PCS FM Dipole

yugo · Post by **yugo** » Sat Mar 09, 2019 1:18 pm

I bought the PCS FM Dipole from you and am now trying to tune it. According to the included documents the antenna should be tuned to 87 MHz. At first I measured (outside) without changing anything. By adjusting the gamma match I got an SWR of roughly 2.4:1. The output power was at 5.4w. Also I noticed that the transmitter (!!!!!!!!!!) heated up quite quickly. It was at 60°C in 5 minutes and I placed it on a heatsink (no metal case yet). So I cut the antenna 0,5cm on each side and measured again. Played around with the gamma match and got values from 2.4:1 to 2.6:1 but the output power was now higher (about 10w - 12w). The transmitter heated up quickly again.

Frequency and mounting position are always the same.

Would you recommend me to cut it down a little bit again? Or am I doing something wrong?

yugo · Post by **yugo** » Sat Mar 09, 2019 1:24 pm

My transmitter is the MAX PRO 3000+ FM Exciter (forgot to put it into the bracket with those exclamation marks). The frequency I want to tune it to is 87.5 MHz.

ABC FM · Post by **ABC FM** » Mon Mar 11, 2019 7:05 pm

one thing that is not in user manual is information about element C. This part of gamma match is also adjustable and it can be pull out cca 20-30cm. If L1 for elements A is exact as in manual, pull element C one by one cm, and in correlation to element B adjust best vswr.

After this little secert about element C i adjusted this antenna for less then 5min at swr 1.1. Antenna worked fine, but i recommand rubber tape for uhf connector.

Post by **pcs** » Wed Mar 20, 2019 7:59 pm

Thank you