Quest For a Lowband Skip Antenna

[chgomonitor]

While waiting for the next sunspot cycle to get going I've been contemplating putting up some sort of low band (30-50 MHz) antenna in order to better catch some decent long distance skip. (This assumes that that there are still some decent users of low band out there after the last decade's mass exodus to 800 and digital, LOL).

Last year I strung a vertical quarter wave dipole cut for 32 MHz on stand-offs aside my tower. It proved to be the ultimate man made noise catcher and I couldn't scan a thing 30 to 50. I suspect some sort of ground plane vertical would be more effective.

Problem is, at these sizes home brewing something sturdy enough to last a few years gets a little tricky.

I've done some web searches and there doesn't seem to be much out there at reasonable prices in terms of a commercial land mobile base antenna, other than amateur 6-meter antennas.

I suppose I could try chopping a CB quarter wave vertical.

Does anyone have any good suggestions or tips on constructing such a beast or web links to same?

Any reasonably priced low band quarter waves out there?

Happy Scanning! - Ted

 

[ka3jjz]

Did you try looking at the links at the AC6V supersite?

http://ac6v.com/antprojects.htm

There are several 6 meter projects there - if the article has all the formulas for retuning, you should be in business, design wise.

Just thinking out loud here - I wonder if anyone has had any luck hearing lo band skip on a loop? When we're talking skip - even Es or the now rare F2 variety - antenna polarization losses tend to be much less of a factor. As loops generally have less sensitivity to noise, that might be a possible solution. I'm not entirely sure about the bandwidth of a loop at these freqs, however. Still worth looking into.

73 Mike

 

[prcguy]

I have a military 30 to 88MHz whip antenna I might part with that you could make into a ground plane. It originally had a ground plane base but that got used on another project.
prcguy

 

[djeplett]

There also was the Archer/Radio Shack 20-014 scanner antenna. It had three vertical elements and the largest was cut for VHF-Lo. You can find them on eBay from time to time...

 

[KC0QNB]

After doing some checking other than building your own antenna there is not a lot of choices for low band antennas any more but I did find this
Building your own might be cheaper, if you can find the stuff.

 

[kb2vxa]

Any antenna that receives local stuff reasonably well will work more than wonders when "the skip is in". Any experienced ham will tell you that you can work the world on 5W and a wet noodle when the band is open.

 

[klogd]

Last year I strung a vertical quarter wave dipole cut for 32 MHz on stand-offs aside my tower. It proved to be the ultimate man made noise catcher and I couldn't scan a thing 30 to 50. I suspect some sort of ground plane vertical would be more effective.

Possibly your dipole didnt work well because it wasnt high enough?
Higher you go, further away it will be from noise-makers.
Also, if you're feeding a dipole with coax, unless you use an "ugly balun", the coax shield will become part of the antenna, and this could be picking up noise that way. Google for ugly balun if you choose coax.

The best choice for broadband use of a dipole is ladder line, 300 or 450 ohm, because coax is only at its lowest loss at 50ohms impedance, ladder-line will have less loss even though the impedance of the antenna is all over the place. Ladder-line will not act as an antenna as long as its dry and kept away from anything metal, because its balanced and has common-mode rejection.
However, ladder-line requires a balun to match it to 50ohm coax. Or better yet, an antenna tuner that works up to 54MHz with balanced line, such as MFJ-947B maybe. Such a setup would be perfect for shortwave listening as well VHF-LO.

Even though you're not transmitting, an antenna system which is impedance matched (or low VSWR) will have the most gain.

If money is no object (doubtful), the alternative is a steppir. They have a vertical which mechanically changes length to always give 50 ohms, works on HF & 6 meters, but its a $700 antenna, ouch! dipole (or loop), with ladder line and balanced tuner would be more bang for the buck.

 

[N1BHH]

Do like many people do, build a vertical dipole. Just build a dipole for around the middle of the range. I have built one for Low Band using twinlead as the elements and mounted it high in a tree. I have one ten meter ground plane I built that works nice. It only has two radials as I have only two tie off points. Makes a great scanner antenna, if you get it up 25 feet or more you can hear loads of stuff, even High Band and UHF and 800 with no huge difference from any other antenna.