Kenworth T880 NMO mount

[norcalscan]

I'm looking to not reinvent the wheel and seeing if anyone has any experience putting in NMO mounts on newer model big rig tractors like the Kenworth T880 (all fiberglass body). The only factory antenna mounts I'm aware of are CB mounts on the mirrors with coax ran inside the mirror mount. I've had luck reusing the CB mount hole with the typical thick-mount NMO like Laird MABVTO but 1/2" barely fits and puts physical strain on the mount, where the second duplicate install I did snapped the metal off, busting the solder connection and forced me back to the drawing board. There's no rods, grab bars or anything to mount to outside. Some of the other 1" long NMO-to-UHF mounts are way beyond 1" in length and won't fit in the mirror mount. Kenworth rep is no help.

I'm hoping to stick to the mirror, or an unknown purpose-built solution for this. Right angle bracket randomly screwed to the back of the cab is always a go-to, but leaving that as last resort. This is for 5/8 no-ground-plane VHF use.

I'm about to drop a bunch of money on a few more thick-mounts that have stronger-looking bits that broke on the MABVTO, but wanted to try this forum for a last chance. Thanks!

 

[kayn1n32008]

I'm looking to not reinvent the wheel and seeing if anyone has any experience putting in NMO mounts on newer model big rig tractors like the Kenworth T880 (all fiberglass body). The only factory antenna mounts I'm aware of are CB mounts on the mirrors with coax ran inside the mirror mount. I've had luck reusing the CB mount hole with the typical thick-mount NMO like Laird MABVTO but 1/2" barely fits and puts physical strain on the mount, where the second duplicate install I did snapped the metal off, busting the solder connection and forced me back to the drawing board. There's no rods, grab bars or anything to mount to outside. Some of the other 1" long NMO-to-UHF mounts are way beyond 1" in length and won't fit in the mirror mount. Kenworth rep is no help.

I'm hoping to stick to the mirror, or an unknown purpose-built solution for this. Right angle bracket randomly screwed to the back of the cab is always a go-to, but leaving that as last resort. This is for 5/8 no-ground-plane VHF use.

I'm about to drop a bunch of money on a few more thick-mounts that have stronger-looking bits that broke on the MABVTO, but wanted to try this forum for a last chance. Thanks!

pretty much your only option is a 'L' bracket into the body, and put a 1/2 wave on it. VERY common where I live as anyone that goes on the oil/logging/resource roads needs a VHF radio. a 5/8 wave antenna needs a ground plane to function properly.

my kinda go to is a Larsen WB-VHF which is a 1/2 wave. Cut it for the middle of the frequencies you use, or if you are all over the place(Like we are in Alberta) cut it for 161MHz and you will be fine for 148-174MHz.

 

[mmckenna]

Yeah, you need a 1/2 wave, not a 5/8. All 5/8 wave antennas will require a ground of some sort. 1/2 wave do not.

I've always found that being able to fabricate your own mounts was an important skill in this industry.
I've seen State of Oregon highway trucks with some interesting mounts. They are using the large tri-band antennas, which are about 20 inches tall and pretty wide bases. They have a nice stainless or aluminum reinforced bracket on the back of the cab, sort of like you took a cube and cut it diagonally.

 

[n3obl]

Are we talking vhf or uhf? One poster talked about an Tk-880 then another mentions vhf antenna??

 

[mmckenna]

Are we talking vhf or uhf? One poster talked about an Tk-880 then another mentions vhf antenna??

Not a Kenwood TK-880 UHF radio, a Kenworth T-880: https://www.kenworth.com/trucks/t880/

 

[kayn1n32008]

Kenworth T880 (all fiberglass body)... This is for 5/8 no-ground-plane VHF use.

Are we talking vhf or uhf? One poster talked about an Tk-880 then another mentions vhf antenna??

VHF on a Kenworth rig


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[DJ11DLN]

Not a Kenwood TK-880 UHF radio, a Kenworth T-880: https://www.kenworth.com/trucks/t880/

That threw me too when I first clicked on the thread yesterday. Had to go back and re-read the title because things weren't making sense. Big difference between a Kenwood and a K-Whopper.

 

[cmdrwill]

One possible thick plate NMO mount. This one has UHF female connection for the cable.

 

[norcalscan]

Thank you everyone for the insight!

Yes - Kenworth, not Kenwood, Haha I failed and missed the resemblance since I usually deal with TK-890 for UHF.

My mistake on the 5/8 whip. I knew about the no ground plane needed, but as I wrote this I had 5/8 in my head. Did the math on the Maxrad 1322HD's that I have and they are indeed 1/2wave. Cut them down to 162Mhz to get the 150-174 range needed for what we do. Thanks for the heads up on that.

cmdrwill - I just ordered/tried that mount on the spec that it was 1" in length, when indeed it is exactly 2" in length, which is 1" too long to fit in the mirror mount. Otherwise it would have been perfect.

