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N9TAX Slim Jim VHF/UHF antenna

Discussion in 'Amateur Radio Equipment Reviews' started by KV4JW, Apr 20, 2019.

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  1. KV4JW

    KV4JW Ham Member QRZ Page

    First, a quick note - I don't normally like to do "antenna" reviews just because there are so many variables at play when installing and operating. However, I've had such a positive experience with this item, I felt very compelled to go over a few things that I love (and not so much) with this antenna.

    I like antennas, and I like to build antennas, and I like to test antennas. I've always been a very firm believer in how important a proper antenna is with any type of radio station. When I began toying with building ladder line/twin lead slim jim antennas, I noticed there were a few different models being sold around the internets and that piqued my curiosity. I began reading about the well known "Ed Fong Slim Jim" that's known for being installed inside a PVC pipe as well as the N9TAX Slim Jim. Both of these antennas are similar, yet different, and while I can't really comment much on the Fong antenna, I did decide to purchase a N9TAX just to take a look at how the item is constructed.

    Approximately $30 later, mine arrived in the mail. I wasn't expecting much for $30. I knew roughly what the antenna was made of. Just a length of 450 ohm ladder line, some bits of heat shrink tubing, an SO-239 (or N) connector, and that was it. The total cost for all of the parts likely in the $5-$7 range, I'd estimate. The parts I didn't really care much about though. I wanted to get a look at the antenna and see what the creator is doing to make it dual banded, examine the quality, and most importantly, put it on the air and test it's performance.

    I didn't do any kind of EZNEC antenna modelling stuff, I didn't put it on an analyzer, and I didn't put it on an SWR meter. I could have, but I didn't for ONE REASON. Modelling the antenna, and seeing what it's SWR curve is only tells a very small portion of the performance story. It only tells how the antenna is matched and as we all know, a dummy load is a PERFECT match, and a very poor radiator. Plus my meters, are simply mine, and likely won't agree with yours or whoever elses. With one meter you have a measurement. With two, you have an argument.

    Aside from that, most hams who have an interest in this antenna aren't going to spend hours analyzing it and picking it apart. It's a $30 antenna that's meant for easy, fast, simple deployment. Don't let that fool you though, because my little experiments have shown this thing is a hotrod, and rather well built might I add.

    First things first, let's talk about construction. It's a length of ladder line that's been modified in a few places, cut to a specific length, with some other little tweaks here and there. I will not go into details about the lengths or anything, but I will say - the materials used and the construction of this is five star. These antennas are all hand made. One after the other. No assembly line, no machines to do soldering, it's obvious that this antenna is HAND MADE by a human being who knows the craft well. Look at the pictures. Look at the SO239 that's been soldered on. Look at the heat shrink tubing. That is NOT cheap brand heat shrink tubing. That's thick, industrial heat shrink tubing with ADHESIVE on the inside of it. Why? Because quality. Even the ferrite choke bead has been heatshrinked over (I always just secured mine with a ziptie on each side to keep it from moving), another nice touch that adds to the quality factor.

    The ONLY thing I don't like about the construction is the type of 450 ohm ladder line used. It's solid conductor, and not stranded. That's more of a personal preference, as I've worked with stranded and I guess am a little spoiled from it's flexibility. The solid ladder line is stiffer and will be tougher to coil up and uncoil, and I'm not used to that - so again, I'm spoiled from my use of stranded. I'm sure there may be a reason the creator doesn't use stranded though.

    Performance. Wow, is this thing a performer. I challenge you to find a less expensive, dual band, equally well constructed antenna that is ready to go out of the package. The N9TAX Slim Jim isn't perfect, and it isn't a solution for everyone, but man, it's pretty cool and for such an inexpensive item, it seems to live up to it's hype. My initial testing was simple. I just hung the antenna from a string in the center of my radio room, and connected it to my Icom ID51A with a 10' RG8X coax. There are several repeaters that I like to test with, so I'll post their distance from me and the S-unit signal I received from them. I also understand this may not be an accurate test, because repeaters in different locations are at different heights, and with varying terrain, so for all of the purists out there, let's just call this test an "approximation".

    Repeater #1 is appx 45 miles away. 5 watts output accessed the repeater, received the repeater with S7.
    Repeater #2 is appx 31 miles away. 5 watts output accessed the repeater, received the repeater with S9.
    Repeater #3 is appx 29 miles away. 5 watts output accessed the repeater, received the repeater with S8.
    Repeater #4 is appx 74 miles away. 5 watts output accessed the repeater, recieved the repeater with S7.

    (FYI, repeater 4 is very high coverage, and high in elevation.)

    For fun, I lowered my output power to 2.5 watts and tried again. I accessed all of the same repeaters, with approximately the same S unit results.

    I felt this to be rather impressive, again, as the antenna was INSIDE my home merely hanging from a first story ceiling. It would be different if the antenna was 20' in the air, but, it wasn't. I really feel like if one could hoist this antenna up in a tall tree, it would really shine. What's the SWR curve look like? I don't know, I don't care. What's the EZNEC model look like? Who knows. Again, I don't care. What I do know is that this is an inexpensive lovely little antenna that will fit in your pocket, that works, and who can complain about that?

    I will mention, that due to the type of antenna this is, it probably won't like to be "near" much of anything, conductive or not. That's a general statement and based on my experience building my own antennas of this type. So just keep that note in mind, that when you hang it up, try to hang it in the middle of a room, or in a fashion where objects aren't relatively (1-2') close to it. I've seen where some people will secure it to a wooden dowel rod or fiberglass flag mast, and while that's "okay", it's very likely going to impact the performance of the antenna to be less than optimal. Remember, this antenna likes it's "personal space" so let it hang free and in as much of an open area as possible.

    My final impression is that it's worth what it costs. Can you make it yourself cheaper? Of course, but then, you're going to be out the time of tuning and constructing it, and that's worth several dollars. Plus, if you have a problem, who's there to help you? You're going to be researching and experimenting and spending MORE time on something that's designed to be simple and easy.

    If you're a new ham and want to get on the air quick and easy, I highly recommend one of these. Hang it in your attic and no one would ever be the wiser (a plus for those with HOA restrictions). Emergency ARES use? Keep it rolled up and in your go bag or glovebox. It deploys in seconds and can have you on the air in less time than it takes to make a PB-J sandwich. Connect it to your HT and easily double (triple?) your range. Thunderstorm outside? No problem. Use it indoors!

    I've been involved in amateur radio since 2001, and I really am in love with this simple and effective antenna.




    Last edited: Apr 20, 2019
    KD8ZUW likes this.
  2. KF5FEI

    KF5FEI Ham Member QRZ Page

    I have one to use when the weather gets too intense to use an outside antenna -- works well. We've used them in the field also, and it beats screwing something together and trying to find something to mount it to.
  3. N8FVJ

    N8FVJ Ham Member QRZ Page

    I use that antenna and it works perfect. I place inside at a window and contact repeaters 30 miles away with full quieting and 25 to 50 watts power.

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