[GreenKeys] 'Russian woodpecker' of old...

[WA5CAB at cs.com]

Another thing to keep in mind before going gaa-gaa over the numbers quoted 
is that pulse-echo RADAR is inherently low duty cycle.  You send out a pulse 
and then you sit and wait a while for returns.  Other things being equal, 
the higher the duty cycle the shorter the maximum range.  If returns come 
back after you start transmitting again, you are not going to hear them.  And 
significant returns from a previous (to the most recent) pulse are confusing 
and difficult to sort out.  So in the sense of radio transmitters operating 
continuously, your normal assumptions will be off by an order of magnitude 
or two.

In a message dated 10/14/2010 11:06:52 PM Central Daylight Time, 
comcents at bellsouth.net writes: 
> On 10/14/2010 10:32 PM, tony j. podrasky wrote:
> >Hey guys;
> >
> >Thanx for the links - fascinating stuff!
> >
> >I read an article that said this thing was running 10MW of power.
> >
> >Now, I'm not much of an R-F person - but can someone tell me
> >where the heck do you get a tube that can handle 10MW?
> Think multiple tubes in parallel.
> >   How do
> >you make a power supply to handle that?
> Think 20KV @ 1KA...
> >What about feedline?
> From the photos - they were using ladder lines...  Hard to 
> judge how far apart - but even at 20KV - a couple of feet 
> would do - and again - in parallel...
> >What keeps things from arcing all over the place?
> >
> I suspect that's the reason for the shape of the "driven" 
> elements...  If you want to read some interesting things 
> about antenna arcing (corona)  - and how it was solved - 
> read about HCJB and the birth of the cubical quad. The 
> cubical quad isn't the only "form factor" to deal with 
> corona; but it was one of the earliest.  I suspect the cone 
> shape of the feed ends of the elements (and the rounded ends 
> at the opposite ends of the elements) serve the same purpose.
> 
> best regards...
> 
> -- 

Robert & Susan Downs - Houston
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