Transmit on Ham Bands BMAXSCAN1000 or Larsen 150/450/800

[cellphone]

Hi All,

I am setting up a Kenwood TK-790H/890H dual band radio for my car. I am debating on doing two 1/4 wave antennas or a dual band antenna. I will primarily be using it for monitoring 154-155, 460mhz, but will be transmitting occasionally on 144/440mhz ham bands.

I am a huge fan of both PCTEL BMAXSCAN1000 and Larsen 150/450/800 on vehicles for scanners as these are outstanding performers for receiving the public safety bands. I have never used these for transmitting.

Has anyone transmitted with either of these antennas on the ham bands? How is the SWR on the ham bands? These antennas are rated for 100 watts. The radios are rated at 110 watts, so I am also concerned about going over. I don’t have the radios set up yet, but I will probably try to burn up some antennas once I get them installed.

I am interested in other dual band ham antennas that everyone has used for monitoring public safety. I have used dual band ham antennas in the past for monitoring public safety bands, and the ones I have tried are very poor receive performers on 155 & 460 as they are too narrow band only for ham bands. Anyone have a recommendation on a short (about 16”) dual band ham antenna that still performs well in receiving the public safety bands?

 

[buddrousa]

With that type power you should stay away from the dual band duplexers and run 2 antennas.

 

[cellphone]

For the duplexer, I am planning to use a Comet CF-416A if I go with a dual band antenna. I was not really concerned about it as it is rated for 800 watts VHF and 500 watts UHF. I am more concerned about high SWR with these antennas and damaging the antenna by going slightly over the power rating.

 

[ko6jw_2]

You might want to check out the Comet CA-2x4SR. It is designed for 144/440, but also for people involved with SAR. It can transmit up to 160Mhz and and 465Mhz. You won't be transmitting in those ranges, but the low SWR should make it a good choice for ham use and public safety monitoring. That way you can get by with one antenna. I have also used the Austin Spectra. It offers 2 meter and 440 transmit and is an excellent scanner antenna for all bands (tunable for 30-50Mhz). Not sure on the power handling.

 

[krokus]

I agree with the Comet CA-2x4SR, but consider the new spring base option. Otherwise this antenna is pretty stiff, and hitting overhead stuff with the antenna tends to stress the mount.

Sent via Tapatalk

 

[cellphone]

Thanks for the info! The Comet CA-2x4SR looks a great antenna for what I need, but about 2 feet longer then I would like. This one would not clear the garage.

I did find another option that is rated at 200w. It does specifically include the ham bands, but I will probably give it a try and test SWR to see if this will be an option for transmitting on 146 and 446.
https://www.tessco.com/products/displayProductInfo.do?sku=15243&eventPage=1

It looks almost identical to the PCTEL BMAXSCAN1000, but rated for 200w.

 

[mmckenna]

From what I've seen, the Larsen antennas are resonate more towards the 154/460 areas of the VHF/UHF bands.

A duplexer will add some additional losses (both TX and RX). Not a lot, but between the duplexer and the slightly off tune antenna, I think you could do better.

If you are willing, I'd strongly suggest going with two separate 1/4 wave antennas. I've run both ways, and I like the separate antennas.

1/4 wave antennas are very broad banded. I've got a VHF on my truck and running it through an antenna analyzer shows less than 2.5:1 SWR from 140MHz up through 170MHz.

Also, the dual band antennas are usually pretty good at VHF since they are often 1/4 wavelength. Where you -might- have some issues is on the UHF band where they act as a co-linear stacked antenna. The radiation pattern gets smashed down pretty flat. Not always a bad thing, but quite a bit different than the radiation patter the VHF side will have.