| K5DAM |
Rating:      |
2009-04-21 | |
| Senior - best antenna yet!! |
Time Owned: more than 12 months. |
It hears well, talks well and tunes everywhere that the Army MARS matrix requires. I really have no idea where it is resonant in that it seems to be happy everywhere except perhaps the 5-6mhz band. I really need a broad, 500W capable, 60 meter band antenna.!! That seems to be where the NVIS propagation is anymore. I don't think I have seen Critical Freq make it up to 40 meters in a couple of years now. or so it seems.
My Senior is hung SW-NE at 50' on one end, sloping down to about 35' at centerpoint, then out 50 feet to a support at 35' then I take the last 20' back at right angles across the yard dropping to 25'. It works very well at low 4mhz across the entire state of Texas and well into LA, AR and OK. When dropping into the ham bands at 90 to 120 meters, it works very well into the western states out to CA and up to WA.
The ladder line is laid across the polyester guy lines some 6' above the roof of the house. Strong antenna construction, it withstood Hurr.IKE last fall and we were clocking 110mph here at the QTH using my Vantage Pro2. Lost a lot of branches in trees but the antenna did quite well.
This antenna is the best I have had for all bands (I use a MT-3000A tuner) and I rate it above my previous favorite - the DX-CC. However, again, this antenna does not like 5 or 6mhz as much as it likes 75 to 120m. I do not use 20 or 40m although I have done some early afternoon testing out to Lubbock (~500miles) on those frequencies and it tuned well and sometimes we had a path.
I may get a Junior for a portable antenna to supplement the maypole and the screwdriver.
Finally, depending on the QRM, I can hear stations which many nearby operators cannot, and almost everyone I can talk to, I can hear. Depending on propagation and noise of course.
Highly Recommended antenna to all. |
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| KI4MCW |
Rating:      |
2009-03-30 | |
| Great product, with some quirks |
Time Owned: more than 12 months. |
I've had the Junior model in my backyard for a couple of years. Tx and Rx performance has been very good 80m through 10m, with tons of European, Central American, and Caribbean contacts, despite only being 25 feet up in fairly dense woods. Using the same feedline and rigging on the same trees, I have tried a couple of different flattop dipoles, but none have matched the receive performance of the Cobra. As many have said, the simple design and quality materials make for an excellent multi-band antenna.
Having said that, it is important to note that the Cobra does have its quirks, mostly pertaining to the feedline. That window line is a critical, radiating part of the system, and must be treated accordingly. It should not lie on the ground, be twisted into a ball, or be wrapped around or taped to a pipe. It should not be cut short, nor should it be heavily modified. If possible, it often helps to elevate the feedline - even just the last 20 feet or so - so that it can freely radiate and receive just like the dipole section. And yes, as others have mentioned, you will probably need a wide-range tuner, and on some bands you will lose a lot of power and/or signal inside the tuner.
If you can only get the Cobra up 10 feet, don't have a tuner, or you do not have any way to deploy 100 feed of feedline (that is a lot of wire), the Cobra series probably won't work well for you. If you are able to work within these constraints, though, and are looking for a single antenna that you can throw up in a tree and be done with, you will most likely find that this antenna works very very well.
A couple of other thoughts, mostly standard canon. (1) Higher generally works better, especially if you're trying to tune 80 and 160. (2) Longer generally works better, so if you have the room for the Senior, you'll find it easier to tune 80m CW (and 160m, of course). (3) If you want to model this antenna (in EZNEC, etc.), you must include the feedline. (4) Given the quirks mentioned above, this design is fairly forgiving as to what =kind= of feedline you use. The window line that came in the bag would not pass muster with the XYL here, but a high quality foam-core twin lead from Lowe's was acceptable (i.e., less visible), and has worked well. (5) Experimenting? Try extending either the feedline (to 150'? 200'?) or dipole sections (100' per side works =really= well - see previous comments re: Radio Shack as a source).
73, Rob KI4MCW |
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| KB1QBZ |
Rating:      |
2009-02-27 | |
| Needs A Good External Tuner on 80/75 and 10 |
Time Owned: 0 to 3 months. |
This is an update to a review I wrote about two weeks ago.
I have space limitations problems, so had to go with the Jr (73 ft).
Antenna is 30' above ground on one end, 40' above ground on the other (best I could do with the trees I have). The antenna runs east/west. The west end of the antenna is right near the roof of the house. Given the height, it's mostly omnidirectional on 80/75/40, more bi-directional on 20, and even more so on 15 and 10.
I haven't done a good job with the ladder line (I have it running too near the ground and the excess ladder line is in coils that are a bit tight -- which is definitely against the manufacturer's recommendations). But ...
It's working nicely on 40 and 20 with just the LDG AT-897 Autotuner attached to my FT-897. 15 is so dead that's it hard to tell, but my testing indicates that I'm getting a good signal out.
Originally, I was not getting a good signal on either 80/75 or 10, BUT ...
... when I switched to using a good external tuner (MFJ 941 Versa Tuner II), it was an amazing difference. I'm pretty much working anybody who's sufficiently above the noise level for me to be able to understand them on 80/75 and can work all the local hams around me on 10 (plust some nice DX when 10 opens up).
Both 80 and 10 are sensitive in that you have to retune every 100Khz or so, but that's what I was told to expect.
I've also tried the antenna with the Elecraft KAT100 autotuner for the K2 and gotten very good results (equal to the MFJ).
In two weeks, I've worked most of 3- and 4-land on 80. Much of 4-, 5-, 8-, and 9-land on 40. AZ and NV on 20, along with Finland, Aruba, Scotland, and Japan (also on 20). All at either 100 watts CW (K2), 100 watts SSB (FT-897), or 5 watts CW (K1).
