The I-Max-2000 antenna exposed on steroids 

Thanks for the feedback. I know that Solarcon made different revisions to this antenna so I will point out something about the mid section capacitor. I have measured it on two separate capacitance meters that I trust with one of them being a modern L/C meter with plenty of range and both meters are measuring the mid section capacitor at least on this antenna I have at 10pF. The ECG meter reads 10.0pF and my newer L/C meter reads it at 9.77pF. I've read on other websites that it was 42pF too but the likely that two capacitance meters would be inaccurate is pretty low. I also checked it on a cheap "do it all" volt meter and it too reads in the same ballpark. I think when the HAM radio operators did their measurements it may have been with a different revision of this antenna. I also want to point out that when I made this video I mentioned the IMAX being around 4 feet longer than your average 5/8 wave but in my brain I had a Biden moment when I was making the video and I accidentally made a reference to a half wave antenna and only caught it a couple days later so I just wanted to point that out. I know the MACO 5/8 ground plane antenna is around 20.5 ft in length for the 11 meter band and the IMAX is about 1.7 feet longer in length.

*_@ Soulwagon_* I don't understand why you believe the strongest point of radiation is 6 feet up from the bottom feed point. - The current is maximized 1/4 wave down from the tip, where the tip is one of two highest voltage points - the first being 1/2 wave down from the tip @ 180° phase from the tip. I believe this would provide the point of maximum current, and thus *maximum radiation,* to be 1/4 wave down from the tip or _about_ 13.5 feet from the bottom of a bottom-fed full-size 11m 5/8.

@@flash001USA It almost appears that the center capacitor is pulled apart a bit - is this just an optical illusion? Would pushing it in all the way provide closer to 42pf?

@@SoonDumpingAllGmailAccounts You nailed it Santa Cruizer, if that antenna radiated at the 6ft mark from the feed point, the SWR would be around 6,000 to 001 !😏👍

@@ericdee6802 The CBer up North, Rosco, says SWR is a good thing, the more the better and says it stands for Strongest Wattage Radiation

No I think you're correct about the inline cap. I was surprised when I found that in the antenna. You normally expect to find coils in an antenna but not that often caps. I too built up the 49:1 torrid transformer and used that on my horizontal long wire and it did a good job of matching. I'm just intrigued by the broad-banded matching setup in the Imax so this is why I decided to take this little project on.

Since this video I have done the build. Here's the video link if you would like to see the build. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-B_P-kUANsuo.html

@Shotgun Cat The Sirio Gain Master antenna will handle a 500 watt RMS continuous carrier and 1000 watts for short transmissions. For the average person this is probably more antenna they will really need unless you are wanting to join the Channel 6 Super Bowl. The Sirio Gain Master is a "Kick-Ass" antenna and whenever you go from a 1/2 wave antenna to a 5/8 wave will almost always be a win-win for the station. The IMAX is unique in it's design because of it's design with the 10pF series cap in it's mid section of the antenna. it's the magic bullet to the IMAX. which helps to reduce a lot of wasted RF going into space by keeping it's pattern close to the earth and this is where it differs from a lot of antennas. I've tried many vertical antennas and the IMAX has had the best ears and some of the best reports from stations over the other antennas I've used. Going back to the Sirio antennas, one of the better Sirio antennas that's even better over the Sirio Gain Master is their Sirio 827. I have one but I have not set it up yet. What makes this antenna a winner is it uses 8 radials instead of the usual 4 radials you see on most ground-plane antennas which gives this antenna great ears and a very good and uniform TX pattern. You may want to take a look at this antenna. It's rated at 1000 watts continuous RF carrier and a 3000 watt short time transmit use. The peak rating will be much higher. Here's the link for you if you would like to check it out. www.sirio.store/index.php?main_page=product_info&cPath=2_88&products_id=444

@Shotgun Cat That's interesting that you mentioned the thick wall antenna material. Right now I'm running a Sirio Tornado 27 which is a 5/8 wave antenna and It's really a great antenna for the money but there are two things I can point out about the antenna that I don't like. (1) The Sirio antenna bandwidth is narrower than my old IMAX-2000 (2) The loading coil is not DC grounded which I prefer because it helps control random static buildup on the antenna coax by grounding it out before it gets to the radio but other than that the antenna has served me well. Going back to my last reply to you, the Sirio 827 is built like you are describing with very thick walls for the antenna. They barely flex in the wind and they are also DC grounded. They also addressed an issue with the Tornado 27 by really beefing up the insulator spacer at the bottom of the antenna with a thick solid fiberglass rod that then has a PVC jacket over it so it's technically stronger than the actual antenna that it's supporting. I'll check out the Mr. Coiley Build you mentioned because I'm always looking at antennas. Thanks for the tip.

