The Ham Radio Thread

[TurboMinivan]

This week I placed the same antenna on a magnetic base on top of the 4runner and was able to hit the repeater from my house in West Layton and communicate fairly well from Farmington.

Okay, it sounds like you've verified the antenna itself is not the problem. Good so far.

I am looking for some suggestions on how to determine if my problem is with my mounting location on the spare tire mount or do I have a problem with the NMO base/mount and cable?

I've seen many many people state (or complain) that tire mounts on the back of a Jeep are the single worst place to attach an antenna--CB or ham. Sure, it is extremely common to see CB antennas put there... but it's also extremely common to see Jeeps with CBs that don't perform worth a damn. Coincidence? Maybe.

Either way, I am not going to rush to judgement about your particular situation without further testing. If you want to do a test that won't cost any money, remove the mount from your tire carrier and relocate it elsewhere on your vehicle, then see if performance improves. If it does, the location is likely to blame. If not, then I'd start looking at the mount and/or cable itself.

 

[Kevin B.]

I am looking for some suggestions on how to determine if my problem is with my mounting location on the spare tire mount or do I have a problem with the NMO base/mount and cable? All suggestions are appreciated.

Can you rig the magmount to the spare tire carrier?

 

[lhracing]

Can you rig the magmount to the spare tire carrier?

Simple but effective idea, when I place the magmount on the tire carrier it seems to work just fine. Now I have a place to start. Thanks!

 

[Kevin B.]

Simple but effective idea, when I place the magmount on the tire carrier it seems to work just fine. Now I have a place to start. Thanks!

Well that makes me nervous, because I just put a 2/70 on the fender. I hope it likes the mount I rigged.

 

[TurboMinivan]

I just put a 2/70 on the fender. I hope it likes the mount I rigged.

It should (though I haven't seen your exact mount). The fender mount works very well in my Suburban, and it worked great in my Metro.

 

[lhracing]

So I found a problem in the P-259 connector and I repaired it and the tire carrier mount works much better. I checked the SWR on the magmount and the tire carrier. The tire carrier is much worse. The average in testing at 144.5 and 147.5 on the tire carrier is about 3.0 and on the magmount it is about 1.8. Any ideas?

 

[moab_cj5]

Got notice today I have been granted my new Vanity Call Sign. I am now WI7SON.

 

[Kevin B.]

^ I'm going to remember that much better.

 

[Kevin B.]

So I found a problem in the P-259 connector and I repaired it and the tire carrier mount works much better. I checked the SWR on the magmount and the tire carrier. The tire carrier is much worse. The average in testing at 144.5 and 147.5 on the tire carrier is about 3.0 and on the magmount it is about 1.8. Any ideas?

I'm out of ideas, other than to maybe make a new short-run coax to isolate issues with the antenna itself?

But school me on SWR testing. Is the meter you use different than the one you'd use for CB or are they the same beast?

 

[moab_cj5]

^ I'm going to remember that much better.

Glad I can be of assistance...

 

[moab_cj5]

I'm out of ideas, other than to maybe make a new short-run coax to isolate issues with the antenna itself?

But school me on SWR testing. Is the meter you use different than the one you'd use for CB or are they the same beast?

You use an antenna analyzer for HAM, and don't test the same way you would with CB. With HAM, the analyzer does all the testing independent of the transceiver. With CB the meter goes inline between the transceiver and the antenna.

@lhracing What wave length is your antenna? If it is a 1/2 wave, it doesn't require a ground plane (a large flat reflective surface under the base of the antenna) so the spare rack might be fine. If it is a 5/8 wave or 1/4 wave, it will require a ground plane for optimal performance. Also, some of the antenna's have a small metal tab in the base that makes contact to the center of the mount. You may want to ensure to bend that down to make sure it is coming in contact with the connector on the mount.

You are close enough to me we can check it out sometime and see if we can figure out what's going on.

 

[DAA]

I'd check the ground on that rack first.

- DAA

 

[lhracing]

I'd check the ground on that rack first.

- DAA

I was concerned about this so I used a jumper cable from the antenna mount to the frame and it did not seem to do much.

 

[lhracing]

You use an antenna analyzer for HAM, and don't test the same way you would with CB. With HAM, the analyzer does all the testing independent of the transceiver. With CB the meter goes inline between the transceiver and the antenna.

@lhracing What wave length is your antenna? If it is a 1/2 wave, it doesn't require a ground plane (a large flat reflective surface under the base of the antenna) so the spare rack might be fine. If it is a 5/8 wave or 1/4 wave, it will require a ground plane for optimal performance. Also, some of the antenna's have a small metal tab in the base that makes contact to the center of the mount. You may want to ensure to bend that down to make sure it is coming in contact with the connector on the mount.

You are close enough to me we can check it out sometime and see if we can figure out what's going on.

The antenna is listed as a 1/2 wave. I think the mount is a little low, it places the antenna between the tire and the runner's back door so it is fairly shrouded. In this location it may be as good as it gets.

It would be great if you wanted to look at, any help is appreciated.

 

[lhracing]

I'm out of ideas, other than to maybe make a new short-run coax to isolate issues with the antenna itself?

But school me on SWR testing. Is the meter you use different than the one you'd use for CB or are they the same beast?

I used a CB SWR meter because that is what I have. I did use the procedure shown in this link, https://www.kb6nu.com/no-vhf-swr-meter-no-problem/

My actual readings may not be exact but the difference in the readings between the two mounts I think is telling me something is still off with the tire carrier mount.

 

[mesha]

Well, I passed my general test tonight so that is nerdy.

 

[Mouse]

Well, I passed my general test tonight so that nerdy.

I've been practicing for the technician test and am averaging close to 90%. Is there somewhere close to Ogden where I can test when I'm ready?

 

[moab_cj5]

I've been practicing for the technician test and am averaging close to 90%. Is there somewhere close to Ogden where I can test when I'm ready?

I forget where to look for tests, but I took mine in Clearfield.

 

[DAA]

Not sure how up to date this list is but here's a bunch of test location info: http://user.xmission.com/~uarc/testinfo.html

I took mine in Bountiful and my understanding is that test takes place monthly.

- DAA

 

[DAA]

Here's some Ogden specific info http://www.ogdenarc.org/vetest.html but it looks like the next one isn't until June.

- DAA