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Reviews Categories | Antennas: HF Mobile & Accessories | KJ7U Screwdriver Help

Reviews Summary for KJ7U Screwdriver
KJ7U Screwdriver Reviews: 39 Average rating: 4.7/5 MSRP: $359.-459.
Description: 160-6 Meter HF Mobile Antenna
Product is in production.
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VE3MT Rating: 5/5 Nov 29, 2012 18:48 Send this review to a friend
Peforms Just Great Very Pleased  Time owned: 6 to 12 months
I ordered a 6~160 HD Antenna From Larry back in Mar. 2012. It was damaged when it arrived US Post, Customs Or Canada Post?? But anyway spent about a month trying to get it to tune. Many e-mails back and forth with Larry. Finally talking to Him on phone we discovered the Ant. had been dropped on the end where the whip threads on. Not actually visible. Sent it back to Larry's shop 10 days later brand new one back here in Canada.
Extremely happy with the service and the performance of the ANT. mostly used on 160 m Everyone is amazed it's a vertical Ant. Tunes nearly 1.1 on 6~160 Nothing but good words to say. as the saying goes try it you will like it. DE Barry VE3MT/VE3BLM
KF6E Rating: 3/5 Apr 21, 2012 16:05 Send this review to a friend
Not getting very good results mobile  Time owned: more than 12 months
I recently replaced an ATAS-120 (trunk lid mount) with the KW version of this antenna. I expected a significant improvement in performance, but experienced none.

I had used the screwdriver in a fixed configuration, ground mounted with 25 radials, and got pretty good results. On the car, it works no better than the ATAS (an antenna with a bad rep), and on 40, it's much worse. Even with the 72" whip (almost twice the length of the ATAS whip) I get very poor performance. I don't hear many stations, and most of the stations I do hear don't hear me.

I'm using a trailer hitch mount on a Nissan Altima. I added nuts for three horizontal collapsible antennas to serve as radials. Even with the radials extended, I get mediocre performance. I did ground the mount to the frame of the car, but haven't done extensive bonding of the body sections. (It's the same configuration as with the ATAS, which worked better.)

Any suggestions?

73, Frank
N9NAQ Rating: 5/5 Jan 15, 2012 17:40 Send this review to a friend
solid performer  Time owned: 0 to 3 months
I purchased the 6 - 160 standard model used from a ham friend, and installed it on my voyager on top of an existing Breedlove mount. It works very well and I have to agree that it really does work on 160! I can often join a group with multiple stations copying me barefoot, at least in the wintertime. I did need to get a few parts from Larry to mount it to my particular setup, but he supported it 100% even though I did not buy it from him. I would not hesitate to do business with him. 73 de N9NAQ
N2LJD Rating: 5/5 May 7, 2010 11:32 Send this review to a friend
One TOUGH Antenna!  Time owned: more than 12 months
I can't recall how long I've had this antenna; three years at least. Yesterday (5/6/10) I lost it going around a corner in my Dodge Dakota (rear-bumper-mounted). Recovered it, took it home; only damage seen was my quick disconnect. Reconnected everything. Motor smoothly sent it up and down and my SWR swung perfectly into place as always - and I use the stock manual controller. Further, I always get good signal reports and "N2LJD/mobile" on 160 always guarantees a pile-up!
KE7HPT Rating: 5/5 Feb 3, 2009 12:38 Send this review to a friend
From 160 to 6 meters, This Antenna Works!  Time owned: 6 to 12 months
I have owned my 6-160 for about 11 months now. I have it mounted off the side of my Dodge PU extended from the trailer hitch. It gets a lot of use as I drive about 5,000 miles a month for work.

I am most impressed with how well 160 meters works. If I can hear them I can talk to them. I get complements on how good the system sounds and wow you must be brave to try 160 mobile! If only they new how easy it is. The rest of the station is an Icom 7000 and controller form BetterRF Company. The SWR is always under 1.5.

Up until a few weeks ago I had not made any 6 meter contacts. During the January VHF contest I was mountain toping with a bunch of yagiís for the VHF UHF bands when I was asked if I had 6 meters. (The other station really wanted DN16 on 6 meters) I had not even thought of using 6 in the contest. I told him all I had was a screwdriver vertical but letís give it a try. 300 miles was no problem. He got the grid square he needed and I made several more 6 meter contacts for the contest.

