[600MRG] Rudy's book...and other info.

[Kenneth G. Gordon]

On 25 Jan 2018 at 13:46, Rudy Severns wrote:

> Thanks for the kind words Ken.  One important point however.  Originally I
> posted six chapters, the sixth one was on inductor design.  

Which I need VERY badly!!!! :-(

> I have been doing a total rewrite of that chapter which is now ready
> except for one final read-through edit.  I will try to have that
> available in the next few days so hold off with the binding!! 

OK. :-) 

There is plenty of very interesting and valuable information in what I have now, so no need 
to hurry. I 've got a lot of reading to do.

> The changes are very important, especially for all the bucket-inductor
> users. 

Well, some time ago, I did some work with an OLD program which is supposed to be able to 
calculate necessary inductor values, and physical parameters for base-loaded verticals, and 
came up with 680 uH, something like 83 turns on an 8" diameter form (PVC), 12" long 
wound of #12 stranded THHN insulated house wire, spaced, to be mounted at the bottom of 
my 55' vertical.  

"Q" was reportedly 450.

Vo at the top of the coil appeared to be about 9500V, which is "handle-able". Antenna 
effeciency seemed to be as much as 5%, which isn't bad considering how crappy the 
antenna really is.

Yet when I plug the value of the inductor into my MMANA-GAL model of my vertical, I get 
strange results.

The model of the vertical-alone matches empirical results almost perfectly. Adding the 
base-loading coil makes it go all bonkers.

Then again, I am not (yet) very good at antenna modelling so, I am almost certain my model 
isn't quite right either.

I also tried to model a 132 foot sloper, or sort of sloping-inverted "L", I guess you could call 
it, for 472 kHz, and the results are weird, so I gave up on that for the time being.  

It is looking like the sloper part is only a capacitive top-hat for the 40 foot vertical feed-line 
which is connected to the "bottom" end of the sloper...according to the model, at any rate.

The top end of the sloper would be in the top of our 110 foot tall pine tree, and the bottom 
end would be on top of our home at about 30 feet AGL, then about 40 feet of feed-line 
vertically to the transmitter, which is in the basement.

I am not pleased.

Thanks again, Rudy.

Ken W7EKB


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