If I'm not mistaken, I stumbled across a RU-vid video where someone showed how to build your own a little over a year ago. Yeah simpler is the way to go. The main reason for my choice of building or decoding the 5/8 wave antenna like this one is from everything I have learned and understand, a 1/2 wave doesn't offer anymore gain than a 1/4 wave antenna or at least if you are building a ground plane antenna. I can tell you hands down that an IMax 2000 antenna totally outperforms a M-400 or what some people call a star duster and I actually tested this myself and was blown away at the TX and RX performance between these antennas. After reading about the gain difference between a 1/4 wave and a 1/2 wave antenna I decided to always stick with a 5/8 wave antenna. It also comes down to what you really need as far as the distance with others that you talk to even on a local level. Right now I am running the Sirio Tornado 27 and it's decent but the IMax 2000 did a bit better and the downfall about the Sirio Tornado 27 is it is not DC grounded by it's design so it can give you static issues. I do have a Sirio 827 that uses a loaded matching coil and that antenna has better specs all the way around. I think I'm going to convert my Tornado 27 over to a 827. I already know what needs to be done and it just comes down to finding the time to pull the antenna down and do the mods. That's another story for another time. Thank you for your reply and info. 73's, Flash.

That's the "BEST" damned description I think I've ever heard someone explain this antenna! The center capacitor does somewhat make the antenna act as if it is electrically shorter and I proved that to myself just by experimenting and tinkering with the design. I like how you broke down the explanation of the outer tuning rings and that makes sense too. You mentioned the matching coil and although they overlap the coil onto itself they do it out of phase by turning the coils opposite of each other and according to the manufacturer, they claim this helps with the reactance which helps achieve the clean smooth wide bandwidth. I can tell you for a hard core fact that the capacitor in the center of the antenna plays a BIG factor in the wide bandwidth too. Have you seen the video where I built this antenna? I was able to fine tune the antenna for a near perfect mirrored response from the center tune of the antenna to the lowest to the highest frequency spread of the 2 Mhz bandwidth this antenna has. I demonstrate this on an antenna analyzer. Here is a link to the video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-B_P-kUANsuo.html

Yes but if it behaves as a Halfwave - or similarly with the A99 - it shouldn't require any 1/4 wave counterpoise, *but the Imax does,* and I have tested this by wrapping a 5T choke in the coax directly beneath the connector so the shield could not act as a counterpoise and the SWR increased from 1.2:1 up to 3:1 - until I added a 1/4 wave counterpoise radial at the top of the U-bolt area, which caused it to once again provide a low 1.2:1 SWR. EDIT: The Imax 2000 was mounted on a wooden 4x4 mast.

@@SoonDumpingAllGmailAccounts I haven't told anyone to put a choke at the feed point of this this antenna in a long time, the a99 either. It is simply not effective there, and often does more harm than good, as you found out. I have been telling people to put said choke seven to eight feet down from the feed point. This, with the foot or so of coax that is inside the antenna should come out to a familiar length... and it is the best place for said choke for both of these antennas. This is also why you had better results with the so called "counterpoise" wire. For it to be effective, you have to put a choke where the current is, and on the a99 and Imax antennas, that is actually not at the feed point, which by the nature of said antenna designs is a current null. Sure, in some cases, depending on the length of the feed line and how it was run it might appear to do some good, but that will not be the case in every situation. That air choke you used is reactive by nature, not resistive (i.e using ferrite beads make resistive chokes). As they are reactive, how they are used and where they are placed is very important, yet no one ever considers this, people just assume that they have to go at the same place on every antenna and that is it. Again, as you found out, they can be double edge swords...

@@stevenhitt6954 Agreed, and the reason I tested it was to prove to a friend who told me & others that an Imax doesn't require any counterpoise, so I proved it does and that it typically uses the coax & mast for it's counterpoise. How I got the best performance from my Imax years ago was to install it on a solid 6' fiberglass rod atop the 5-section Tv push-up mast and wrap a 5T x 4.5" dia choke around the fiberglass rod and right below the connector, then I attached 3 102" wires from the top U-bolt downward at a fairly steep diagonal angle - maybe 60° - 70°. It added a full S-unit to the signal up into the mountains about 90 miles from here. How would you find the right size specs to build a 10pf cap utilizing 1" or so dia aluminum tubing - and to handle at least 10KW?

@@stevenhitt6954 Also, thank you for taking time from your busy career to help out youtubers. Maybe soon we'll be able to QSO on 20m or 40m from here in Cali to MO(?).

