The AM Forum

I was recently given an Hi-Q 5/160 RT screwdrivet antenna. The manufacturer says no installation information is available and I wonder if anyone has a copy of same.

I can figure that out but to mount it on the bottom of my Acura TL I plan to about an 18 in. long 3 in wide flat piece of aluminum (1/2 in?} fabricated in a straight line with a hole for the antenna and two holes to drill into the wheel well. I will fasten it to the wheel well with SS bolts. with smaller backing plate with the 2 holes on the well lined up the top side of the wheel well to distribute the stress.
I welcome any thoughts.
Carl

Hi Carl,

I've run one of those on my VW TDI for a few years. I found with the large mass up top that it tended to waggle a lot and put a lot of strain on the mount at the base. On the VW, it literally started to tear the body metal after a few months and I had to weld the area even though it had a pretty good backing plate on the other side. It had not been a problem with smaller antennas previously. I was using one of the husky breedlove ball mounts. The mount was fine, the sheet metal around it was failing. I eventually solved that by adding an upper support bracket just under the coil with a few pieces of flat aluminum formed into a triangle off the body and about 2 inches of heavy insulating material like FR4 between that and the lower tube beneath the coil.

It worked pretty well, but oddly, I get better reports off a TarHeel MT-200A on the same setup. Not sure why. I plan to do some antenna range experiments once I get things set up here for that this summer.

I made a few contacts on 160 with it, but it needed a larger base inductor than the one that worked well on 80-10. If I'd quadrupled the inductance down there I'd have been able to get a better swr.

Good luck with it.

Thank you Frank,
I plan on using 3/4" aluminan 18 inches long coming out the back of the car. It will be bolted through the spare tire well (no tire included) right next to the reinforced area for the rear tow hook.That should be a fairly strong point. The first set of bols will be about 8" in.
I plan to reinforce the top part of it with a 3/4 inch plate and additionally another piece of thinner aluminan or plywood.
Being behind the car should help with wind resistance somewhat. That is where I had my K7UJ screwdriver mounted.
If you are going to NF I will be there. look for a blue aAcura with Maine plates 95707.
Appreciate your feedback

I had great luck with the other setp, including working England on 75 mtr SSB at greyline.
Looking forward to this. Just bought a FT-892 to use with it
73
Carl

Carl,

Sounds like that should be a solid setup. I never felt like the antenna itself was being strained by the motion, just the base of the mount I had been using with good success with other antennas. The Hi-Q is just a bigger, beefier, antenna and my mount wasn't up to it. Sounds like yours should be.

Will the coil be above the roof line? I think the coil is fairly sensitive to nearby metal.

I ran mine with a West Mountain Target tuner for a while with reasonable results but it had some issues sensing the turns and also eventually started to need more current to move than the box could provide.

Are you using a base matching inductor? I found about 10 turns 1/2 inch diameter worked good on 80 up. Too small for a good match on 160. I used a 8 foot steel whip with a breedlove fold over mount so I can get in the parking garage.

Sadly I won't be at deerfield. Plan to do it again sometime soon but this year is kind of busy right now and it's a 7-8 hour drive. If I'd planned better I could have combined it with a trip to Portland I had to make and will have to make again soon.
 

I'd love to use something like that on my van - seeing that it is tunable, but there's so much vertical metal everywhere  that would mess with the coil - and like modern vehicles it's paper-thin except in a few places so a regular whip is not good. It's also tall vehicle, so mounting the antenna high is not the best way to go.

I ran a screwdriver on a mini van by putting a strap on bicycle rack on the back, and building a plate across it and mounting the antenna to that at the base of the window area. It got it up away from the metal beside it, and away from ground to reduce the losses,  and because it was mounted to the rear hatch it would swing up with it. I ran a 2 inch ground strap of copper from the plate to the hinge and got to ground under that. The strap was folded in such a way that it allowed the hatch to go up and down without an issue. I ran a full sized screwdriver on it with a 60 inch whip most of the time or if I was mostly on the low bands, a full 108 inch whip. That setup worked very well and I did it on several vans through the years. That might be an option for you on your van.

Possibly.. My van has two doors - Ford E150 type. Previously I had a HF whip on the front of another van but it had a different bumper that stuck out quite a bit.

I think you could put a bike rack on one of the doors and do that mount in the same fashion. Or come up with another way to mount the plate across the door with metalwork if you were willing to go that far. Let the door open normally, run the ground strap sideways to the hinge area for ground.