As a new ham radio operator starting on my journey to my first 100 DX entities (DXCC), I am looking for any help I can get to get those contacts in the logbook. Most of the countries I have already logged have been by happenstance. I see a country come across the cluster so I tune down and make the contact. Not all countries are that easy. In fact, many of them are limited to small windows of opportunity!
Generally speaking, the lower they are on the “Most Wanted” list, the easier they are to get. The higher the entity is on the list, the harder it is to break through the pileup and confirm it! This can be for multiple reasons including, but not limited to, political sanctions, a limited number of radio operators in the entity or unpopulated islands that have limited access and/or environmental barriers that make activation of the island difficult, if not, impossible.
ClubLog.com is a website that keeps statistical data of the current 340 entities by mode, band and specific DXCC entity. (You can find this data by clicking here) You can see very easily where on the list where a specific entity is ranked.
Now what does this have to do with a 1 QSO antenna??? I’m glad you asked! I’m getting there, I promise!
Obviously, the entities toward the top of the list are going to be the more sought after contacts to make. So whenever one of the rare ones come on the air, you want to put all of your resources toward making that contact. After all, you are up against the world in order to make that one contact. It isn’t difficult to find radio operators, local and internationally, that have some pretty powerful stations. They include tower(s) with rotatable beams, amplifiers and other expensive equipment that set them apart from the entry level station that may include a dipole and 100 watts.
SO… If you don’t have the thousands of dollars to put up an 100 foot tower that only holds a mono-band 5 element rotatable beam that is fed with a 2 kilowatt amplifier, how are you going to come out on top of the pileups and make that one contact to that rare entity? THE 1 QSO ANTENNA!
Just a brief description, my base station consist of a 100 watt rig that goes to a parallel dipole for 10, 15, 20, 40 and 80 meters. Factoring in my theoretical coax loss, I’m only getting 87 watts to the antenna. The dipole is not rotatable and I do not have an amplifier. For general QSO’s and small time pileups, I can usually hold my own. Taking the general figure of 2.15 dBi for in ideal dipole in free space, that is the basic setup of most entry level stations around. A typical beam may have 6 dBd (8.15 dBi) of gain compared to a dipole. That puts the station with the beam 4 times louder than the dipole station using the same transmitter. That’s a lot to overcome and we haven’t even mentioned amplifiers yet!
In any event, my search started with a question… How can I get the most out of my station with the least amount of investment? I found that the antenna can make a world of difference with minimal investment! For less than $100, I was able to build a directional antenna that gave me the gain of most beams. The trade off for this particular antenna is that it is pretty much for one band and one direction. Let me show you what I found.
Roger Sparks, W7WKB, published an article in QST in December of 1995. He called it the Super Sloper. (It is also located in the ARRL publication More Wire Antenna Classics Vol.2. What he ultimately showed is that you can make a directional mono-band antenna in multiple of 1/2 wave segments with a passive director spaced between 0.02 and .04 wavelengths apart. If hung in a sloping fashion at an adequate height, it has the capability of providing 6.1 dBi of gain! That is quite the difference of 2.15 dBi for the ideal dipole.
Here is the supply list:
150′ of #14 copper stranded wire $28.95
(3) Ceramic insulators $2.97
100′ of 450 ohm ladder line $38
20′ of 1/2 PVC pipe $4
200′ of 550 paracord $20
4:1 Balun $5 (at local ham fest)
I am not going to get into the theory or specifics of the antenna itself just because it was described so well in the article available here.
Given the location of my natural antenna supports (trees), location of the radio shack and the required asimuith for the sloping antenna, I chose to go with antenna number 4 as seen in Table 6. It is for 20 meters and it is based on the 2/2 wavelength design. I could have gotten a tad more gain with the 3/2 wavelength version (#2 or #3) but I just didn’t have the room for the additional length in the intended direction of the slope! The overall length for the 2/2 antenna turned out to be 88′ as opposed to 124″ for the 3/2 antenna.