Yes you would be correct about the .64 wave but what people do not realize is that won't be the case over the whole band.The .64 wave will be at it's sweet spot or in a somewhat narrow band of channels.

The way I came up with the reference test resistor value was to try a few different "ballpark" values that I expected the range to fall into. Keep in mind that there was also a lot of stray inductance and capacitance the way I did this but this was just to be used as a diamond in the rough reference for a quick go/no go test. When it comes to length, there are two things I need to point out here. I made a mistake in the video where my brain was thinking of a 1/2 wave end fed antenna but the very early I Max antennas from 20+ years ago radiating element were around 22.5 feet. This does not include the mounting bracket. The more recent ones measure 22.0 feet from their radiating element. They did this to please the HAMS and they knew the antenna would still function in the 11 meter band. The older antennas would center tune almost dead center of 27.18500 Mhz where these newer ones like in this video can be tuned at best to resonate around 27.600 or 27.700 Mhz. When I purchased this antenna years ago to replace one that was struck by lightning I couldn't understand why it didn't tune dead center of the 11 meter band and after some research I was able to figure it out. The newer I Max antennas can be modified to resonate dead center of the 11 meter band but the extra length has to be added between the 1st and the 2nd section! If you try to add length past the 10pF series cap in the second section you will mess up the lobe and it still won't tune correctly. Before I forget to mention it, I did finally do a knock-off build and it kicked ass. If you haven't seen that video you can find it on the channel. Thank you for your feedback.

I would venture to say if the upper capacitor was removed you would find this antenna much closer to a half wave. That being said, I'm willing to bet something closer 1.5k ohm might be a better match. That being said, I think duplicating Sirio GPS 27 feed coil would give a more robust feed system without all the Jedi capacitor tricks. That way it's a true DC shunt fed with the antenna at the same DC potential as the mast.

I thought of doing the same thing too. I've always wanted to reverse engineer their design but I couldn't justify dishing out that kind of money for the project. The I-Max-2000 now cost around $185. When I purchased my first one it was less than $70! The day I did the swap I knew I was eventually going to make this video. I plan on building this and once I get it worked out I'll do a "how to" follow-up video and share this.

@@flash001USA I'm interested in what your design will be. I built my gasifier from your design, and it worked first time producing the "Halloween Orange" flame. I find your attention to detail refreshing, and I look forward to your backpack Antenna design.

It doesn't quite work that way.

Thank you for your feedback. As to the series capacitor, if you remove the series capacitor all bets are off and the antenna will not tune. You could probably cut it down to a 1/2 wave end fed antenna and make it work but it won't load correctly as the 5/8 wave design it was intended for. In the video and the drawings I could have done a few things differently but the video itself allows people to see first-hand how the antenna was built. I used drill bits as my coil forms because they are going to be spot on as far as their diameters go.The I.D. will be what I stated in the video but you would be correct that the O.D. will be larger in diameter. In other words, the O.D. will be the diameter of the coil form + the diameter of the wire itself added together. I took the I-Max 2000 and did what I haven't seen anyone else online do which was not only to dissect the antenna but I tinkered and tested everything with the antenna to learn what affected what. In the end I was actually able to build a custom design that resonated dead center of the 11 meter band with both the lower and the upper ends of the SWR balanced out. On a ending note I can tell you what I did miss in the video and what others who have dissected this antenna missed too and that would be pointing out that the tuning rings are technically closed loop coils that couple to the loading coils to rubberize them which allows you to fine tune the antenna as a whole. The tuning rings can only shift the resonance of the antenna by 5 or 6 channels or better yet, 50Khz or 60Khz tops. From what I figured out, the tuning rings really serve more of a purpose of truing or fin tuning the 50 Ohm resonance point of the antenna's length. I did build a follow-up to this video with an actual working bug-out antenna based on this design that worked quite well.

The Antron-99 is built on the same design but it's only a 1/2 wave antenna. I'm not sure if the Antron-99 has the 10pF series cap in the mid section or not but the loading coil design is almost identical. As far as other fiberglass antennas go, I haven't checked out any other fiberglass antennas. I did sit down and build the I-MAX 2000 from what I learned and you may find this video to be interesting. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-B_P-kUANsuo.html

There junk. Get a real antenna not this cheap gimick.

