna whip all the way down in the base either, leave it about a 1/4" from the bottom. Getting the SWR around 1.5:1 is fine, anything lower than that will not make any difference and not worth the effort. For 2 meters tune the antenna for low SWR at 146.000, this will give you good results across the band.
 
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SWR isn't something to disregard completely, but it's not absolutely a biggy. Most radios will tolerate something around a 2:1, but getting it under that isn't a bad thing. SWRE is not the biggy everybody makes it out to be.
You want to be careful when tuning any VHF/UHF antenna by adjusting length. Take small 'bites', not big ones. And when the SWR get's somewhere close to 1.5:1 (or lower) on the center of the band or the frequency you use the most... QUIT! If you don't go just a tad to far with that... you're doing better than me in most cases, oh well.
- 'Doc
 
Your radio will tolerate a 2 to 1 SWR without problem. It does cut down on the radiated power.
The post that said the higher SWR just made heat is not totally correct. The radio wave will go up and back down the coax to the radio and then back up and down and whatever part of it not lost to a slight bit of heat or radiation from the coax will be radiated by your antenna.
Most newer radios cut back the power with a high SWR as not to hurt the radio. Some start cutting back at 1.5 to1, most at about 2 to1 SWR
If you can get to a 1.5 to1 towards the band edges and as close to 1 to 1 in the middle of the band, that's doing very good.
Just remember, you won't have a 1 to 1 or 1.2 to 1 across the entire band. You tune the antenna for the best SWR in the middle of the band or if you use one frequency the majority of the time, you can tune for the best SWR at that frequency as long as it does not raise the SWR too high at the band edges.
An example, maybe the frequency you use most is at 145.940. You tune your antenna for that frequency to a 1 to 1, but at the upper band edge, the SWR is 2 to1. That's OK as long as you realize you won't put out as much power at the top of the band.

73's John KF7VXA
 
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