HF antenna Back Stay vs. Screwdriver antenna

[BocaIII]

Does anyone have any direct experience comparing HF antenna using the back stay vs. a screwdriver antenna. Since I have used a screwdriver mobile for years with great success, I was thinking the screwdriver should work as well or better on the boat. The install is a little easier since it eliminates the need for a tuner.

Thanks ahead for comments,
Jack

[btrayfors]

Originally Posted by BocaIII

Does anyone have any direct experience comparing HF antenna using the back stay vs. a screwdriver antenna. Since I have used a screwdriver mobile for years with great success, I was thinking the screwdriver should work as well or better on the boat. The install is a little easier since it eliminates the need for a tuner.

Thanks ahead for comments,
Jack

Jack,

A screwdriver antenna would work just fine, provided that it was built well enough and of materials to withstand the marine environment. Also, it would probably be necessary to support the antenna in a couple of places, not just at the base, because of the sometimes violent motion at sea.

You could expect the antenna to work as well as -- or maybe better -- than a traditional backstay antenna on the high bands (say, 10mHz and above) due primarily to its low vertical angle of radiation.

On the lower bands, however, a well-installed traditional backstay antenna might have the edge, especially on 7mHz and below. The greater length is important, no matter how good the center loading of a screwdriver antenna.

Here's a comparison of some options for marine antennas I did several years ago: MarineAntennaChoices2

Cheers,

Bill

[BocaIII]

Bill,

Thanks for your comments. Based on my knowledge, I agree with your comments. A little of my background, I am an electrical engineer by education and a ham radio operator. My high sierra screwdriver works exceptional well on MARS freqs below 3.3 Mhz.

Hi-Q makes a screwdriver for marine application. It was original built for the German navy for use on submarines. And yes, it requires major mounting supports which is just another simple engineering project.

I was hoping to hear from some one with actual experience using a screwdriver in this application.

Thanks again,
Jack

[btrayfors]

Jack,

Maybe you'll find someone who has used one and can compare to his/her backstay antenna. But, there are likely to be very, very few out there. I know sailors who have used them ashore, and those who have used them on their boats, but not together with a backstay antenna.

I'm glad your High Sierra works well on 3.3mHz. But, the question is, compared to what? I know for a fact that the length of the backstay is very important on the lower bands. One of my sailor friends whose boat was next to me one winter used to like to talk to his buddies in England (from Washington DC). He tried just about everything, because he's an avid ham and an experimenter. He had multiple antennas of all sorts. He found that when he increased the length of his end-fed antenna to over 55', it made a whale of a difference on 75 meters.

Whatever. The screwdriver will work very well, and unless you plan a lot of DXing on the low bands, I'd not be concerned about it.

73,

Bill
WA6CCA

[BocaIII]

Bill,

I really appreciate your comments...they are reaffirming my thinking.
My High Sierra screwdriver performance is compared to my 102' G5RV base station.

Thanks again, 73's
Jack
W4GRJ / AFA4DG

[btrayfors]

Originally Posted by BocaIII

Bill,

I really appreciate your comments...they are reaffirming my thinking.
My High Sierra screwdriver performance is compared to my 102' G5RV base station.

Thanks again, 73's
Jack
W4GRJ / AFA4DG

Most welcome, Jack.

It's really hard to compare those two antennas, since the G5RV is almost certainly in some sort of a horizontal setup.

One thing I've found over the years in experimenting with many types of antennas on boats as well as on land is that vertical takeoff angle is extremely important, especially for DX. A simple single-band vertical dipole for, say, 20m....rigged low down to the deck and hoisted with a spare halyard....will outperform almost any antenna you can think of on a sailboat.

Vertical dipoles work extremely well over land as well. When I moved to this house some 14 years ago, I used some of the tall trees to hoist vertical dipoles on 20 meters and 15 meters. I also had a 120' long commercial folded dipole, rigged horizontally about 30' off the ground.

With an antenna switch, I could switch antennas easily. What I found over the years was that about 90-95% of the time the vertical dipoles WAY WAY outperformed the big horizontal antenna. You could hear the difference, and it was even more pronounced on transmit.

About 5-10% of the time, however, the horizontal dipole was close to...or even sometimes a tiny bit better than....the vertical dipoles. I judged this to be those relatively rare instances where incoming signals were at a relatively high angle.

The real DX-ers -- those who do extravagant DX-peditions to tiny islands around the world -- discovered vertical dipoles a few years back, and were astounded by their results. Some claimed as much as 18 or 20db "gain" as the result of the extremely low takeoff angle which reduced the number of ionospheric "hops" to the receiving station.

That sure parallels my experience, both afloat and ashore. I can work into Eastern Europe easily with 5 watts QRP, and get in on first call!

Sorry to wander off topic, but antennas -- especially on boats -- are my passion. At least one of them :-)

73,

Bill
WA6CCA

[SoonerSailor]

As an vertical antenna gets shorter than 1/4 wavelength, its radiation resistance falls. That means for a given "ground" resistance, less of the power is radiated and more is dissipated in the ground resistance. So a really high quality, low resistance ground will pay greater dividends with shorter antennas than with longer ones. Fortunately, you can have a really low resistance ground system on a saltwater boat with a lot less wire than you need on land - that screwdriver antenna will probably work well.