Thanks for the feedback. The Antron 99 is a 1/2 wave antenna which is why it's around 18 feet in length. The IMax-2000 is a 5/8 wave antenna so it measures around 22 feet in length. Most of your 5/8 wave antennas will almost always be much longer than the 1/2 wave antennas.

and what is your conclusion? :-)

Thank you for the reply. This is a follow-up to this video that you may find interesting. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-B_P-kUANsuo.html

Thank you for your reply and feedback. You would be correct that when I mentioned 18 feet that I made reference to a 1/2 wavelength antenna and I did that by accident and didn't pick up on it until a few days later. The I-Max length specs are 22.5 feet. My first ground plane antenna was a MACO v5/8 and it had been a while back since I assembled it but I did assemble it by their frequency chart and at 26.0 Mhz they specified a length of 249 inches. At 27.0 Mhz they specified a length of 248 inches and at 28.0 Mhz they specified a length a bit over 232.5 inches length. This is what was in the back of my mind when I was making this video. Even at 26.0 Mhz center frequency for the MACO their actual chart length for the antenna was 20.75 feet and for a center frequency of 27.0 Mhz the chart gave you a measurement of 248 inches which is only 1 inch longer from 26.0 Mhz to 27.0 Mhz. They state "an overall length" so these numbers are only to get you in the ballpark but I know you are aware of that. The physical length difference with the I-Max and the MACO is just a bit under a 2 foot difference length with the I-MAX being the longer of the antennas. When I assembled my first I-MAX and laid it next to the MACO I was replacing I remembered the length difference which made me decide to go look at the MACO pdf file where I got the actual numbers before I did this video. I'm not sure why the MACO is physically shorter than the I-MAX but it definitely is and a almost 2 foot difference is a lot. As far as crunching the numbers they are apparently different for a real world 5/8 wave MACO. That probably could apply to other 5/8 wave ground plane antennas but don't hold me to that. I also know that Solorcon the builders of the I-MAX claim to fame was that it was a much longer antenna than most of the 5/8 wave ground plane antennas on the market and comparing it to a MACO they would be correct. I was having a Biden moment when I mentioned a 4 foot difference between the I-MAX and other 5/8 wave antennas because my mind for some reason made reference to a 1/2 wave antenna and as mentioned, I didn't pick up on it until a few days later. That was my bad. Still even with opening mouth and accidentally inserting foot my main goal for this video was to show people how the matching network was designed in the I-MAX and to build my own a wide-band roll-up bug out antenna based on the I-MAX 2000 antenna. I'm decent at what I do and I understand antennas but antenna theory isn't one of my strong points which is why I was asking for any knowledgeable people watching this to hopefully help out and fill in the blanks as to how they made this antenna so broad banded like they did. My first I-MAX was set at a center frequency of 27.0 Mhz and it covered from 26.0Mhz all the way up to 28.0Mhz with a most excellent SWR across a 2 Mhz span. Both the MACO and the Sirio I run now are only good for a 600 Khz bandwidth at best before you need a tuner. Once again, thank you for your feedback.

Almost forgot.... The main snafu I picked up from the I-MAX 2000 exposed website was the spark gap. I tried to point that out in the video.

@@flash001USA I have lots of Joe Biden moments myself and increasing as I age. LoL Well, the formula assumes 14awg wire. If you went with larger diameter, say even 10 AWG, the antenna would be physically shorter because of increased efficiency. Going to tubing, like the Maco gives you far more surface area, better efficiency and at, say 12-15 times more surface area than a 14 gauge wire, a much shorter antenna. (also because of lower radiation resistance and velocity factor, but that's way too much to get into on a post, much less the chapter in a book) As far as the center capacitor in the IMAX, it serves two, but related purposes. One it to increase bandwidth and the other is to add capacitance to the radiating element so the antenna will "look like" a 50 ohm load without the use of radials. But adding extra capacitance lowers the efficiency by introducing energy loss. The IMAX is a "compromise" antenna. You trade better bandwidth for less efficiency. If bandwidth is your goal over better radiation, it's a good choice. I've viewed the IMAX using two antenna modeling programs. In the original "IMAX exposed" article, he claimed it has .8DB over a half-wave dipole. However, when you add Q-factor into the equation (real life) and the center capacitor, the IMAX has about -1.6 to -1.8 DB loss over a 1/2 wave, wire dipole! I know that you're familiar with electronic and Q-factor (efficiency) is governed by the laws of physics (unchangeable). You can make an extremely efficient antenna that will radiate extremely well, with very little loss over a more narrow frequency range. But you can never get something without sacrificing another. Modeling the IMAX 2000 with ZELAND IE3D (probably the best antenna modeling software I'm aware of) shows a very interesting thing. Since the IMAX uses the coax shield (and consequently the mast, u bolts, etc) as a "counterpoise" (in place of radials), I can model the antenna mounted in 10 scenarios and yield 10 different radiation patterns. I'm an electrical engineer, but not an 'expert' in antennas, however, basic principles apply. I have a 10 meter beacon (@ 3 watts) and use a direct-fed, 1/2 wave vertical dipole and I have 10's thousands of reception reports from all over the the US and 59 countries. It's uses no coils (which introduce loss), no capacitors (which introduce loss) as a tuning network isn't needed, nor is a counterpoise or radials as "both halves" of the antenna are already present. If it were me, I'd use a half-wave, center fed vertical wire, or even two 102" whip antennas, center fed, as an option. Either will outperform an IMAX in every scenario I've tried to model. Not that it's relevant to the IMAX, but I have an A99 on my roof at 35 feet (yeah, I can hear the groans) and my wire dipole at 20 feet. Never, not even once, did I ever have a better signal report or a single received signal that was better on the A-99.

