Marconi's story. My Experience With My I-10K.
All I've ever heard is that the I-10K is the best 5/8 wave, the trombone matcher shows less-loss, and matcher allows for fine tuning for both the match and the antenna length at the base of the antenna.
A generally accepted claim that most guys believe is the I-10K was designed to be survivable in bad weather, and the kit is made-up using superior materials. IMO, this is true, even though I find issues that I would change in the design. The issues may cause some problems, but I doubt they are generally detectable in performance and just using our radios.
Regarding 5/8 wave CB antennas I've always heard it declared by many CB operators that, "...a 5/8 wave is a 5/8 wave is a 5/8 wave,"
Bob85 and I have had our I-10K's for a long time, so Bob, if these models are even close to accurate...then maybe Jay's I-10K, truly is a bit different.
So, I took a modeling point of view and this is what my Eznec models predict. I simply added the trombone matcher to the model to see if it would tune the antenna. Attached below are my results. Your results may differ.
Purpose for this thread:
According to Eznec, it looks like adding the very large horizontal matching element has an effect of producing a significant amount of horizontal RF...along with ample vertical RF gain at low angles, and very little nulling in the usable CB pattern at low angles. IMO, this improvement in the model with the matcher added is noticeable and may well be of benefit, even though the gain difference is minimal at best. The maximum angle is also raised up 2% degrees from a typical 5/8 wave 9* degrees at 32' feet, and must be considered. I'm not sure if this horizontal RF advantage can be detected just using a radio however.
The I-10K always worked well for me during DX back when the WWDX.com was doing contests regularly. When I first got mine I seem to recall that DX was strong, so little local traffic was working, and I was not keeping signal reports back then either. So, most of my experience with this antenna was during the DX period that followed a few years later. I've never really tested during times when local traffic was prevailing since then either, but I was of the opinion that my I-10K worked no better than my Starduster.
I also don't think DX signals give us reliable signals for comparing purposes, so basically I have never really tested my antenna with local contacts and recorded much, excepting in Jan, 2011, I did put it up at 55' feet to the tip and compared it to my new Gain Master at 56' feet to the tip...and the Gain Master produced better local signal reports by and average signal from 6 regular locals by 7.3 Sunits to 7.8 Sunits for the GM and these guys ranged from about 30 - 70 miles away. A couple of comparison signals were about the same, but most were not.
Edit Note: sorry for the sideways results in the Antenna Work Sheets...I don't know how that happened...they all went into the printer the same. If you wish the PDF file allows you to increase the size of the print and to print the images to your printer.
Attachment #1
The two models below are:
1. Overlay of the two models below with the gain noted for the model without the matcher.
2. "I-10K wo_m 32' symmetrical" - modeled without trombone matcher, & the radials are also symmetrical.
3. "I-10K w_m 32' symmetrical" - modeled with the trombone matcher.
Note; the small asterisk ( * ) on the pattern images page that is beside the antenna titles... indicates the antenna in the overlay that is highlighted for the frequency, gain, and angle of the antenna in the list.
Note; the pattern and match difference on the "Source Data" sheets for each model. This matcher also works to adjust the match if I change T1 & T2 lengths on the model, so the added series type matcher also works, and not just play a look see part in the antenna view generated by Eznec.
Attachment #2
Email from Jay in early 2002, this shows much of what was being claimed at the time.
Attahcment #3
I-10K Review available on the Internet.
Attachmemt #4
My tuning work sheets repeated 7 years after I first got Jay's antenna and put it up the same day in 2002. These reports measured the antenna thru the feed line with my Autek VA1 and using an inline meter to compare any difference using a feed line. This antenna with the tuner added produces a very typical bowl shaped SWR bandwidth distribution and this is IMO...both very good and maybe unusual. Check out the BW notations for both results by the Analyzer and the inline meter. With improved match, I also saw improved bandwidth, but <2.00:1 for 1.4 to 2.00 mhz was about typical.
