TopBand: 2-wire beverages (part 2)

[Lee Wells]

de KT4ZX - Lee Wells - leewells@lexmark.com

Once I got home last night, I made a couple mods to the 2-wire 
beverage box.  When I opened up the box, I noticed that one ground 
wire MAY have been shorting to the signal wires...I made sure this 
was well insulated when I put it back together.  The other thing I 
did was add a 50 ohm terminating resistor that gets switched in to 
the unused port.  So about midnight I wandered back outside to 
reinstall the box (the neighbors surely think I've lost it now!).

And now the results......

	- 160 still doesn't have much of a F/B ratio.  I finally 
	found one US station that would go up or down by a 2-3 S 
	units (on a Icom-745) when switching directions.  
	Europeans were still down in the mud, with no noticable 
	difference front to back.

	- 40m is a different story!!!  Listening to some broadcast 
	stations on 40 I was able to see a 20-30 db difference 
	(S9+40 to S9+20).

	- 80m looked good too.  I heard some US stations working a 
	TK6.  Off the back (west) all I could hear was static, off 
	the front the TK6 was easy copy!  The US stations also showed 
	a 3-4 S unit drop when switching directions.

	- WWV on 5 MHz is 20db stronger off the back.

	- WWV at 2.5MHz shows almost no difference (maybe 5 db) 
	front to back.

So I'm beginning to think the low frequency response of this thing 
is way off!  Does that mean I didn't use enough turns for the 
transformers????  Or is this really a fair comparison since at 7MHz, 
the beverage is somewhere over 3 wavelengths long.

Any ideas on whats going on here????

Thanks again....
	--Lee




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