@@timmack2415 Yeah after I replied to you last night it hit me about the antenna wire diameter that the larger the diameter the shorter the antenna can be to some extent. You're also correct about the Q factor and that also applies to broad banding coils in transmitters and receiver circuits. When I was designing diplex filters for the cable industry those had bandwidths starting from 50 Mhz all the way up to 1.2 Ghz and trying to control the roll-off and insertion losses was a pain in the backside that required top shelf hi quality inductors, capacitors and a really smart board layout along with a bit of tilt EQ'ing thrown into the mix so with just with that experience I understand the trade-off with losses vs bandwidth. Years ago I used to broadband off the shelf CB radios for customers when I did channel expansions and it worked but the trade-off was reduced sensitivity on the receive so I can understand how that would also translate over to a antenna. When my I-MAX was set up I talked all over the world (under the right conditions) with no more than 100 watts and even if the antenna was a bit lossey it was worth it for the wide coverage for me. Somewhere in my saved documents I have a design for an ultra narrow band antenna that can be set up to be tunable even on a mast and the claim was it would give you a very clean low noise rejection to the adjacent channels along with a good gain in a smaller package. One of these days I may try that build. Anyhow once again thanks for your feedback. Take care, Mike

@Greg Webb Here is a good online calculator that also gives you explanations of everything. www.omnicalculator.com/physics/dipole#how-is-dipole-antenna-length-calculated

1/2 inch and 3/8. Buy real galvanized split washers...not zinc coated that will be rusted in less than six months.

If the steel whip is the same length as the original fiberglass top piece it won't change a thing. The issue is you can get away with trimming the antenna shorter for higher bands but adding length to it doesn't have the desired effect. From what I've learned disassembling and rebuilding this antenna if you want to lengthen it for lower frequencies you would need to do it by adding length to the mid section BEFORE the internal 10pF cap that's in the mid section. You may find this video interesting. I was able to do a working design on this antenna based on what I learned disassembling this antenna. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-B_P-kUANsuo.html

@@flash001USA Thanks for the info

I cut a 102SS down after the threads stripped on the original for mine. Didn't consider the added weight. It did last a couple more years though before the center section broke inside.

I can see how you would see the top and think the top section was trimmed down by a few feet but it wasn't. Originally I had planned on cleaning and resealing this antenna but decided to do a break down for this video instead. I also said the antenna was 18 feet in length which was just a mistake on my end because my brain was thinking of a 1/2 wavelength antenna which I not only corrected in a second video but I also corrected it when I measure it in this video. Yeah that was my mistake. The odd thing was when I was making this video I kept thinking and remembering my first antenna being 24 feet in length but it had been so many years since I put the first IMAX-2000 up that I thought that I was imagining 24 feet. Later I did the research and figured out what in the hell was actually going on! Are you aware that Solarcon was making changes on these antennas and the end users (That would be us) were clueless unless you were somehow made aware of the changes? In their later revisions which is what I have in this video, they decided to cater this antenna to the HAMS for the 10 meter band thinking that because the antenna had such a wide bandwidth that people wanting to use it on 11 meters wouldn't notice it. They were WRONG and now their new IMAX-2000 antennas ship with 4 sections and you can now set it up for 10 or 11 meters depending on which section you choose to use. I guess they figured out very quickly that they were losing out on sales for CB operators. Now with that said, My first IMAX-2000 that I purchased which was one of their earlier builds more than likely was 24 feet in length. That antenna worked great and it tuned dead center of the 11 meter band. When that antenna was sent to antenna Heaven thanks to a direct lightning strike, I replaced it with what I thought was purchasing the same antenna but when I ran the antenna analyzer on it, the antenna appeared to be better suited for the 10 meter band and I thought at first that I was doing something wrong on my end. If my memory is correct, I think that at best I was only able to get this second IMAX-2000 in this video to resonate at 27.500 Mhz which is why I went with a different antenna because I couldn't get the sweet spot to resonate any lower with this IMAX-2000 in the video. I even tried to add a few inches to the top of the antenna to lower it's resonace spot which is probably why you thought it had been modified. Besides the tape that I later put on the top section to seal it that you see in the video I tried to add 2 extra inches of length to the top of the antenna which made ZERO difference on the SWR. Later I was to find out that you have to lengthen it between the lower and mid section to lower the antenna's frequency or it's resonate spot because of the inline capacitor they placed in the mid section. The outer tuning rings will affect the resonate spot some but they really play more into fine tuning the 50 ohm match on the loading coil more than fooling the antenna into thinking it's either electrically longer or shorter. From what I figured out and by Solorcon's own actions of adding the 11 meter extension kit to their new IMAX-2000 antennas they sell, I was right on what I was seeing on this second antenna not resonating in the 11 meter band like their earlier builds. I hope this makes sense.