All I've ever heard is that the I-10K is the best 5/8 wave, the trombone matcher shows less-loss, and matcher allows for fine tuning for both the match and the antenna length at the base of the antenna.
A generally accepted claim that most guys believe is the I-10K was designed to be survivable in bad weather, and the kit is made-up using superior materials. IMO, this is true, even though I find issues that I would change in the design. The issues may cause some problems, but I doubt they are generally detectable in performance and just using our radios.
Regarding 5/8 wave CB antennas I've always heard it declared by many CB operators that, "...a 5/8 wave is a 5/8 wave is a 5/8 wave,"
Bob85 and I have had our I-10K's for a long time, so Bob, if these models are even close to accurate...then maybe Jay's I-10K, truly is a bit different.
So, I took a modeling point of view and this is what my Eznec models predict. I simply added the trombone matcher to the model to see if it would tune the antenna. Attached below are my results. Your results may differ.
Purpose for this thread:
According to Eznec, it looks like adding the very large horizontal matching element has an effect of producing a significant amount of horizontal RF...along with ample vertical RF gain at low angles, and very little nulling in the usable CB pattern at low angles. IMO, this improvement in the model with the matcher added is noticeable and may well be of benefit, even though the gain difference is minimal at best. The maximum angle is also raised up 2% degrees from a typical 5/8 wave 9* degrees at 32' feet, and must be considered. I'm not sure if this horizontal RF advantage can be detected just using a radio however.
The I-10K always worked well for me during DX back when the WWDX.com was doing contests regularly. When I first got mine I seem to recall that DX was strong, so little local traffic was working, and I was not keeping signal reports back then either. So, most of my experience with this antenna was during the DX period that followed a few years later. I've never really tested during times when local traffic was prevailing since then either, but I was of the opinion that my I-10K worked no better than my Starduster.
I also don't think DX signals give us reliable signals for comparing purposes, so basically I have never really tested my antenna with local contacts and recorded much, excepting in Jan, 2011, I did put it up at 55' feet to the tip and compared it to my new Gain Master at 56' feet to the tip...and the Gain Master produced better local signal reports by and average signal from 6 regular locals by 7.3 Sunits to 7.8 Sunits for the GM and these guys ranged from about 30 - 70 miles away. A couple of comparison signals were about the same, but most were not.
Edit Note: sorry for the sideways results in the Antenna Work Sheets...I don't know how that happened...they all went into the printer the same. If you wish the PDF file allows you to increase the size of the print and to print the images to your printer.
Attachment #1
The two models below are:
1. Overlay of the two models below with the gain noted for the model without the matcher.
2. "I-10K wo_m 32' symmetrical" - modeled without trombone matcher, & the radials are also symmetrical.
3. "I-10K w_m 32' symmetrical" - modeled with the trombone matcher.
Note; the small asterisk ( * ) on the pattern images page that is beside the antenna titles... indicates the antenna in the overlay that is highlighted for the frequency, gain, and angle of the antenna in the list.
Note; the pattern and match difference on the "Source Data" sheets for each model. This matcher also works to adjust the match if I change T1 & T2 lengths on the model, so the added series type matcher also works, and not just play a look see part in the antenna view generated by Eznec.
Attachment #2
Email from Jay in early 2002, this shows much of what was being claimed at the time.
Attahcment #3
I-10K Review available on the Internet.
Attachmemt #4
My tuning work sheets repeated 7 years after I first got Jay's antenna and put it up the same day in 2002. These reports measured the antenna thru the feed line with my Autek VA1 and using an inline meter to compare any difference using a feed line. This antenna with the tuner added produces a very typical bowl shaped SWR bandwidth distribution and this is IMO...both very good and maybe unusual. Check out the BW notations for both results by the Analyzer and the inline meter. With improved match, I also saw improved bandwidth, but <2.00:1 for 1.4 to 2.00 mhz was about typical.
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