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Messages - Lamewolf

#1
Antennas / Re: EFHW sloper array?
November 02, 2020, 09:35:21 AM
I used an EFHW sloper on 60 meters using a 49:1 transformer at the feed point that was at 7' and the far end of the wire (88') was 70' high in a tree.  Radiation was somewhat directional toward the feed point which was pointed toward the west.  But it did give good all around coverage too and had a flat swr of about 1.2:1 on all 5 channels.
#2
Antennas / Re: Easy to Make Doublet for QRP
November 02, 2020, 09:31:45 AM
I made a similar antenna for portable operation but I made my elements 44' long for a total doublet length of 88' and fed it with lightweight 300 ohm TV twinlead and my little homebrew Zmatch tuner for 10 thru 80 meter coverage.  The wire elements on mine was made from insulated #20 speaker wire.
#3
Antennas / Re: End fed windom
November 02, 2020, 09:21:14 AM
I built a Windom, but I prefer the term "Off Center Fed Dipole" and I have no issues with RF because I also incorporated a good CMC choke in the same box with the 4:1 balun - works super good !  Initial resonance is set to 3.450 mhz to get 40, 20, 17, 12, 10, and 6 meters as close as possible, then I use a capacitor with a bleeder resistor across it for protection to move 80 meter resonance up the band without effecting the other bands.
#4
Antennas / Re: Balanced Line Linked Dipole
November 02, 2020, 09:12:53 AM
If you are feeding a dipole with ladder line, skip the links and just make it a half wave on the lowest band of interest and use a 1:1 current balun at the end of the ladder line with a short coax jumper to the tuner.  An 80 meter dipole fed with ladder line this way will work 10 thru 80 meters and is a very efficient antenna !
#5
Don't use an AM broadcast radio as electrical nose can travel several hundred miles at those frequencies.  Instead use a scanner set to the aircraft band 116 to 136 mhz AM where the noise only travels a few miles.  Or if you have a portable rig such as the Yaesu FT-817 that will do  2 meter AM, use that.  A 2 meter, 3 element beam can be used and bought commercially or easily built.  Even a simple dipole made from stiff wire such a coat hanger wire.  You could even make a quick and easy 2 meter, 2 element beam with coat hanger wire and use a piece of 1 x 2 inch wood for the boom.

#6
Stations only 50 miles away require NVIS propagation many times, so deploy your EFHW low to and horizontal to the ground, or as an inverted V with the center of the wire about 20 feet high and the ends about 3 feet high.
#7
Antennas / Off Center Fed Dipole
July 03, 2020, 09:39:56 PM
Been away for a while and just got back on tonight, so I thought I would share the antenna I have been experimenting with that seems to work gangbusters and most places without a tuner.  Its an off center fed dipole that covers 80, 40, 20, 17, 12, 10, and 6 meters.  The initial resonance is set to 3.450 mhz (yes, below the band edge) to get the bands 40 and up at resonance.  But to move 80 meter resonance up the band without changing the other bands you put a capacitance between the balun and the long leg of the antenna.  I operate around 3.825 mhz and two 180pf 5KV caps in series gives me around 95pf @ 10KV and gets my swr on 3.825 a 1.2:1 for no tuner operation.  2:1 swr points on 80 meters starts at 3.745 mhz and extends to the top of the band where its only 1.8:1.  Below 3.745 I do use a manual tuner if I'm using the amp, but if I'm running barefoot, the tuner in my Icom 7300 matches it just fine.  40 and 20 meters needs no tuner at all, but 17 meters is a little above 2:1 - around 2.3:1, so I use a tuner there too. 12 meters needs no tuner at all, and 10 is usable from 29.0 to 28.680 without a tuner, and six meters is a bot above 2:1 but again, the tuner in the 7300 takes care of that no problem.  On WSPR mode running only 3 watts, I'm being heard all over the US and Europe with it.  The balun is a hybrid balun  that contains a 4:1 Ruthroff voltage balun to convert the antennas feedpoint impedance of around 200 ohms to 50 ohms, then it has a 1:1 Guanella current balun between the 4:1 and the coax to block common mode currents from the outside of the coax shield.  Hope some of you decide to try it, its been a real success here and fun to build !
#8
Antennas / Re: Chameleon SPIKE mount.
April 05, 2018, 08:35:46 AM
I always have my 31' Jackite telescopic pole with me, makes things quick and easy.  Actually, I can use it as a multiband vertical by feeding a 31' wire with radials with my SGC 237 tuner - it will do 10 through 160 meters that way if needed but  I  usually use an 88' wire as an inverted V or inverted L.
#9
Antennas / Re: Chameleon SPIKE mount.
April 04, 2018, 11:44:07 AM
After reading through this thread, I must say:

1. Wire is much much cheaper and more efficient.
2. Pouring liquid around a ground rod that short I doubt will make much difference and a few "wire" radials would work better.
3. Speed of deployment in my book can take a back seat to performance anytime, but I can deploy my wire very quickly - about 5 minutes in most cases !
4. Wire is lighter than stainless steel parts and rolls up nice and neat to fit in the pack.
5. I can buy a lot of wire for the price of these antennas.
#10
https://www.sotabeams.co.uk/mountain-endfed-halfwave-tuner-kit-40-17m/  <----- This and 66 feet of #20 insulated wire wire will get you all you need on 40 and will also work 20, 15, & 10 if needed.  Its the very efficient end fed half wave antenna.

Rick
#11
Antennas / Re: New Elecraft AX1 Antenna.
December 13, 2017, 03:09:40 PM
Quote from: cockpitbob on October 20, 2017, 01:50:50 PM
Interesting.  MFJ and others have a lot of similar products, but they are all 1 band.  To me the most unique thing is that the telescoping part collapses from 3.5' down to just 6".  The 3/8"-24 mounting stud seems too beefy. 

I'm having a hard time envisioning making any 20meter contacts on an antenna 1.2meters tall, but then, the MFJ Hamsticks I use on my car work great and they are only about 2.25meters long and mounted 3/4meter below the roof.

MFJ does offer one that is multiband with a moveable tap lead that works similar to the Outbacker mobile antenna.  The MFJ-1899T !
#12
If you want 40 thru 6 meters, you might want to look into an off center fed dipole for 40M, its 22' on one side and 44' on the other side fed with a 4:1 current balun and then coax to the radio.  If its adjusted correctly, it can cover 40, 20, and 10 and possibly portions of 6 meters without a tuner, and 17, 12, and 15 meters with a tuner.
#13
Antennas / Re: Trapped EFHW info
June 21, 2017, 09:55:02 AM
Excellent article on EFHW for multiband use here: https://www.nonstopsystems.com/radio/frank_radio_antenna_multiband_end-fed.htm
#14
Antennas / Re: The SotaBeams Valley Tuner on 80m.
June 21, 2017, 09:54:51 AM
Excellent article on EFHW for multiband use here: https://www.nonstopsystems.com/radio/frank_radio_antenna_multiband_end-fed.htm
#15
Antennas / Re: The SotaBeams Valley Tuner on 80m.
June 21, 2017, 09:06:09 AM
Quote from: Lamewolf on May 27, 2017, 01:12:56 PM
The MFJ-16010 will do it too !

Or you could use a 64:1 transformer like the one I posted here: http://radiopreppers.com/index.php/topic,1292.0.html