| Home |
| Search |
| Today's Posts |
|
|
|
#1
June 13th 05, 08:39 AM
|
|||
|
|||
Not quite. Look closer - http://www.arrowantennas.com/j-pole.html
You assume it should result in common-mode currents. And you know what happens when you Ass u me. But....Common mode current on the feedline can't be avoided no matter how the antenna is fed. I agree that the antenna is quite usable without decoupling, and I've found that the 1/2 WL ringo's usual "gamma loop" feed is also fairly good as far as that. But there is no way to totally avoid all currents, without some form of decoupling. If you believe you can, try some tests adding decoupling sections. If you don't see an increase in performance, I would be *very* surprised. In some cases, it's possible for the currents to add, and produce a gain at low angles, but it's fairly unlikely. Most of the time, the pattern is skewed upwards. It takes at least two decoupling sections to fully decouple an elevated vertical. To me, you have none, although maybe you could argue that your feed of feeding qualifies as a first decoupling section...Lets say you win, and this is the case...You still need one more, if you want to be fully decoupled... If you believe you are now, I'd be willing to bet you are deluding yourself. Thats not to say the antenna doesn't work ok as is...I'm sure it probably does, except the most retentive of users...I've used loads of halfwaves with no decoupling...But those were all on 10m, where it's not so critical. BTW...The results of adding decoupling sections will vary from user to user, depending on their lines. But if the antenna is totally decoupled, the amount of current will be the appx same for any user, no matter feed length. When I say total, I mean as much as practical. I don't believe you can totally eliminate all current. There will always be a small amount. I doubt I would change the antenna....Would make it cost more... I'd consider a super deluxe version for a higher price, if they wanted full 2 section decoupling...:/ And if I went that far, I'd use a dual 5/8 design to get more gain. You'd be reinventing the isopole...:/ MK |
|
#2
June 13th 05, 04:06 PM
|
|||
|
|||
|
|
|
#3
June 13th 05, 06:02 PM
|
|||
|
|||
|
Sniped
I don't believe you can totally eliminate all current. There will always b= e a small amount. Agreed, but it is small enough I don't think most people could see a difference in performance if it had a choke or not. All I am saying, to say the antenna won't work with out a choke is just wrong. I doubt I would change the antenna....Would make it cost more... I'd consider a super deluxe version for a higher price, if they wanted full 2 section decoupling...:/ =A0And if I went that far, I'd use a dual 5/8 design to get more gain. =A0You'd be reinventing the isopole...:/ MK I have an "Isopole" here in the shop, it works good, maybe one of the best 5/8 wave antennas I have ever tested. I think it could be built a little better. I have seen a lot of them that were broke. But that is comparing apples to oranges The OSJ is a simple 1/2 wave antenna that has 0 dBd gain. No magic. Again, I just think it is wrong to tell someone the antenna won't work with out a choke. 73 Al Lowe N0IMW |
|
#4
June 14th 05, 12:54 AM
|
|||
|
|||
|
Hey Al,
Don't let the nay-sayers in this NG bother you, and don't waste your time arguing with them. Some of them can't stand the thought that any antenna which differs from their personal pet(s) might be good. Others can't grasp the idea that when model predictions and actual results differ, it's the results that count. Still others can't seem to understand that effects too small to measure usually do not matter in the real world. Your antenna is beautifully made, very reasonably priced, and you are (apparently) making a successful small business with it. Your customers are delighted, and refer their friends. You are starting to attract imitators. How many of these accomplishments can the nay-sayers claim? Keep up the good work... the XYL and I love our three OSJs! And they are now pretty much standard in our ARES/RACES organization. NO complaints heard to date. 73, Ed, W6LOL "Al" wrote in message oups.com... Sniped I don't believe you can totally eliminate all current. There will always be a small amount. Agreed, but it is small enough I don't think most people could see a difference in performance if it had a choke or not. All I am saying, to say the antenna won't work with out a choke is just wrong. I doubt I would change the antenna....Would make it cost more... I'd consider a super deluxe version for a higher price, if they wanted full 2 section decoupling...:/ And if I went that far, I'd use a dual 5/8 design to get more gain. You'd be reinventing the isopole...:/ MK I have an "Isopole" here in the shop, it works good, maybe one of the best 5/8 wave antennas I have ever tested. I think it could be built a little better. I have seen a lot of them that were broke. But that is comparing apples to oranges The OSJ is a simple 1/2 wave antenna that has 0 dBd gain. No magic. Again, I just think it is wrong to tell someone the antenna won't work with out a choke. 73 Al Lowe N0IMW |
|
#5
June 14th 05, 03:18 AM
|
|||
|
|||
|
Hey Al,
