144MHz, CB, CD, XM All flush mounted in dash

[fzj80kidpen]

Wow

 

[alia176]

Sweet install. I was considering installing my 2M in the dash but was worried about the heat dissipation. what're your thoughts on this? Maybe one solution would be to move the stereo down one DIN slot and mount a 2M radio on the top slot. This would place it directly below the cooling fan.

thanks.

 

[Slomo]

Sweet install. I was considering installing my 2M in the dash but was worried about the heat dissipation. what're your thoughts on this? Maybe one solution would be to move the stereo down one DIN slot and mount a 2M radio on the top slot. This would place it directly below the cooling fan.

thanks.

Thanks for the complement. I was worried about the heat issue as well and I discussed it at length with the guys from Ham Radio Outlet in Fullerton and they said that the heat would not be a problem. I did purposely leave a 1/4" gap between the top of the 2M and the head unit and angle the back of the 2M down to help let the heat travel right out and IIRC the cooling fins on the back of the 2M stick back a bit farther than the head unit allowing them to radiate thier heat upward without too much interference or trapping. FWIW It has not been an issue yet and I had an identical setup in my 4Runner before this (same actual 2M) and never had an issue there either. I like your idea about the 2M on top but there is no way I am going to re-do this setup, too much time. Just realized that would put the mic cord in front of the volume buttons for the stereo also. If it has any heat related problems I will post up in the future.

Let me know if you decide to flush mount your 2M and need better pictures, I might have a few more.

 

[Slomo]

Update and correction

Originally Posted by Slomo
In setting up the system prior to installation I learned that the two radios must be completely separate electrically which ruled out using a splitter to permanently attach both radios to the one antenna base. To alleviate this problem I used an MFJ Enterprises 2 Position 450 MHz switch. This switch brings in one coax cable from the antenna mount and sends it out to 2 radios. The unique feature of this is it completely breaks one connection before it reconnects the second, thereby preventing the two antenna circuits from ever crossing. It also has the benefit of lightning surge protection for the radios, though unlikely it is nice to have.

After installation and use of the above system I ran into problems using the CB. In power testing both radios worked and connected to the external speaker. However when I used the CB it would recieve clearly but would transmit a loud buzz only. As this is the first time I have tried to share an antenna base with these two radios that is where I looked first. All connections checked out ok and after further investigation I determined that despite the fact that the switch did not allow the circuits to directly connect they were close enough that the 2 meter blew out the CB's transmission even when turned off.

To alleviate the problem I removed the MFJ Enterprises switch and installed a Comet Co. Ltd system duplexor (Part # CF-706). This sufficiently isolated the two systems and all work perfectly now.


Pic 1 Duplexer and package
Pic 2 Duplexer installed below main center console just enough room to fit.

 

[alia176]

Good job dude. I was thinking of doing the duplexer thing on my vehicle too. What antenna are you using for the CB? Is it a 10 m antenna tuned to 11m?

Thanks.

 

[Slomo]

Thanks. I am using a Radiall/larson Low Band Coil 27-30MHz with black Teflon coated 49” tunable whip. For the ICOM I use a Radiall/larson VHF coil 144-174MHz with black Teflon coated 49” tunable whip. They are obviously very different coil/whip combo's but screw into the same base mounted to the roof. Their tuned length per Radiall/larson instructions just happens to coincidently be 49" for both. I just switch assemblys depending on which radio I want to use at the time. I was able to set it up this way because I never have the need to use them both at the same time. Very happy with the results.

 

[rubirnr]

Antenna duplexor but multiple antennas

Excellent writeup. I am using this as a template for my installation, which is similar to yours. I have to admit I got a little confused with regard to your use of the duplexor. After reading this post again, I see now that you are choosing which radio you are going to be using for the event.

Does this mean that you are swapping antennas in the roof mount when you decide to use the CB or the race radio?

When I first read this post, I was thinking that I could choose a single antenna that would work with both my Yaesu 2m and Uniden CB, but I realize now that is not going to work.

Best regards,
Jerald

 

[Slomo]

Excellent writeup. I am using this as a template for my installation, which is similar to yours. I have to admit I got a little confused with regard to your use of the duplexor. After reading this post again, I see now that you are choosing which radio you are going to be using for the event.

Does this mean that you are swapping antennas in the roof mount when you decide to use the CB or the race radio?

When I first read this post, I was thinking that I could choose a single antenna that would work with both my Yaesu 2m and Uniden CB, but I realize now that is not going to work.

Best regards,
Jerald

Thanks.

You are correct, I just put the coil/whip that is appropriate for the radio I plan to use when I go out. I tried to find a way to use the same antenna but all those with much more knowledge about radios than me said it is impossible. After some thought I decided I would never really use them both at the same time anyway. I only use the CB for trail runs. I was told that even if I did have two seperate antennas up there they would have to be at least 4 feet apart to minimize bleed over. I think it would be bad since I got bleed over that made me unable to transmit anything on the CB by just having the 2m indirectly sent through the same switch but powered off.

I attached a few shots of my antenna storage in case you are interested. I have them (CB, 2m, 2m 1/4 wave) bundled with velcro straps and a bungee cord up and under the 3rd row seat mount and over the wheel well through a loose zip tie I put on the seatbelt anchor. Works awesome and zero rattles or movement and they are totally out of the way untill need them. I used to forget to put them in the truck.


Good luck,
Mo

 

[alvarorb]

Mo,

Very nice setup. Congrats.
Regarding the antennas, I used to run two antennas in the roof of my 80. I should say roof rack. One on the dead center, the other all the way to the back. About 2' from each other.
No bleed problems.
Last year in our Pre Cruise Moab trip half the group had 2m, the other half CB.
We were using both radios all the time. Specially when we separated into two groups to explore. Having both radios operating at the same time was very handy.

Regards

Alvaro

 

[Slomo]

Thanks for the info Alvaro, good to know.



Of course now I have to think about adding a second antenna mount and making all of my previous antenna work obsolete.

 

[alvarorb]

Mo,

Here's my blog entry on the antenna install

Regards

Alvaro

 

[Slomo]

Much appreciated.

Mo

 

[Slomo]

Update #2

Ok this is getting old.

FWIW in case someone references this thread, the Duplexor has failed and I am getting the same bleed over problem. I am just going to put in a second antenna mount and be done with it.