2 Meter vertical antenna gone directional

[one-eyed Jack]

It's a Diamond F23A three element (5/8 over 5/8 over 5/8). Worked well for years and now it picks and chooses the repeaters it likes by direction. The elements are wire inside fiberglass tubes. Maybe damage from the weather. Google Diamond F23A and look at the inst. sheet. If you haven't heard of a three element vertical, you have now. Jack. W1FKG.

 

[timbo]

It's a three element vertical antenna. I can't see any way it could be direction unless there is some metal within a 1/4 to a 1/2 wavelength away from the radiating element/s acting as a reflector (or director). Is it on the side of a tower or metal mast?

 

[AHM]

I'd never assume the horizontal pattern was completely isotropic,
because it has three radial elements - not (say) a solid disc - as a counterpoise.

If it was measurable, it ought to have three lobes; hopefully equal.
So, rotating the antenna (pause to roll eyes at rotating a vertical antenna )
as little as 30° ought to run the complete gamut from peak to null.


It's also important to be a shrewd observer of the behavior of your local repeaters,
because both WB1GOF/R/2m/FM Westford and W1BIM/R/2m/FM Paxton (at least)
have had lids not merely kerchunking the machines,
but deliberately jamming some but not all of the users.

So if (for instance) the very first test transmission on a machine seemed OK
(especially if it had been idle and you didn't have to break in to a round-robin for a test),
but the first QSO with a human didn't live up to those expectations -
for instance, if it seems as if the repeater can't hear you,
it could be someone sending a carrier at the repeater
via a narrow beam antenna; to desense the input via FM capture effect.

Shrewd not just because you want to diagnose problems correctly,
but because if you don't realize you're getting jammed,
and you or your helpful monitoring station hem and haw
about the problem, it feeds the lid and means they'll stay on you.

Part of "never feed the jammer" means
you don't acknowledge the QRM in any way.
If you think you're getting jammed,
and one side or the other of the QSO just can't copy the traffic,
then you have to just say, "oops, gotta go; 73's" and QSY or pull the plug.

If the other op is clueless,
their confusion feeds the jammer even if you don't take the bait.
I have definitely heard that happen.

And of course you can't tell the clueless helper,
"hey, someone's jamming me", because that feeds the jammer.


I expect you two guys know the drill in theory way better than I do.

I'm just giving you a heads-up that you have to bring your A game
on 2m in Metro West.

 

[one-eyed Jack]

HI. The Westford machine, 146.955 comes back full scale with the Diamond and I've made contacts. The Paxton machine no, but fine with my 10 element beam. The Diamond was OK in all directions at the NH house. The little vertical which I replaced with the big one here was fine also. I'll have to take the Diamond apart and check the innards. Jamming? Been working 2M here forever and have never noticed any. Have worked a lot of repeaters with the 75w Icom and the rotatable beam. If you google the F23A ins. sheet you can see how flimsy things are in the fiberglass radomes. Jack. W1FKG. PS. I'm monitoring .955 on the Diamond.

 

[dans]

Unless I’m missing something the diamond f23a does have some directionality. Here’s the pattern from the web site

Diamond® Antenna ~ F23A Radiation Pattern

 

[DispositionMatrix]

Unless I’m missing something the diamond f23a does have some directionality. Here’s the pattern from the web site

Diamond® Antenna ~ F23A Radiation Pattern

That's the E-plane.

 

[bfm]

So, that's what the flashing light in the tree does!

 

[one-eyed Jack]

That's the E-plane.

Thanks. Didn't know that when I bought it. I'll just replace the POS with a 5/8 vertical. Not about to mount it over the beam to be able to rotate it. For sale: F23A. LOL. Jack.

 

[one-eyed Jack]

Thanks, guys. Been licensed for 55 years and "back then" HF was easy 'cause all you had to do was run wires thru the trees and use this funny thing called a "key". Now with this new fangled VHF/UHF stuff, not so easy, altho I did graduate to 6M AM for a While. Sorry that I tossed away the home brew 2M copper J pole that I made years ago. The beam works great, but what do you suggest for a simple 2M only vertical for "back-up"? I have the mast and coax and 2 way coax switch in place. Jack. W1FKG.

