RHF wrote:

On Jan 26, 9:21 am, "RHF" wrote:
On Jan 26, 6:11 am, David wrote:



On Fri, 26 Jan 2007 02:03:04 GMT, Telamon

wrote:
In article ,
David wrote:

On Thu, 25 Jan 2007 03:06:28 GMT, Telamon
wrote:

If you use a cable TV Balun you'll get a quick and dirty 4:1
transformer and a marked improvement.

http://www.radioshack.com/product/in...103912&cp=&sr=...
gkw=matching+transformer&kw=matching+transformer&p arentPage=search

Those don't work well below 10 MHz. 15 MHz and higher they are OK.

How do you know?

I tested them.

What is the low frequency limiting component?- - I didn't go as far as that.
- - This unit is made of a ferrite core and
- - a couple of very small value capacitors.
- - I would guess the core was the problem.
-
- I've reverse engineered a bunch of them.
- The ones with caps are very rare.

- Offhand - I can only come up with two reasons to
- put Capacitors in-side a Matching Transformer :
- 1 - To make it [Narrow] Band Specific {Tuned}
- 2 - To make it [Wide] Band Rejection {High -or- Low}

Example - Shortwave Baluns and Accessories
http://www.kintronic.com/site/subassemblies/baluns.asp
Kintronic Laboratories offers two types of Shortwave Baluns.
First is a discrete Discrete Component Shortwave Balun
with Tunable Capacitors to permit a 1:1 Match at any
Frequency in a Single Shortwave (HF) Band of operation.

New Longwire Balun 9:1 Transformer High Performer
-by- LowBander on eBay
http://cgi.ebay.com/_W0QQitemZ180078653482

About Baluns - What is the Best Balun ?

The best ones are the ones I build myself!

I have one that has been in use since 1988.

dxAce
Michigan
USA