ham antenna ideas?

cak · 02-07-2007, 10:22 AM

Probably seems like a strange idea to many, but I'd like to mount a 2m/70cm antenna on my 911. I'm looking for suggestions from those who have tried...

The "obvious" thing is to drill the Targa bar for an NMO mount, but I'm not going to do that

I'm thinking more of a trunk lid lip mount, probably on the engine decklid. Not a great location for efficiency. This is primarily for APRS, so that's OK with me.

73 de chris K6DBG

david914 · 02-07-2007, 10:45 AM

Don't they make a 2m glass mount antenna (a la cell phone)? That would be the least invasive to your car. You could mount it in the middle of the Targa glass right behind the Targa bar.

cak · 02-07-2007, 10:54 AM

Quote:

Don't they make a 2m glass mount antenna (a la cell phone)?

Yes, and I'm considering that. It means a fairly long cable run under the targa bar trim (lots of interior disassembly). I'm kind of hoping to avoid that ... though I guess getting to the engine compartment isn't much better!

rouxroux · 02-07-2007, 11:05 AM

I've had great results with the "through-glass" cell phone-type antenna sold by Antenna Specialists. Before that, I was using a Larsen "Long Ranger 5/8 wave duck" on a clip-on window mount going to a HT.

73

RSBob · RSBob's Garage

If those suggestions don't work for you, my first targa had an aentenna mounted to one side of a U-shaped plate (painted black) . The other side of the plate was then mounted by bolts through the engine grill. No part of the car was drilled or altered. Sorry, no pic of it.

WHCJr72S · 02-07-2007, 11:36 AM

I am assuming that this is for your 1973. There are two bolts that hold the rear bumper on. They are located on the top part of the bumper and you could make a flat plate that bolts to them and mount the antena to it.

cak · 02-07-2007, 11:40 AM

Quote:

There are two bolts that hold the rear bumper on.

Yup, but it's really better to mount higher than lower (for 2m, the antenna will be between 19 and 38 inches in length).

I'll spend a little time investigating how the targa bar interior is mounted.

Thanks for all the ideas!

RoninLB · 04:34 PM

This has a CB antenna mounted on the lid. It's a temp 1/4 plywood bolted with long screws w/a piece of rubber separating the wood from the grill.

The antenna length is not long as I can enter a garage without scraping. Short length hinders effectiveness. I also have a longer one that I'll be using as I'm riding w/another pelicanhead soon and distance will become important. There is a ratio of antenna length that should extend above the roof line if it's base is below the roof. There is also db selection. There is also different antenna designs. such as straight rod vs wrapped wire around rod etc.

i know nothing about ham antennas... have fun

RoninLB · 02-07-2007, 04:35 PM

i couldn't add another pic to above.
hope this matters

cak · 03-20-2007, 08:47 AM

I finally got a Larsen "Kulglass" through-glass dual-band antenna and mounted it at the base of the rear window (it's rather tall). Easy install, works OK, SWR is a little high but acceptable - that seems to be the nature of the beast.

A couple of days later I wanted to install replacement throttle springs and discovered that the coupling transformer housing interferes with the engine decklid! I can open it enough to work, but not to engage the lift cylinders. I'll get a remount kit and try it a little higher, but I may be back in the market.

RoninLB, how did you route the cable into the passenger compartment?

RoninLB · 03-20-2007, 10:37 AM

Quote:

Originally posted by cak

RoninLB, how did you route the cable into the passenger compartment?

from engine compartment down into tunnel area into the cabin.

cak · 03-20-2007, 10:47 AM

OK. I was sort of afraid of that. Is there a good way to exit the tunnel? I haven't really poked around that area much at all yet.

RoninLB · 03-20-2007, 10:54 AM

i entered through the transmission's nose area outer section of the rubber boot as it enters the shift coupler area. Inside the shift coupler area i cut a hole in the cover and ran it next to passenger seat.

defcon65 · 03-20-2007, 11:26 AM

I had a college buddy who made a 2m 'trap antenna' and mounted it to his Ghia for mobile DXing. I'll look for the picture when I get home - it was a god-awful looking assembly of wire coils, PVC pipe, aluminum tubing, coax cable and exhaust clamps. Laugh if you will, this guy was a ham radio savant and EE major, he used to talk to guys 500 miles away on about two watts output.

rouxroux · 03-20-2007, 01:45 PM

defcon55, are you sure it was 2m and not QRP 10m or 20m? 200 miles is not that big of a deal if you live in an area served by repeaters with any height, If you have some pics, I'd love to see em. (Now if he was DX'ing 2m on 146.52 simplex at 200 mi., I'd be really impressed)!

...I used to operate "Field Day" 10m CW mobile in a Vega back in the 70's. I'd drive to the top of Monte Sano mountain in Huntsville, Al, park at one of the overlooks. Had a knee-mounted "flight board" with a vibroplex bug on it and a 10m trap vertical on the middle of the back bumper, complete with a fishing line guy wire to the top of the hatchback. Looked strange, but quite a bit of multiplier points! (People used to laugh when they'd get a QRP DX CW QSL!!!)

cak · 03-20-2007, 03:33 PM

Quote:

(People used to laugh when they'd get a QRP DX CW QSL!!!)

They may laugh ... but that's all I do! Working on QRP CW DXCC (from home, not mobile)...

73 de chris K6DBG

rouxroux · 03-20-2007, 04:11 PM

I forgot to add QRP DX CW / MOBILE...that's what I meant. WAS was fun QRP, thank God I did it during sunspot cycle 22...that was years ago. hi

cak · 03-20-2007, 05:35 PM

Ah. Yes, adding /M to that makes it a lot more interesting.

I did QRP WAS over the past year or so. A good challenge
here at the bottom of the cycle! I *think* there are enough DX entities in the western hemisphere that I can get DXCC. Will be tough, but fun.

Back to pcars...

defcon65 · 03-21-2007, 07:09 AM

If my memory serves me correctly (this was in 1989) it was a two meter handheld with two watts output, those details seem to stick in my mind. The trap antenna was about six to eight feet tall and made out of 1" aluminum tubing with the traps constructed of copper wire wound around short sections of 1-1/2" PVC tubing placed at intervals up the pipe, which was bolted to a piece of wood that he clamped to the front bumper. It was the freakiest looking thing I ever saw. He used my shop to build it and I remember that the length of the coil wires and spacing of the traps was a critical adjustment that required his trusty 100 pound mil surplus oscilloscope.
It was a running joke with my roommates at the time, having 'marconi' back there twiddling on his antenna every night. I was amazed when he demonstrated the completed rig, talking to other hams on the east coast from a parking lot in Iowa City with two watts power!
He got this design from an old issue of '73' magazine - one in his collection of about 500 radio mags. He was a unique individual, for sure - his intellect was about one inch wide and ten miles deep - all electronics and radios. Last I heard he was working for a defense contractor in Connecticut on submarine communication systems.

Grady Clay · 03-21-2007, 08:27 AM

Chris,

There should be four little threaded inserts in the Targa bar for mounting a ski rack. They are well grounded as they are in the Targa bar sub-structure, not the SS cover. As I recall they have plastic plugs in them and are partially under the rear top/side window seal.

You can make a nice bracket to mount the antenna. You might make sure the SS cover has a good RF ground.

I would think the best route for the cable might be at the upper-rear of the door window.

Best,
Grady