Help with 2m/70cm HT setup in van

another_mike

Adventurer
I currently have a HT (Kenwood D74a) on 2m/70cm. Tx and Rx from inside the van is less than stellar. Ive decided on mounting an antenna to the drivers fender. The majority of the time im using APRS.

Why a fender mount? My van is already like 9 feet tall. I have a full length roof rack and that space is already taken up by a 300 watt solar panel, roof vent fan and road shower. Possible a few more things in the future so permanently mounting on the roof is not currently an option. Maybe once everything is configured to my liking ill go there. For now, the fender will do, and im sure any antenna outside the vehicle will work better than the HT inside the vehicle.

I just ordered the mount from here: https://www.wearecb.com/hood-cb-antenna-mount-van.html While this mount is 3/8", obviously they make 3/8 NMO mounts, so antenna options are open. Length of cable from base of antenna to the HT connection (SMA-M) will be 6 feet at the most.

I was leaning toward using a Comet SSB-5 NMO. At 38", this will put me close to the highest point on my roof, so no need to worry about getting out to fold it down/remove it.

Once I install the mount and I confirm there is room, I had this in mind: https://www.theantennafarm.com/catalog/laird-technologies-mabt8-1154

Now the radio end connector. Should I end it in something like a PL-259 to make any future decision for a mobile transceiver easier? and just use jumper to make it SMA-F? The HT being 5w max, might this give too much loss?

Advice welcome, thanks.
 

DaveInDenver

Middle Income Semi-Redneck
I'd probably crimp an SMA on and use a PL259 adapter in the future.

It's probably close to a wash as far as losses between that and a PL259 soldered directly on the RG-58. SMA (and BNC & N) are much better connectors and even at UHF are pretty low loss so either way most of your loss is in the SO239/PL259.

One thing to watch is an SMA on the end of RG-58 might put quite a bit of strain on an HT connector, so watch routing and try to prevent much coax hanging on it.
 
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sonoronos

Usually broken down on the side of the road
This might sound kind of silly, but do you think it might be helpful to use a speaker-mic with the HT? (https://www.eham.net/articles/38032)

Kind of to Dave's point about the SMA connection and strain. Maybe fixing the HT using a mount would make life easier on you.

I don't think SMA connectors will have any problem with 5W output power.
 
Last edited:

another_mike

Adventurer
This might sound kind of silly, but do you think it might be helpful to use a speaker-mic with the HT?

Kind of to Dave's point about the SMA connection and strain. Maybe fixing the HT using a mount would make life easier on you.

I don't think SMA connectors will have any problem with 5W output power.
not silly at all. I definitely plan on getting a speakermic.
 

wirenut

Adventurer
I've found Diamond antennas to be much more rugged than Comet antennas. I've had 2 Comets, both broke at the loading coil after hitting tree branches. I've had many, many Diamond antennas, all but one had the open spring looking coil in the middle which is just steel whip so very durable. I have one Diamond with a plastic Comet type loading coil and it has not broken in many years of tree strikes.
I would try to put no more stress on the HT's SMA connector than you have too. I would use a short jumper of very small flexible coax between the incoming coax and the connector.
 

BigJimCruising

Adventurer
Sounds like you do some off roading to remote places? If so skip the Comet and Diamond antennas. I've tried them and just about every other type of mobile antennas throughout the years while spending ten's of thousands of miles off road. They just won't hold up to those harsh conditions. They're fine for streets and highways but not off road. The only antennas I've found that can take the abuse is the Larson brand. Either the center load or the center open coil if you're dual band. If I remember right its the Larson NMO 2/70. I prefer the open coil but just watch it around trees and make sure the rod screws are tight and add a little lock tite to make sure!

As for the radio connection, go with the pl259 with a long jumper. You'll want to upgrade to a full power radio soon! I started out the same way and soon found the need for something better. Plus handhelds can get very hot when used a lot.

Happy trails!
 

another_mike

Adventurer
Sounds like you do some off roading to remote places? If so skip the Comet and Diamond antennas. I've tried them and just about every other type of mobile antennas throughout the years while spending ten's of thousands of miles off road. They just won't hold up to those harsh conditions. They're fine for streets and highways but not off road. The only antennas I've found that can take the abuse is the Larson brand. Either the center load or the center open coil if you're dual band. If I remember right its the Larson NMO 2/70. I prefer the open coil but just watch it around trees and make sure the rod screws are tight and add a little lock tite to make sure!

As for the radio connection, go with the pl259 with a long jumper. You'll want to upgrade to a full power radio soon! I started out the same way and soon found the need for something better. Plus handhelds can get very hot when used a lot.

Happy trails!
Thanks for the advice, but I already went with the SBB5NMO antenna. Wont be doing too much offroading this year in the van. Headed out to Colorado in about 2 weeks but going with another friend who only has a 2 wheel drive stock van, so ill have to compromise on campsites. Although, we are both bringing dirt bikes, so we will get our offroad fix. Went with a BNC connector since my Ed Fong roll up antenna shares the same connector. I did get a 12" jumper with RG174 to relieve strain on the HT's connector. Also got a SMC34 kenwood speaker mic, its smaller than I expected.

Im sure a mobile radio will be in my future.
 

rho

Lost again
Thanks for the advice, but I already went with the SBB5NMO antenna. Wont be doing too much offroading this year in the van. Headed out to Colorado in about 2 weeks but going with another friend who only has a 2 wheel drive stock van, so ill have to compromise on campsites. Although, we are both bringing dirt bikes, so we will get our offroad fix. Went with a BNC connector since my Ed Fong roll up antenna shares the same connector. I did get a 12" jumper with RG174 to relieve strain on the HT's connector. Also got a SMC34 kenwood speaker mic, its smaller than I expected.

Im sure a mobile radio will be in my future.

You'll have a mobile rig before too much longer. HT's in mobile use are flat out too cumbersome for extended use. Plus, uh, they tend to fly if you start getting the truck rocking and bouncing around...
 

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