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Reviews Categories | Antennas: HF: Yagi, Quad, Rotary dipole, LPDA | JK Antennas - Navassa 5 Help


Reviews Summary for JK Antennas - Navassa 5
JK Antennas - Navassa 5 Reviews: 15 Average rating: 5.0/5 MSRP: $1,185.00
Description: HF Yagi for 10, 12, 15,17 & 20 Meter Amateur Radio Bands
Product is in production.
More info: http://jkantennas.com
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NA1DX Rating: 5/5 Oct 26, 2015 17:17 Send this review to a friend
5 Starts for DXing and Contesting  Time owned: 3 to 6 months
Over the last year I looked at a number of options from log periodic to other multiband yagis. I had one major restriction, and that was wind load of my rotor on top of an AB-577 tower.

I narrowed my options down and decided that when I went to the Dayton 2015 Hamvention, I would investigate further.

During my visit at Dayton, I sat in on some very interesting sessions. One session included antenna analysis using a signal generator and some free software. I was also able to look at the construction of a number of the antennas of interest. Those who did not attend, I emailed and spoke with about their products.

The Navassa-5

One of the antennas that were being recommended to me were manufactured by JK Antennas & Systems and distributed by DX Enginnering. This antenna is based on a collaborative design by E73M Daniel Horvat and Ken Garg. At Dayton, I spoke with Ken Garg of JK Atnennas. Ken showed me the construction of the Navassa 5 with a 6 meter kit.

I was very impressed by the components of the design and construction. The element to boom mountings have uniquely machined saddle clamps. The element components taper with good overlap. Everything is pre-drilled with stainless hardware. The boom and sleeves are also the same Aluminum 6061-T6 material as the tapered elements.

The next thing I considered was the gain verses wind load to my Mosley TA-33. I compared the two using manufacturer’s data sheets, summarized below. The gain of the Navassa was potentially better, plus was designed with 3 additional bands, 6m, 12m, and 17m. One of the nice things about the design that I liked was there were no coils that could fail over time. I could add additional band kits to the Mosley, but the Navassa 5 was designed originally as a 5 and 6 band antenna.

There were no data sheets on the Mosley TA-33 with the WARC kit added. The Navassa 5 has two elements per band, whereas the Mosley TA-33 tribander arranges the 3 elements in a way that gives up optimal gain on one band for gain on the bands. The weight was favorable and the wind load was within specifications.

Test Scenario

I designed a scenario that included my Elecraft KX3 and Buddipole dipole transmitting 0.8km away across the family farm towards my QTH. As I noted earlier, I learned about some antenna field testing at one of the Dayton sessions. One of the product used was S Meter Lite, a no-cost program that displays your receiver's S Meter signal strength in a window. It also collects data samples that can be presented as an antenna pattern plot. So my test scenario included trying to use S Meter Lite connected to my Elecraft K3 to collect field strength data on receive, for each band and antenna.

I would test the Mosley TA-33, then immediately lower the my tower and raise it with the Navassa-5 and test. This would potentially reduce variation due to weather conditions from one day to another.

Navassa 5 Construction

With my test scenario mapped out, my next step was to obtain and build the antenna. Ulis/K3LU came over and helped me get construction started. Ulis/K3LU recommended I put a tarp under the antenna while constructing in case I dropped a nut or washer. It is much easier to find such small things in the grass. The construction process went really well. I followed the instructions carefully. The hardware kit was complete with spare hardware for each step of the process.

I also used a picnic table to rest the boom on, with saw horses to steady the initial elements and prevent the antenna from tilting.

Testing

Barry/K3NDM and Rob/N3HU came over to help with the initial testing. Barry/K3NDM helped me calibrate S Meter Lite with the K3. He then went across the farm with to key down during the testing. Following best practices, Barry/K3NDM self-identified after each key down transmission. Funny thing was he was mostly transmitting at 0.1w but stations heard him and tried to work him after he identified.

Rob/N3HU communicated from the home QTH, relaying to Barry/K3NDM when to transmit and stop as I ran S-Meter Lite and rotated the beam 360 degree, storing the data, and resetting the beam.