I have had some minor problems with the antenna. With just a phone call or email Larry is right there eager to fix the problem (usually operator error). I have never had such good customer service. Although I have only used the 6-160 I am sure he puts the same high quality craftsmanship in all his antennas.
W0ODZ Rating: 5/5 Jan 31, 2009 06:05 Send this review to a friend
Heavy Duty Whip Holders for large length steel whips  Time owned: more than 12 months
I work for a company that use's a great amount of 102 inch whip antenna's and larger. We use them on Semi Trucks,very large earth moving equiptment,4X4 pickup trucks, trackhoes, and on very large dump trucks.Over the years, we have broken, many original whip holders, that the set screws have come loose or just stripped out on the original installion. I was asked one day if I could locate, any manufacture that makes a Heavy Duty whip holder, that has large set screws that would work on recycling new and old steel whips, that would work for commercal aplication.I was told, that Larry Welding,KJ7U, offered just what we were looking for! His Heavy Duty Whip holders, are made on a CNC machine and have large set screws. I ordered a large amount of these whip holders, and repaired every broken steel whip we had, laying in the garage for years.These Whip holders, work great, for anyone that uses these large steel whips that they cut down to a Freq. of their choice.We started to use them on 4X4 trucks, sandbuggy's, rock crowlers, with great sucess! If your looking for, a very good quality, Heavy Duty whip holder, for a screwdriver antenna, or repairing old stripped out antenna ferrals, these are by far the best ones we have tried and used. My call sign is W0ODZ, and I live in the State, of Arizona.
W0ODZ Rating: 5/5 Jan 30, 2009 20:23 Send this review to a friend
Shorty II Screwdriver  Time owned: more than 12 months
My call sign is W0ODZ. The reason I purchased the Shorty II is, I needed a multiband screwdriver antenna that I could mount on a Quad Magnet Mount Base. I currantly use is Magnet Mount setup because, I use this on a toolbox, behind the cab of a pickup truck. When I'm on the job site, the Shorty II and the Mag Mount is then placed on the Road Grader, that I operate for a living.Shorty II, operates 6 meters through 160 meters, using a 78 inch whip. SWR's is Flat at 1.1 to 1.2 across the entire band. This screwdriver antenna is 20 inches high and raises 9 inches. I used the Shorty II on many Semi Trucks with the Quad Magnet mount with great sucess and preformance! If your looking for a portable mounted screwdriver antenna, by far this is the very best you can buy! We used this on a mini-van, pickup truck, Semi Trucks, and on the rear of a road grader, and it has preformed Excellant with no problems.
N0UJQ Rating: 5/5 Feb 2, 2008 16:27 Send this review to a friend
Made the right choice  Time owned: 0 to 3 months
I have used the "Standard" 6-160 KJ7U on both my '93 GMC Jimmy and a 2006 Chevy 1/2 ton PU with extremely good results on 40 meters up to 15 meters. 10 hasn't been open yet to try it, but I cannot imagine this will be anything less than stellar on 10. First time i've seen 60 over S9 on the Icom 706IIG was with this antenna and worked France with +40 over.

The screwdriver works well on 75 meters in the evening and night. While mobile near Springfield, Mo I was able to hear every check-in to the Kansas Sideband net and Weather net on 3920, so I figure it works well. I need to come up with an NVIS antenna for 75 during the daytime. I seem to be able to work 75 meters out to about 80 miles during mid day.

The most surprising thing is how well this antenna works on 160 meters. I have several friends here in NC Kansas, Nebraska, Texas and Oklahoma and I was able to keep in touch with all of them during a recent trip to Springfield, Mo. Working 350 miles on 160 meters is no problem with 100 watts. I talked to several guys in Kentucky on 1968 that said I was the best sounding mobile signal they've ever heard. So yes, this thing works on 160.

I've worked only a couple of stations on 60 meters. One of them was a mobile near Chicago (I was near Wichita, Ks) and we had 57 copy on each other (mid day).