 

[AHM]

HI. The Westford machine, 146.955 comes back full scale with the Diamond and I've made contacts.

Good, good.

The Paxton machine no, but fine with my 10 element beam.

The two machines are only 15KHz apart.

If Westford happens to be transmitting,
then an omni at your home QTH (close-ish to Westford)
may well have trouble working Paxton.

But a beam aimed at Paxton might shrug off Westford.

The Diamond was OK in all directions at the NH house. The little vertical which I replaced with the big one here was fine also. I'll have to take the Diamond apart and check the innards.

May a good idea.
Easiest point of electrical failure might be corrosion at those set-screwed collars.
If one of your kids put it up on the chimney,
keep double-checking the other subsystems
between now and their next visit.

Jamming? Been working 2M here forever and have never noticed any. Have worked a lot of repeaters with the 75w Icom and the rotatable beam. If you google the F23A ins. sheet you can see how flimsy things are in the fiberglass radomes. Jack. W1FKG. PS. I'm monitoring .955 on the Diamond.

At least five ops banned from Westford.
(Although two are /SK, so they haven't bothered us lately).

Thanks. Didn't know that when I bought it.

Sure you knew that, Jack. That is an elevation plot - not azimuth.
The major lobes are horizontal.

It is unpossible that the left and right side of the plot are asymmetrical like that
unless a polar (top-down) plot had some variation.

But the fact that they couldn't be bothered to show the polar plot,
implies to me that it's no big deal.

I'll just replace the POS with a 5/8 vertical. Not about to mount it over the beam to be able to rotate it. For sale: F23A. LOL. Jack.

Don't jump the gun.

Sorry that I tossed away the home brew 2M copper J pole that I made years ago. The beam works great, but what do you suggest for a simple 2M only vertical for "back-up"?

I use a dual-band mobile mag-mount
slapped on top of a toaster oven.

 

[timbo]

One of the best vertical 2 meter antennas I ever owned was the AEA Isopole...it was simple, easy to build up and lasted forever. I owned one many many moons ago (mid 80s)...When I moved from Derry, to Concord in 1986, like a fool, I gave it to my uncle who still is using it and he says it still works like a champ.

It looks like it's still in production but with a different manufacturer:

Spectral - Home of the legendary ISOPOLE Antennas

Spectral - Home of the legendary ISOPOLE Antennas

www.isopole.com

$189

 

[CatSnoutSoup]

Unless I’m missing something the diamond f23a does have some directionality. Here’s the pattern from the web site

Diamond® Antenna ~ F23A Radiation Pattern

Well unless I am mistaken (and if I am someone speak up)...

That is an e-plane graph, a polar representation of a sectional slice of the electrical field, and what it shows is the strongest lobe of this vertical oriented antenna is radiated toward the horizon presumably in all directions relative to the magnetic field (H-plane).

If it was me I would be checking the current feed line with an analyser, and checking the antenna in its current location with an alternate feed line (short and known good).
There is the possibility that the issue is not "directionality" but low ERP and coincidental location of higher sensitivity in the machines that you are able to bring up.

@one-eyed Jack your mission should you choose to accept it is to find out for sure what is wrong with what is by all accounts a well regarded antenna design before trashing it.
(Please read the following part in an ominous voice) The device you are reading this message on will self destruct in 10 seconds..........

 

[AHM]

@one-eyed Jack your mission should you choose to accept it is to find out for sure what is wrong with what is by all accounts a well regarded antenna design before trashing it.
(Please read the following part in an ominous voice) The device you are reading this message on will self destruct in 10 seconds..........

I'm worried more about replacing the wrong subsystem than impugning Diamond's reputation.
Jack can afford to get yet another antenna, but if it doesn't help...

 

[CatSnoutSoup]

I'm worried more about replacing the wrong subsystem than impugning Diamond's reputation.

