DAS26miles
San Fernando Valley, California
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Joined: 10/11/2003
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This setup has been a long ongoing process of trial and error. Below are photos of how I attached the CB in the cab and how I mounted the NGP Firestik antenna to my awning stop bracket. The best match I can get on the antenna is 1.7:1. but the channels I use, 13,15,17and 19 are all about 1.2-1.3:1.
By mounting the radio to an oak board, I can take it out easily and it doesn't get too much in way of my wife jumping out of the seat to use the restroom while driving.
The antenna coax is secured to the side of the MH by little self sticking cable mounts. They seem to be holding up so far. The antenna mount is attached to a 1/2 piece of plywood and secured with a bolt that attaches to another piece of plywood on the other side of the awning stop bracket. This doesn't interfere with the awnings operation. I don't like having the antenna on the right side because of trees. But the antenna did come with a spring and I am only 11'8" high.
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RicJones
So. Cal.
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Joined: 10/29/2007
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Nice creative install. How did you get the cable into the MH?
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Benntexas
Texas
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Joined: 06/18/2008
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I got one quick question and realize it has been years since I ran a two way of anykind, but I do know cbs real well.
Where is your ground for you antenna? the ground it the one item most people forget about. I am sure you have one but what is it connected to?
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DAS26miles
San Fernando Valley, California
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Joined: 10/11/2003
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RicJones- At first, I ran the coax along the side into the outside radio hatch cover. Then ran it thru the radio compartment wall and into the base of the dinette. But the coax was right next to the magnet on the speaker. Plus it kept turning on the radio by remote. So I decided to run the coax all the way down the side and right up thru the floor. Had to drill a hole thru the aluminum sheathing, foam and carpet. Then I sealed the coax and hole with sealant to prevent water or other stuff from entering the inside.
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DAS26miles
San Fernando Valley, California
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Joined: 10/11/2003
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Benntexas- I used the Firestik NGP (no ground plane) antenna. It uses a special coax with some sort of counterpoise built in. No the greatest setup, but it works and I am getting out a few miles and receiving the same. I could have gotten a 3 foot antenna which would probably have given me better gain, but I was concerned about the height.
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helperzack
Port St. Lucie, FL
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Joined: 08/23/2007
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Nice application. I like how you mounted both the radio and the antenna. I guess after a year or so in the weather, the outside mount may have to be redone, but that looks like a minimal job.
Does anyone know how long a coax run can be? I have a 32' class A and was thinking of running from a CB up front, out the firewall, then maybe try to find some way to get up on top. Just trying to figure out how to not drill any holes. Or at least only one. Any suggestions will be greatly appreciated.
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DAS26miles
San Fernando Valley, California
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HelperZack- I didn't want to drill and holes in the side or especially the roof for an antenna. That's why I mounted it to the awning and down the side and under the MH and came up thru the floor. It's easier to drill a hole in the floor, run the coax thru and goop it up with sealant. I found many holes in the floor that were done this way by the manufacturer.
The NGP antenna coax is only 17 or 18' long and can't be cut. With the Firestik, you can add more coax with a barrel connector and it is recommend to do it in 9' segments.
I know the plywood pieces that the antenna mount are attached to won't last but a season or two. I have tought about using 1/2 inch plastic blocks cut to the dimensions and drill holes accordingly. I may use one of the hard plastic cutting boards. Seems to be the right thickness and plastic won't rot like the plywood will and can't be grounded. Another option is to use steel plate 16 or 18 mil thick. That should be strong enough not to bend or break.
* This post was
edited 07/06/08 12:57pm by DAS26miles *
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Benntexas
Texas
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Does anyone know how long a coax run can be?
exact portion of the full wave length,, i.e. full length, half or quarter works best ,, For general principals CB runs on 11 meter band.. So 11 meter is roughly 33 feet, so go from there.
And another thing, if you have a length you have to bundle up to stash somewhere,, do not make a nice neat roll of it.. make a roll and then twist into a figure 8 and put a tie wrap to hold that form. Something about inherited harmonic frequency currents..
It has been a long long time since I had m fist class operators license, and memory is not what it once was.. :-( I am sure some old ham operator will jump in and make corrections to my post very soon. :-)
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othertonka
Stockton, CA
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Joined: 11/15/2003
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I don't know if you have a Tap Plastics store in your area, but you can get palstic in all colors and sizes that you could use to replace the plywood. Here is a link.Tap Plastic
Othertonka
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klhutch
Sububan Chicago
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helperzack wrote:
Does anyone know how long a coax run can be?
The answer depends. For a normal antenna the coax can be any convenient length. The loss of the coax increases with length but at these frequencies even the longest MH imaginable will not suffer to any significant degree from coax loss, as long as the VSWR is reasonably low. Even 3:1 or 4:1 are reasonably low from a coax loss point of view although your transceiver may not like a VSWR that high. With most antennas there is no requirement that the coax be a specific length or a multiple of some length. In many installations cutting the coax long and coiling the excess to create an RF choke is a good thing and it can be good to do that at both ends of the coax.
These Firestik NGP antennas appear to be a special case. From reading the information on their web site they appear to be variants on a "sleeve dipole". The sleeve dipole can be a fine antenna but Firestik seems to be making theirs in an odd configuration. If I understand what they are doing correctly it is a clever idea, perhaps too clever by half. If you are using one of these antennas then you had better follow their directions exactly. There are better ways to make sleeve dipoles but they would be more expensive. The cheats they appear to be using require that you do things the way they say to do them if you want good results and even then ....
Ken
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