GRA-SMA24 Antenna Length Advice

[jill551243]

I have a gra-sma24 16.22" antenna to be hooked up to a wireless mic pack . I cut it to several different lengths to find the strongest signal, but none of them got a strong/usable signal at all.

I did the calculations using 2440MHz (channel 7) for the desired frequency, since this is the center of the frequency that my mic pack uses.

tested lengths are as follows:

full - 4.5in
half - 2.25in
quarter - 1.25in
any advice would be appreciated, its likely that I'm missing something blaringly obvious

 

[mmckenna]

You'd want 1/4 wave, so 1.25

However, I'd be concerned that there is some loading coil in the base. That antenna is designed for 2 meter/70cm and 1/4 wave on 2 meters would be a bit over 19". Yet, that antenna is only 15.75 inches long. So, cutting it to 1.25 probably won't jive with whatever is in the base.

Using an antenna analyzer, like a NanoVNA may help you, but simply sticking the antenna on top of the analyzer won't be accurate.

 

[mmckenna]

Personally, I'd just contact the company and order the correct antenna:
parts@saramonicusa.com

That'll likely be cheaper than messing around with ham radio antennas, purchasing a NanoVNA and learning how to use it.