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Categories | Antennas: HF: Verticals; Wire; Loop | Cobra UltraLite Multiband Antenna Help

Show all reviews of the Cobra UltraLite Multiband Antenna

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KJ7MX  Rating: 5/5 May 22, 2019 19:45  Send this review to a friend!
Great Antenna!  Time owned: 0 to 3 months
I've only had the antenna up a week but so far I'm really impressed. I have it up in an inverted vee configuration with the center at 30' and the ends around 15'. I run it through the MFJ 912 4:1 balun located outside the shack underneath the deck. There was about 25' of left over twin lead which I wrapped in a 4' loop underneath the deck. The balun is grounded to an 8' ground rod.

I replaced a GAP Titan that I'd been running for about 7 years, so that is my baseline of comparison. The GAP did well when the bands were better a year or two ago, but the noise level was extremely high - rarely less than S8 or S9. In addition it was sending more and more RFI back into the shack to the point it was screwing up my computer, the cable tv box, and of course my radios. I was no longer able to use my linear or my outboard mfj electronic keyer. I tried a 3kw 1:1 balun on the coax line and it burned it up running 400 watts.

With that said I put the Cobra Ultralite Jr. up in about an hour, came down to the shack, turned on my TS-830 to 40m and crossed my fingers. The first thing I noticed was that I was hearing static crashes from a distant thunder/lightning storm in the midwest. The band just sounded "odd" until i realized my noise level had been so dang high with the GAP vertical that it drowned out the static crashes! I was hearing more stations on 40 than I had ever heard, and for the first time in 7 years I was hearing the band the way it was supposed to be. Next test was to check transmit loading. My MN-2000 tuner was able to dial it down to 1:1 on all bands except 80m below about 3.650, where it will only tune it to 2.5:1. 75M tunes to 1:1. Next was to fire up the AL-80A and check the RFI. Previously 40m with the linear would light up the computer, computer speakers, and lights, and somehow turn my Astron 35amp 12v supply off. I gave it the smoke test with 600 watts and no RFI! I mean NONE! I checked every single band with the linear and found a very slight noise from the computer speakers on 20m. Slight as in if you weren't listening for it, you wouldn't hear it. So the RFI is 99.9% cured.

Next was to check my signal on the SDR stations. I'm in WA State and the Cobra put me 2 s units above the noise in Utah, where my GAP always had me barely readable in the noise. For the first time I was able to hear myself in GA, PA, and DC on 40m.

One last example is that I frequently check into the Noontime Net on 7283.5. There has always been some sort of broadcast carrier that sits on that freq that forced use of a notch filter. With the Cobra, that carrier is gone. Not down in the noise, but gone. The signal strength of the various net control stations are about the same, however the noise level is now between S4-S6 instead of S8-S9+.

So far I'm very impressed with the Cobra in comparison to what I was using. No RFI, noise level has decreased 4-5 S units, and I'm getting as good or better reports than I did with the Titan. The only drawback is that I can't get the SWR down below 2.5 on 80m CW band. I'll be raising the height by 20' at all points, so maybe that will help some. I had to take the Titan down to install the center pole for the Cobra and was going to relocate the Titan to another corner of the yard. Now, it's going to be relocated to the local dump. 
Product is in production.
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