VHF aerial specs and VSWR

[Keith-i]

I'm looking to replace the VHF aerial on my rib, with the Shakespeare 5400-XP looking like a good candidate. However, I don't really understand the differences between the different specs of the various other models. The 5400 is quoted as having nominally 1.5:1 VSWR@ 156.8Mhz with a 3MHz bandwidth whereas others are <1.5:1 and one or two <2.1:1 with 18MHz bandwidth. Should I be concerned?

 

[lw395]

From memory, the top of the VHF band is162 MHz, so 3MHz BW doesn't look good.
But if, like a lot of people, you only want the simplex channels and not AIS etc, it will be fine.

https://en.wikipedia.org/wiki/Marine_VHF_radio

Which channels do you use?

It will still function at shorter range on other channels.

 

[William_H]

I don't think you should be concerned re the specs. What you need is an antenna for the RIB which does not require a ground plane. In other words the one you want looks like a GRP tube perhaps 1.7 metres long or so with a coaxial cable emerging from the base going to the radio. The alternative type you do not want might be stainless steel rod perhaps 18 inches long sometimes longer where the centre of the coax connects to the rod and the braid outer of the coax connects to metal mount. As in mast or metal cabin top. That is the ground plane. However this latter type may be OK if you have a metal post to mount it on top of. ol'will