FELLOW HAMS! - VHF/UHF Antenna Inquiries and Genuine Tech Question.

Hey all. Finally got around to taking (and passing) my test. Although my VEC does the snail mail filing... So no call sign issued just yet (feels like waiting the 10 days for a firearm in my tarnished brass state).

I've been sitting on my radio for some time now (wife bought it for me xmas of 19' as more motivation to take and pass the text) and I'm finally getting around to installing it. The one thing I've been lagging on is deciding on and purchasing my antenna option. If you've got the experience and some info on this, please feel free to chime in. While I thoroughly intend on playing radio here and there during my commute or on trips, my main intention was to keep my self and wife/kids (wife will be going for her tech ticket shortly) in communications when we go camping (out of cell coverage) and they decide to stay behind at camp instead of hit a trail with me. Majority of where we're at is socal desert regions. Sometimes flat, sometimes hilly, sometimes deeper vallied. I understand 144/440 are mainly LOS, and there's a decent chance that I still might not be able to connect simplex, but a lot of the areas (like ocotillo and anza) have a repeater somewhere close enough and 'visible' enough on a taller range that we can communicate through. We'll both be going for general class in the near future so we can have fun with the HF game, and hopefully alleviate some of that.

Anyway, this is the situation, and current options I've been looking at.

Truck has a softtopper on the bed that stays up +80% of the time, and a Ubox roof rack that is typically half (pass side) covered in gear. *overall height isn't really a concern as long as it'll fold over. I don't plan on installing/removing it frequently for any reason.

1st option: Tailgate style mount, w/ a Comet SBB-5 (1/2 wave) antenna. Ideally with the lower mounting height at the tailgate, I'd prefer something like the SBB-7. But back there you really don't have a good ground plane. SBB-5 is not ground plane dependent. SBB-7 requires one, so probably the 5.

2nd option: NMO through the roof (oh yeah, I'll forking drill the hole, you betcha), with most likely an SSB-2 (or similar 1/4 wave). With the roof rack being steel, and sitting about 4" above the roof, I'm willing to bet (and have also been advised) that the rack will absolutely demolish antenna performance, especially for one that short.

3rd option: Using the roof rack as a mount, for (probably) an

$65 SBB-2 146/446 MHz Dual Band Mobile Antenna 18" PL-259

SBB-2, or at that point maybe a compactenna. I'd be concerned about the ground plane provided by the roof rack. I understand that an RF ground works a bit different than an electrical ground, but all of the physical ground plane kits I've seen for base stations or larger mobile antennas radiate in all directions out from the base. The roof rack cross bar would only be on one axis. Or I could cross a steel bar perpendicular to the existing cross bars, and put the mount at the intersection giving me the metal surface over 2 axis.

4th option: The good ol' lip mount on the hood/fender mount up front. I'd probably still consider the SBB-5 here, or, if it's believed that the hood being heavy to one side of the antenna would still work well enough as a ground plane without creating a heavy bias on the antenna's radiation pattern, I'd be willing to throw the SBB-7 up there.

so there... my long-ass-winded waste of time. Hope someone has some experience/information, and I look forward to whatever I may receive so long as it's not flaming.

 

I’ve had good luck with a Larsen lip mount NMO on the hood and the Larsen 2/70 NMO antenna.

 

Thanks. Good to know. Is that the standard/full size (1/2 wave) 2/70? Larsen antenna models confuse me sometimes. It's like, 15 different 2/70s with various pre/suffixes for color, mount type, length, etc.

 

This is what I have

https://www.theantennafarm.com/catalog/index.php?main_page=product_info&products_id=1712

 

I have a friend locally that used this mount for his dual-band antenna (NMO 3/8) setup on 2018 Tacoma:
https://www.victory4x4.com/product/VT3CB-BARE.html

I am still working to convincing my wife to let me do this to our 2019 Pro.

 

If you garage your truck look for the antenna that mounts to your roof rack and is motorized so you can pput it down. Larsen makes a great antenna and mount. But there are plenty others.

I haven't mounted mine yet...but I might screw a 3 inch piece of sgeel bent at 90 degrees inside the bed and let it stick out the side of the truck under your topper. Then drill through the steel and use an nmo mount or even a mag mount.

 

I have tested a lot of antennas. This antenna is fantastic. Probably the best on the market for a VHF/UHF amateur radio antenna.

 

This is what I used. Works great and doesn’t stand out or draw too much attention.


https://www.tacomaworld.com/threads/amateur-ham-radio-bs-and-callsign-thread.260643/page-235
See post #4697

Made by Victory...

https://www.victory4x4.com/product/VT3CB-BARE.html

 

I don't garage. Sunbathe all day ery'day. I have considered this along with the whole rago (and similar) mounts. My only concern with that route is that I (believe, educated presumption) that I'll be limited to one of the antennas that's ground plane independent, which seem to be mostly 1/2 wave. Not really a problem, just won't let me explore other options in the future (that would require a decent ground plane) with that same mounting setup.