I have run 1/4 wave, 1/2 wave and 5/8 wave antennas and from what I've seen is the following: the 1/4 wave and the 1/2 wave antenna are pretty close to performance both on TX and RX at about 50 feet up in the air. You can take both the 1/4 wave and the 1/2 wave and run them low to the ground and get great ground wave performances with them and they will shoot skip quite well when the conditions are right. The 5/8 will work close to the ground too but I'm not sure if it's performance is the same low to the ground. When you put any of these antennas up around 50 feet up in the air, there is a noticeable difference in performance on a 5/8 end fed antenna compared to a 1/4 wave or even a 1/2 wave up at the same height and this is where you WILL notice the difference on the both the TX and the RX performance. The 5/8 will almost always have better RX and TX with your locals you speak to. I have run and tested the following antennas all in the same day where I built an automatic keyer that would key my base station up for 3 seconds on with a 6 second rest so that I could read the TX signal from the base in the mobile and I had strategic open areas such as parking lots etc where I recorded the results and while I was doing this I had a video camera recording the base radio RX meter so I could see the difference on how it received from the mobile and around 6 or 7 miles there was a very noticeable difference on signal strength from the base to the mobile and visa versa from the mobile back to the base. I did this test with low power around 5 watts from the base. I also had a few locals who joined in and they seen the same results. The locals were in the range of the closest being around 12 miles and the furthest being around 22 miles away. The antennas under test were the following: Star duster or M-400 (1/4 wave) Antron-99 (1/2 wave) and the IMax-2000 (5/8 wave). Both the TX and the RX was noticeably better with the 5/8 wave including the audible S/N ratio compared to both the 1/4 wave and the 1/2 wave as signals dropped. Right now I'm running a 1/4 wave star duster on top of the shop that's only 20 feet in the air and it will shoot skip quite well with a barefoot radio, talking into NY or Texas with no problem but the locals who are used to my base station can tell the difference from the home base to the shop base signals. When it comes to RF, antennas and lobe patterns or performance in the real world compared to technical specs it's like practicing voodoo. It's all about your location, your radio and your equipment and the height you choose to run your antenna.

Yeah I'm aware that it's technically a .64 wavelength antenna and that's also depending on the sweet spot frequency and it's not going to stay a true .64 wavelength across the band it's tuned for. I want to point out that when I made this video I mentioned the IMAX being around 4 feet longer than your average 5/8 wave but my brain had a Biden moment when I was making the video and I accidentally made a reference to a half wave antenna and only caught it a couple days later so I just wanted to point that out. I know the MACO 5/8 groundplane antenna is around 20.5 ft in length for the 11 meter band and the IMAX is about 1.7 feet longer in length. The IMAX is a little bit longer then the average 5/8 groundplane antennas on the market. In reality the IMAX antenna is around one or two feet longer than a lot of the aluminum ground plane antennas on the market today. My main reasoning for making this video was to show people the guts of the antenna and how they laid it out for the matching Network. I was surprised when I found the capacitor in the midsection.

@@flash001USA Yes i have the Imax which has been up for 10 years now and personally i like it although they benefit from ground planes to help eliminate CMC although a coax wound choke just below the feed point helps. A good upgrade would be to increase the thickness of the radiator and even use silver coated wire. The biggest weakness is the construction as the GRP sections are a bit weak and many are having them snap or splinter in high winds, a copper radiator or even better silver coated is far better than aluminium as it is a much better RF conductor and more efficient , maybe a mix of the Imax and Sirio Gainmaster would be interesting! :) LOL

