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vhf beam

Weld? Bit of threaded rod or a bolt with the head hacksawed off. The ID of the tube is about 4mm so M4 rod / bolt should do.If it’s a bit loose, some fine wire or solder wrapped around will do. Too tight, ream it with a drill or file. You can always use a few spots of superglue to hold everything in place as there will be plenty of metal to metal contact.

In fact you’ll probably not even notice if the reflector is a bit short. Sure, maybe the gain or pattern is a fraction of a dB off but so what. :wink:

I used the 6mm X 1m aluminium tubes from the original design. Rather than using small connecting leads I managed to attach s couple of piggy back spade connectors directly to the end of the element and connect the coax directly. I’ve not properly measured the SWR yet and will get a few photos of the actual connections when I get back home.

Arrow antennas can be handheld or attached. You can get information like weight from the page with all the instructions. For example, the 4 element 2 m Yagi weighs 20 oz.

http://www.arrowantennas.com/inst/inst.html

Antenna ranges for gain measurements are expensive to rent or build. I guess he could calculate the gain, but that would be theoretical. You don’t trust antennas without gain figures, I don’t trust published gain figures.

wunder

How did you connect them? Blue sized would be too small to fit 6mm tube in … unless you soldered , that is if you can solder Ali?

This is how i was checking swr , fiberglass pole coax is brand new rg58 mu spec .

Trip out in the morning to b & q i think .

Matt 2E0FGX

2 Likes

Just read the article again , banana plugs sound a great idea , i got some in my connections hoard .

Gives me something to play around with tomorrow.

Matt 2E0FGX

I used the blue spades but drilled the hole bigger and snapped the blue section off this picture then used some screws I had lying around which fitted directly into the centre of the poles. I then bent the connector slightly so I could attach the coax.

Great one , cheers .

Im going to try banana plugs 1st due to having some.

Thank you

Matt 2E0FGX

Had a good few hours sorting this out , 6mm tube and even sodnt a few hours on the lathe making some locking collars as choc blocks dont fit over 6mm tube that can find .


Only thing the driven element stop colars are quite close and if it span the screws will hit each other , some heatshrink or tape over should work … now i could use banana plugs in the tube ends or ring conectors under the screw heads …

Thoughts please .

Matt 2E0FGX

Banana plugs would be nice and quick to connect, but if the wire comes out of the end of the plug, it will have to curl round to the coax - like a half turn coil, which is not ideal.
Maybe if you just used the banana plug pin, and soldered the wire to it so that it comes away at 90 degrees…?

It’s looking nice!

Cheers , thought il put a bit of effort in this time , yes im going to solder banana plugs on but on centre with expossed dilectric keep that part as short as can due to radiating with no screen.

As you can see i cant make the overlap much shorter .

Matt 2E0FGX

As “wunder” shared they can be hand held or mounted.

They work fine in my opinion but my biggest issue is that while the elements are light (made of arrows?), the main shaft is unnecessarily heavy and bulky.

It all works fine . Went out yesterday after tea time . Sadly no contacts on ssb but on fm had a few good contacts . Swindon to farnborough, wasnt really high around 800ft asl .

Just need to find best mounting for it while on a sota pole its hard to turn the pole with the guys pulling the pole down .

Any ideas ?

Matt 2E0FGX

2 Likes

Not that I’m very experienced with 2m Yagi activations, but the problem you’re having was exactly what lead me to using a tripod. Works great in the horizontal plane and either way dead easy to rotate.

Paul
M0SNA/W6PNG

Thanks Paul, im going to have to look out for a compact lightweight tripod .

Matt 2E0FGX

Video of vswr testing before went out last night .

Matt 2E0FGX

1 Like

An SWR as flat as that across the band indicates a fault of some sort.

Any ideas ?

I attach a piece of velcro tightly to the mast where the guying ring should be. The ring then settles on the velcro strip (red). This gives a bit more flexibility.

The other point is to fix the lines as far from the pole as possible to keep the angle low an don’t strain them too hard. However, looks good in your pic.

Ahoi
Pom!

Seems, there is ‘a bit’ of coax between the antenna and SWR meter killing all reflected power. :wink:


(from 2E0FGX’s pic)

1 Like

Not a twitch from the reflected power meter needle - is it working?

Is this SWR/Powermeter for the 2m band or for shortwave only?

Joe