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 wasnot. I threw some wire in the pond back there to see if that would helpmy terrible RFI issue. Fixed it, I was running this with zero ground atthe 1:49 UNUN attached to a endfed that is 148 feet long. I can tune up 10,17,20,40,80,160 with noproblems 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 71Fbottom 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.
The adventure(s) continues. Gotta love this hobby!