[OZAPRS] Bad signal on 30m

[Norm McMillan]

Terry Neumann wrote:
> Richter, Mike W wrote:
> 
>> Getting RF Feedback using a TinyTrak should not be a surprise - the
>> inputs and outputs go direct to the chip without ANY form of filtering
-
>> I suggest putting a 1k resistor in series and a 0.01uF to ground on all
>> pins that run off the board.
>> Mike VK2BMM

...snipped...
> 
> G'day Mike and others,
> 
> This is good advice.   I went even further as I thought (perhaps in the 
> wrong direction).   I used minature rf chokes (from Jaycar) on all the 
> significant in/outputs from the board, and built mine TT3 board  into a 
> diecast box as well.

I have had this thought in the back of what passes for my mind for a 
couple of days (Its 41degC here and the mind is a little rubbery!!!) 
Terry did you stick with the DB9 connectors or use something smaller? 
(Mini Din???)

> 
> This unit has been used in both of our vehicles on 30 metres and on 2 
> metres and appears to be free of  RF issues - so far.
> 
> It may have been overkill, but I'm a farmer, and agricultural 
> engineering principles invariably find their way into all situations 8-)

Beats me you didn't weld up a plate steel box out of an old square water 
tank ;)
> 
> Is there any merit in using rf chokes as opposed to using resistors, or 
> vice versa??

RF chokes will have a lower DC resistance.
Resistors will carry a larger current before the smoke escapes.
RF chokes will form a resonant cct with the bypass capacitor.
Resistors will likewise form an RC timing network at some frequency.
RF chokes are around $0.70 ea, Resistors around $0.03.
Guess the last line gets it!
> 
> Regards,
> Terry VK5ATN
> 
> 
> 
>

-- 
Norm, VK2XCI,
Voice of The Edge of The Outback.
QF27wd
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