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Reviews For: JK Antennas JK 401

Category: Antennas: HF: Yagi, Quad, Rotary dipole, LPDA

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Review Summary For : JK Antennas JK 401
Reviews: 7MSRP: 795
Description:
40M Hi-Q coil loaded rotatable dipole. The JK401 is a simple Hi-Q coil loaded rotatable dipole, with a small footprint as well giving great performance on 40M. This antenna is made for the Ham operator that ís looking for a compact dipole antenna to work on 40M. It is made with very high quality materials and the best in its class in the market in terms of mechanical construction and electrical performance. This Dipole has a good 250KHz bandwidth and great as an accompanying antenna on top of the mast with any Tri-bander or other Multi-band Yagi. Try our JK-Navassa5 and the JK401 to enjoy 6M through 40M on the same mast !!
Product is in production
More Info: http://jkantennas.com/jk401.html
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0074.9
K3NQ Rating: 2020-05-20
Fabulous! Better than expected performance. Time Owned: 0 to 3 months.
I purchased this antenna along with a Navassa 5 to replace my trusty, 25 year old Force 12 C-4. The 40m element of the C-4 had always been a disappointment. Perhaps I was expecting too much from a linear-loaded, one-half size rotatable dipole, but comparative signal reports were poor on FT8, and the element only had an effective 2:1 bandwidth of less than 100 KHz.
As with my Navassa 5, I was bowled over by the quality of the JK-401 parts, and Ken's hands-on support. Construction was quick and straightforward. Once lofted, the antenna's resonant frequency was about 50 KHz lower than my target 7100 KHz. I blamed this on a lower than optimal installed height, and numerous interactions with surrounding metallic objects. A quick shortening of the element tips (easy because they're held in place with a SS hose clamps), moved the center frequency to 7100... with a 2:1 bandwidth that covers all but the top 30 KHz of the band. Two thumbs up!
My only sorta-criticism revolves around the initial difficulty I had leveling the element on my mast. I spoke with Ken who surmised that my mast was not exactly 2'. Indeed, with my micrometer it measured between 1.92' and 2.09' in distinctly out-of-true diameter. i was ultimately able to level the element, but for those of us struggling with an uneven galvanizing job on our masts, I would have preferred stacked u-bolt mounts, rather than a single point mount.
In summary, this is a great performing and reasonably
priced antenna that should last forever. Ken provides unprecedented after-market support, and I'd buy my JK antennas all over again!
N6WIN Rating: 2018-10-18
Excellent for multi-mode Time Owned: more than 12 months.
I wanted a second antenna on 40m to backup my 2 element JK 40m and installed it offset by 90 degrees. The intent was to be able to work to the Pacific Northwest both on CW and SSB.

The antenna was easy to build with a great mechanical design. Electrically it worked as I expected keeping my Acom 2000A and Alpha 78 happy even high into the SSB portion of the band.

I was able to easily switch in the PNW while running the rest of the country during our CQP and also during weekly CWT's.

I am very happy with this antenna's mechanical and electrical qualities.

Ken's customer service is very good, especially considering how busy he has become.
WO4O Rating: 2018-05-28
I'm rating this at 4.5 Time Owned: 0 to 3 months.
My JK401 was installed in April 2018 and is mounted at 107Ft, on top of a rotatable mast (with a Force 12 C3E Tri-bander below it at 100Ft).

With a Kenwood TS-590SG barefoot (and without engaging the internal Antenna Tuning Unit) the JK401 does cover a "good 250KHz bandwidth" (as advertised).

However, my JK401 has a good, but more narrow 100KHz bandwidth when using my SPE Expert 1.3K-FA amplifier (without an ATU) - because my amp becomes unhappy above an SWR of 1.7:1. (This is the only reason for less than a 5 rating in this review.)

For CW, my main mode of operation, the JK401 is set for 7.000-7.100 to keep the amp happy.

Today is Memorial Day 2018. I waited until after operating the CQ WW WPX CW contest (May 26/27) to write this review. I wanted to test the JK401 on 40m CW. It's near the bottom of the sunspot cycle. The JK401 helped me put nearly 900 40m CW QSOs in the log within 12 hours this past weekend. Most of the those QSOs are with DX stations. DXCC in a weekend? No problem.

Bottom line: The JK401 works.

For my rare occasions on 40m SSB, I operate barefoot.

(And, occasionally I wear socks in FL.)

73 de ric wo4o
Grand Island, FL
KB0SS Rating: 2017-05-04
A 40M Rotatable Dipole Beast !! Time Owned: 3 to 6 months.
After spending months reading specs, comparing antennas, reading reviews and comparing again and talking to the manufacturers, I finally bought a JK 401 40M Rotatable Dipole to work with my Navassa-5 with the 6m add-on antenna. I have not been disappointed!

The JK401 40M Rotatable Dipole Antenna is a best of class antenna and is a 5+ in my book.

