[Lowfer] SIW WM a bit better now

[wa3tts at verizon.net]

Mike (& All): The two EWEs are more or less orthogonal, and orthogonal loops have long been phased to be electrically rotatable.  It is easy enough to combine them in-phase and not get involved in phasing circuits.  


I use 75 ohm feed lines from the antennas to the radios, maybe in 40 to 50 meter lengths. At the radio location I normally convert from 75 ohm to 50 ohms through a pair of 1.5:1 isolation transformers---then into 50 ohm  filters and LF/MF converter(s).


I realized I could turn the 1.5:1 transformers around to convert up to 112.5 ohms from 75 ohms, then combine the two transformer outputs to the 56 ohm range with a T-fitting.  With the antennas more or less orthogonal and the


40 to 50 meter long  transmission lines  not really making a material phase difference at 1750 meters, the result is the antenna pattern shifting approximately half way between the NW and SW antennas to peak about West.  The EZNEC pattern looks like this....




https://www.dropbox.com/s/v32277r3e7dvz5f/WH0DEG.jpg?dl=0


I would expect the different transmission line lengths to make a difference at 160 meters, but at LF it does not seem to matter much...


By the way, finding that reversed antenna transformer is what got this working well. It seemed like I was getting cancellation in some directions instead of addition for awhile. That got me thinking I


had a 180 degree phase reversal going on somewhere.  When I found the reversed transformer winding, the in- phase combination for NW and SW to West started to work like it should...


73 Mike wa3tts









-----Original Message-----
From: N8OOU <n8oou at meekfarm.us>
To: lowfer <lowfer at mailman.qth.net>
Sent: Wed, Nov 7, 2018 8:19 pm
Subject: Re: [Lowfer] SIW WM a bit better now


Mike, thanks for the capture. Taking the u-turn out of the vertical maybe helped light up a few more pixels on your screen. Is phasing your two antennas together a new idea? Off hand I don't remember reading about any previous reports of you doing that. Thanks for listening. 73 de N8OOU - Mike Meek On 11/7/18 2:06 PM, wa3tts at verizon.net wrote: > Mike, Garry, & All:  A tad better visual capture in mid-afternoon.... > > > https://www.dropbox.com/s/9eftel9o6l1cvtk/siwmn78b.jpg?dl=0 > > > > 73 Mike wa3tts > ______________________________________________________________ > Lowfer mailing list > Home: http://mailman.qth.net/mailman/listinfo/lowfer > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Lowfer at mailman.qth.net > Post must be less than 50KB total for message plus attachment! > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Lowfer mailing list Home: http://mailman.qth.net/mailman/listinfo/lowfer Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Lowfer at mailman.qth.net Post must be less than 50KB total for message plus attachment! This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html