WYSE's Ham Radio Site

Neil Klagge, Chief Operator

                                   Antenna Contents:

 

 

               Inverted "L" antenna for 160 thru 6 meters

The idea of trying to get the virtual length to 88 feet was taken from some work done by the late W4RNL. He found that a center fed dipole of 22 or 44 or 88 feet per side was a good compromise for multiband work when used with a balanced feedline and/or a balun along with an ATU.  

 

                          My Big 190 ft vertical loop

 

 

                        Other antennas I have tried:

Various windoms and other OCF dipoles, a G5RV, center fed dipoles, inverted-V's, and a zepp.  None of these work very well on the lower frequency bands unless you can get them up to about 60 feet or more (at least in the center). A vertical antenna keeps the majority of the signal from warming the clouds directly above, even tho' you will lose 3 or more dB to the ground system. The inverted-L is a compromise vertical that works pretty fair if you dont have the ability to get the entire antenna vertical. It certainly beats a low horizontal 160 or 80 meter antenna by far, in my experience.

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                      A 600 meter small loop antenna


Revised 2010/02/07

It is an equilateral triangle, 27 inches on each side, 7 turns, tuned with an old 2 ganged BCB variable. The variable has a total of about 500 pf. A fixed 1000 pf capacitor is paralleled with it to get the loop to tune from 525 kHz to near 430 kHz. The loop has a horizontal side on top with the apex pointing down. I use a one turn triangle inner loop to feed the coax cable to the FT100d tranceiver. The inner loop is about 13 inches on each side with all sides parallel to the outer 7 turn loop.

By rotating the loop I can null out the local noise. I have been able to receive WD2XSH/20 on 508.6 kHz in Oregon , VX9BDQ near Vancouver, BC, and WE2XGR/6 in New York state. I have also copied several Canadian NDB's in British Columbia with this loop (I had to add more capacitance in parallel to get down to those frequencies). All this was done from inside my basement shack with the loop at about ground level !

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                    A 6m idea from ON8DC, Erik

    Here is Erik's explanation of his modification to the R7000 for 6 meters: 

What I did: I added a y/4 rod at a y/4 height. (y/4*0.93 =138cm in my case the distance from 2 rods is 5cm ) The swr at the base goes as low as 1.2 measured with my VNWA. It is about 2mhz wide .The top of the rod needs to be fixed by isolator.     (Note:  "y/4" = 'quarter wave')      

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                                 My Mobile Antenna

I use the bottom section of a 40 meter hamstick with a 3 inch stinger instead of the usual 4 foot top section. This is so that I can drive into my garage without having to remove or lower the antenna. It also is less displeasing to my lovely wife. The antenna is self resonant in the 30 meter band, but I use an LDG z-11 Pro antenna tuning unit to cover 60 meters thru 6 meters. It won't quite tune 80 meters unless I use extra matching capacitance box between the ATU and the coax lead to the antenna. I have worked HI and AK on 20 meter CW with this setup, but my BEST DX so far was EW8O, "Mik", in Belarus, near Russia!!  I was driving on interstate 80 near Cheyenne Wyoming at the time and running 80 watts CW output.

 

 

                                   A "coaxial" dipole

This dipole uses the outer braid of the coax as one half of the dipole. The coaxial coil of 15-20 feet of the coax forms an RF choke which establishes the length of the left half of the dipole. It is shorter than the wire side (right side) because of the velocity factor (~0.62- 0.66) of RG-58 coax.

To tune the antenna to resonance at the operating frequency, you must "roll" the coil left or right to lenghten or shorten the coaxial radiator section of the dipole.

  

                                  QRP End-fed Antenna

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My 3 band OFC dipole

A Three Band Off-Center-Fed Dipole (OCFD) laying on the roof...

 The following is an approximation of what YOU MIGHT experience if you try this on your roof. You will have to experiment with the folded back ends of the wires to achieve best SWR on the three bands.

 

              A comparison between two receiving antennas

On 25-26 April, 2015, I did a test between two receiving antennas on 80 meters using the WSPR 4 software.

1) The E-probe (PA0RDT type at 20' AGL) was fed to the FT100d tranceiver.
2)The 40 meter OCFD is drooped over the peak of the roof, which is 17' AGL (with the majority of the middle half of the wire running N/S) was fed to the FT857d tranceiver (the peak of the roof runs E/W).

Over a period of 12 hours overnight, each antenna decoded exactly 13 UNIQUE stations, but the Eprobe copied a total of only 218 decodes, compared to 257 total decodes on the OCFD.

Earlier during the day I had noticed that on 17 meters, the OCFD did FAR BETTER even on UNIQUE decodes compared to the Eprobe.

My conclusion is that the effectiveness of this eprobe drops off as frequency increases thru-out the HF bands.

 

                  A second comparison of two antennas

This is the second comparison between two of my antennas as receiving antennas on 80 meters: 
 
On 26-27 April, 2015, I did another test between two receiving antennas on 80 meters using the WSPR 4 software.

1) My 40 foot top loaded VERTICAL was fed to the FT100d transceiver thru an LDG auto tuner. There are three top wires of 25' each, sloping at ~45 degrees from the mast which makes it similar to a 1/4 wave on 80 meters. This antenna is the MFJ2990 with its 4:1 balun at the base.

2) My 40 meter OCFD* fed to the FT857d transceiver was also tuned to 80m thru an identical LDG auto tuner. The OCFD is drooped over the 17' peak of the roof with the majority of the middle half of the wire running N/S, while the peak of the roof runs E/W. This antenna is half as long as it should be for 80 meters, besides being handicapped by the fact that it is laying on the shingles of the roof, and at only 17' at its highest part.

In a 12 hour period overnight the VERTICAL decoded only 182 spots while the OCFD decoded 203 spots. The OCFD won the battle in spite of its above mentioned handicaps.
 
I am now planning to use the OCFD as a receive antenna whenever I want to use the vertical to transmit with. This should give me the best results on both transmit and receive.

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Capacitive coupling to a loop

Here is my method of coupling to my 600 meter loops: