I use 5/8 vertical antenna for 4m FM local communication. It is 260 cm long aluminium antenna with 4 radials tunable in the range 66 - 88 MHz and was made with SO239 connector based on my request. It's gain is 2,9 dBd. Power handling is 500W with 100% duty and 1kW with 50% duty cycle. It was delivered already pretuned exactly to 70,5 MHz as I requested. The SWR is absolutely perfect 1:1,0 with the bandwidth of 2 MHz up to SWR 1:1,5.
A very important role plays the usage of the correct length of the coaxial cable feeding the antenna so the SWR is not effected by the cable. It can be said this rule applies to any antenna fed by a coax cable. This is often forgotten and it affects the SWR. The requested length can be easily calculated.
I always monitor, call CQ and communicate on
70,450 MHz FM
from my base location.
I transmit with the power 25 W using 25 kHz bandwidth. We don't QSY from 70,45 as it is not necessary because just a few people are using this calling frequency and 4m band generally in our area.
I am capable to increase the power up to 50 W because I own a 50 W version of AT-5189.
Note that mostly 25 W versions are available on eshops.
