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J-Pole Antenna

I will admit that there are better antennas out there than a j pole,.....but for the over cost of materials and a couple of hours time you can be on the air....and they do work fairly well

plus the satisfaction of knowing that you put it together from bare parts and it actually working is well worth the time :wink:

And the plans that you posted Jay is the same that I used for my j pole...I cut mine for 146.500 and by the time I got it all put together and on a pole ..I checked swr and according to my meter it was about a 1.3 to 1 .... I was happy with that and left it alone
 
I have to agree, that distance between elements is a bit short. I can't remember the exact distance on the two that I have but it's something like twice that '1.8' inches, closer to 4 inches. That separation distance shouldn't change much, if any, over the whole 2 meter band. If the tubing you used to make the antenna is something like 1/4 inch to maybe 3/4 inches, that separation isn't a huge biggy, just varying the 'height' if the 'tap' points on those elements a little should still give you a good match. Since the distance between the elements isn't exactly 'typical' (narrower), I think the tap points should go 'down' more than you might think (but try both up/down).
- 'Doc

(I don't have the time to calculate (or find the dimensions) right now but if someone else doesn't supply them I'll do so later today. Sorry.)
 
As for building a J-pole antenna versus throwing money down and walking out of the store with a commercial antenna, I wonder how many antennas were sold along the Gulf Coast to get people back on the air after loosing an antenna immediately after Katrina. Oh wait a minute.....most places were either damaged or closed because of lack of power. maybe it is a good idea for someone to be able to actually build a crappy antenna like the J-pole and get on the air instead of trying to buy something after the fact and going without.

While I do agree with Channel Jumper about the antenna being an important part of your station I also believe that it is not always the best idea to go through the years as an appliance operator without actually building antennas and gaining an understanding of what works and what doesn't for a particular setup. Anybody can throw money down,if they have it, but the whole spirit of amateur radio is experimenting and what is any easier to do that than with antennas.My first 2m antenna was a homemade J-pole and then the extended J-pole came shortly after. Then came the pair of homemade four element quads before settling with the eleven element yagi that I have now. There is no doubt that the 11 element yagi is the best used so far but for my application it is really overkill. I don't work 2m very much at all and may actually go back to a omnidirectional low gain antenna when I rebuild my antenna system this summer. That sort of goes against what Channel Jumper suggests in the way of getting a good performing antenna but in my case it's what works for me. Hell I may even build another J-pole an put it up. :biggrin:
 
I'm using 5/8 inch (Lowe's called it 1/2 inch) tubing and I have decided to leave the separation of 3 1/4 inch between the two vertical's alone. The long piece is 58 1/4 and the shorter piece is 19 3/4 inches.

Yesterday I bid on an old Heathkit GD-1B Grid Dip Meter at $36.95 and forgot about it. This morning I got an email that I was the high bidder and just paid for it thru PayPal. Now to figure out how to use it. LOL

Using the calculator found on 2 Meter Jpole Page it looks like the long vertical element is about 1/2 of an inch too long and the shorter element is just under 3/4 of an inch too long. Anyway I'm having fun. This morning I am going to make these two corrections and give it a whirl.

Harold
 
did you correct the way your coax connects to the antenna yet ?
 

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An Alternative View to Homebrew

To all of you who are encouraging homebrewing of antennas I say "Thanks". It is a lot easier, and sometimes cheaper, to purchase a production antenna. Clearly it supports those who run those establishments. On the other hand, there are those among us who do not simply wish to buy and talk, or rattle someone's receive. We want to do something of our own, and are willing to take any performance hits that might bring. I have made some antennas I've scrapped because they were less than stellar performers. I have made some that are phenomenal performers, too, and the 4 element Yagi homebrew in the air now differs nothing from any I could have purchased - tubing, connections, Gamma . . . the difference is it is the joint enterprising effort of a friend and myself, and no amount of arguing otherwise changes its great performance or the satisfaction I've derived from its making and its use, as have operators in Ireland, England, Hawaii, Italy. New Zealand, Australia/Tasmania, across Canada, The West Coast, Jamaica, Bermuda, Virgin Islands, Puerto Rico, and other points on the globe. I am operating less than 50 AVG Watts. My system is my antenna. It works.

My several other homebrews have given me satisfaction, too. I am well aware of when they are sub-standard performers, and when they rock the house, and neither discourages me, while both encourage me.

Should I give up and go spend $$ on a store-bought one? Only if all I want to do is wiggle or rattle someone's receive. . .

I do not mean to be combative, but neither am I willing to be ignorant.

As I understand it, Amateur Radio operators are responsible for HUGE strides in electronics/communications development. I say, "All Hail the Homebrewers!!
 
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Yes Booty I did correct it. I'm still making changes and from what I can tell I have a bad SWR meter. When I hold down on the mike button the meter goes all the way to the right and then just slowly drops back to zero. I am able to set it properly but for only a couple of seconds. The SWR right now is 1:2.5 which I can live with if I want to run on 25 watts which is plenty to reach my local repeater but I would like to get it down to that reading for the full 60 watts. Back to the hacksaw.

Harold
 
Well I'm happy to say that my SWR is now just nugging off the 1:1 mark at 60 Watts and doesn't move at all on 25 Watts. To begin with I forgot all about the longest element that is the part below the elbo. It is supposed to be between 18 to 20 inches long and I had it well over 3 feet. I cut it to 20 inches and it's working perfectly. Been smiling quite a bit these past 15 minutes or so. I got on a local repeater and talked to a mobile unit that gave me a healthy 599. I'm not going to touch that antenna again except to tape up the feed line at the connections to keep the moisture out.
I want to thank everyone for all the help, it's much appreciated.

Thank you all,
Have a blessed day,
Harold
 
Yes Booty I did correct it. I'm still making changes and from what I can tell I have a bad SWR meter. When I hold down on the mike button the meter goes all the way to the right and then just slowly drops back to zero. I am able to set it properly but for only a couple of seconds. The SWR right now is 1:2.5 which I can live with if I want to run on 25 watts which is plenty to reach my local repeater but I would like to get it down to that reading for the full 60 watts. Back to the hacksaw.

Harold


Maybe I missed it but what kind of SWR meter are you using? Is it meant for VHF or is it a CB type SWR meter? If it is a CB meter then it is probably wildly off when used at 2m and God knows what the SWR really is.
 
Well I'm happy to say that my SWR is now just nugging off the 1:1 mark at 60 Watts and doesn't move at all on 25 Watts. To begin with I forgot all about the longest element that is the part below the elbo. It is supposed to be between 18 to 20 inches long and I had it well over 3 feet. I cut it to 20 inches and it's working perfectly. Been smiling quite a bit these past 15 minutes or so. I got on a local repeater and talked to a mobile unit that gave me a healthy 599. I'm not going to touch that antenna again except to tape up the feed line at the connections to keep the moisture out.
I want to thank everyone for all the help, it's much appreciated.

Thank you all,
Have a blessed day,
Harold


I guess I was a little slower typing than you were. I'm sitting here watching the latest Harry Potter movie as I type. Good to see you have the match better.

As a note, you keep saying your signal report was 599. The last number is only used on CW by the way. It indicates the tone of the received CW note ranging from pure and clear to raspy and full of AC hum.
 

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