Friday, 9 May 2008

10m delta loop antenna?

Had a long chat with 9M2AU yesterday about 10m, antenna tuner and antenna. He suggested that I should look into a delta loop antenna design. It has simple and easy to assemble and to source for the parts and it has gain too. Since I'm at my base at that time, I fired up my Safari browser and look for the delta loop antenna using google and found few interesting websites that I've already bookmarked. As said, it looks really simple .. and no antenna tuner is required. To find the overall length of the loop, just follow the following equation:

length = ( 1005 / centre operating frequency  ft ) * velocity factor
e.g.: for 1
0m, overall length = ( 1005/28.450 ) * 0.75  = around 26.3ft 
Since it is a delta loop (triangle), divide the final length by 3 to get the equal length of each side.

Sample delta loop found in the following website (requires 4:1 balun):

How to brew a 4:1 air-wound current balun? Here is the instruction found in this website (PA3CNJ).

This air-core balun is wound using the following components :
40mm diameter grey PVC pipe with a length of 9.5cm
2 endcaps 40mm PVC
Simple zip cord (multi-stranded core insulated wire)
8 turns bifilar wound
2 banana type chassis connectors
1 SO239 socket

Terminals B and C are wired to the banana chassis connectors for hooking up the feedline. The SO239 terminal center pin is wired to C and it's shield to D. Make sure to connect D and A together. As can be seen on the image at the top of this page, the wiring enters the PVC pipe and all connections are made internally. In my case - since I am using the balun inside - I did not glue the endcaps to the pipe but used a couple little screws instead. This way the balun is easy to service should the need arise.

NOTE: Let give the credit where it dues, the above instruction was originally taken from H5ANX design.

There are some other delta loop designs that do not require balun too. GOOGLE is your friend!
Found another one:

1 comment:

Saj said...

Hello OM,
Thank you for referencing the 4:1 air core balun. That was created out of necessity when i did not have access to ferrite cores.
The beauty is that you get multi-band performance with the balun. Eg. 40 will give you all bands between 40 and 20. while 20 gives you full 5 band capability (20,17,15,12,10).

New project - Ubitx - Radi2cino

I've always been interested in building my own radio. I've seen many projects available on the net which I could get my hands dirty ...