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[KM1H]

Good for you.

In the 60's the only test equipment I had was an Allied Radio Knight Kit VSWR bridge wired for a 50 Ohm load.

Using some B&W Miniductor from a hamfest, a wide spaced variable from the same place, some wire and alligator clips I got it tuned. The signal source was the Central Electronics 10B I used to drive a 2M transverter with a steady carrier from about 300' away. I did get nipped a few times since even with about 8Wthere was a lot of RF voltage.

It did well in DX contests without radials as in the QST article and even better when I added about 10 or so over the glacial sand. A 8' ground rod went into the fresh water table from the beginning and Ive no idea if it helped any.

Bandwidth is unknown but the no tune CE-100V barefoot at 100W had no problem over the full 300 kHz and at 1200W from the NCL-2000 nothing arced or fried. I still use that rig and amp at the vintage gear bench.

Carl

[K4RVN]

Thanks for input Carl. I enjoy fooling with antennas and it gives me pleasure at low cost. In addition I learn a little now and then.
I'll be measuring the wire to construct the Bobtail soon, you know measuring twice and cutting once. I'll use one piece for the horizontal and two end verticals. Then I'll add the center vertical and solder it to the horizontal. I'll be putting fire in the wire with an AL 800H so using pretty heavy stuff for the high voltage in the tuning unit. I'll be posting later about the results when I install the antenna. Not too many know about Bobtail curtains from actual experience including me.

Frank

[K4RVN]

I completed the Bobtail Curtain for 20 meters about 2 weeks ago. It also has the added reflector and director as written in the MFJ article. While it will get 59 reports into Europe running 900 watts, my hex beam using an A/B switch at the same time, same power, gives 10 over 9 reports . I have checked it several times into Europe, and in the states. I am not pleased with the antenna as it does not live up to its claims on 20 meters as some have written. A friend of mine is coming next week who knows more about tuning antennas than I do to see if he can improve the results. My MFJ 259 indicates the antenna is tuned just fine, however I am no expert just average if that. It works but not worth the effort in my opinion for 20 meters. I think my efforts would have been better to have built a three element wire Yagi beam. We will see when my expert comes over next week. Due to support problems I ended up facing the antenna Broadside and directed  into Europe not toward VK land to the west. I decided I did not want to stay up all night or get up early for the VKs unless I can work them long path.

Frank

[KB2WIG]

Just for a laugh, have you tried it without the added reflecter?

How high is it above ground?

I've been thinking about one for 40m......

klc

[W1VT]

My 40M half squares seem to be more effective in to VK than Europe.  A dipole is often better into Europe, a much shorter path than going almost halfway around the world to Australia.

Zack W1VT

[KZ4USA]

Simple wire beam out of inverted vees maybe 6el will get you there too.

[K4RVN]

The three vertical elements are about 7 ft. above ground to bottom of the  three 1/4 wave verticals for 20 meters. So the horizontal wires connecting the verticals are about 24 ft. above ground. The LC network is mounted on a 7 ft. above ground post which limits the height. The Lc network voltage feeds the center vertical. This antenna does not need height so it is written.
Zack, I have used  several 40 meter half squares over the years including the a half square array with a reflector. In general Bobtail curtains work better on 40 meters than they do on 20 meters according to what I have read. My 40 meter half squares worked well.
A hex beam is better  on 20 meters than either a Bobtail or a half square in my experience because one can rotate it toward the person you are in QSO with. I have not tried it without the reflector or director but have been considering doing that next. It will then be more bi directional perhaps which is not what I want. If the Bobtail does not play better than the Hex beam on 20 meters for long distance, I will take it down after my antenna garu checks it out next week. I like to experiment and the LC network can be used on 40 meters as well as 80 meters. I have no antenna for 80 meters now.

Frank

[W1FBV]

How high is the hex beam?  Is there much ground clutter near the bobtail?

Jim, W1FBV

[K4RVN]

Don't exactly know what ground clutter you mean but the ground space under the Bobtail is clear without clutter. The hex beam is 50 ft. high on 20 meters atop a 40 ft. Rohn 25 tower with a 12 ft mast. My hexbeam is a K4KIO 5 band mounted on a Glen Martin Hazer that I modified. Here is the article about a reflector and director from MFJ.

https://www.mfjenterprises.com/antennatalk3.php

 I have determined that the Bobtail on 20 meters is not worth the effort to me as a horizontal beam is easier to install. A wire Yagi will most likely  out perform it where a half wave length height is available. I have about 60 to 70 ft. height trees for support.
WA 4 PUB and I will be checking out the Bobtail Curtain next week as I could have made a mistake in construction measurements or other.