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}

I would suspect that any TV type Matching Transformer
that had Capacitors in-side it would be designed to have
them act as part of a Low Band Rejection Filter for the
AM/MW {Shortwave} Band and 'pass' only the Higher
VHF and UHF TV Bands.

somebody educate me please ~ RHF