If you have a question, you call or leave a message and your phone rings 5-10 minutes later. That's great customer service. I've never experienced customer service this good.

The antenna comes in 1 box. The assembly instructions are well written and it goes together easily. It is very well constructed and solidly built. There is ALOT of aluminum in this antenna. With stainless steel bolts/nuts for element joints and mounting, this antenna is going to out last many other antennas. The element section joints are pre-drilled so it is impossible to get the element dimensions wrong. During assembly I mounted the antenna on a 5 ft pipe. I verified all measurements, element positioning, and made sure the SWR on was reaonable this close to ground – and to verify I made no mistakes in assembly. After that we lifted the antenna off the pipe and walked it over to the tilted over tower. We got it mounted to the mast – then raised the tower – and remeasured the SWR – right on specs!

My JK 401 is mounted just 18 inches above my Navassa-5 on a Heights Tower Systems 100mph 60 ft aluminum tilt over tower – 200 ft from the shack. We did have a nasty high wind front move thru – 65 mph gusts. The JK401 took the wind burst just fine. This antenna is the most well built antenna I have seen.

The antenna works really well! I work SSB mainly. The JK401 can also take the power. With legal limit just rotate, transmit and be heard on usually the first or second call. Really nice combination with the Navassa-5. I have not had any problems making contacts on 40M.

The performance measured so far is right on the specs from the factory.

You won't be disappointed with this antenna!
LU5OM Rating: 2017-02-26
Outstanding Quality! Time Owned: 0 to 3 months.
This is a top quality rotary dipole.
Ken Garg, of JK Antennas, went out of his way to reply to my many emails and phone calls, before I decided on the purchase.
The antenna was extremely well packed, when it arrived here, both large parts and hardware (all stainless steel) were properly identified and, as others have said before, the extra nuts and bolts are really handy. One always looses something during assembly.
I assembled it by myself. Once installed, the antenna was a bit higher in frequency for my operating style. All it took was a quick email to Ken. In fact, the only adjustment required is that of the tip sections.
The aluminium material and the precising cutting/ milling of the different parts and tubing, warrants the "Outstanding quality" summary, I wrote above.
The antenna also shines in its elegance at 70 ft (you may have a look at the JK Antennas Gallery section to see it).
As far as performance is concerned, those of us who live far away from the heavily populated areas, do appreciate the upgrade from the regular inverted-Vee. This antenna works very very well indeed.
Would I buy another product from JK Antennas? The answer is: a very firm YES!
Please allow me to take the opportunity to thank my friends Jim, W9VNE, Clive, GM3POI, Dick, K4JJW and Vic, W9RGB, whose guidance and suggestions in this matter, were most valuable and helped me make the right deision.
Thank you Ken. You should be proud of your products.
73 Manuel
LU5OM & CT4IK
K0AL Rating: 2016-05-28
GREAT PRODUCT Time Owned: 3 to 6 months.
The construction of this antenna is outstanding. Very well machined and far superior to most other USA produced amateur antennas. I appreciated the extra hardware which was included with the antenna. I was a bit skeptical of the performance until I put it on the air - I was amazed at its performance. True, it sits at 95 above ground and I was comparing it to tree supported dipole antennas but I am very pleased I decided to purchase this antenna. I have wondered, if this dipole is so good, what the JK 403 would do??
AE8M Rating: 2015-05-19
high quality product, excellent customer support Time Owned: 0 to 3 months.
This review is based only on the building experience since the antenna was erected within the last 2 weeks. The high rating is based on the robust design, quality of materials, customer support and the ease of assembly. I have a small neighborhood lot (70 feet wide) and a lightweight tower. I wanted a reduced size 40M rotating dipole that would not overlap the neighbor’s yard. I also had a preference for a clean appearance that did not include linear loading or capacitive rods, or a support rope to reduce sag. I looked at products from 5 vendors and selected the JK401. The JK401 is a conventional shortened dipole using inductive loading, 47 feet long and very robust.
I wanted to mount the antenna on a 3 inch wide square tube at the top of my tower. Since this is rather unconventional, I contacted the factory via e-mail to make sure my custom mounting was acceptable. Ken at the factory responded almost instantaneously.
The hardware was top notch, as was all the material. The hardware for each joint was packaged in a separate bag and clearly labelled. The labelling was so good that that the antenna could almost be assembled without the instruction book, using just the hardware bag labelling. More than ample spare hardware was provided. JK provided a tube of conductive grease to prevent seizing of the stainless steel hardware and for use in the overlapping joints. Up in the air, the antenna has a modest amount of sag, much less than my previous rotating 40M dipole that used a truss supporting system. A balun is required, but not supplied; so one was purchased from DX Engineering. The JK401 was also purchased from DX Engineering. Electrically, the SWR minimum frequency and bandwidth closely match the factory curve. No tuning or tweaking was required. I am confident that the JK401 will be maintenance free for many years.