LOST JEEPS
http://www.lostjeeps.com/forum/phpBB3/

Installed two ham antennas on fenders
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=45&t=59015		 Page 1 of 1
Author:  Draco [ Sat Feb 19, 2011 7:47 pm ]
Post subject:  Installed two ham antennas on fenders
Today I installed two ham antennas on my front fenders.

Image

At this point I ONLY have the antennas mounted and the coax cables routed through the passenger side firewall. I bought most of the odds and end for the radio power (40A relay, terminals, wire loom, etc), so maybe I'll mostly get it installed tomorrow.

The big surprise was how far forward the antennas are raked. I knew they wouldn't be vertical but thought any slope would be more subtle.

Visible in the foreground is a Larsen dual band antenna on a Larsen Dodge Ram mount. That mount fit perfectly. It's a little on the light side, but stiff enough for the wispy antenna.

On the passenger side you can see a good bit of a 20m band hamstick. That's on a Firestik Dodge Ram mount with a heavy duty spring. The Firestik mount is much thicker and stiffer than the Larsen mount. Unfortunately it doesn't fit as well, so I had to make a shim out of a strip of 1/16" thick x 1.5" wide aluminum. The antenna is mounted with a quick disconnect. The fiberglass base is maybe 4 ft tall. Then there's a wire whip that sticks up more than 3 ft above that. The whip goes out of the picture.

Also visible is my CB antenna in the OEM location (AdamisAdam / Tokyojoe procedure). Note how different the rake of that antenna is.

I drove around a city block and everything was well behaved. But just driving out of my neighborhood I was having to dodge trees because of that tall hamstick.

I'm not real happy about the forward antenna rake. I can probably live with it though. Maybe it's just a question of getting used to it.

Oh, you can also see the Boulder Bars I installed last weekend.

[edited: 1/16" thick Al strip, not 1/6" strip]
Author:  Draco [ Sun Feb 20, 2011 8:21 pm ]
Post subject:  Re: Installed two ham antennas on fenders
I think the solution to the large Hamstick forward rake is to put a ball mount on top of the Firestik mount.

Image

Flat Top swivel ball Antenna Mount from Breedlove Mounts, see http://bellsouthpwp.net/b/r/breedlove1/index.html.

That's for a 3/8-24" mount, like for a CB antenna. If it doesn't work on top of the Firestik mount I'll buy a backing plate from Breedlove and turn the mount into a fender ball mount. The Firestik mount has a 1/2" hole. I'll have to bore it out to 5/8".

I haven't found anything for the NMO mount. That one doesn't bother me so much so I'll just live with it until I think of a better solution.
Author:  Draco [ Sun Feb 27, 2011 4:24 pm ]
Post subject:  Re: Installed two ham antennas on fenders
I ordered and received the Breedlove ball mount. It's a nice piece of hardware!

Unfortunately the standard version would not work underneath a Firestik mount. It uses a larger size hex head screw (bolt). The hole in the mount could be bored, but there would be interference between the bolt head and the fender. So that's out for now. I'll just leave it as-is for a while and maybe use the Breedlove mount on the rear of the vehicle later.

I finished all the interconnects of the radio this weekend, which means soldering PL-259 connectors to the ends of the coax cables, and hooking up the power relay.

I used a YH185B relay, which is rated for 60A. The radio draws a max of 22 A and has double 25A fuses (one each for 12V and return). For control of the relay I tapped into fuse #25, which is "hot in run" and for trailer electrical stuff. I wanted to tap into #22, which is "hot in run or acc", but I had already tapped into its neighbor #32 for the CB, and there was no room.

I coated the terminals on the relay with a polymer "liquid electrical tape", and then wrapped everything with regular electrical tape. I initially mounted the relay to the underside of a body panel by the dash (rear of the hood compartment). But then I realized that was a drain area for rainwater and I was going to have water running onto the power relay. Oops.

I couldn't find a better spot so for now it's just dangling in free space. Functionally everything is great. But there ended up being a little more of a rats nest than I wanted near the battery. Maybe I can clean it up in coming weeks when I'm more motivated.

The ground on my UHF/VHF antenna got broken when I installed the NMO mount. I tried to repair it just to get up and running but was unsuccessful. The ground connector was quite delicate and now I realize wouldn't have worked well very long. So I ordered a heavier duty Larsen NMOHF mount, which is for either low or high frequency applications despite the name.

I won't really be operational until I replace that antenna mount. I could operate on HF in theory.

In any case, the radio has power and the faceplate lights up when I activate the power switch! Hopefully I'll get operational for real next weekend.
Author:  Draco [ Wed Mar 09, 2011 1:16 am ]
Post subject:  Re: Installed two ham antennas on fenders
I largely have things working. The HF system appears to work fine. So far I've only used the 20m antenna. Someone at work lent me an MFJ-259B antenna analyzer

Image

I'm definitely going to have to buy one of those. It was very easy to tune using the data sheet of the antenna manufacturer (Lakeview). You just turn the frequency tuning knob to find the resonant frequency (lowest SWR on the meter). It was too low, so looking at the chart I knew to saw off about two inches of the whip to get the frequency I wanted.

I don't know what's going on with the dual band antenna. I replaced the broken mount with the NMOHF mount

Image

You need a special tool to press in and deform a ground cap to cover the conductor lead. I ordered one but it hasn't been shipped. Maybe the guy who's been machining them for the last 25 years for Larsen has the flu. In the meantime I soldered the cap in as best I could and covered the whole thing with liquid electrical tape. That will work until the tool comes. Plus I bought a spare.

I can receive okay on 2m, but when I attempt to transmit the SWR appears to go through the roof. That suggests something is horribly wrong. But the borrowed antenna analyzer measures a reasonable SWR on that band. So maybe it's just an operator error on my part. The meter output on transmit is programmable. I think I have it set to meter SWR, but will check it again.

Someone at work has a nearly identical radio (FT-897D), though he says he doesn't use that one much. He's very experienced so he should be able to figure it out.

I have the faceplate on a gooseneck, and an external LDG FT-Meter sitting on the shifter console. That may not be robust enough for off-road use, but it works for now.
Author:  BugginKJ [ Wed Mar 09, 2011 11:45 pm ]
Post subject:  Re: Installed two ham antennas on fenders
Wow what amazes me is clouds in AZ :goink: Now I know who to send my buddy to in Mesa :JEEPIN:
Author:  Draco [ Fri Mar 11, 2011 12:27 am ]
Post subject:  Re: Installed two ham antennas on fenders
BugginKJ wrote:
Wow what amazes me is clouds in AZ


Yeah, you don't see so many cloudy skies here!

I did solve the mysterious transmit meter problem. It turns out that the analog meter output via a small audio jack underneath the faceplate is configured separately from the digital meter display on the faceplate. So the digital meter was configured to display SWR, but the analog meter was configured to display power.

I had to dive deep into the bowels of the extended menu system to make the analog meter display SWR on transmit. Once I did that everything was fine!
Page 1 of 1 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/