After a few operator hick-ups, we got the process down. Just in time for a few more friends to come over to help me lower my tower, switch antennas, and raise the tower with the Navassa 5 for testing. Ulis/K3LU, Bill/AB3TM, and Peter/K2LRC watch the guys as I lowered the military surplus tower. The crew then helped take the antenna off and lift the new antenna on the mast. It was a regular tower raising part. I think they came for the refreshments more than curiosity about the new antenna.

Barry/K3NDM, Rob/N3HU, and I ran through the test scenario again for the 6 bands of the Navassa 5 with the 6m kit.

Test Results

One of the very interesting findings from all the plots was that the 12’x24’ metal shed below the south end of my antenna could be seen consistently in the antenna plots. The shed definitely perturbed the signals for both antennas. I am not sure how big an impact during operating it is, but it showed how such interaction of metal objects and disturbs signals in the real world.

Even with the low tech scenario and tools, the plots showed patterns and gain significantly consistent with the manufacturer’s antenna modeling plots.

With the field test complete and matching the predicted models, I was excited to see how it would do chasing DX on the WARC bands, as well as, contesting and chasing DX on the other bands. I was also excited to have a simple 6m band option.

The antenna has been proving very good during DXing. During the CW North American QSO Party (NAQP), my tower crew and I operated Multi-2 as NA3DX PVRC Explorers. Bill/AB3TM and I had now problems running with the antenna. Figuring that a majority of the stations during NAQP operate barefoot at 100w, we proved a simple well designed 2 element per band antenna can hold its own and perform at the ability of the operators.

Conclusion

If you desire to upgrade to a new tribander, you should seriously consider the Navassa 5. It is a no comprise strong, light, broad banded antenna that can increase your own fun meter DXing and contesting.

Contest Results

During NAQP we used the antenna against my old antenna on a spare AB-577. The Navassa-5 was a cut above the Mosley AB-577. Both antennas were at the same height. We did very well placing top 10 for NAQP Multi-2 SSB.

During CQ WW this past weekend, the antenna did a great job. I worked the CQ WW SSB all bands 100w for about 10-12 hrs of real operating this past weekend. Mostly with the Navassa 5 on 20-10. I made over 500 contacts with over 60 countries on each of the upper bands.

This is the first DX contest since installation with the tower up 48-50'.

I have been very pleased when chasing DX. I rarely have any problems making contacts on 20, 17, 15, 12, and 10m. If I do, I can go QRO, work'em, and go on to what ever else I need to do.

One of the things that occurred was the ability to work stations off the back of the beam during the contest, mostly stations around 3-4k miles or less. This an experience I had with the other tribander. The difference front to back was around 2-3 S units. I did not work the JAs off the back, but worked them well when I swung the beam around.

The beam width was broad, with about 1-2S units on the edges depending on the distance, and maybe 3-4 S units 90 degrees to the ideal heading. Often I could start working a station 90 degrees to the beam heading and complete the exchange by the time the beam had swung on.

The two elements per band seem to work better than the 3 element trapped beam, often busting pileups with my 100w contest plan.

I would love to compare the beam to the same beam up 100' ft. Stack and phase them!
 
N8RR Rating: 5/5 Jul 31, 2015 06:17 Send this review to a friend
Excellent Performer  Time owned: 0 to 3 months

Some of my friends in the local DX association are space and tower limited. Hal W8HC is one of those who currently lives in a space restricted QTH. This compact 5 band antenna uses 2 monoband elements on each band and only uses a 12' boom. Hal purchased the antenna at Dayton and asked me to assemble and install it at my QTH for a performance review so that he would know what to expect at his location.

The Navassa 5 was installed here for direct comparison in A versus B tests with my other antennas to see how well it might work for W8HC and some of my other my DX chasing friends. The comparison antennas were a Force 12 C31XR on 20/15/10, a M2 20M5 on 20M and a HyGain 5 el yagi (125CA) for 12M.

In the A vs B tests during decent conditions the winner is determined by which antenna has the instantaneous prop advantage when the switch is made. The moment to moment QSB variability is greater than the gain differential between the antennas. In marginal condx, with the signal buried in the noise, the larger antennas will sometimes generate slightly better copy.