I have not been able verify if it works well on 6 meters. I did work one repeater in Topeka on 6, but could not find anybody for a QSO and the range seemed limited - not sure if it's the screwdriver or the repeater - so I cannot say how well it works on 6.

It is important to note for those of you that do not own one - this antenna tunes continuously from about 1.650MHz up to near 30MHz on a 72" whip. To use 6 meters you tune near the 40 meter position. The base of this antenna does get longer when you tune lower in freq. It does not require a balun or a capacitance hat.

10-160 meter performance = 5 stars
6 meter performance = unknown
Ease of installation = 5 stars
Quality of construction = 5 stars
Value for money = 5 stars
WA2DVV Rating: 1/5 Jan 28, 2008 04:50 Send this review to a friend
not good  Time owned: more than 12 months
i have two kj7u's the Kw and standard models, both have been back 3 times each-i just repaired the Kw model myself-im done with Larry-his Repairs are Expensive! and it was bad construction that is causing the problems-Kw motor broke,sloppy hot glue-spun-gear assymbly ate unsoldered 12v and disc caps finger twist connections-the antennas work's well--but construction practice is Very Poor.
VE9GC Rating: 5/5 Dec 2, 2007 06:18 Send this review to a friend
Amazing mobile!  Time owned: 0 to 3 months
I have had various HF mobile setups over the years. An Atlas 210X with the requisite Hustler resonators, an Icom 706 with the Hustlers, a Little Tarheel 40-6M screwdriver which worked quite well. I missed the 75 mtr operating with the the Tarheel so started looking around for a replacement. The problem was that I wanted something "relatively" small and didn't want to fabricate a monster mounting system on my near vintage Auid 100. After a lot of reading, I narrowed it down to one of Larry's antennas. The interesting thing about reading about screwdriver style antennas is that just about every manufacturer tells you theirs is the best. Some even go so far as to bad mouth their competitors. I emailed Larry several times looking for more information and he was always prompt in his replies. I also contacted some current users of the Shorty II who gave good endorsements.

Well I took the plunge, and ordered up the 6-160 Shorty II. I figured I would go all the way and if I wanted 80 meters, why not 160. A few days later the antenna arrived. When I first saw the box I thought oh no he shipped the 6-160 KW antenna. In fact it was the Shorty II which is really quite a monster compared to the Little Tarheel it replaced!

Like many hams, I was anxious to get this beast mounted. I read through all Larry's instructions, and in typical ham fashion ignored some of the direction. I had to fabricate a penta mag mount (thats right 5 magnets) to hold this beast steady. Fortunately the Audi 100 has a large trunk deck. Not having all the recommended materials at hand and really wanting to try this thing out I screwed on a 4ft collapsible whip, ran some RG58 that I had from another mobile mount, Used some monster cable from an audio amp install kit as my ground. Sorry Larry, I know this is not your recommend install and I will eventually replace the RG58 with 213 and maybe run heavier ground strap too.

Now for the real test I tuned the antenna onto 40 meters - and with little jiggling of the motor switch found the sweet spot and 1.1 SWR, Same on 20, 17, 15, 10. Mmmmm, let's try 75 - flat match again, raise it up some more and bingo 1.1 SWR on 1.825. First day with it mounted I worked Italy on 20 meters with one call in a pile up running the IC-706 barefoot. Saw my first ever 40 over signal on 20 meters in the mobile. Went out one evening to check out 160 and heard an F5 on CW sure wish I had my key in the mobile! The only band I have had difficulty getting a match on is 6 meters, but I am sure that has more to do with my setup than the antenna. I am sure I will eventually get that one figured as well.

Now the Shorty II is a rather large antenna and flanked by SG7500 and a SG7900 I do get some strange looks and some questions of course any HF mobiler is used to that.

I am so satisfied with this antenna that I am seriously looking at getting either the standard 6-160 or the KW 6-160 to use as a base antenna.

I do wonder just how much better it might be if I follow Larry's instructions. My whip is shorter than recommended, the coax and ground strap not to spec but it sure is working!

The only slight negative is the noise from the motor and learning just how to jiggle the switch for the best match. Now if I could find an auto resonator that can handle the motor current life be would almost perfect, but then again I can live without it.

If you want to see photos of the penta mount just email me.


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