AdamisAdam / Tokyojoe install question: AR-1A and splitter?

Draco · **Posted:** Fri Dec 24, 2010 12:28 pm

I've committed to the AdamisAdam / Tokyojoe solution for a CB antenna, see:

http://www.cardomain.com/ride/718416/2004-jeep-liberty-aurora-co-us?p=1

I'm buying the radio, SWR meter and from the local TTT truck stop CB shop. But I don't think they'll have the Firestik AR-1A splitter / filter, and am pretty sure they don't carry Wilson antennas, so I ordered those online. I assume a different 3 ft antenna like a Firestik would work, but went with the Wilson.

There were a few things about the parts list that confused me.

The #7 "CB cable mount" initially confused me, as the name suggested to me it was some kind of mechanical mount. That is apparently what Cobra refers to as the "connector box" in their manual, see https://cobra.com/Manuals/75WXST.pdf

There's one thing that is still confusing me. The parts list refers to both #1 "Firestik AR-1A" and #3 "splitter".

The Firestik AR-1A, see http://www.firestik.com/Catalog/AR-1A.htm, is a splitter, plus some filters and maybe some other stuff to get the proper impedances at the three ports. So why on earth would you need a second splitter?

Here are a few wild guesses as to how the splitter might be used. (1) Maybe it allows you to hook up a second, longer, mag-mounted antenna for trail runs. (2) Maybe the genders on the splitter allow it to be used as a gender changer. Either way, you'd end up with an un-terminated, un-used coax cable.

I just don't see what the point of the second splitter is. So much so that I didn't order one.

???

As a postscript, I do like the Dodge Ram mounts, but am keeping that reserved for an amateur radio antenna. (Just need to win the lottery!)

Tokyojoe · **Posted:** Sun Dec 26, 2010 3:01 pm

You have the radio and the cb radio and they both need to be connected to use the antenna.

Draco · **Posted:** Sun Dec 26, 2010 3:19 pm

Thanks for the response!

I understand that a splitter is needed. What I don't understand is that there seem to be TWO splitters in the parts list.

The AR-1A is a splitter. Firestik calls it the "Match-Maker CB/AM/FM, CB Antenna Splitter". It has three RF ports: one for the CB antenna, one for the CB, and one for the radio.

But in your diagram, there is clearly a second splitter (part #3).

Oh, maybe you're using this second splitter for the CB, and only using two ports of the AR-1A (CB antenna and radio). That would certainly work.

Here's my guess of what happened. AdamisAdam's original install has only a coax splitter and no AR-1A. But that doesn't work, so he buys an AR-1A and plugs it between the splitter and the radio. The original splitter is really no longer necessary as the AR-1A is also a splitter.

I'm going to try to install it with just the AR-1A.

Thanks again!

Tokyojoe · **Posted:** Mon Dec 27, 2010 1:08 am

It's been about six years since I did the install and I just can't remember. Perhaps one of the guys that did it more recently can remember since AdamisAdam really doesn't come on here anymore since he got rid of his KJ.

As I looked back at my pictures, you probably don't need a "splitter" but I am not sure if I was able to find a straight cable with the same connectors on it without getting that splitter. That could have been the reason.

Draco · **Posted:** Mon Dec 27, 2010 9:43 pm

OK, I'm 99% sure I understand it now. I finished the mechanical installation of the antenna. The spring and antenna are in place, though I'm not sure what is supposed to happen with that ground wire. Reading the Wilson instructions it looks like that wire is used optionally. I'll have to read up on that.

I removed the passenger side knee-knocker and side-kick panels and disconnected the antenna coax. The OEM cable coming from the antenna is a standard Motorola AM/FM type male plug. The CB antenna connector on the Firestik AR-1A is a SO-239 female socket.

So, what is really needed is an adapter with a Motorola female socket on one end and a PL-259 male plug on the other. In other words, one needs a PL-259 to Motorola female adapter, like this:

http://www.walcottcb.com/12mfpl-pl259-to-motorola-female-12-long-p-198.html.

Now I need to figure out how to get one of those ASAP.

The "splitter" used was really a splitter adapter with one PL-259 and two Motorola female connectors. I found some but lost the URL's. That can be used as an adapter if you just don't use one of the female connectors. But that's not as clean and the unused, unterminated connector is a way for noise to get into the system.

Another thing worth mentioning is that the 3' coax needs to have a male plug PL-259 on one end and a female socket SO-239 on the other to go between the AR-1A (male) and the Cobra connector box (female). I ordered a 3' coax but it turned out to be male on both ends so it's not going to work.

JeepinJarhead03 · **Posted:** Tue Dec 28, 2010 4:11 am

If you're talking about the ground strap that came ON the actual wilson antenna, it's for use on non-grounded applications like fiberglass motorhomes, boats etc

with the method you're using, the mount being grounded to the body, and the body to the chassis etc is the proper grounding method for your install, you can wrap the ground strap of the antenna around the base and ziptie it, or clip it off and tape it down to the antenna, i'd suggest leaving a few inches of the wire so that it can be pigtailed later if you move the antenna to a different location or vehicle where the ground strap would be necessary

I'm assuming this is what you're referring to, most of wilsons antenna's have this strap since one of their bigger markets is the marine and RV application

if this isn't what you're referring to, i apologize and just ignore me

Draco · **Posted:** Tue Dec 28, 2010 11:29 pm

Thanks, JeepinJarhead03, that's exactly the kind of information I needed.

The installation is almost done. The antenna is in and I'll just leave the ground wire tied to the antenna until I've tried the radio.