During my testing there was only one DX station that could be copied on the bigger antennas that could not be copied on the Navassa 5 (VK2SSI on 12M on a nearly dead band). Every other station on any band that was copied on the bigger antennas could be copied on the Navassa 5.

Every station that was called on the Navassa 5 was worked, most on one call. Weak signals, pileups, it did not matter.

During a brief visit to 20 SSB (I am a CW guy), unsolicited reports were received in pileups from EU as best signal from NA (1.5 KW w/AL-1500 and Navassa 5) from multiple stations. The performance was impressive for a 12' boom antenna.

The Navassa 5 exhibited about 3 S units of front to back ratio on each band, very good directivity.

My QTH is on a small hilltop. The Navassa 5 is mounted 30' above ground level at the tower base. The C31XR is at 35' and the 20M5 is at 56'. The HyGain 12M yagi is at 40'. Due to steep sloping terrain under the antenna, it is not necessary to have high towers here to develop good DX response.

If the Navassa 5 were my only antenna for 20 through 10 meters, my confidence level is high that I would be competitive in every pileup based on the current results. Without hesitation I can say to my friends the Navassa 5 will make you a serious player in the pileups. As with all antennas the location will impact the results but the Navassa 5 provides high efficiency, good gain and good directivity to help with DXing success.

The antenna is well made to withstand 100 MPH winds. The mechanical construction is first class, as is the case with all JK products.

The tested Navassa was equipped with two elements for 6 meters, technically making it a Navassa 6. No testing was done on 6 meters.

The JK Antennas customer service is second to none, in my experience.

There will soon be at least two, and maybe more, Navassa 5 antennas in service locally, including this one at W8HC. I am confident my friends will be happy with the performance.

73 Charlie N8RR
 
W8MLS Rating: 5/5 Jul 10, 2015 10:16 Send this review to a friend
Fantasitc Antenna  Time owned: 6 to 12 months
I have my antenna on a Universal Tower at 45'. I use a AlphaSpid rotor to rotate the antenna. The antenna is performing very well. I usually see at least 2-3 S units in the FB/FS measurements. I have worked mostly 20m since I got the antenna up (1 month ago) and have not been disappointed. The build of the antenna is very stout. There is a lot of aluminum in this antenna. JK uses stainless bolts/nuts for the elements which makes building the elements a snap. If you want a high quality antenna at a great price point you can't go wrong with JK.

Mike, W8MLS
 
K4JAF Rating: 5/5 Apr 6, 2015 09:56 Send this review to a friend
Great Antenna  Time owned: 0 to 3 months
This antenna was a replacement for another 5 band antenna which had performed great for a number of years but mechanically needed major work. I am very pleased with the construction and performance on the HF bands. I have it about 40 feet up on the old tower and highly recommend for a smaller 6 band HF antenna. All parts are quality materials and assembly is quite easy. SWR curves are almost identical with the listed specs on JK's website. I do believe listed front to back ratios are quite conservative as I see much higher values. I did install the add-on 2 elements for 6 meters and does an amazing job for such a small antenna on 6. Worked several South American stations on 6 in the last few weeks.

You cant go wrong choosing the Nevassa 5 from JK Antennas. Jim K4JAF
 
W2VK Rating: 5/5 Feb 27, 2015 17:03 Send this review to a friend
Very good HF 5 band Yagi  Time owned: 3 to 6 months
I have used multiband antennas for years. I started with a vertical, switched to a hexagonal beam and finally to Yagis. I use a 40 foot crank-up tilt-over tower.

The Navassa 5 is a small Yagi with very good performance. For example, I was trying to contact a southern Pacific island based on a 10 minute old spot. I heard a very faint voice and swung the beam a bit to see if the signal would get stronger. After swinging the beam about 180 degrees it turned out to be a mobile station in the United Arab Emarites coming in at S9+. I worked him first call. I also do not have a problem working pileups.

I have had this antenna for 4 or 5 months now. I work eastern Asian stations that I never heard before. That could either be because the stations were not on the air before or that this antenna makes that much of a difference.

I have not had any problems caused by weather or anything else. This is a typical JK Antennas model. It is high quality from the parts to the manufacturing.
 
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