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Reviews Categories | Antennas: HF: Yagi, Quad, Rotary dipole, LPDA | JK Antennas JK404 Grande Help


Reviews Summary for JK Antennas JK404 Grande
JK Antennas JK404 Grande Reviews: 2 Average rating: 5.0/5 MSRP: $5450
Description: The JK404 Grande is a contester and DX'ers dream antenna for 40m. This is full size elements for the 40m band.
This antenna has excellent F/R and gain across the 40m band while maintaining a good SWR. Even though the elements are full size, the antenna is wind rated for 90 MPH. The antenna is made with our high quality, heavy duty materials and hardware.
Product is in production.
More info: http://jkantennas.com/jk404-grande.html
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N8RR Rating: 5/5 Jan 7, 2014 08:50 Send this review to a friend
High Performance Antenna  Time owned: 3 to 6 months
In 2013, a JK Antennas Model 404 Grande was installed at WT8V near Charleston, WV. I was involved in every aspect of the installation from site evaluation to antenna assembly and commissioning. My role can best be described as Project Engineer in terms of the commercial world.

The JK Model 404 Grande is a full size 4 element 40 meter yagi on a 45' boom. The standard configuration is rated for maximum wind speed of 90 MPH and 18.3 sq ft windload. The elements do not require trusses unless heavy ice or snow loading is expected. The WT8V antenna was purchased in the standard configuration.

This is one heavy antenna, weighing in at a bit over 325 pounds. The 3" OD boom is reinforced with a .25 inch x 6' sleeve in the center of the boom and the boom sections are reinforced at the connections with .25" x 2' sleeves. Two steel cable trusses are used on the boom section.

The designer W3JK makes heavy use of reinforced elements. The center tubing sections are 2" OD on each element. On the reflector, driven element and first director elements there are 10 telescoping tubing segments after the 2" center section and on the front director there are 9 segments. Double wall element thickness is provided either from the factory on the larger tubing segments or through substantial overlap in the telescoping segments.

The elements are attached to the boom via a heavy aluminum channel. The elements are attached to the channel through precision machined saddle clamps, three on each element half. The split driven element, reflector and directors are insulated from the boom with machined insulator clamps.

The driven element is direct fed via 50 ohm coax through a 1 to 1 balun. WT8V purchased a W3JK balun, which was very well built and heavy duty. The SWR bandwidth at commissioning was 300 khz with less than 1.3 SWR.

The JK 404 Grande 40M yagi is by far the best built antenna I have ever assembled. Not only is it heavy duty, the fit and finish of the components are exceptional. All the pieces were there, and it all fit together precisely. The instructions were clear.

How does the antenna perform? I run a good performing shorty forty at an optimum height for my terrain on a WV hilltop. With my antenna, 303 countries have been worked on 40M since July 2009 and with great pileup success. I expected the 404 Grande to outperform my antenna, but was not prepared for the real world difference.

WT8V has a dominating signal out of North America on 40M with the JK 404 Grande, as those who have heard his signal from the DX end know. The most impressive factor to me is how well the antenna receives. Most experienced DXers know that receiving well is the key to success. We all dream of being able to out hear our competitors. Nothing is more discouraging to a DXer than to hear others in the same geographic area working stations who are inaudible in his receiver.
On numerous occasions I have listened to WT8V working Asia long path in the afternoon. A realistic estimate of the number of these stations that I can copy on my shorty forty would be perhaps 50%. My band noise is much higher than WT8V's and many of the stations I can hear are difficult copy.

I attribute WT8V's lower overall band noise to the great front to side and front to rear/back achieved by the 404 Grande. The higher basic gain of his antenna over mine (theoretically 2.2 db) also contributes to a better signal to noise ratio on the bigger antenna. We both run the same receiver (FT5K).

Seldom am I surprised on the radio, but the first time listening to Asia long path on the 404 Grande at WT8V, I couldn't believe the signals. It sounded like a 20M short path opening to Asia on a good day. This is no exaggeration. In fact, I feel at a loss to adequately describe how well WT8V can hear Asia on 40M long path. One would have to hear it to believe it.

Installing one of these big antennas would require an infrastructure change at N8RR. Not sure at this stage of the game if this is in the cards but who knows? If I stay away from WT8V's station, the temptation might be resisted.

The JK 404 Grande is highly recommended as a superior quailty, high performance product. The customer service provided by Ken W3JK was exceptional. We did not have any issues with the assembly, but Ken still called several times during the process just to check on progress. When was the last time you had the owner of an antenna company call your cell phone while you were on the tower checking to see how things were going?

Charlie N8RR
 
WT8V Rating: 5/5 Oct 20, 2013 18:38 Send this review to a friend
Ferrari of Antennas  Time owned: 0 to 3 months
It all starts with the first phone call to an antenna manufacturer, having purchased three (3) large Yagi antennas in the last 3-years has given me some experience with each manufacturers “customer service”. On advice from my two good friends, 9K2GS and A41MO I decided to call JK Antennas and discuss a 40-Meter full size antenna. The phone conversation lasted over an hour (on a Saturday) and each question I had was answered in detail. At the end of the call I placed the order for the antenna. For the record, I had already spoken with two other large manufacturers of full size 40-Meter antennas prior to this call.
The antenna arrived and the quality of a manufacturer always shows up in the way an item is packed and shipped. This is by far the best packed antenna I have ever received, being a tower climber in this area has afforded me many antenna assemblies and installations and we have never seen any antenna this well packed. Upon unpacking the antenna the “heavy-duty” and quality of the boom, elements and associated hardware left all of us impressed. When I say all of us, I was extremely fortunate that my best friends in Amateur Radio showed up to help assemble and install and they can vouch for this review, they are N8RR who spent hours researching using HFTA Software to determine the best location on the mountain and the correct installation height, K8KT, WB8CQV, W8IW, K8RRT, WD8CCC, WV8RC and WV8FV.
The instructions were straight forward and all the hardware was labeled so no confusion on what went where. The best part was the owner of JK Antennas was available over the phone and any question we had was answered in seconds, you can’t beat being able to speak with the engineer/designer/manufacturer of the antenna you are building. The machining of all the boom and elements was the best we had ever seen, extremely precise, no slop in any of the joints or fittings, no de-burring of the aluminum was needed, everything was smooth as glass.
During the lunch break the conversation focused around the antenna and the gentlemen listed above combined have assembled and installed well over 100 antennas from every manufacturer in the last 50+ years. The conclusion from the conversation at lunch was almost all antenna manufacturers scrimp on the quality of one part or another and JK Antennas scrimped on nothing, everything was super heavy-duty, high-grade quality components and no corners were cut in producing the best antenna we had ever had the privilege of assembling.
Now the real test, how does it play on the air. The analogy I would like to use is why buy a car that will go 200 mph if you never drive it over 55 mph. We have had the antenna on the air now for one-week and it has far exceeded our expectations. The SWR is 1.2 at the bottom of the band and 1.3 at the top of the band and flat across the majority of the middle. Its mid-October, the band was not in the best of conditions this past week but we managed to start a pile-up with Japan long-path each day on 40-Meters starting at 5:00 PM EST and holding it until 6:30 PM EST, even working mobile stations in Japan. To me, that’s driving the car 200 mph. The front to back rejection and the side to side has really impressed me and others who have operated this station. I have another 40-Meter antenna 600-feet away we used as a comparison to the JK Antenna and the JK 404 Grande has twice the performance characteristics of it.
In closing I will say it’s the best $5k I have ever spent in Amateur Radio. I would like to thank Ken for all his time and patience in helping to bring this station into the forefront on 40-Meters.
 


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