Terry’s DIY Antenna Adventure

11/30  DIY Antenna Project Starts.

Terry N5LOW embarks with a homebrew 10-40m horiz delta loop antenna design at his QTH.  The loop meanders from a tree, to fence post, to a banister at varying heights.  1/3 wavelength on 3 legs @ ~46′ each.  Using a 4:1 impedance balun to bring the impedance of the delta loop down to 50 ohms.  Also using a 1:1 choke balun for common mode/RFI performance.

The home wound 4:1 current balun is verified to produce good results on his NanoVNA.


12/2  Theory vs Practice 

Terry reports, “..tuned up nice but has horrible RX”


12/3  Staying warm during the Cold Front

Terry notices that the 1:1 common mode choke (fed downstream from the 4:1 balun) was noticiable warm. Terry removes it but  still has issues w/ antenna….


12/27 Deep Dive look at 1:1 choke designs

With new focus on 1:1 choke designs, Terry builds up an improved choke.  He’s currently (pun intended) built a 1:1 current balun that’s working great.  Terry plans to use it for upcoming Winter Field Day (WFD) on 12/28.  Will help with expected high RFI environment (mulit ops).

Well done and good lookin’!

12/30 Football Season

Change up the play, use the old End Fed antenna and 1:49 UNUN Balun.  But wait, gotta use the football for optimal impedance matching performance to fix the RFI.

“Here is a picture of my outdoor antenna range.
I had a rat nest of wire , one I thought  was a ground was
not.  I threw some wire in the pond back there to see if that would help
my terrible RFI issue.  Fixed it,  I was running this with zero ground at
the 1:49 UNUN attached to a endfed that is 148 feet long.   I can tune up 10,17,20,40,80,160 with no
problems in the shack.  
Improvements , shorten up the leads,   install it in a box.
Other data,  at 28mhz  10M  I found the pl259 at 68F  and the top of coil  71F
bottom of coil  68F ,
N5LOW  Terry”


1/1  A New Attention Getter.

Retiring the Delta Loop- too much RFI performance.  Found a new alternative antenna to try… an wire colinear antenna… the W5GI Mystery Antenna.

See http://www.iw5edi.com/technical-articles/w5gi-mystery-antenna

The adventure(s) continues.  Gotta love this hobby!

1 thought on “Terry’s DIY Antenna Adventure”

  1. Nano-VNA, calibrate to cover the band you cut the ladder to 1/2 wave. Attach VNA to open ladder line and use
    S11 phase. Find the place where the graph show zero degrees. That frequency is exactly 1/2 wavelength of your ladder. Trim as required.


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