Usually a mobile install requires somewhere around 108 inches depending on the rig, placement and bonding. The extra length is usually provided by the spring.
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Bearcat 980 w/ AD-203
- Thread starter Spidermonkey
- Start date
So the bearcat swr tells me 9 when I try and use the calibrate. I hooked up my trusty swr meter and I get around 7. Would 6" make that much difference? Im thinking it might. I'll need to go get a spring I guess and retry.
I'm wondering maybe the bearcat Is a dud. Its doing some weird stuff. It wouldn't turn Off at one point...turn the switch off but stayed on...had to turn on and off a bunch of times beforr it went offt. Then I noticed my PA speaker is getting static through it when its on PA and continues to show the cb channel. Strange.
I'm wondering maybe the bearcat Is a dud. Its doing some weird stuff. It wouldn't turn Off at one point...turn the switch off but stayed on...had to turn on and off a bunch of times beforr it went offt. Then I noticed my PA speaker is getting static through it when its on PA and continues to show the cb channel. Strange.
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This is a stainless whip? or fiberglass? and you did check the insulators on the mount I would not keep at you about this but I have seen it many times when an insulator missing on top or put on the bottom I'm assuming it's a standard mount with an insulator on top and the bottom forms a ground link with the connector/adapter.
And that is true but I have run these without a spring many times with little effect but Spider you should try a spring as tba02 suggests just to make sure it just may make the difference.
Yes..triple checked..insulator at the top to isolate the antenna. Even checked for resistance between the antenna and ground to make sure and open resistance.
I'm thinking this radio may be a dud. Wish I had another to test with to see the swr on a different radio.
I'm thinking this radio may be a dud. Wish I had another to test with to see the swr on a different radio.
As I stated earlier you may want to get the spring as tba02 suggested it may just make the difference in most instances 6 inches should make a difference if you had an antenna analyzer you would be able to see the resonating point of the antenna and it would tell if it's too short or too long. I don't think the radio is the problem it would be incredibly unusual for that to be the case.
I was all excited as I know a full 1/4wave antenna is the way to go...but now I'm a bit deflated. It is installed to the frame of the truck using a 4 bolt style mirror mount bracket. I buffed the frame to bare metal and put electrical grease between the bracket and frame for a good long lasting connection. The antenna comes up from the frame right between the box and cab of my truck. And yes...its not/ wont touching anything as I will put a piece of rubber on it to keep from contacting when driving. Right now its not touching anything and has minimum 1/2" clearance around it between box and cab.
If you don't have a spring try this. Take an alligator clip and solder a 6" piece of solid copper wire to it and clip it to the top of the antenna it should show a positive response, as a matter of fact, make it 8 inches long and then you can trim it as you check the match. If the match is higher on 40 than 1 the antenna is to long snip an inch off the copper wire and test again. Do this until you see the same match on 1 and 40 it's a good experiment.
Lol...I tried this earlier with no change. Because no change I figured it might not work that way...
Also...the fact that the PA is acting likevan external speaker except when the mic is pressed makes me wonder...
How well did you test the coax? Check the center lead to shield? Check for crushed/pinched coax? Check the PL-259 connector for good solder joints? Check continuity of center end to end and shield as well? 50 ohm coax @ freq is demanding and unforgiving. Must be right. This isn't DC you are dealing with here.
1/4 wavelength @ 27.205mhz (ch20/AM test only) is approximately 105.5 inches.
Might also have to bond the door that has the mirror mount to the chassis/frame with braided wire to create enough counterpoise for the antenna.
1/4 wavelength @ 27.205mhz (ch20/AM test only) is approximately 105.5 inches.
Might also have to bond the door that has the mirror mount to the chassis/frame with braided wire to create enough counterpoise for the antenna.
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you said the 102 whip is bolted to the frame and coming up between the box and cab of the truck,,, your way too close to the cab and box, the whip cant be running that close to the cab and box,, get the antenna out from between the cab and box,, there is too much metal surrounding the antenna, you will never get a good swr like that
unbolt the bracket from the frame and get the antenna above the box of the truck, use a set of visegrips or C-clamp and try it on an upper corner of the box and see what your swr is
unbolt the bracket from the frame and get the antenna above the box of the truck, use a set of visegrips or C-clamp and try it on an upper corner of the box and see what your swr is
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I was wondering if between the box may be a bad idea as the first 2 feet of the antenna is running up between the cab and box. My idea was that a full 1/4 wave antenna sticking 5' over the truck roof would be good....perhaps not. The truck has a fiberglass tonnaue cover so I may have to rethink my antenna mount options. I think I now have a very nice RG-8U that's about 4' too short to reach where it needs to go if antenna is mounted higher. Anyways...I'll try moving the antenna tomorrow and see where I get.
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