J-pole Caculator Program?

[Rippey574]

Does any one have a J-pole Calculator that lets you change the tube size from 1\2'' to what ever you want? I have found an abundant calculators but all of them have fixed tube size. I would like to have one that lets me change size so I can make large surface area ones and micro poles.

 

[elocutionist]

Changing the pipe diameter should only affect the antenna bandwidth (the range of frequencies where the antenna is a good match - low VSWR). The length of the elements should be nearly constant based on your chosen center frequency no matter the diameter used.

Christopher

 

[Rippey574]

So basically the larger the diameter the better bandwidth? Do you or any one know the usual bandwidth for the 1/2 inch?

 

[ledouxfan59]

So basically the larger the diameter the better bandwidth? Do you or any one know the usual bandwidth for the 1/2 inch?

That is correct ,
i have one i built out of 3/4 copper and its virtually flat through the whole
2 mtr band , thats a bandwith of 4 mhz ,
i cant tell you what the bandwidth would be on one made of 1/2 inch
but it's certain to be narrower
and you also end up with a sturdier antenna .
just build it with your standard measurements , then adjust the gamma match
for lowest vswr.

your mileage may vary , and you dont say what your planning on using it for
it may perform on a wider scale if its just used for rx


73

 

[ka5lqj]

J-pole "caculator".....

Does any one have a J-pole Calculator that lets you change the tube size from 1\2'' to what ever you want? I have found an abundant calculators but all of them have fixed tube size. I would like to have one that lets me change size so I can make large surface area ones and micro poles.

Michael,

If you're going to mount this antenna outside, may I suggest the "Slim Jim" from www.hamuniverse.com. It's not a commercial antenna site, but rather one for antenna experimenters. The "Slim Jim" is sort of like a beefed-up, J-Pole. The antenna is 3/4 wavelengths high on the long side and slightly less..1/2 wave on top and 1/4 wave on bottom with a "gap" in-between. You'll see the diagram and even pictures. No, the guy in the photo is NOT me, that's Richard, LOL!

I've built the antenna, using RG-8U for feedline and it works! It has a lower "take-off" angle to the horizon, so you "hear" farther and talk farther out in all directions. No, it won't beat a good, multi-element quad, but you should hear more stations. When I had mine up at 40 feet, I could work the 147.33 mhz repeater in Alexandria, LA. (125 miles away!) with 50 watts from my Icom 706 MkII-G. At 30 feet (when storms blew through) I had no trouble accessing the 146.88 repeater in Nachitoches, LA, about 70 miles away with the Icom.

I have not built a 440-470 mhz version, yet. But I will be moving this year at some point and will set one up at the new place.

The good thing about this "hobby" is it allows you to 'experiment' with different forms of antennas and different materials: wire, pipe, omni-directional, quad's, yagi's, longwire, top-loaded, base-loaded, etc.

Here, I'm terribly restricted as to lot size and living near the State Hospital's trauma center's helipad. :-( The new place, outside of town's lot, is still narrow, but very long and has a workshop to build antennas out of the heat, rain, and cold. ;-) I'll even have room for towers (YEA!!)

Respectfully submitted,
73,

Don/KA5LQJ

 

[elocutionist]

I think you can get about 3-4 MHz bandwidth (1.1 VSWR) from a 1/2" diameter element j-pole. I'll see if I can find a reference for that.

 

[Rippey574]

ledouxfan59----
I had originally drawn it up for 3\4 copper also. My grandfather (which is a ham) recommended we follow the design and materials. He couldn't recall the details from when he made them. So we used his old 10M beams (most where damaged when he cut his tower down). They where 1/2'' AL. We made it to gather in his garage. My J-pole was set up for 2M, more specifically 145.800MHz. I love to listen to the ISS. I also like to practice antenna theories and designs. I was burnt out on Coax Dipoles and they just where not to good for sky gain (compared to a J-Pole and strait wire only). Also I have restrictions on my antennas due to this not being my personal house I live at. I was always told they where narrow but extremely worth it if you get it tuned right. As of this I still cant use it for TX, having a hard time finding a local place for a HAM test (tech first then general, with more luck extra after that).