@@markcarrington2358 There were three reasons why I didn't replace my old IMAX with a newer one. When I purchased my first one it was around $70 including the shipping. The second one was around $109 with shipping and unlike the first one which tuned dead center of the 11 meter band, the second one wanted to tune at 27.600 Mhz then I found out that they actually moved the sweet spot around on it so that it would work in both the 10 and the 11 meter band without any trimming. They should have left it alone but they didn't. They had quite a few unmentioned revisions that you would only figure out if you visited forums on the subject but the tuning thing was a bit annoying. My first antenna was able to hit it's lowest SWR dip at 27.000 Mhz with the rings all the way down and it shipped from the factory tuned almost dead center of the 11 meter band right at 27.185 Mhz right out of the box. I ran mine centered at 27.000 Mhz and it covered all the way from 26.000 all the way up to 28.000 Mhz with a good and acceptable SWR with no tuner. My second antenna went on the same pole in the same spot and with it's rings tuned to the lowest point would reach 27.500 Mhz and at first I thought I was imagining things or I did something wrong but then I found people discussing this online and their point was you couldn't stretch the antenna but you could cut it so why didn't they leave it alone from the original setup? My last reason for not making the purchase was the antenna's price now! It hovers around $190 NOT including shipping. I purchased the Sirio Tornado and it works good but it doesn't have the bandwidth of the IMAX. You are correct about using a current choke especially if you just mount it to the side of a house.

@@flash001USA Yes you are right. i have also heard that when Solarcon was taken over the quality went on the slide and some of the newer Max 2000's were only around 22' long and would not SWR on 27 and some suppliers stopped selling them. Mine is a original and like your's i put it up on a 36' mast and i live in a rural location so it's all in free space and the SWR was 1.0 at 27.100 without adjusting the rings and no higher than 1.4 from 25.800 to 28.000, and just as you have said over here in the UK the price as doubled so will not be getting another new one. Looking at the Sirio 2016 as the guy's love them over here and are only 2/3 the price of the Imax and well built with high power handling. Keep up the good work! :)

@@markcarrington2358 my max 2000 sucks. Can't tune properly. I will be taking mine down soon and going back to the a99. So much for the upgrade!

Not sure which caps you are making reference to. The one that's inline with the antenna or the coupling and matching cap on the matching coil side?

Are they both double capacitors? I thought the one at the bottom was just a single.

@@billyjoejimbob75 Yeah it is basically two capacitors that share a common plate if that makes sense.

Totally makes sense. I probably just wasn't paying enough attention.

I don't blame you. I wouldn't trust an I Max 2000 made in China either. I could only imagine the shortcuts they would gladly pull to get the antenna out the door.

No they are not made in China. Still made in the USA. Stop spreading lies.

I replaced my top section with a light weight 102” whip. Less wind load and brought resonance down from 29 MHz to 28 MHz. Now 12 and 15 have acceptable / good swr. 17m has fairly high swr but still seems to work ok. Most of the time this antenna works better than the 2 element Yagi mounted just below it.

To me the interesting part of the design is the way they configured the two coils out of phase. I also like the way they used the brass sleeve as two separate capacitors.

Yeah they still sell them. Go to Google and type something like purchase a I Max 2000 antenna. You should see a lot of companies and retailers pop up and then you just go through the list and find the best price that you can get it for. I hope that helps.

@@flash001USA The problem is I’ve been told and heard that the newer I max2000 are smaller than 24 feet and they now come in 4 piece sections due to making them easier to ship I guess. I’m looking for an old school one that’s still 24 feet. If you have and ideas again I’d very much appreciate it! Thank you 🙏

@@Fox250R You could go with a Sirio 827 but it looks like they are out of stock. They also have a Sirio 2008 antenna that is in stock and this too would be a great antenna that would actually be a step above the Tornado 27 antenna I have by them now. Here is the link. www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=21

@@flash001USA sweet I’ll check it out thank you!

I personally don't think it helps. I purchased a ground plane kit and I didn't see any difference in the performance of the antenna. Maybe there are others who will say otherwise but for me I didn't see any noticeable difference on transmit or receive or any difference in the SWR either.

@@flash001USA much appreciated. Thank you for your time and talent.

That's possible. I was only aware of the I-Max 2000 antenna exposed website. They also talked about the Antron-99 antenna too. I know that both antennas are pretty much based on the same matching circuit. Here is a link to the I-Max 2000 if you would like to check it out. cbradiomagazine.com/the-imax-2000-exposed/

If you're asking about the IMax-2000 the earlier antennas were great. They changed the center tune on the later ones to accommodate the 10 meter band and it still works on 11 meters but the lowest frequency you can get a good SWR on the newer IMax-2000's is around 27.500 Mhz

@@flash001USA So not a good choice for 27 mhz and ssb?

