2M/70cm Mobile Antenna Mount

[Nashua Area Radio Society]

Hi folks.  I am planning to install a mobile rig in my RAM 1500 and am looking to use a bed stake hole mount such as this:

https://www.gigaparts.com/firestik-ss-294a-stake-hole-mount-compact-w-k-4a-stud.html

Opinions/experience suggestions on this type of mount and 2M/70cm antenna selection?  Options for a tri-band (6M/2M/70cm) antenna?

Many thanks!

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[Fred Kemmerer]

Are you planning to do FM for repeaters and simplex or SSB for weak signal say on 6m?

This arrangement will certainly work but you might want to also consider a lip-mount NMO on the top edge of your door.

[caption id="attachment_97731" align="aligncenter" width="300"] Diamond NMO Lip Mount[/caption]

I have this arrangement on my F-150 and it’s much easier to route the coax cable from the antenna to the radio. You can route the antenna coax it inside the door sealing gasket until you get to the hinge area then route the coax to your radio from there. The antenna is also mounted higher on the vehicle which will improve radiation performance. Here are some more pictures of the VHF/UHF radio installation in our F-150.

There are lots of good choices for NMO standard whips for this sort of mount as well.

[Nashua Area Radio Society]

<p style=”text-align: left;”>Thanks Fred.  I expect mostly FM repeaters while driving to/from central NY periodically.  I’m looking at this as an opportunity to potentially work with 6M, but is it practical while driving?</p>

[Fred Kemmerer]

Hi Luke,

Some things to consider RE 6m. First, most activity on 6m these days is made using the digital FT8 mode which probably will not be possible while driving. Second, most 6m stations use a horizontally polarized antenna, and repeaters are mostly vertically polarized. All of this means that you’ll probably need a second, horizontally polarized antenna like a halo if you want to do 6m mobile.

You might want to try 6m at home first and see what’s available on this band before you invest the time and $ to do it mobile.

[Nashua Area Radio Society]

Hi Luke,

I’d like to provide some experience on mobile VHF work.  I’ve been running VHF/UHF mobile since 1994, and I no longer use anything other than permanent mounts.  I’ve found the absolute best mount possible is an NMO mount.   These have the absolute best connection to the truck body, both electrically, mechanically, and RF-wise.  My commute is 75 miles each way, and I can hold the repeaters I use for almost the entire trip.   For the pickup truck V/U rig I run a dual band FTM-100  FM rig (this includes fusion C4FM.)

I buy my vehicles, run them at least 200,000 miles, and don’t give two craps about worrying about a 3/4″ hole “affecting resale.”  My last commuter vehicle ran 250,000 miles (a mazda 3) and I enjoyed excellent ham radio operation for the entire period of ownership.  Toss a $3 cap on the antenna mount, and the wholesaler will think it’s a GPS antenna when they drag it to the auction.

For installation, I pop the dome light out of the interior, and drill through the roof with a pilot hole.

Then, from the outside, I’ll use a step-bit drill to cut a super clean hole to install the NMO mount.

My preferred antenna is the Larsen NMO 2/70:  https://www.hamradio.com/detail.cfm?pid=H0-000566

the coax is then run over the headliner, and down the B pillar.  This way you don’t have any gasket issues.

As for 6 meters, I run a second radio. my second radio is my 6m-160 FT-891.  The antenna that I am using is the Hustler mono-bander.  I have that mounted to a custom rack over the bed of the truck.   This is a full size pickup, so there is plenty of room for a second radio – you just need to figure out the mount.   I found a base from Havvis that mounts to the center console seat bolts.   here is the link to the seat mount:  https://www.havis.com/products/SUB_BRKT_HUMP_1PC_SILV_14_20_TAH_15_20-122310-963.html

I’m still working out the details on the HF installation – these things take time, and you need to try something to see if you like it.

The 891 also has FM, and I’ve been finding quite a bit of phone FM activity on 6 meters!  the other really cool thing about 6 FM through repeaters… dare I say you get almost 100 mile coverage.

I think 6m FM is something we should do more of, and of course it is vertically polarized.

There are plenty of options out there.  I hope Fred’s and my suggestions help you sort out how you want to go.  Have fun out there!

 

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