The CB is in and has power. I used an add-a-circuit to tie in to the "Radio / Frt Door Lock Switches / Body Control Module" slot (#32 in the 2003 KJ). For now I have a 5A fuse in there, which is in parallel with the 2A fuse in the power cable itself. Maybe I should use a 2A fuse instead.

I did not see how I was going to be able to route a 3' cable between the AR-1A and the "connector box". Not saying it's impossible, just don't see how. So I went to the local truck stop CB shop and had a 6' cable made, PL-259 on both ends with an Aries double-female (double SO-239) gender changer. That was a piece of cake to route.

So now I'm just waiting for the PL-259 to Motorola female adapter from Walcott CB. That's supposed to be delivered on Wednesday.

Next I need to decide where to put an external speaker. Also, where to put the microphone clip. Planned to use the bezel to the right side of steering column but am no longer sure. The locker switches are mounted on the left side bezel, and I have to baby them. Not sure I trust the right side bezel for the heavy microphone and other electronics.

The antenna tip JUST slips under the garage door without contact, yay.

Tokyojoe · **Posted:** Wed Dec 29, 2010 2:51 am

Never had any problems with my location for the handset.

Draco · **Posted:** Wed Dec 29, 2010 12:51 pm

Thanks Tokyojoe for the reply about the handset.

I'll go ahead and do what you did. Did you use self-tapping screws into the plastic or did you drill through-holes and fasten with something like machine screws and nuts? I'm thinking the latter would be more reliable.

My adapter is "out for delivery", it should be here soon!

Draco · **Posted:** Wed Dec 29, 2010 10:13 pm

My installation is done-done, except for installation of the external speaker. I have one, but want to play around with it before installing permanently.

I essentially followed the AdamisAdam / Tokyojoe procedure, but I have one major recommendation. To connect from the OEM AM/FM coax connector to the AR-1A, you should use a PL-259 to Motorola female adapter.

http://www.walcottcb.com/12mfpl-pl259-to-motorola-female-12-long-p-198.html

The adapter goes from the OEM coax cable to the antenna input of the Firestik AR-1A. This is illustrated below, though you can't see all of the adapter.

I went to the local truck stop CB shop and had the system tuned immediately. I'm really glad I did this rather than tuning it myself. First of all, they only charged something like $12.50. The SWR measurement of 4.0 showed immediately that there was a big problem. I suspect that I had not inserted the adapter into the OEM cable firmly enough, and indeed that was the problem. After mating the connectors more firmly, the SWR dropped to something on the order of 2.0. The technician was able to tune the AR-1A potentiometers and the antenna length to get an SWR of about 1.5. He was surprised, pleasingly I think, with the use of the OEM antenna mount.

So electrically the Wilson antenna is working very well.

I wasn't real thrilled with the way it was shaking around in the wind. Maybe it's just a question of getting used to it, but there was some major vibration of the Wilson antenna. So I swapped the antenna almost immediately for a 3' Liberty L-1300 antenna. By complete coincidence, Liberty is the antenna brand. I can't find any information on-line about that antenna, but it is a simple base-loaded steel whip antenna. It cost $15.99 at the truck stop. Here's a photo of it with the medium duty spring:

I ordered a heavy duty spring from Walcott, but they didn't pack it. Still have to see about getting a credit. The CB shop only had medium duty springs in stock. It's probably just as well. This antenna may not perform electrically as well as the Wilson, but it's well behaved in the wind. I was able to forget this antenna was even there on the drive home. Unfortunately I didn't ask what the SWR measurement was. It couldn't have been too bad or the technician would have said something.

The microphone clip is installed. I opted for through holes, 8-32 5/8" machine screws, washers and nuts. Word of warning: when you mark your hole locations in the bezel, make sure you know which way is up! Guess what happened when I tried to mount the bezel. Fortunately the clip location worked flipped upside down, but I was hoping to cheat it away from the steering wheel and instead it got cheated towards the steering wheel.

JeepinJarhead03 · **Posted:** Thu Dec 30, 2010 2:31 am

Glad ya got it sorted out! Hows your RFI ?

Tokyojoe · **Posted:** Thu Dec 30, 2010 5:42 pm

I had moved to the Heavy Duty Spring a long time ago but a couple years after I had done the antenna mod. The heavy duty spring is the way to go. The medium spring will cause the antenna to flop around on bouncy trails but I think it looks cool when driving on the highway and it is leaning back in the wind.

Draco · **Posted:** Thu Dec 30, 2010 10:46 pm

JeepinJarhead03 wrote:

Glad ya got it sorted out! Hows your RFI ?

If you mean self-induced RFI from my own vehicle, I haven't noticed any problems there.

I have noticed some interference (1) driving by power lines and (2) parked at a convenience store, I think because I was underneath some fluorescent lights.

I was out all day today on a trail run and it worked great for that. We were quite close together so range wasn't an issue. The antenna got brushed both from the side and from above by tree branches. In fact it got swiped by some very low branches and bent way the heck over. No problems there either.

Tokyojoe wrote:

I had moved to the Heavy Duty Spring a long time ago but a couple years after I had done the antenna mod. The heavy duty spring is the way to go. The medium spring will cause the antenna to flop around on bouncy trails but I think it looks cool when driving on the highway and it is leaning back in the wind.

I did receive the Firestik heavy duty SS-3H spring that I ordered from Walcott. That thing is stiff! It's definitely too stiff for the lightweight base loaded whip I have on now. I may play with it later with a heavier antenna. My guess is there's a fair bit of stiffness variability between the "heavy duty" springs of different manufacturers.

AdamisAdam / Tokyojoe install question: AR-1A and splitter?

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