Thanks for the reply!

 

Appreciated, 2 votes for the Larsen so far. I dig it.

I can't find any particular information regarding the requirement for a ground plane with this one. As far as I've learned, most if not all common antennas need a ground plane. The Comet stating that it doesn't got me wondering if it's specific to it being a center fed 1/2 wave, and other 1/2 waves like the Larsen are the same (not requiring a legit gp) or if that was specific to the Comet.

How to you particularly have it mounted?

Thanks for the reply!

 

Appreciate the info. I have seen these, and have considered fabbing one myself (no offense to Victory, just one of those 'did you have to spend the money on what you have the skills to make' kinda things)

I have two reservations with this mounting option. The first being that I've been advised by a few other the older hams I hang out with that depending on my antenna choices, I could have issues with coupling with the A-Pillar. So far I haven't seen anyone with the V4x4 mount complain about it, but I don't know how they're using their system. Trail coms at shorter distances might not be an issue, but if my wife and I are trying to communicate over a shitty distance on shitty terrain, I'd want to make sure I've got everything set up as best I can to minimize loss and maximize tx efficiency. Yeah yeah... I know that's not what 144/440 are good for anyway... we're working on our generals.

Second reservation is RF exposure. I know that's not all that close, and with a dual band rig I'm max 50w anyway, but I would be a little tincey bit concerned over extra long trips if we happen to be making lots of contacts, or even if it's just a decently time consuming trail and we spend the time chatting with our other ham offroaders.

Thanks for the replies!

And sorry for so many quotes posted above, totally forgot about using multi-quote.

 

Here's another vote for the Larson NMO 2/70 antenna. I've used this antenna with both a fender mount and through-the-roof hole mount. The rooftop position gives noticeably better performance for send/receive vs fender mounting. I've never mounted an antenna on a roof rack but I'd imagine if it was grounded properly performance would be pretty good.

 

Good to hear a comparison. Thank you!

The rack mounts similar to the prinsu/uptop/etc racks using the OE mounting locations in the rain gutter. So the only real grounding it would have is through the bolts that go into those threads. I would like to believe that would provide decent ground... Except that I went kind of overkill when I installed the rack, using sealing washers (technically insulated connection), and placing thin sheets of butyl rubber between the mounting feet and the side rails. I can't think of where I could bond the rack to, so I'd probably have to undo that stuff first :/

I'd wonder if running a ground all the way down the back window are to a suitable chassis ground would be helpful at all and easier that undoing what's already done with the rack.

 

Template here

 

Alright folks. Picked up my gear today. Went with the Larsen 2/70. And picked up an nmo mount for it...

Now back the the question of placement;

Straight in the roof? Not caring whether or not the steel roof rack is going to fork with the ground plane or signal. And refrain from using the rack (too bad I bought it to put stuff on) because the one thing EVERYONE I've spoken to agrees on is putting shit around the antenna (especially my steel and aluminum cases) will definitely fork with things. But for some reason half of them say the rack won't??

Or

Mount it on a plate that spans a couple of the rack's cross bars and let the rack act as the ground plane (from my understanding of rf ground planes, the roof would also still be part of that wouldn't it? It's more like a metallic reflective surface). Still in which case trying to not load metallic objects onto the rack that are high enough profile to pass the base of the antenna.

"Honey, the HAM guys said I need to upgrade to Plano cases for the roof... Sorry, guess I have to..."

 

Of the two choices, I think the second would be your best bet. If you can find someone with an antenna analyzer, you could use that to confirm that your SWR is stable across both bands, and therefor that your rack is probably giving you an adequate ground plane. Or just, do what most of us do: mount it, "see if it talks" and call it good.

 

I was actually trying to buy an swr meter at the time as well (I like to own useful tools, even if they're only used once or twice), but couldn't find one readily available on the shelf that wasn't a large expensive base station type unit. I have no friends (no cool friends that play radio at least), lol, and am not part of a HAM club (yet?) to borrow one. Are the cheapies on Amazon any decent?

That is a good point though. Mounting on a plate can be easily undone, and the nmo can be migrated into the roof down the line. I can't undo a hole in the roof that I discover works poorly. I was digging the idea of the coax dropping straight into the cab though.

Next thought. Both windshield moldings are packed to the brim with wiring, so going down them to the firewall grommet is out of the question. I don't particularly have an interest in smooshing the coax in the door. So it sounds like I'm going to be running down the back of the cab, and along the frame over to one of the plugs under the door sill. I'm mostly ok with this, unless someone else has a better way of getting inside?

Thanks for the reply!

 

Finished up mounting everything today. Will take pics when it's not dark out. Ended up putting the nmo mount and the Larsen on the middle crossbar. I will at some point acquire an swr meter to see how that's actually working out. As of tonight, I was able to pick up some rag chewing on the Santiago peak repeater, 147.435, and it came in clear and crisp (I'm in Eastvale). Didn't seem like any other activity on the other somewhat local repeaters. Still not transmitting as my callsign still hasn't been posted.