Don't let the nay-sayers in this NG bother you, and don't waste your time arguing with them. Some of them can't stand the thought that any antenna which differs from their personal pet(s) might be good. =A0Others can't grasp the idea that when model predictions and actual results differ, it's the results that count. =A0Still others can't seem to understand that effects too small to measure usually do not matter in the real world. Your antenna is beautifully made, very reasonably priced, and you are (apparently) making a successful small business with it. Your customers are delighted, and refer their friends. =A0You are starting to attract imitators. =A0How many of these accomplishments can the nay-sayers claim? Keep up the good work... the XYL and I love our three OSJs! And they are now pretty much standard in our ARES/RACES organization. =A0NO complaints heard to date. Thanks, Ed, W6LOL You are absolutely right. There is an old saying "You can't please all the people all the time". That's why I put the Money Back Guarantee on everything I sell. The return rate is less than 1 in 1,000 units sold. That's good enough for me. That's it, I am done. Thanks for all the fun. 73 Al Lowe N0IMW |
|
#6
June 14th 05, 04:07 AM
|
|||
|
|||
|
Al:
This room is less about antennas than it is about egos, hero worship, and the "good ole boys club." I have seen egos here large enough to chase all the air from the room--leaves one breathless... a couple of these guys are even "LEGENDS IN THEIR OWN MINDS!", now that's gotta count for something! Perhaps we will eventually get some 25 to 45 year olds in here and restore some progressive thinking, discussion, debate and argument which civilized men can conduct in productive ways... those who have had their day in the sun (or 15 minutes of fame) will eventually move on. Right now, there is little point in fighting the "status quo" here--they turn like a pack of wild dogs in attack if even someone poses an original thought, or explores an unconventional path... one poor long tall drink of water from Texas is taking his lickings for this now. It does have the effect of chasing off fresh new minds which would be of interest to us who would enjoy group participation--rather than a lecture by a dinosaur (and I can say that even being close to "dinosaur age" myself.) Hang in there OM... if you have measured those swr's and know your product, people will give it a go... .... the construction seems well done and should provide service for many years... Should be more than satisfactory for someone just wanting to get on the band(s) and not become an antenna guru. Heck, with an L-Match on it a guy might be surprised how wide that bandwidth can become... Warmest regards, John "Al" wrote in message oups.com... Hey Al, Don't let the nay-sayers in this NG bother you, and don't waste your time arguing with them. Some of them can't stand the thought that any antenna which differs from their personal pet(s) might be good. Others can't grasp the idea that when model predictions and actual results differ, it's the results that count. Still others can't seem to understand that effects too small to measure usually do not matter in the real world. Your antenna is beautifully made, very reasonably priced, and you are (apparently) making a successful small business with it. Your customers are delighted, and refer their friends. You are starting to attract imitators. How many of these accomplishments can the nay-sayers claim? Keep up the good work... the XYL and I love our three OSJs! And they are now pretty much standard in our ARES/RACES organization. NO complaints heard to date. Thanks, Ed, W6LOL You are absolutely right. There is an old saying "You can't please all the people all the time". That's why I put the Money Back Guarantee on everything I sell. The return rate is less than 1 in 1,000 units sold. That's good enough for me. That's it, I am done. Thanks for all the fun. 73 Al Lowe N0IMW |
|
#7
June 14th 05, 06:53 AM
|
|||
|
|||
|
This room is less about antennas than it is about egos, hero worship,
and the "good ole boys club." Speak for yourself....I rarely deviate from the topic of the NG...On the other hand....That John Smith/Bret dude often goes off on weird tangents....... Hang in there OM... if you have measured those swr's and know your product, people will give it a go... SWR has absolutely nothing to do with common mode currents.. Even someone just wanting to get on the band(s) should be aware of that. It's for their own good. MK |
|
#8
June 14th 05, 07:10 AM
|
|||
|
|||
|
.... what is never GOOD is having another tell one WHAT IS GOOD for
them... if you do that in normal life, expect to get told off as often as here... John wrote in message oups.com... This room is less about antennas than it is about egos, hero worship, and the "good ole boys club." Speak for yourself....I rarely deviate from the topic of the NG...On the other hand....That John Smith/Bret dude often goes off on weird tangents....... Hang in there OM... if you have measured those swr's and know your product, people will give it a go... SWR has absolutely nothing to do with common mode currents.. Even someone just wanting to get on the band(s) should be aware of that. It's for their own good. MK |
|
#9
June 14th 05, 06:33 AM
|
|||
|
|||
|
Don't let the nay-sayers in this NG bother you, and don't waste
