CB Tour PAk Coil Reading 06 Ultra

[Yo J]

I am testing out the CB system for a trip, that I have not used in years, and when I measure the resistance (see red circle) the coil reads as a short?

It this normal for this setup?

http://www.harley-davidson.com/en_US/Media/downloads/Service/isheets/-J03647.pdf

Figure 4


[attachment removed after 60 days by system]

[Ken R]

I don't think that's right.  The loading coil should be completely above ground, no continuity to ground.   (The tip of the plug being isolated from the shield which should be at ground.)

[Yo J]

I am not sure Ken everything I find sez that it should show a short..I wonder where I set the swr at? Probably the antenna...

http://www.wilsonantenna.com/tuning.php

[Coyote]

Reading a DC short to ground is normal when using a Gamma match to end feed the antenna. Every antenna I sell at my company will read a DC short to ground. Lots of good reasons for that but I won't get into the technical reasons here. Fire it up, you'll be fine. 

[Ken R]

Reading a DC short to ground is normal when using a Gamma match to end feed the antenna. Every antenna I sell at my company will read a DC short to ground. Lots of good reasons for that but I won't get into the technical reasons here. Fire it up, you'll be fine. 

Well, I thought I still had the HD loading coil from my '02 Ultra, but I guess it's gone. 

I sure thought that the coil was simply in series with the center conductor of the coax, isolated from ground.  The antenna mast IS isolated from ground.  The shield was grounded to the frame and ground plane plate in the bottom of the tourpac.

Ken

[Yo J]

Reading a DC short to ground is normal when using a Gamma match to end feed the antenna. Every antenna I sell at my company will read a DC short to ground. Lots of good reasons for that but I won't get into the technical reasons here. Fire it up, you'll be fine. 

So do I set the SWR by trimming the whip?

[Nebraskarider1]

Reading a DC short to ground is normal when using a Gamma match to end feed the antenna. Every antenna I sell at my company will read a DC short to ground. Lots of good reasons for that but I won't get into the technical reasons here. Fire it up, you'll be fine. 

Is this different than setting one up in say a truck? The shield ends up grounded to a mirror bracket and the center conductor passes through an insulated stud. Not arguing but you got me curious now. I always thought on a truck if you had continuity between the 2 you had a short, just curious.

[Coyote]

I'm just saying a DC short doesn't necessarily mean an antenna is bad. It depends on the matching network used. If it's just a straight loading coil, then it wouldn't measure short to ground. I don't have the older loading coil on my bike. I'll dig through some electrical manuals on the previous units and see if I can find anything conclusive.

[Coyote]

Based on the drawings in the electrical diagnostics manual, you should have a loading coil only and it should not measure to ground if disconnected from the CB radio unit. At least that's the way I read it. The surefire way to know is drop an SWR meter in and measure the return loss.

[Yo J]

The surefire way to know is drop an SWR meter in and measure the return loss.

What SWR reading should I get if the coil is shorted improperly?

[Coyote]

You will probably easily be above 3:1

If it's working, maybe 1.5:1

[Ken R]

Based on the drawings in the electrical diagnostics manual, you should have a loading coil only and it should not measure to ground if disconnected from the CB radio unit. At least that's the way I read it. The surefire way to know is drop an SWR meter in and measure the return loss.

That's the way I remembered it, too. 

My system's SWR was 1.2:1, but I was having reception problems. 
Checked the coax and found that it had several breaks in the center conductor where it passes by the motorcycle's steering head.  Harley uses RG58 coax.  I replace the entire coaxial cable with the same length of RG58AU (stranded center conductor).  I couldn't get the SWR below 2:1 from that point on . . . . but the reception problems went away.   I even changed the coax again and also experimented with substitute whips, longer and shortened so I wouldn't be irreversably cutting the original whip.  It was very frustrating.  But the radio worked o.k. in xmt and receive.

I think the motorcycle frame and small ground plane are just barely adequate; there's just so much one can do on a motorcycle. 

Ken