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102" whip as base antenna on a metal post questions..

CB590

CB590

W9WDX Member
Jun 29, 2016
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Trenton Nj
www.590dx.com
I have a metal 'top rail' about 10' long that I use on my house for antennas (2m/70cm dual band comet)..

I was entertaining because of my budget a 102" whip on a 3/8 stud to SO-238 type mount.. and mount to said metal pole and trim for 10m use.

I know I need a ground plane to make sure I get a good radiation pattern..

Can I use 12awg wire (I have a new 100' spool) and run them at downward angles to the wood deck frame and use I bolts to hold taught??

I'm guessing they would also need to be about 8' each piece. How many of these would I need (at the minimum) to make it happen and workable?? Unit is 50w max.
 

Just thought about it a Tram 1295 (NMO to 3/8 stud) would work with my Tram 1470 ground plane kit that's on the post already for testing purposes. All I would need is to extend the four 20" ss radials to 8' each..

I would disconnect the 2/70 rig and use that existing 12' of coax (LMR240) from the shack to the pole. It has an N connector under it so it should be drier than PL259..

I do own an SWR meter to check after install.

Does this make better sense??
 
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K3ACZ said:
Just thought about it a Tram 1295 (NMO to 3/8 stud) would work with my Tram 1470 ground plane kit that's on the post already for testing purposes. All I would need is to extend the four 20" ss radials to 8' each..

I would disconnect the 2/70 rig and use that existing 12' of coax (LMR240) from the shack to the pole. It has an N connector under it so it should be drier than PL259..

I do own an SWR meter to check after install.

Does this make better sense??
Click to expand...
give it a try...post your results...I currently am using a 102 inch whip as a base set up with 2 copper wires (8 gauge) each 109 inch in length at approx. 20 degree angle off antenna bracket and have swr's almost flat and seems to work very good.....good luck with the install!!
 
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I don't have a 102 whip yet. I do however have a 5' Firestik II 5/8 wave rated at 1kw max that gives me 1-1.3 or less all day long in my truck on 10m when tuned down with the 'tip' and 1-1.1 on 11m when turned up. It has a 3/8 stud also. Gonna try that first before I buy the $25 whip..

Just ordered the NMO-stud adaptor..

Stay tuned
 
I've used a whip and 1 radial on 11 meters and it works pretty good. 3 to 4 equally spaced would be better. 12 awg radials and a 102 whip will take thousands of watts so you're good there. You should get a good match by starting with the radials too long and trimming for low swr.

I'm not sure about the tram ground plane thing. Some of those ground plane things aren't even on the ground side of the antenna. All you need is a way to connect the radials to the coax shield at the feed point. You can attach them to the antenna bracket and I've even soldered them to the pl259 connector in a pinch.
 
543_Dallas said:
I've used a whip and 1 radial on 11 meters and it works pretty good. 3 to 4 equally spaced would be better. 12 awg radials and a 102 whip will take thousands of watts so you're good there. You should get a good match by starting with the radials too long and trimming for low swr.

I'm not sure about the tram ground plane thing. Some of those ground plane things aren't even on the ground side of the antenna. All you need is a way to connect the radials to the coax shield at the feed point. You can attach them to the antenna bracket and I've even soldered them to the pl259 connector in a pinch.
Click to expand...

The Tram ground plane mount has the SO239 grounding right to the metal bracket and the 4 radials come off it at the base of the NMO and are held on with setscrews.

I'm thinking I may also have either 12 or 10 awg in solid copper here on spools which may be better than stranded.

Trying to figure out how to attach it well to the 4 ss radials.

Was going to start with like 9' lengths and work my way backwards.
 
So here is the Tram ground plane bracket as shown with 22" SS radials.

IMG_20170511_084903.jpg


I could drill 4 holes in the top of the bracket for the ground wires and use 4 screws/nuts and connectors for the 12awg. The N connection passes thru the bracket directly with the ground shield per 'norm', so yes its grounded.

IMG_20170511_084822.jpg


Or drill the brass side holes out to accommodate the 12awg and then use the tiny setscrews to hold in place. Keep in mind the holes are only about 3/8" deep. The 2nd down side is once I make the holes bigger for the wire, the existing radials will no longer fit so the bracket can't go back to original if I decide this is bad or end up buying an Imax 3 months from now.

IMG_20170511_084810.jpg


Or as last option extend the existing 22" SS radials out to 9'.
But being stainless radials I'd have to use like mini copper compression clamps or something.?

Thoughts or best way using this bracket??

(I'm leaning toward drilling out 4 corners on bracket top and installing 4 ss screw/nuts and attach ground plane 12awg wire that way..)
 
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So I drilled the top of bracket with 4 holes.. Just got to grab some ring terminals over weekend and add the 12awg.. Still waiting on the NMO-Stud adaptor..

Should I also try and run the original ss radials as well or will that cause other issues?

IMG_20170511_110117.jpg
 
IMG_20170513_082159.jpg


So I ended up with four 10' pieces of 12AWG wire mounted up. The ends will end at eyeloops screwed into top rail of my wood deck.

Currently raining, will have to wait to put up.
 
Ended up with just 3 ground plane leads of 12awg at downward angle. All about 9' long. I'm using the Firestik II 5' model as that's what I had laying around.

SWR is 1.2 on 1 and 1.6 on 40 with the little red 'cap' on. While not perfect its way better than that no ground plane mess and I have my SWR meter inline so I get constant readings.

The no ground plane antenna did not allow SWR meter inline as it would skew numbers real bad with that 'special' coax with counterpoise built in.
 
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those no ground antennas are pretty lousy. even a k40 mag mount stuck to an outside AC unit worked better for me. at least until the AC kicked on.

now that you've tried out your theory, are you going to purchase the 102?
 
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The adjustable 102" whip I found is $39 shipped. The Solarcon A99 is running about $80.. Kinda torn right now.. I like the wide band of the A99 and 'gain' it may offer, but not necessarily the length.. (In mobile home park)..
 

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