Only problem I face with this antenna is that it tests my patience (sometimes) while tuning, especially when switching bands….but I mastered the art in few weeks>>. Now I have an antenna which tunes continuously from 80 meters all the way up J.
From: Rajesh K [mailto:kc2kby@airtelmail.in]
Sent: Friday, November 23, 2012 5:48 PM
To: 'HamBrewers@yahoogroups.com'
Subject: RE: [HamBrewers] Question on Loop/ Delta Loop
Dear Madhukar,
I had similar problems at my QTH, compounded by noise from my PC also. I installed a dirty loop for an antenna and got rid of the problems 95%. I was able to bring down noise form 59+ down to 57. My setup is very simple. I put up 4 casuarina poles (with hooks on the top) on 4 corners of my terrace and ran longest possible loop – about 360 feet. I used braid and center conductors from old coaxial cables. The loop terminates in V shaped formation from the top of 2 poles at nearest point to my shack. From the feed point, I run a ladder line (home brew) with 320 wires 1 inch apart separated by quarter inch rings of electrical pvc pipe. Length of feedline is approximately 15 feet. Ladder line connects to MFJ 901 tuner which has a balun inside. Balun is a must for this type of setup. "Balanced Balanced Tuner" is better (google it) if you want to homebrew a new tuner. If your LDG tuner has a built in balun (4:1 or 1:1 doesn't matter), you are OK. Otherwise, wind about 18 – 20 feet of RG213 or RG-58 on 4 inch PVC drain pipe (Close wind) and put it in between the rig and the tuner. If you don't want to run ladder line, terminate the loop in a dirty balun (coax wound on PVC) and run coax to your tuner. I tried both and had better performance with ladder line. My tuner tunes this antenna to all our bands (good thing is it is continuous from 80M up to 10 M J) and works best in 80, 40, 20 meters and little less perfect on upper bands. When the conditions were good last year (round about this time up to March-April), with just 40-50 W, I had many DX contacts including several from the other side of the globe in 20 and 40M. One variation you can try on this antenna is to have 2 shorter poles (about half of the other 2) and give some degree of "slant" to it. I have the same antenna for about 2 years now and don't want to try anything else. Take care if you have any power lines running or transformer near your QTH. Also, add a power line filter before your PS. It helps a lot. Make sure you solder the joints if you have any in your antenna. If you put up lesser length loop, you will be able get better performance on higher bands. Try and get that slant if possible. Good luck and let me know how it goes.
73
Rajesh VU3RGK.
I face a very high level of electrical noise at my new Permanent QTH - being just about 300 Mtrs from HT Lines - becoming a Permanent QRM too!!
This is present at unacceptable levels - s-9 + most of the times. This made me consider a Loop/Delta Loop Antenna for 7 Mhz to handle the noise issue.
Planning for a Horizontal installation - I understand that this gives me only Ground Waves - OK for now.
I need clarifications on the following issues.
1. Most of the Links that I see on the web is for a full wave design. What limits the use of a Half Wave Delta Loop??
2. Where should bthe feedpoint be?
3. What will be feedline impedence??
4. What kind of Balun is required to feed to a 50 Ohm cable?
5. What else is to be considered??
I have a LDG - Z-100 Plus antenna tuner.
