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Reviews Categories | Antennas: HF: Vertical, Wire, Loop | N6BT Bravo 84 Vertical Help


Reviews Summary for N6BT Bravo 84 Vertical
N6BT Bravo 84 Vertical Reviews: 1 Average rating: 5.0/5 MSRP: $995
Description: The latest Next Generation antenna from N6BT is the 2-band, 40-
80/75-meter Bravo Vertical. It provides full coverage on 40 meters and
2 segments on 80/75 (approximately 70 kHz each, 2:1 VSWR). The
Bravo 84 is an asymmetrical, vertical dipole. The Bravo design is a new
type of vertical: it is a vertical dipole with asymmetric feed and a
horizontal resonator. The resonator probably looks like two radials, but
it functions differently than “classic” radials. The Bravo 84 comes with
rigid guys, so additional guying is not required, except possibly for
extreme weather conditions.
Product is in production.
More info: http://www.n6bt.com
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NA6O Rating: 5/5 Dec 17, 2015 10:10 Send this review to a friend
Works great for limited spaces  Time owned: 0 to 3 months
The Bravo 84 is a novel off-center fed (asymmetrical) vertical dipole for 80 and 40 m utilizing a 29-foot vertical element and a pair of 18-foot horizontal elements that function as resonators. On 40, it’s basically full-sized while on 80 it is center-loaded. A pair of aluminum tubes serve as rigid “guys” in addition to the main vertical element which is set straight in the ground. Relays in a local enclosure select the band and also switch between two portions of 80 m. A simple switch box for remote control is supplied and requires 12V at 200 mA. The relay box includes a properly-designed common-mode choke.

Assembly: Tubes are logically bundled and the important joint pairs are marked. Holes were cleanly and accurately drilled for 1/8-inch pop rivets, which are supplied. There is plenty of overlap and several rivets at every joint. This is good, reliable construction practice. The main base tube with loading coils and the relay enclosure is pre-assembled. The manual has enough photos and notes that I had no problems with assembly and it only took a few hours.

Installation: The complete vertical assembly slides into a supplied PVC pipe that I set in a small hole filled with concrete, 2 feet deep. The two guys bolt to any rigid support you might make. I used lengths of 1-inch galvanized pipe set in concrete. I had a helper to walk up the vertical but it turns out it’s so light I could have done it myself (most of the weight is at the bottom). Then attach the guys and clamp on the resonator. The whole thing is amazingly rigid and did not budge in 50 MPH gusts. For remote control, I used sprinkler control cable, 3-conductor #18, which is cheap and ok for direct burial. The reason I bought this antenna is that I am in a CC&R neighborhood and at this point I’m hoping nobody rats on me. Painted with flat grey primer, the slim vertical element is not too obvious.

Tuning: Do not attempt to tune this antenna without an analyzer or VNA. The instructions include a very clear and orderly procedure. Much tweaking of the various coils will be required to walk the resonance into the region of each band. It took me about 2 hours all together. All of 40 m is covered with less than 1.5:1 SWR. On 80, you can pick two portions and adjust to suit. I only operate CW and digital, so mine almost overlap. You will want to use a tuner on 80, especially with a solid-state amplifier. The final SWR minimization is tweaked with a small coil, also known as a hairpin. It very slightly affects resonance. A perfect match was obtained at resonance. 80 m 3:1 SWR bandwidth was 75 kHz in each portion. This is typical of a shortened, loaded design.

Operation: For reference, my other antennas are very low dipoles (at 15 feet) and a Wellbrook shielded receiving loop. Based on RBN measurements and S meter observations, the Bravo 84 gives me just about a 3 dB advantage working across the US on 40. On 80, I don’t have good data yet, but for the first time I can work reliably into Asia and Oceania. No Europe yet, but we’ll see; it’s never that easy from CA. SNR on receiving is not as good as the low dipoles or the receiving loop, but that is expected especially in my extremely noisy suburban environment. Overall, I’m glad I bought this antenna and would recommend it to anyone with space limitations. Also talk with Tom before buying to get his recommendations in case he has something new to offer. He is sometimes slow to respond to email and you must be patient. But he really knows his stuff.
 


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