Help with Antenna Selection

[daugherh]

So currently I'm running an XPR5550 on the UHF 440 amateur band as well as with GMRS and some locals. I currently have a basic 1/4 wave NMO antenna on my truck and while it's been pretty decent, I think it can do better. I occasionally miss transmissions, or they cut out during the conversation. I'm thinking about upgrading to a 5/8 wave and was curious which of these 2 would be my best choice.

The B4503S, link here, a 450-470 MHz rated antenna, has really good reviews but I'm wondering if it's able to be pushed down to the 440 range for amateur use or is it too far out of range.

The other one I'm looking at is the B3803WS, link here, rated for 380-520 MHz, but wondering if such a wide bandwidth range is just going to eliminate any benefit to using it.

What would be the better choice if I want to use the 5/8 wave on 440 HAM and GMRS? Or just stick with 1/4 wave?

 

[mmckenna]

I doubt that the B380S will cover all that spectrum. It would need to be tuned for your section of the band. Likely, it just comes with a longer whip to allow the end user to tune it where needed.
The B450S3 is likely 'pre tuned' or fairly close to where you need it.

A couple of things to ponder:

A 1/4 wave antenna will have a lot of useable bandwidth and easily cover 440MHz and GMRS with respectable SWR. I did that for years.

I did try a 5/8th's wave antenna once. Narrower bandwidth, so SWR was higher. Tuning for 440 gave high SWR on GMRS. Tuning for GMRS gave high SWR on 440. Tuning in the middle gave less than ideal SWR on either end. Plus, I did not notice enough of a difference with the 5/8ths wave over the 1/4 wave. I eventually went back to the 1/4 wave.

Sounds like topology is getting in between you and the transmitter. Adding the 5/8'ths wave antenna probably isn't going to make a noticeable difference in most cases, but it's worth trying.

 

[daugherh]

I doubt that the B380S will cover all that spectrum. It would need to be tuned for your section of the band. Likely, it just comes with a longer whip to allow the end user to tune it where needed.
The B450S3 is likely 'pre tuned' or fairly close to where you need it.

A couple of things to ponder:

A 1/4 wave antenna will have a lot of useable bandwidth and easily cover 440MHz and GMRS with respectable SWR. I did that for years.

I did try a 5/8th's wave antenna once. Narrower bandwidth, so SWR was higher. Tuning for 440 gave high SWR on GMRS. Tuning for GMRS gave high SWR on 440. Tuning in the middle gave less than ideal SWR on either end. Plus, I did not notice enough of a difference with the 5/8ths wave over the 1/4 wave. I eventually went back to the 1/4 wave.

Sounds like topology is getting in between you and the transmitter. Adding the 5/8'ths wave antenna probably isn't going to make a noticeable difference in most cases, but it's worth trying.

Awesome information as usual. Thanks!