@@unclequack5445 Their earlier antennas were great until they changed the sweet spot on the antennas. They felt there was more of a market for the HAM operators then there was for CB but they still work for CB. I had an earlier one and that thing talked like a million bucks until it was taken out by a lightning strike. The one in this video was my replacement and when I set it up I couldn't understand why it wouldn't tune like the first one did until I did a bunch of research and realized they screwed with the formula. In my opinion you would be better off with something different. I'm using a Sirio Tornado 27 and it's a great talking antenna but they have one that's a bit better than the Tornado called the Sirio 827 and it's built like a battle ship. I have one in the box but I won't set it up until spring. For now while the weather is cold and damp I'll stick with the Tornado 27. Here is the link to both antennas just in case you are interested in looking at them. www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=185 www.sirio.store/index.php?main_page=product_info&cPath=2_18&products_id=417

@@flash001USA Yo Flash Thanks' for that I'm looking for a replacement for my A-99 the top mast looks crooked from the ground it's not straight all the way up it bothers me every time I look at it I will get by with it for now I should have got a different one.

@@unclequack5445 You're welcome. I owned a A-99 1/2 wave antenna when they first came onto the market. They're ok but once you switch over to a 5/8 wave antenna you'll wonder why you didn't do it sooner. The A-99 won't touch the 5/8 wave antennas on performance and you'll notice it on both RX and TX.

The Antron-99 is a 1/2 wave antenna but the IMAX-2000 is a 5/8 wave antenna with a few mods to allow the antenna to be a bit longer and they accomplished this by adding a 10pF series cap in the mid section of the antenna to make the lobe stay lower in the antenna so that it had less RF energy radiated into space.

Yes/No Yes/No Yes and no all at the same time. Technically it will only operate as a .64 wave on a small handful of channels above and below the center tuned sweet spot. This same remark will also apply to 5/8 wave antennas too.

I've heard a lot of good things on this antenna and this design in general.

@@flash001USA yes sigma 4 style but gold in colour, had clamps instead of jubilee clips and gamma rod never came out was a beautiful antenna think it was 7/8

@@gmcc5709 I looked it up after reading your comment and it is a 7/8 wave antenna. I'm always interested in in topics like this so thanks for the info.

Lol, Let's not spoil it for any of the kiddies out there that may be reading these replies.

.64 wave at and around it's resonant frequency for sure.

To be honest I prefer aluminum over the fiberglass myself. Don't get me wrong because a good fiberglass antenna will talk just as good as an aluminum antenna provided it's set up correctly but then again that goes with any antenna. With my fiberglass antenna I used to notice the static sound whenever a rainstorm would come over and it would be a sizzling sound every time rain drops would hit the antenna and that would be followed with a buzzing sound going up and down in pitch once the rain went from a sprinkle to a steady rain. It was definitely strange. What's weird is I thought that was something that was only unique with fiberglass antennas but I'm hearing those same sounds with the aluminum antenna when a rainstorm comes over. There doesn't even have to be lightning or thunder. It's as if the raindrops themselves have a static charge built up on them when they hit the antenna. It doesn't do it all the time so I'm not sure if it's something to do with atmospheric conditions or what. Have you ever experienced what I'm talking about?

Not sure if that would work with that high of a frequency. It would be tiny for sure.

Any antenna is simply the length of the element cut to the frequency you wish to use. Most antenna's like the I-Max-2000 use some sort of circuit to broaden the range of the frequencies to be used. 1/4 wave 1/2 wave 5/8 wave are just the length cut in a smaller segment to shorten the antenna. This in turn reduces it's ability. Ideally a full wave is optimal but not practical as the length becomes unusable with frequencies like CB. Most 2.4ghz antenna's are rather small in that frequency range, and can be made in a wide range of configurations. I made a directional helix design about 15 years ago and had a line of site range of over 50 miles. it was only 2 feet long. ;)

@@nasanction If you look at the MACO v/58 it is around 248 inches for the 11 meter band. That applies to most of your basic 5/8 wave antennas. The I Max is 270 inches in total length according to the specs. I still think by them using the inline series cap they are making the antenna electrically shorter so they can add more element into the air but I'm not sure. That's interesting about the 2.4ghz setup you made. I haven't worked with any hi frequency stuff like that other than using my cellphone lol.

@@flash001USA I still have that 2.4ghz helix antenna somewhere, If I run across it I'll take some photo's for you. The backside was simply an 8" aluminum pie pan and the element was copper wire coiled around a 1" pvc in a helix pattern around 2 ft. long. It's been a long time, so I don't remember the actual spec's.

@@nasanction What you're describing I think I have actually seen something like that somewhere along the line. It seems like I read somewhere where people were making homemade directional internet extender antennas.