[sdiy] Transformer question ( skin effect )

Tom Arnold xyzzy at sysabend.org
Mon Apr 11 20:06:10 CEST 2011


> Some things I wonder about without checking into it...
> Your problem is only a Transmit mode problem - you don't
> need the boost during receive as it is a much lower power mode.
> So noise developed for the boost is only during TX and probably
> not much is sensitive to it then. 

Yes, in fact this board has an RF sense circuit, which is fine as long as
you have enough voltage to run the reciever, which drops out around 11volts.
Battery is rated down to 10.5 ( actually 10.1 I found ) so a lot of life
left that I can use otherwise.

> You may just be able to utilize a large capacitance bank and
> large guage wiring to get the boost you want compared to what
> you are starting with.  Maybe look into cap banks used for these
> outrageously loud car stereos.  All those design and implementation
> techniques would apply to your problem/goal.  Pulling power out
> of the bank may give you a lower source impedance source and
> be a big help vs just a battery source.

That would give me current, but I need the voltage to be Alternator level
and not Battery level. Only drawing 17amps or so on the one radio.  Just
need to keep te voltage up to the efficient range for its outputs.  And I
want to make sure it'll be okay if I forget to turn off my APRS rig and it
happens to transmit a beacon while I'm on HF.

> Lastly, why in the heck do you need more than the ~100W a 
> typical XCVR has?  Are you bringing a linear out with you to
> the beach??  Maybe just work on making a better antenna?

This is my mobile rig. A mobile whip on 80m is not the most efficient thing
in the world so I'm trying to make the radio as happy as possible.

-- 
 -----------------------------------------------------------------
 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -  "...is it a virus, a drug, or a religion?"
 - AF6YW            -  Juanita Shrugs. "What's the difference? 
 --------------------         -- Neal Stephenson,  Snow Crash


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