your time arguing with them. At this point, I don't consider my thoughts, arguing.... Just stating the fairly obvious...Don't ignore spillover currents if you want superior performance from an elevated vertical on VHF/UHF. Some of them can't stand the thought that any antenna which differs from their personal pet(s) might be good. I could care less...He didn't invent the J pole... Others can't grasp the idea that when model predictions and actual results differ, it's the results that count. The actual results count...I could care less about the models. I've tested all this in the real world, with real antennas. Still others can't seem to understand that effects too small to measure usually do not matter in the real world. Total BS in most cases....I seen the lack of decoupling totally ruin otherwise decent antennas... I've personally tested and seen easy 3-4 s unit differences in the same exact antenna , with and without the decoupling section connected. Decoupling is critical to high performance on VHF/UHF. All the best designs include it. Your antenna is beautifully made, very reasonably priced, and you are (apparently) making a successful small business with it. Your customers are delighted, and refer their friends. Yes, I agree. I know many people that use his arrow yagi's for SAT work...Just because his J pole doesn't have a decoupling device doesn't mean he doesn't build good antennas...Not that many people decouple J poles...I've never understood why...But there it is... You are starting to attract imitators. The J pole has been imitated numerous times.... Or are you talking about arrows? How many of these accomplishments can the nay-sayers claim? Ugh....I'm not in the antenna biz...But If I were....but If I were.... I would decouple *all* my VHF/UHF verticals. Myself, I doubt I would even sell a J pole... I'm not particularly fond of the design... I would sell a super duper isopole II..... Decoupling out the ying yang... And yes, I'm sure it would cost more than $39.00... MK |
|
#10
June 14th 05, 06:52 AM
|
|||
|
|||
|
nm5k:
I agree with you on some you say, and on some of it disagree... Some, like me, care most about getting something up you can use and/or tinker with... and I work with computer models all day, I like to get my hands dirty... Others want it to be perfect "on paper"... This is not a case of one being right over the other--and no matter what their goal--I would like to accept it as a valid goal without question. It helps to try to formulate answers to help the particular person in question towards obtaining their goals--as opposed to impressing them with ones personal knowledge--well, unless that is what they wish and/or that is acceptable to them. There are men with good sound knowledge here, I do not question that--just sometimes they could present it in a manner which is more pleasant and tolerant... either way I will accept it, however I think some of the "faint at heart" are chased away... And in any case, it does not hurt to know the fine details of something--take the balun/choke and feedline currents for example--heck, you can run with the currents... and, if you ever get tired and wonder what it would be like to run without them, doesn't hurt to have gained the knowledge to quickly wind a current balun and chuck it in the line... Warmest regards, John wrote in message oups.com... Don't let the nay-sayers in this NG bother you, and don't waste your time arguing with them. At this point, I don't consider my thoughts, arguing.... Just stating the fairly obvious...Don't ignore spillover currents if you want superior performance from an elevated vertical on VHF/UHF. Some of them can't stand the thought that any antenna which differs from their personal pet(s) might be good. I could care less...He didn't invent the J pole... Others can't grasp the idea that when model predictions and actual results differ, it's the results that count. The actual results count...I could care less about the models. I've tested all this in the real world, with real antennas. Still others can't seem to understand that effects too small to measure usually do not matter in the real world. Total BS in most cases....I seen the lack of decoupling totally ruin otherwise decent antennas... I've personally tested and seen easy 3-4 s unit differences in the same exact antenna , with and without the decoupling section connected. Decoupling is critical to high performance on VHF/UHF. All the best designs include it. Your antenna is beautifully made, very reasonably priced, and you are (apparently) making a successful small business with it. Your customers are delighted, and refer their friends. Yes, I agree. I know many people that use his arrow yagi's for SAT work...Just because his J pole doesn't have a decoupling device doesn't mean he doesn't build good antennas...Not that many people decouple J poles...I've never understood why...But there it is... You are starting to attract imitators. The J pole has been imitated numerous times.... Or are you talking about arrows? How many of these accomplishments can the nay-sayers claim? Ugh....I'm not in the antenna biz...But If I were....but If I were.... I would decouple *all* my VHF/UHF verticals. Myself, I doubt I would even sell a J pole... I'm not particularly fond of the design... I would sell a super duper isopole II..... Decoupling out the ying yang... And yes, I'm sure it would cost more than $39.00... MK |
| Reply |
| Thread Tools | Search this Thread |
| Display Modes | |
|
|
Hybrid Mode