Not bad.
Would probably be even better if I could mount the antenna to run north/south instead of east/west.
This is my first time working with ladder line and it's a pain to deal with relative to coax. I had to put up some plastic poles to hold up the ladder line on its way from the antenna to the house. It is worth it for an antenna like this.
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| W6UQZ |
Rating:      |
2009-02-25 | |
| Great DX Wire Ant |
Time Owned: more than 12 months. |
This little ant (the Jr.) is quite a fabulous performer for a wire ant, even when hung in an "inverted U" config @50' in a tree behind a 3-story house, with the ladder hanging in loose coils in bottom branches. It's the only wire ant I've ever bought, and I've made many, including directional arrays.
I feed mine with RG213 via a giant toroid 4:1 balun, so no ladder line into the shack. RECOMMENDATION: trim 19' from the ladder line, and add two 36" lengths of ordinary stranded ant wire at the ends. This brings the resonant freq to about 4 mhz, with harmonic resonances at 17M, 15M, 10M and 6. Weakness: the center plastic insulator, which broke at the hanging point in a windstorm.
This ant. plays very well on 80m - 6M. With 100 to 600W, I've easily worked DXCC on several bands, incl. 3Y0 (30M in pile, 100W), 5T5 (17M 100W), VQ9 (17M), 3B7, VP6, E51, XW1, V85, mni others. It even loads on 160, and is a good listening ant there for high angle. Have worked East Coast many times on 6 (from Monterey) with this wonderful ant. as well.
Again, the weaknesses are minor mechanical problems with the center insulator, and improvements that are easily done to the design to fit your particular installation. Enjoy! W6UQZ |
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| NZ4Z |
Rating:     |
2009-02-11 | |
| Good, but needs improvement |
Time Owned: 6 to 12 months. |
| Well, I played this antenna for several months (Sr. Version) and had good results with the exception of 160M. That may have been due to my set-up. I was 50ft at the apex, and 20ft with the ends, and just never could get 160M to play. Now, my only 2 complaints....... 1. the center and ends need to be beefed up, the ice storm we just had wiped mine out, just demolished the center connection point. The plastic needs to be MUCH heavier. 2. I called and advised the owner what had happened, and that his connection point failed, he only offered to repair it if my ladder line had only split 5ft or less, mine split 20+ft. I feel if your gonna offer to fix something, you either do, or you don't, and not put limits on what you will fix. After all, it was the flemsy center connector that failed. Would I recommend this antenna.....yes, for 10-80 and warm climate. |
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| KD0FDJ |
Rating:    |
2009-01-21 | |
| works good, but replace end insulators with something tougher |
Time Owned: 0 to 3 months. |
| The antenna performs, but during a windstorm the flat plastic end insulator broke at the rope mounting holes. If you mount the antenna in trees with an eyehook and counterweight, either rig the downrope so that the antenna can be easily re-raised, or reinforce the end insulators so they won't be as prone to breakage under strain. |
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| KI6DYR |
Rating:      |
2008-11-25 | |
| Great Antenna For Fast Deployment |
Time Owned: more than 12 months. |
| I have owned this antenna for several years and the first time that I used it I wasn't overly impressed. But that was because of its low altitude and not the fault of the antenna. Having just moved to a new QTH and with snow coming in tonight I strung it back up and immediately hit a 100 watt station in Russia. This antenna does what it says that it will do -- get one on the air and with good reports. It isn't my SteppIR, but it is a good antenna. |
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| SLJOY |
Rating:      |
2008-10-25 | |
| Excellent Wire Antenna |
Time Owned: 6 to 12 months. |
I built the first one, was given the second one, and purchased the third one. I currently have the two antennas up #1 E+W at 70 feet flattop, and #2 N+S with a 60 foot apex inverted Vee with ends at 10 feet. The antenna works best when high, and the ladder line needs to be totally uncoiled, standard wire antenna installation procedures apply as usual. The inboard radio tuner has been sufficent, although I do use the Palstar AT1500DT.
The antenna performs well for me, at my location, very, very nicely on all bands at least equal to, but mostly outperforming my resonant 1/2 wave fan dipole on most occasions. Nicely constructed also! 73 W1RGO |
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| KC2MBC |
Rating:      |
2008-10-01 | |
| Great Product/Great Service |
Time Owned: more than 12 months. |
| 3 years ago, purchased a Sr model. Crazy Upstate NY T-Storm winds took a piece of antenna and snapped it, then wrapped it in a knot around some branches...still trying to get it down, so ordered another. I didn't even get a chance to send an email about the order status. The charge hit my card yesterday, and I got the antenna this morning. Seems to me, I got simular service with the first antenna as well. K1JEK is a great businessman with huge integrity and reliability. Thanks Joe, you are a great example for businesses! The antenna itself is light, nearly invisible and I personnaly love the performance. I am active on HF Traffic Nets and rely on good reception and output to get the message through. Location is only good if you have a good product, I am blessed in both aspects. I built my own multi band wire contraption that caused the trees to bend...put out/received well, but it was very visible. With the Cobra, the neighbors don't know it's there unless it's pointed out. It is up 60 feet as a flat top and is very durable and reliable. |
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| K1NLY |
Rating:      |
2008-09-25 | |
| Rugged/lightweight |
Time Owned: more than 12 months. |
This one tough antenna that tunes all bands. A tree fell directly on it. I called Joe to order another. He said put the parts in an envelop and send them to me. He saved me an antenna and fixed the old one for peanuts. Great guy, great service, great antenna. Thanks Joe.
73,
Harry K1NLY |
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