Time for DX again
The Atlantic storm/hurricane season ends on November 30, and we are now over the season's peak. I am now planning the installation of my DX antennas. I say installation instead of re-installation, because my radio station operations will change from last year. I do not plan to put us the same six [6] antennas as before, and the main reasons are [a] on 40 and 80 meters there is significant illegal Radio Frequency interference caused by a local business operation, which has REFUSED to stop generating a band of illegal Radio Frequency signals which are affecting other legal radio frequency users, even after the NTRC, [the legal authority given the responsibility for keeping the radio frequencies free from all and any illegal radio frequency transmissions,] has issued the offender with a cease and desist order.
On Independence Day I saw the following news item on Facebook, it was also on YouTube. It explains what is happening to amateur radio and amateur radio operators in Saint Kitts-Nevis, but up to now it is only talk and no action from the authorities. I do not believe that anything was mentioned about the years spent negotiating with the illegal offender before the matter was finally presented to the NTRC.
https://www.youtube.com/watch?v=ehFoVCOW1Dw&feature=youtu.be
The other reason why I am installing different antennas this season is because [b] the eleven [11] year sunspot cycle is on the upswing, the high frequency band conditions are improving. Even with my HF antenna in storm/hurricane mode, [on the ground,] I am hearing DX nets and signals, from Europe and Asia. This sunspot cycle will peak in the next five years. For more information see the following links.
https://edition.cnn.com/2020/09/15/world/solar-cycle-25-nasa-noaa-scn-trnd/index.html
My favourite DX and operating band is 40-meters, but the local illegal radio frequency interference just kills my amateur radio. I will install an antenna with the hope that the interference problem is resolved real soon, like yesterday. My antenna design is simple, it is a top and bottom hat half wave vertical dipole. It is the only antenna that has given me exceptional performance, and one which I recommend for anyone interested in making real DX contacts on a budget. After I had my 40-meter design working for a while I found this 80/160 meter version on the internet. Take a look at it here.
qsl.net/ei7ba/low_band_antennae.htm
All that is required are [a] a piece of aluminum tubing one eighth [1/8] of a wavelength long, and wire for the top and bottom hats. I am using ordinary house electric wire, it stretches, but I can live with that. Electric wire with less stretch is better. The antenna will look like capital I, and can be center fed, but my model is fed at the junction of the vertical section and the bottom hat. The whole antenna can be made from wire and suspended from a tower or pole, or house roof, even on the slant, just get the bottom hat at least 5 feet above the ground. The ends of the bottom should be above 5-feet also, sloping upward is better. My antenna is mounted above my 6-ft chain link fence.
The antenna is 1/2 wavelength from tip to tip. 492/freq or 468/freq as you feel, and adjust accordingly. I use the 492/freq because I like to tune it down.
Here are the dimensions that you need. [1] the vertical section is 1/8 of a wavelength. [a] 984/8=123.[b] On 40-meters, 7.150, that is 123/7.150= 17.2-feet. This is the vertical element. In my experimental model a few years ago I used a 20-foot piece of aluminum tubing, and it worked exceptionally well. The top and bottom hats are just the loading wires that make up the 1/2 wavelength of the antenna. To calculate the hats [c] 492/7.150=68.81-feet, subtract the vertical section of 17.2-feet=51.61-feet for two hats, [d] so divide by 2=25.80-feet. Each hat is 25.8-feet, multiply by two for balance loading. So that each hat is 51.61-feet and the vertical element is 17.2-feet.
The vertical section/element can be made longer or shorter than the 17.2-feet, with the corresponding length adjustment for the top and/or bottom hat. This lends itself to experimenting with longer top hat and shorter bottom hat, to facilitate the guy wires for the hats. This top and bottom load vertical vertical dipole needs a matching unit at the feed point to match it to the coax cable. In my previous 40-meter model a 20-foot piece of coax did the trick. I did not have an antenna analyser, and trial and error worked for me. Fine tuning this antenna with an antenna analyser gets maximum performance.
My ham buddy V44KO encouraged me to try 80-meters and it was working great for me. Before my sunset I could make DX contacts into England and the Netherlands on 3.798 MHz, the DX window. I was beginning to like this band. If the local RF interference goes away I will try it again. with the top and bottom load vertical dipole.
Here are the dimensions that you need. [1] the vertical section is 1/8 of a wavelength. [a] 984/8=123.[b] On 80-meters, 3.800, that is 123/3.8= 32.36-feet. This is the vertical element. In my experimental model a few years ago I used a 28-foot piece of aluminum tubing, and it worked exceptionally well.The top and bottom hats are just the loading wires that make up the 1/2 wavelength of the antenna. To calculate the hats [c] 492/3.8=129.47-feet, subtract the vertical section of 32.36-feet=97.11-feet for two hats, [d] so divide by 2=48.55-feet. Each hat is 48.55-feet, multiply by two for balance loading. So that each hat is 97.11-feet and the vertical element is 32.36-feet.
Feel free to send an email here if you need more information or data on this top and bottom vertical dipole antenna. I am not into 160 meters but I would suspect that a variety of loading techniques can be deployed. Now that I am thinking about it, I will give it some serious thought.
The only amateur radio bands unaffected by this local illegal radio frequency interference signals are those above 20-meters, 14 MHz. Ready made antennas, being smaller and rotatable are desired instead of fixed home made wire antennas. With the high bands opening up bands it is wise to invest in a quality beam of 4-elements and more. The only problem is that all of these beams are build for operators using the legal limit so they are costly. Whether you use 100 watts or a kilowatt the antenna warranty and lifetime is the same. Sometimes one just has to bite the bullet, and make the investment to get the performance needed.
The antenna above lend itself nicely for the low bands 40 and 80 meters. Where space is limited for the size required. The chain link fence provides an ideal location for the antenna, but everyone does not have a chain link fence and an agreeable neighbour. If you must use a horizontal dipole antenna get the center and most of it up in the air and as horizontal as possible. If possible invest in a rotatable dipole and pipe to send it 40-feet up. That works every time. Your amateur radio success depends on the quality of your antenna. Is your coax cable important, maybe I look at that next. I have been recycling coax cable for years, [hahaha] more to follow.
Comments