I think I will have to go with an L bracket on the back of the sleeper then. That'll unfortunately be the easy part - routing the coax around the crazy interior was what I was trying to avoid. I'll try posting some pictures here when finished, and some pics of the first T880 mirror install that so far is holding up, despite knowing the weakness of the mount, so you get an idea of what I was after.

 

[norcalscan]

Let's see if I get this attachment feature to work...

1 - successful mirror install on the first truck. Attempted to duplicate this onto the second truck...

2 - duplicate the install, Laird MABVT8 thick mount, all good until I did one last turn of the antenna's base to make sure it was secure and it suddenly spun freely. What you don't see is under that plate is a slight recessed area that I have to beef up with a washer to give the mount something to grip to underneath.

3 - what I'm dealing with - the original CB antenna post. A little frustrating needing penetrating spray on a new 2017 truck though. You'd think Kenworth would sell different plates here for NMO mounts or other accessories but nope - I guess it's just to service the connections inside.

4 - the CB solution. I ripped this out and ran new coax/NMO mount. There you can see the depth I have to work with, and why the Laird VTPM is too long (Laird spec says 1 3/8" total stud length, it is in fact 2")

 

[mmckenna]

If it was me, I'd probably be looking at fabricating a flat plate to either bolt to the top of that mirror access hole cover, or replace it all together. Add in a way to route the coax out of there.

 

[westcoaster]

If you have a bunch of trucks to do it might be worth your while to see if a local shop would CNC a bunch of brackets out of stainless....

Might be a steeper up front cost parts cost but may prove to be cheaper in the long term labour cost wise. (maintenance for broken antennas, troubleshooting fragile connections and the time required to install them)

 

[zrock]

They should be able to order the truck with antenna option of your choice. A good partsman would be able to get it for u... the manual for our truck showed 3 different options for antennas

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[Project25_MASTR]

All of the T880's I've worked on were either dump trucks or mixers minus one or two tractors. In all instances, they were owned by some road/bridge contractor and the way things work in the state of Texas, there are benefits to sub-contracting some tasks to historically underutilized businesses (and independents) and the common meet up for that work is CB so all the OEM CB gear has to remain in the truck.

Typically use a thick surface NMO mount on the cab...but these guys are also all on one of 2 SMR's 800 MHz systems.

 

[norcalscan]

They should be able to order the truck with antenna option of your choice.

Thanks - yeah I went this route back in the beginning and no luck. It either comes with the CB mount or a blank plate. However a blank plate could probably be hacked/modified quite a bit easier than the CB one. The truck was out in the field with an HT and just came back in so I'm going to try a few more ideas and report back here. I'm determined (stubborn?) to be on this mirror and not a custom L bracket on back of cab. :lol:

Service manual for the mirror - showing the two parts available.
http://www.lang-mekra.com/fileadmin/user_upload/481_Kenworth_Service_Manual.pdf

 

[cmdrwill]

Looks like the 'plate' has a 1/2 inch hole like many of those CB stud mounts use. You can use a NMO C type mount that fits a 3/8 to 3/4 inch hole.

 

[zrock]

Nice truck... stupid they don't do it as a factory option.. I know our Volvo had it as a factory option...

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[ashleyw]

2018 Kenworth T-880 High SWR CB Antenna Battle Won

I got a new radio in my truck and battled with high SWR. 2.9 on channel 1 & 40. Wilson Trucker 2000 with a 12" shaft to the load coil. I took off the paint on all contact points to the aluminum mirror brackets and installed a ground strap from the antenna base plate and the inner break away hinge on the mirror to improve ground. Also cleaned the powder coating off the mirror bracket contact points where it contacts the cab. 18 foot of coax cable. What fixed my high SWR was a 22" load coil extension which put the load coil at the level of the visor on the cab. I now have SWR of 1.3 on channel 1 & 40. The trick is to get the load coil as high up as possible. So hopefully this helps anyone out there that wants big radios in their KW T880 and battles high SWR's.https://forums.radioreference.com/attachment.php?attachmentid=63719&stc=1&d=1524186627

 

[quarterwave]

I'm not sure about the 880, but they make KW's where I live and I used to work for a dealer here 20 years ago. They made, at least for the 800, a beacon plate, that bolted to the top, and back upper corner of the cab, either side or both, and say about 2 inches above the roof. I have to wonder, if that is an option to add one, then drill it for NMO and use it as the ground plane. The ones I remember were chromed steel or stainless, and were not real thick, maybe more than a sheet metal roof, but were strong as they were made to hold the old 2 and 4 bulb style beacon lights.