ka5lqj----
I booked mark that site, more reading for me! You used the same coax as me, except for on the antenna, I had to use RG-8 which was thinner but Ω's stayed the same. As stated above, I designed mine for 145.800. Which works good for the ISS as long as its directly over head and not cresting. Also performed good for most part of the 2M band and a little above which was sounding like a local business. I think I even heard moon bouncers on it a few times. On occasion, I will hear Spanish a lot. The locals will try to ruse him but he seems not to ever hear. Also heard what sounded like a Britt once. I always to to build my own antennas, hands on is fun and easier to learn. My next set up will probably be a Yagi, I just don't have a target Fq yet or probably all the supplies. I will be going for hand held or portable tripod able size. It is hard work to get it up, but worth it! Wish I was allowed a tower here, just one... It will look like a coax tree with metal branches LoL. I would even bee strapping antennas to guide wires! They folded on the J-Pole because of my 11M dipole in the house kills every thing when I key down. Its in the attic. I told them if I could have one outside it would fix it and I would make it look good. i just restrict my 11M now, that J-pole is no where close to handling it's range.

elocutionist----
Thank you, and good luck. I try-d, most where cross links. or not as i was expecting for "technical information".

 

[ledouxfan59]

ledouxfan59----
I had originally drawn it up for 3\4 copper also. My grandfather (which is a ham) recommended we follow the design and materials. He couldn't recall the details from when he made them. So we used his old 10M beams (most where damaged when he cut his tower down). They where 1/2'' AL. We made it to gather in his garage. My J-pole was set up for 2M, more specifically 145.800MHz. I love to listen to the ISS. I also like to practice antenna theories and designs. I was burnt out on Coax Dipoles and they just where not to good for sky gain (compared to a J-Pole and strait wire only). Also I have restrictions on my antennas due to this not being my personal house I live at. I was always told they where narrow but extremely worth it if you get it tuned right. As of this I still cant use it for TX, having a hard time finding a local place for a HAM test (tech first then general, with more luck extra after that).

ka5lqj----
I booked mark that site, more reading for me! You used the same coax as me, except for on the antenna, I had to use RG-8 which was thinner but Ω's stayed the same. As stated above, I designed mine for 145.800. Which works good for the ISS as long as its directly over head and not cresting. Also performed good for most part of the 2M band and a little above which was sounding like a local business. I think I even heard moon bouncers on it a few times. On occasion, I will hear Spanish a lot. The locals will try to ruse him but he seems not to ever hear. Also heard what sounded like a Britt once. I always to to build my own antennas, hands on is fun and easier to learn. My next set up will probably be a Yagi, I just don't have a target Fq yet or probably all the supplies. I will be going for hand held or portable tripod able size. It is hard work to get it up, but worth it! Wish I was allowed a tower here, just one... It will look like a coax tree with metal branches LoL. I would even bee strapping antennas to guide wires! They folded on the J-Pole because of my 11M dipole in the house kills every thing when I key down. Its in the attic. I told them if I could have one outside it would fix it and I would make it look good. i just restrict my 11M now, that J-pole is no where close to handling it's range.

elocutionist----
Thank you, and good luck. I try-d, most where cross links. or not as i was expecting for "technical information".

if your mainly interested in iss , why dont you look into a quagi design, and use a couple of rotors
one for orientation and another for azimuth ,
you could probably follow them across your sky !

 

[Rippey574]

I will be building one of those at some point, just like to experiment with all antennas. Also hoping to have my licenses soon so j-pole may be easy to use.

 

[fineshot1]

For your reading pleasure

Hey Michael - I was doing some googling around and stumbled across this web site with some good info.
I am not affiliated with this fella but there is some good reading on it.

http://ac6v.com/antprojects.htm

 

[W6KRU]

Hey Michael - I was doing some googling around and stumbled across this web site with some good info.
I am not affiliated with this fella but there is some good reading on it.

http://ac6v.com/antprojects.htm

Rod's website is loaded with all kinds of radio information. I frequently go to his site rather than googling. I used to chat with him on 2 meters on a regular basis. Unfortunately he passed away last year. I think his family is maintaining his site.

 

[Rippey574]

Rod's website is loaded with all kinds of radio information. I frequently go to his site rather than googling. I used to chat with him on 2 meters on a regular basis. Unfortunately he passed away last year. I think his family is maintaining his site.

That is sad to hear. I added to my studding information collection. I wounder if I can mirror the site in the event it does go down.

 

[ledouxfan59]

Rod's website is loaded with all kinds of radio information. I frequently go to his site rather than googling. I used to chat with him on 2 meters on a regular basis. Unfortunately he passed away last year. I think his family is maintaining his site.

Yeah , it was a sad day when rod went sk , great man !!!!
his son has taken over maintaining the site ,
Its not going away any time soon

73