Re: LF: Re: [rsgb-lf-group] EbNaut LF page

[Andy Talbot <andy.g4jnt@gmail.com>]

and another thought ...

I believe a number of OPs use sources that genberate at 2* RF and the PA does the frequency division.  Clearly getting a 180 deg phase shift isn't possible here, as it would need a 360 deg shift at 2* Rf.  Which is no change.

SO what's needed is a circuit that grabs / chops out, (or adds ) a cycle of the drive every time the phase change is requested.    WHich ought to be simple enough - but needs a bit of thought.  

Andy

www.g4jnt.com

On Tue, 18 Dec 2018 at 14:40, Andy Talbot <andy.g4jnt@gmail.com> wrote:

Basically, all you need is the ability to shift the phase of your transmitted RF by 180 degrees under command of a line from the computer

This can be done at RF by a number of means - many involving a centre tapped transformer and changeover switch, or a reversing switch,.  Otr at logic levels using an Exclusive-OR gate.

Alternatively, if you use a transverter from an audio tone, the audio can be inverted usng an opamp -1/+1 gain circuit.   

If you feel a write up of possible ideas would be welcome, may consider summat

Andy

www.g4jnt.com

On Tue, 18 Dec 2018 at 14:34, N1BUG <paul@n1bug.com> wrote:

Hi EbNaut LF,

With material from K3RWR and K3SIW I started a page about using
EbNaut on LF. This is an attempt to help people who are interested
in using EbNaut on LF but having problems understanding all the
complexities.

http://www.n1bug.com/lfmf/ebnaut/index.shtml

I hope I will be able to put much more information there. If anyone
would like to contribute articles, diagrams, photos etc. it will be
very much  appreciated.

I will also try to put some links to other web sites, pages, etc.
but I don't promise to maintain those as things disappear or URLs
change. :-)

Speaking only for myself, I am still struggling to understand
hardware setups. So far, the only EbNaut hardware setup I understand
well enough to build it is K3RWR. All the others still going over my
feeble head. ;-)

73,
Paul

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