RADIOACTIVITIES Newsletter of the Argonne Amateur Radio Club
Volume XLV, Number 9	November, 2004

We wish to thank Loren Thompson KB9CTJ for an excellent presentation about PSK31 today. Also, a special thanks to Vic Guarino, KC9AEW, for setting up his portable 20-meter vertical. Using this antenna and Loren's Yaesu receiver, it was amazing to see how well we could copy many signals from Europe and Russia.

02		WB9THV		Joe		Downers Grove, IL
04		W9WJL		Charles		Madison, WI
11		N9WBK		Sherman		Downers Grove, IL
20		W9QBH		Bob		Riverside, IL
24		WA9CW		Leo		Hinsdale, IL
28		WB9VUT		Fred		Plainfield, IL

Skew paths can take place in the winter caused by stratosphere warming. DXer's follow strong signals peaked at not normal long or short path headings. Common paths are around the North Pole. Mr. DX points his beam twenty to thirty degrees to the side of direct heading away from the North Pole. Example: direct path is fifteen degrees; try thirty-five or if heading is three hundred forty degrees, try three hundred twenty.

Another skew path can be found over the Atlantic Ocean and sometimes this intense ionization locates near the equator. Swing the beam further south toward this intense ionization and you may find stronger signals. Swing your beam to either side of the normal beam heading and maybe find back scatter so beam South Europe comes in as direct route is closed.

Strong sudden ionospheric disturbance (SID) makes bands go dead. Your receiver won't find any signals when you check everything; check WWV. Where did it go? Now you know your antenna works. It's a SID blackout. This happened to me on forty meters. I called till I was blue in the face, and got one fella in Indiana. Long distance stations won't be heard until it is over; a few hours, days, or a week. If you do hear WWV, watch K index. K7 means lots of noise and maximum K index of nine means no propagation anywhere below thirty megahertz.

These angles are what make lower frequency propagation work for DX, high vertical radiation 40 meters and downward but hurts vertical radiation 20 meters and up unless your antenna is at the edge of the sea. DXers should use horizontal polarization on 20 meters and up. For verticals toward the horizon there is almost complete cancellation of signal because of ground reflection. There is a 180 degree phase shift in the reflective ray on the horizon. This phase shift causes signal cancellation at some angle, the phase shift is 90 degrees and the reflected ray is no help. Above this angle the reflected ray tends to add to the direct ray. Here is the angle called the "Pseudo-Brewster" angle.

I can remember my first vertical, it was the remains of a gothum with 160 meter coil. It was broken in shipment and insurance paid for it eventually, and the remains were given to me anyway. Here I was my first ticket KN9UMH and a broken aerial. I put up my Uncles Windom K9IZJ. Later, I took a section of the aluminum, the coil, installed an in ground fence post outside my window, cut an inner tube into strips, tied the aluminum tubing to the post, put down a ground rod, soldered a shield to it, and coil to the bottom of the aluminum center of coax here with alligator clip and clipped my way up to twenty meters and with my third ticket novice-tech-general, I put K9UMH on CW. I tried phone band but no one heard my DX-40 VH-1 combo. Only if I had known about the Brewster angle back then I would have stayed with the Windom.

Having trouble with meters vs feet well - 150/freq MHz is 492/freq MHz feet. Feet converted into meters multiply length by 14.3048. ½ wave in meters 143/freq MHz.

L.A. Moxon, G6XN, favors the use of nylon rope instead of insulators in his book "HF Antennas for all Locations". He says to use nylon use this formula: ½ wavelength 478/freq feet or 145.7/freq MHz meters.

The Greek scientist Archimedes was playing with circles when interrupted by a roman soldier who ended his life. Today we deal with circles in coils. Bending a coil into a circular configuration, the ends of the inductor each being of opposite polarity are now in close proximity to closed loops within the toroidal geometry and self shielding characteristic results. The proof of self-shielding property no dip can be found at resonant frequency. This is characteristic of any toroidal inductor. So the fewer the turns the more difficulty in tap point on a coil when matching impedance.

Nicola Tesla used coils to generate lightning and fluorescent tubes ball fire in his Colorado site with high power at low frequencies. Coil loops have been used in the 1920's and in the 1980's rectangle loop for sub surface receiving antennas. How about today?

Try out 160 by using an autotransformer to get you onto the band. I found an article by W2LT Nov 1973 in 73 Magazine. He says antennas don't have to be self-resonant, but one plate of a capacitor of a parallel tuned circuit; the other plate being Mother Earth. Simply add a coil to resonate that capacitance. Ohla! One radiating system. Maximum current is at resonance. If you have many antennas, tie the feed lines together coax centers to shields all lumped into one wire this one wire will be used to tap the top of a coil. That one wire is over 160 antenna and must match the low impedance transmitter to the high impedance aerial. Now the autotransformer. W2LT used a 5cm diameter 13cm long coil tapped 40 to 50 turns. Bottom end is grounded to our transmitter coax shield the center put 5 inch wire with alligator clip on the end to tap up from bottom end to tenth turn. Try the antenna clip at the 30^th turn for starters. It would be easier to use SWR meter for minimum power on transmitter changes the taps. Change the antenna tap for maximum antenna current. High RF voltages are present at key down. Do your adjusting at key up.

I have just tied my quad coax shorted to my long wire position on my MT3000 tuner and it loaded up fine. It is 7:30PM noise S5 strong signals are S6 some Illinois and Michigan not what I hoped for here along the power lines. Guess I need a loop for receiving under these conditions.

You can make a 40-meter delta from one pole or three using wire lengths by the formula 1005/freq MHz or 136 feet one wavelength. After you get it working think about 80 meters and add to each corner of the delta forty feet upon each then cut equal sections off each end until you reach the 80-meter frequency desired. There are larger delta's possible the one and a half wave delta with ¾ wavelength per side fed at the base the top left open and the 3/2-wavelength delta.

At 30 meters and lower in frequency low radiation angles demand higher heights thus vertical polarization would work better. The delta fed at a corner produces a 27-degree radiation angle based near ground and if the base is inverted fed corner at top the angle is 20 degrees. The simple delta 136' on 40 meters is 80 to 100 ohms. At higher frequencies the delta is smaller and best suited for horizontal polarization.

I came across an article by W4NVK in Oct '69 issue of 73 Magazine titled "Super Gain Antenna". He used a folded dipole 63 feet 2 inches using 3 poles and hung it at 7 feet. Under the dipole is a screen mesh 12 feet wide. W4NYK filed for a patent and I don't know if he was successful or not. I figure a delta could do a better job than an old folded dipole at this low height, also using horizontal radiation working 200 miles by day and 600 to 1000 miles by night with a super signal.

This type of antenna doesn't receive low angles well with a 10 to 15 db rejection gain another 9db gain for the higher radiation and muting the nasty QRM foreign broadcasters. The impedance of the folded dipole is 50 ohms. I don't know what a 7 foot high delta with 12 foot wide chicken wire screen under it impedance would be. For those with the real estate there are the bi-directional delta 2 element phased and three element phased or parasite arrays.

I still use my ¾ on a leg 40 meter antenna and it takes up most of my yard 40 feet at the middle drooping down to two trees about 12 feet from the ground. It is still under study. Next I will try the 1-½ wave delta loop I am planning on shorting the loop on the 40-meter antenna and try 160 meters if it will load as a single wire.