Yeah, not worried about Diamond’s reputation.

I meant “trash” as in dispose of (throw out).

In other words don’t throw out the antenna until you’re sure it is the issue.



P.S.> I do have a Diamond V2000A that is very sensitive to criticism.

 

[drgrant]

Paxton vs Westford has always been a thing. Especially back when what’s his name was still alive and would overdeviate all the time. That was a hoot.

WRT the antenna I would check SWR and such. Westford is so much better than Paxton in this region you can easily work it with a broken antenna….

 

[one-eyed Jack]

Paxton vs Westford has always been a thing. Especially back when what’s his name was still alive and would overdeviate all the time. That was a hoot.

WRT the antenna I would check SWR and such. Westford is so much better than Paxton in this region you can easily work it with a broken antenna….

With the power setting on 5W, Westford will peg the S meter. With 75W, nothing from Paxton. The only difference is the direction. I can hit both with a mag mount on a cookie sheet on the kitchen table. Jack.

 

[drgrant]

With the power setting on 5W, Westford will peg the S meter. With 75W, nothing from Paxton. The only difference is the direction. I can hit both with a mag mount on a cookie sheet on the kitchen table. Jack.

Can you get Waltham (64) with the Diamond? What about Derry NH?

I doubt it’s really directional, probably just lost an element or two, something. Because most VHF gear has no SWR meter, (or even a warning) it’s hard to tell if something bad is happening.

 

[one-eyed Jack]

Can you get Waltham (64) with the Diamond? What about Derry NH?

I doubt it’s really directional, probably just lost an element or two, something. Because most VHF gear has no SWR meter, (or even a warning) it’s hard to tell if something bad is happening.

Waltham strong. Harvard no. Derry .850 good. Billerica good. Fitchburg (.315) good. Westford strong. 8:40 AM Waltham off. All good with the yagi without turning it (pointing west). This weekend I'll hook up the SWR bridge. (Will have help, don't want to navigate the cellar stairs with my back as it is). Could well be a one-way trip. LOL. Jack.

 

[AHM]

Yeah, not worried about Diamond’s reputation.

I meant “trash” as in dispose of (throw out).

In other words don’t throw out the antenna until you’re sure it is the issue.

RGR THT.

I'd tear a corner off Jack's license if he discarded a perfectly non-working piece of gear
instead of crapping up some corner of the house with it.
That's just not the Ham Way.

P.S.> I do have a Diamond V2000A that is very sensitive to criticism.

Me, too; only been used at public service events.
(A circus-class 10'x20' tent with welded aluminum poles
makes for an excellent counterpoise even without those radials).

I wrote like 3 'grafs comparing our actual V2000A with Jack's F23A instruction manual,
then deleted them as overkill.

Paxton vs Westford has always been a thing. Especially back when what’s his name was still alive and would overdeviate all the time. That was a hoot.

Kykker? Pete?

Ask me in person about Pete's NPC approach on short final to
a CMARA lunch in Framingham for Sammy/KB4MPU/SK.

With the power setting on 5W, Westford will peg the S meter. With 75W, nothing from Paxton. The only difference is the direction. I can hit both with a mag mount on a cookie sheet on the kitchen table. Jack.

(We are of course all assuming that Paxton is up and running...).

Try and monitor George's Old Timer's net at 7PM tonight...

... don't want to navigate the cellar stairs with my back as it is). Could well be a one-way trip. LOL. Jack.

As long as Megan knows how to dial 911,
you're in good hands wings.

 

[one-eyed Jack]

Well, guys, the plan now is to drill holes, run wires to bring the home brew rotor controls up into the kitchen with the rest of the gear. The home brew rotor itself will remain down there as it's bolted to the ceiling joists with the st st mast going up thru the house, thru the roof and up to the beam. The 10 element beam and power up to 75W with the Icom V8000 will have me farting thru silk again. Found the Vectronics SWR/watt meter and will put it in line and play with the Diamond vertical. Thanks for all the input. Jack.