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Messages - Lamewolf

1
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 !
2
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.
3
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.
4
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
5
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 !
6
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.
7
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
8
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
9
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
10
Antennas / Re: Trapped EFHW info
June 21, 2017, 08:53:38 am
I already posted a diagram of the 64:1 transformer in a thread here: http://radiopreppers.com/index.php/topic,1292.0.html  in case you want to build one.
11
Antennas / Re: Trapped EFHW info
June 21, 2017, 08:50:17 am
Quote from: caulktel on June 11, 2017, 06:58:42 pm
Hi all,

I normally use EFHW antennas for all my portable ops with a 28ft fiberglass pole, but they are all mono band, so I got this idea to make a multi band 20,40 meter EFHW using these traps from, http://www.sotabeams.co.uk/pico-traps-kit-pair/ I understand how to tune the traps, but I'm not clear on how to determine where to place the trap on the wire. I assume being as I want to use it on 20 and 40, that it needs to be approximately 66 feet long total length, but where do I insert the 20 meter trap, at 33 feet? I have done a lot of searching, but have not found a definitive answer on how to figure it. Do I build the 20 meter section first with the trap at the end and tune it to length, then add the 40 meter section? Any help would be appreciated.

Joel
N6ALT


Use a 64:1 transformer to feed an end fed half wave for 40 meters and it will work 20 an 15 meter also without a tuner and without traps !
12
Antennas / Re: End fed half wave for 60 meters
May 30, 2017, 08:49:37 am
Quote from: gil on May 28, 2017, 04:59:48 am
Thank you. I wish we had 60m here in France...

Gil.


That device will also work with end fed half waves for other bands !
13
Antennas / Re: The SotaBeams Valley Tuner on 80m.
May 27, 2017, 01:12:56 pm
The MFJ-16010 will do it too !
14
Antennas / End fed half wave for 60 meters
May 27, 2017, 08:58:47 am
Been experimenting again with end fed half waves and methods of matching them.  Build a broadband matching transformer to use with my EFHW 60 meter antenna and its working great !  Its flat on 60 meters and close enough (2.5:1) to use with my built in ATU in my FT-450AT on 30 meters and 15 meters.  Thought I would share a diagram on the transformer.
15
Here is a better detailed diagram of what I built.