Manager


Manager - NA4M
Manager Notes

Reviews For: N6BT Bravo V8 Vertical Dipole

Category: Antennas: HF: Verticals; Wire; Loop

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : N6BT Bravo V8 Vertical Dipole
Reviews: 1MSRP: 329.00
Description:
This antenna is the product of over 20 years of vertical development and is intended to provide a low profile antenna that can cover 80 through 10 meters utilizing a remote auto tuner. The remote auto tuner is the key to the antenna system (antenna+tuner+coax) efficiency and some tuners are more efficient than others.
Product is in production
More Info: https://nextgenerationantennas.com/v8-bravo-verticle-dipole
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0015
NI0C Rating: 2020-03-17
Small, sturdy, effective antenna Time Owned: 6 to 12 months.
I've used two previous versions of N6BT's Bravo vertical dipoles-- the Bravo 7K and the 7KR, primarily on the 40, 30, and 20 meter bands. I like the "Bravo" design because of its small size and proven effectiveness for DX work, and because it does not require an extensive radial system.

For band switching, the Bravo 7K required changing jumpers in a coil box near the antenna feedpoint, while the Bravo 7KR used relays to remotely switch coils for the 40, 30, and 20 meter bands. The new Bravo V8 relies on an external tuner for changing bands.

Although the V8 manual indicates use of an MFJ remote tuner, I chose the LDG RT-600 remote 600 watt tuner. My V8 is installed with the radial elements 58" above ground level (54"or more is recommended in the manual) and the vertical element is 19' 10" tall, so the antenna is just shy of 25 feet tall. I experimented a lot with the lengths of the two radial elements in order to get the antenna to tune reliably on 40, 30, and 20 meters. Other variables in my experiments were with and without a common mode choke (Balun Designs 1115), and with and without the furnished hairpin matching coil.

I ended up ditching the hairpin coil altogether, but including the common mode choke at the coax input to the tuner. Given this configuration, I found best results using 106" for each of the two radial elements, just 4 inches longer than that recommended in the manual. The antenna exhibits a 1.0 SWR on 20 meters with the tuner bypassed, and tunes quickly and easily on 40m and 30m using the remote auto tuner.

The Bravo V8 is extremely well constructed and sturdy. The base tube is 1.875" to allow insertion in the supplied 2" PVC pipe to be mounted in the ground. N6BT thoughtfully included a pair of U-bolts for attaching a remote tuner. These turned out to be necessary as the U-bolts supplied with the RT-600 tuner were too small to attach to the 1.875" tubing. I found it necessary to ream out holes on the RT-600 mounting brackets to fit the U-bolts.

It took a lot of trial and error over several weeks to obtain a more or less optimum configuration for my installation and chosen tuner. I wish that I could have arrived at a configuration using the hairpin coil, as I feel that the presence of a DC short at the feedpoint would provide some protection for the tuner against static buildup. The common mode choke definitely improved receiver noise pickup and insures that my 300 ft. coax line is not somehow part of the antenna. Baseline noise levels indicated on my Elecraft P3 panadapter are roughly -108 dBm on 40m, and -116 dBm on the 30 and 20m bands.

Power limit for the V8 antenna is limited by the tuner, and so far I've had no troubles running up to 500 watts CW using the LDG tuner rated at 600 watts. (See update below.)
********************************************
Edit December 14, 2019:

Using the LDG RT-600 tuner, I experienced SWR drift during long QSO's on 40m when using high power. I am still not sure whether the source of the SWR drift was heating in the common-mode choke, or in the tuner itself. I tried two high quality chokes and got the same result. I finally replaced the tuner with the MFJ 998RT (rated at 1.5 KW), with the Balun Designs 1115du common-mode choke at the input, and am much happier. No more SWR drift.

The MFJ tuner works faster, and will even achieve a good match on 80 meters. (N6BT advertises the V8 will work on 80 meters if the antenna is located properly, away from buildings and other objects.) I am sure my installation is pushing the limits, but I am now working some DX on 80 meters using this antenna only 24 ft. tall, with only the two 9 ft. radials that are five feet above ground.
********************************************
Edit March 17, 2019

I can no longer use this antenna on 80 meters. I discovered that the ability to achieve a good match on 80 meters was caused by a very lossy PL-259 connector at the output of the tuner. This plug eventually heated up and shorted out. After repairing the connection, I found the best match I can achieve on 80 meters is SWR = 3.5:1.

However, the lack of 80 meter capability in my installation is not a deal breaker for me. I continue to be pleased with the performance of this antenna on 40, 30, 20, 17, and 15 meters, and am regularly breaking DX pileups with it. For me, it serves as an effective, low profile, low maintenance antenna in my advancing years.