J Pole...Thoughts on this?

[piratefm]

Looking to start with around 4 watts right now. What are your thoughts on this J Pole?

I'd invest in a VSWR meter to fine-tune it on my side.

https://www.superyagi.com/88-108mhz_jpo ... 84551.aspx

Ideally, I don't want to make anything from scratch, but maybe I could modify this if it needed it... Thinking of changing to an N Connector.

ULTIMATELY I would prefer an antenna exactly like this one below....even if I could make it I have no idea where to start. I'm dumb with antennas.
It would be much easier for this to be concealed in the back garden and looks a bit neater.

https://amphenol-antennas.com/datasheets/7034xxx.pdf

Or maybe someone could build me one...that's less money than buying one from Ampehnoel for £287!

[Mr.S]

The superyagi j-pole is absolute Tosh. Don't waste your money. Its got numerous fundamental design flaws. Look at where the mounting support strap is attached and what its made from!!! Your mounting pole would also need to be non-conductive as it would become a reflector.

[piratefm]

The superyagi j-pole is absolute Tosh. Don't waste your money. Its got numerous fundamental design flaws. Look at where the mounting support strap is attached and what its made from!!! Your mounting pole would also need to be non-conductive as it would become a reflector.

Oh thanks for pointing that out. I’ll stay well clear!

[Albert H]

Building aerials is both quite easy and fun to do. You can get the basic materials at your local hardware or DIY shop. You'll need a tape measure, an SWR bridge, lots of 50Ω coax, and some basic tools including a soldering iron.

[piratefm]

Building aerials is both quite easy and fun to do. You can get the basic materials at your local hardware or DIY shop. You'll need a tape measure, an SWR bridge, lots of 50Ω coax, and some basic tools including a soldering iron.

I'm going to have a crack at the Flowerpot antenna. The link you provided in another post makes it look easy to make.

[Wk-end]

[img]https://ibb.co/5knQ7MP[img]
Here is one of there J-poles i remixed lol Im using it now btw
It did take a bit to get it working how i wanted! 230 watts can easy take more!

[Persona Non Grata]

One thing Ive always wondered. Would an "L pole" aerial be technically feasible for mounting in a small space (like an attic)

Basically, a J-pole but with the matching section perpendicular to the radiating element ?

[Zozo]

One thing Ive always wondered. Would an "L pole" aerial be technically feasible for mounting in a small space (like an attic)

Basically, a J-pole but with the matching section perpendicular to the radiating element ?

Perhaps forget the J Pole and consider researching "Shunt Match Antenna" sometimes called "Hairpin Match Antenna". Will work great in an attic.

The radiating element will be 1/4 λ, and your need at-least 4x ground radials @ 90 degrees.

cache_2431491868.jpg

[sinus trouble]

That is an interesting concept ZoZo!

The Quarter wave antenna is a great performer with respect!

My only issue with it is that using ground radials equal to the radiator element seem contradictory to the dipole?

I will have to look further into this to see whats going on here?

[Albert H]

Perhaps forget the J Pole and consider researching "Shunt Match Antenna" sometimes called "Hairpin Match Antenna". Will work great in an attic.

The radiating element will be 1/4 λ, and your need at-least 4x ground radials @ 90 degrees.

The problem with an attic is the attenuation. Especially when it's raining outside! You will lose as much as 90% of your expensively generated signal.

There are all sorts of "non-obvious" aerials you can use. A neighbour of mine uses a quarterwave stub next to the pole that supports his TV receiving aerial. He's isolated the antenna mast from the brackets that hold it to the wall, and mounted the stub near to the bottom of it. The mast then becomes the radiating part of a j-pole! You can't easily see what he's done from the bottom of his garden (which is as close as you can easily get), so to the casual observer, it's just an aluminium pole supporting a TV Yagi. After some tweaking, he got a good match, and it covers a reasonable area with the little 10 Watt rig he runs, as his house is most of the way up a hill.

[Vinylizer]

[img]https://ibb.co/5knQ7MP[img]
Here is one of there J-poles i remixed lol Im using it now btw
It did take a bit to get it working how i wanted! 230 watts can easy take more!

What did you have to do to get this working how you wanted?
I've had one of their slims for a few years now,
never modded it and always seemed to work well.
Checked it with a mfj analyser before putting power through it and it all matched correctly to the freq I asked for.. upto 500w aswell

[Vinylizer]

20230511_160743.jpg

20230510_115102.jpg

After seeing this post and seeing about the mounting and the mast becoming a reflector,
I decided too have ago at making a copper j pole
How am I best attaching this to a mast also what's best way connecting the coax as I've done or soldering the n type straight to the copper ?
Here a picture of the bottom of the superyagi slim with the mounting bracket

20230511_160743.jpg

[Wk-end]

This is what i did. Get rid of the mast clamp..

[Wk-end]

Solder a bit of copper or westflex to the center core and connect to the pole.

[Vinylizer]

Solder a bit of copper or westflex to the center core and connect to the pole.

Looks good is that a brush handle with tape around it?
Would that withstand a bit of wind ? With just zippy ties
Yes I'll solder the centre core to the pole was just wondering whats best should i clamp the connecter to the pole like I have or solder the connector too it

[Wk-end]

Yeah its strong enough to stay up. I forgot to say tape up the main long part of the antennacause of rain water and silicone the connector as well. Yes its a brush handle lol. Use anything non conductive.

[XXL]

I’m pretty sure you can clamp J poles to a metal pole below the bottom J turn at the bottom.

[mpx]

I’m pretty sure you can clamp J poles to a metal pole below the bottom J turn at the bottom.

You should be able to clamp it a few inches below the feed point - but I would use a fibreglass or wooden pole rather than a metal one, or stick a bit of PVC pipe over the top of a metal pole to isolate it. Also, you should have a choke balun like in the photo, coiled coax, 4 or 5 turns, to stop common mode current on the outer braid returning back - balanced aerial, unbalanced coax. A few clip-on ferrites can also help, in addition to the coil choke balun.

Another thing you can do is place 3 or 4 1/4 wave ground planes horizontally below the bottom of the J pole to help further reduce any common mode current and stabilise the radiation pattern.