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Author Topic: Shakespeare Model 390-1MGB Military HF Antenna  (Read 4104 times)
W3TEZ
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Posts: 32




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« on: June 01, 2010, 01:33:52 PM »

hello, i seen the shakespeare model 390-1mgb and the price on it is pretty reasonable. but according to the specifications it says 2-30MHz with tuner. i have a few hf antennas in mind, but i am just curious if anyone knows how good of an antenna the shakespeare verticals are, especially this one in particular. i just want a few opinions because i did not see any reviews of this antenna anywhere and i did not want to buy something and have it turn out to be complete garbage.

Thanks, KC2UJG

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K0BG
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« Reply #1 on: June 01, 2010, 01:46:42 PM »

About all it amounts to is a chunk of conductor, whatever it is. The "43 foot vertical" of recent popularity is just another example.

When you place a tuner directly at the base of a vertical of some undetermined length, there will be frequencies where it works very well. At others it'll be passible, and on some, down right lossy. The radiation pattern also varies a lot. Like any vertical, it requires a decent ground plane under it, or it doesn't work well at any frequency.

When you place the tuner at the base, you end up essentially with a based loaded vertical. Center loading is always better. In fact, a regular old 6BTV, with a proper ground plane (radials), will out perform any base loaded one, all else being equal.
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WW5AA
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« Reply #2 on: June 02, 2010, 03:51:50 AM »

The military does not worry about efficiency. Their tactical use of small vertical antennas actually requires them at times to tilt the antenna horizontal. The only consideration is stupid proof!  As Alan says a 5/6 BTV is cheaper and will run circles around this thing.
73 de Lindy
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NM3G
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« Reply #3 on: July 16, 2010, 04:04:28 PM »

The Shakespeare 390 and 390-1 antennas are 23' fiberglass antennas with copper conductors embedded. The top section is approximately 102" with a 3/8-24 threaded base. the 390 antenna is conductive to the chrome-plated brass base, the 390-1 has a stainless steel clamp about 18" above the base (bottom 18" of fiberglass is insulation only).

These whip antennas are certainly expensive, but in a marine environment they outlast aluminum antennas (I HAD a 5BTV that is now on the bottom of the Pacific ocean ... snapped off just above the mounting plate).

We used them in the Coast Guard for boats and ships with bridge-to-bridge HF requirements. When the boats were wooden or fiberglass superstructure, the antennas worked well. When the superstructure was aluminum, we had to install the antenna coupler outside.

There is no magic to these antennas ... if you need a small profile antenna and can provide a good ground plane, it will work well. If you have the ability to support a similar length of phosphor-bronze wire, you have about the same performance, except the 390 and 390-1 are much easier to tilt over (with the proper standoff and hinge base installed) than it is to remove the wire antenna.

Typical frequency range was from 2.1 MHz up to 22 MHz, and with a good antenna coupler, the antennas worked well.

The lifespan on these antennas used on the small boats (41'-56') and the patrol boats (82'-110') was about a year before the gel coat started showing stress cracks. Failure mode was generally breaking the conductor inside the bottom section. Antennas were routinely replaced during annual maintenance periods, and whenever they broke.

There are those people that believe that the cheapest out-of-pocket expense is the best value are not the ones putting their (and other) lives on the line to save a couple bucks.

For those who need to contain their costs, I recommend you not purchase this antenna, for it is overbuilt for your purposes. If you are performing a marine installation and need reliability, this is one of the antennas I would recommend.

73,
Rick WB3EXR

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K0ZN
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« Reply #4 on: July 16, 2010, 09:05:00 PM »

Hi.

If you are installing this antenna ashore, at home, a 23 ft. piece of ANY copper wire would work just as well....or ANY 23 ft. copper or aluminum pipe (and a tuner at the bottom of the wire). The only advantage of the marine antenna might be mechanical ease of installation. Regardless, a GOOD radial ground plane is required for good performance and ideally, the radials should be a 1/4 wave on the lowest band you want to operate it on. Check the ARRL Antenna Book or any other good antenna book for information
on how radials work and improve efficiency with a vertical antenna. My suggestion would be a 66' Inverted L with a tuner at the base and a radial system; that would work well from 80 through 10 with much better efficiency than a 23 ft. conductor and possibly would be modestly useable on 160.

73,  K0ZN

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