High Gain Mobile Antenna

[mmckenna]

Sounds like a bad coil.

 

[alcahuete]

Sounds like a bad coil.

Ugh! Alright, will be in touch with the ol' Antenna Farm tonight.

Thanks for the help with this!

 

[mmckenna]

Yeah, if you are 100% sure the center tab is making contact, then that's what I'd suspect.

 

[alcahuete]

Well, I haven't put a multimeter on it yet (that's next), but there does appear to be a small indentation on that center tab, from the mount, and all the measurements show that it should be making contact.

 

[WA0CBW]

Have you done a continuity test from the whip to the tab?
Bill

 

[alcahuete]

Have you done a continuity test from the whip to the tab?
Bill

Just got to my good multimeter. Will do it right now.

 

[prcguy]

If alcahuete wants to drive to the coast I can loan him several UHF gain type antennas to test and play with and they are all known to be good. I have other models in addition to the pictures I posted earlier.

 

[alcahuete]

If alcahuete wants to drive to the coast I can loan him several UHF gain type antennas to test and play with and they are all known to be good. I have other models in addition to the pictures I posted earlier.

I really appreciate the offer! I have a ton that are good, and all are working, so I'm good there. Thank you though! This one was meant to replace some 1/4 wave mobiles, and I just got one to test before buying a bunch more.

Have you done a continuity test from the whip to the tab?
Bill

Sooooooo...continuity is good, both above and below the coil.

I'm lost. ha ha!

 

[mmckenna]

Sooooooo...continuity is good, both above and below the coil.

I'm lost. ha ha!

Check for continuity between the center pin and the outer metal ring on the NMO mount for the coil. There should be a connection, as they are a tapped coil.

Never mind, scratch that, I was thinking 5/8th's wave. 1/2 wave should be isolated from the outer ring. You should have continuity through the coil from center pin to whip.

 

[alcahuete]

Check for continuity between the center pin and the outer metal ring on the NMO mount for the coil. There should be a connection, as they are a tapped coil.

Never mind, scratch that, I was thinking 5/8th's wave. 1/2 wave should be isolated from the outer ring. You should have continuity through the coil from center pin to whip.

Thanks! Yeah, it's showing continuity from the center pin to the whip. I tested above and below the coil.

 

[alcahuete]

Well...went out and did some more testing today (after literally doing nothing) and it worked great. I don't get it, but hopefully it stays that way. I will see. I have absolutely no idea what the issue could have been.

Thanks for all the help, guys!

 

[RFI-EMI-GUY]

Here are some pics of what I believe is the biggest baddest UHF gain mobile antenna. I've had this one since about 1979 but have not used it in the last 20yrs. Its ugly to some but I really like it. The Motorola is on the right in the first picture next to a Maxrad 5dB and a Larsen open coil unknown model.

You can see the fold over feature and some of the matching goodies housed inside the base.

View attachment 88027View attachment 88028View attachment 88029View attachment 88030

I have one New Old Stock I bought a year or so back from Mechem. I could not help myself. I had one years ago on a company vehicle running a 100W Syntor. an 8 foot fluorescent lamp would glow nicely near that thing. It radiated great, talked many many miles with that antenna.

There is a NOS one on e-bay for about $70. The seller does not realize it is missing the top element. If I needed another I would try to bargain him down. He wont sell it, nobody knows what it is nor will they be happy paying $70 for it. I would make sure the tuning disc is in there before buying it.

 

[merlin]

Here are some pics of what I believe is the biggest baddest UHF gain mobile antenna. I've had this one since about 1979 but have not used it in the last 20yrs. Its ugly to some but I really like it. The Motorola is on the right in the first picture next to a Maxrad 5dB and a Larsen open coil unknown model.

You can see the fold over feature and some of the matching goodies housed inside the base.

View attachment 88027View attachment 88028View attachment 88029View attachment 88030

I just dug one of these up I forgot I had. Probably the best UHF mobile there is. My problem is I need everything in the last 2 photos including the spring. I tested one working and all of 5 Db gain+ up around 460/470.