[Milsurplus] Re: TA2J High Power Tx in Catalina

[Mike Hanz]

Hue Miller wrote:

>Mike, it seems the schematic was not available.
>

It's there, Hue.  Since you are using Microsoft Outlook Express 5.50 for 
e-mail, I'm making a wild assumption that you are also using Internet 
Exploder...and being a subhuman form of web browser life, it cannot 
display large images without declaring itself helpless in a 
non-intuitively obvious way.  Let me guess...it shows a little *x* box 
up at the upper left corner when you "left" click on the link labeled 
"Schematic".  To use this browser (which I personally will NOT do 
because of security and performance concerns such as this) to download 
large image files, *right* click on the schematic link, rather than 
"left" clicking.  That will bring up a menu that includes "Save target 
as".   When you click on that, you'll be able to download the .gif file 
to your hard drive and view it with an appropriate viewer application as 
I suggested on the web page, or use the IE Picture and Fax Viewer 
offered after you complete the download.  Sorry, but that's the breaks 
for the transgression of using IE.  <large grin>  Mozilla, Netscape, and 
Opera bring it right up, and Opera set at 20% magnification allows you 
to see most of the schematic without messing with it.  All are free, but 
my preference is for Opera, with Mozilla a close second (I can't stomach 
the memory/cpu overhead slowdown on Netscrape, and I have a dual proc 
3GHz PC!)

>I ask, does it use simply a tapped coil as the output, like the BC-230
>or the GF, for example?
>

Well, in a way.  It has eight detachable roller coils similar to those 
in a command transmitter, but with *two* roller taps (plus a grounded 
end.)  One tap is for feeding the output of the 803 PA plate into the 
inductor (through a .004uF coupling cap), and the other tap feeds the 
antenna.  B+ is fed through the RF choke seen at the top in the "left 
interior view."  Through a procedure that is too convoluted to quote 
here, you fiddle with the two rollers to match the antenna (which must 
be at *least* 250pF to resonate.)  You can also strap a 100pF fixed 
shunt cap into the circuit for certain conditions.  For series 
capacitance (above 7.5MHz) you need to buy the "Type MT-36C Series 
Antenna Loading Unit," which may have been a clever marketing ploy to 
get you to spend more money at Bendix.  It's a unit the same size as the 
TA-2J!

>Also- Mike or anyone else - the RDF-1, the HF predecessor to the DU,
>which tuned to 8000 kcs. - do you have any idea how far down the
>reception with it would be, from a standard wire antenna of say, 30 ft. ?
>I mean in the B position, receiving totally on the loop alone, say on
>80 or 40 ?
>

Sure!  Just as soon as you define what "how far down"; "reception with 
it"; and associated receiver actually means. <grin>  I have no clue what 
you are talking about in technical terms.

Best 73,
Mike