how to set high swr's on a 5/8 base ground plane antenna?

Answer 1

I can't imagine why you would want high SWR on the antenna. To achieve this the antenna needs to be detuned from its intended operating frequency. Make the length of the vertical section shorter and the antenna will detune and SWR will go very high.

On the other hand, if you want low SWR which will result in optimized performance, the antenna needs to be properly tuned. Measure SWR at the low frequency end of the operating band you intend to use. Next measure at the high frequency end of the band. If SWR is better on the high end the antenna needs to be lengthened. If it is better at the low end it needs to be shortened. Make small adjustments until it is optimized. SWR will be minimum at mid band, and equal at upper and lower frequency limits.

If you have access to a spectrum analyzer with sweep generator the measurements are very easy taken and you will get much better results. Find a friend who works in broadcasting or radio communications.

Answer 2

First of all, you don't want a high Standing Wave Ratio (SWR), you want it as close to 1:1 as possible. The SWR is ratio of forward vs reflected power in your system, ie; the higher the SWR the harder it is for your transmitter outputs to overcome the reflected power resulting in short output life. I'm not sure if this answers your question or not.

If you are trying to get better receiving results from the antenna, you may need to trim or lengthen the antenna, either physically or electrically. Since this can get a little complicated, go to your local library and check out the "ARRL (American Radio Relay League) Handbook" or the "ARRL Antenna Handbook" it will give you all the information you could possibly need.

Answer 3

you want the lowest possible match, Higher the swr's you have more of a chance blowing your finals.