hi
Hi,
I have read all post so far. First, a lot of thanks to J Player for opening
a new thread. I do agree absolutelly with that. J Player's notes,suggests and
ideas are more than welcome and I could not do anything else but agree and thanks!
Some hints:
* For dish I can advice only Al or Cu.
* 555 to replace with 7555 is just fine.(due to power consumption)
* freq.of 555 is to be tuned a lower than 1khz.
* stabillity is not very important due to purpose of polarisation of the dish,
that's why is 555 choice,dish need some potential and freq. can vary a bit.
* transformer is not only for rising voltage but as a galvanic isolation and
band-pass too.
* dish is better than cage due to wider range of rejecting,although a cage is
very nice solution if you want a narrow angle of "scaning".
"Inside this box you should keep the circuit with the differential amplifier
as close to the antenna as possible..." J Player's note
* This is crucial !!! I do agree 100%. Otherwise all You pick up is a noise!
that's why teflon is used.It should be a teflon holder for antena and pcb
at the same time! No wires at all in between! The rest of the box may be
Lexan or metal.
"I think it's important to define what is the audio to loudspeaker, as there
is no audio generator and then signal comes from antenna. The 1 mF tantal
capacitor at the out of differential stage has a great value and then only
very low frequencies can arrive to loudspeaker, I suppose a sound like "tac".
Very strange the imput stage as on the contrary of instrumental amplifier it
has a single input, also doubbled, and a differential output. I think the
voltage on the Al dish it's not a perfect DC voltage but it has a little
ripple of the oscillator frequency and this is the "carrier" of signal
received." FrancoItaly's notes
Ciao Franco, come e sta? I guess that's all from my Italian!
Well You have right at some points. Audio is "poor" a bit, but enough.You can
mod it if You want. The 1mF tantal is a filter. "Tac" is supposed to hear and
it is allright.Input is ultra high impendace, only way to collect some ions.
Input has a "double" or "twins" but with different level of amplifying, think
about that! Both are leaded in to diff. amp.and only a slice shift You hear
in a speaker.About "carrier", well You might be right.I was thinking to put
some extra filter on it.Open for ideas.
Hi Esteban!
"The audio output connect to an audible signalizer type bip-bip. So,
convert any "bad" tac or tic or etc. in a bip-bip."
Yes Esteban, I agree! I was thinking to mod this anyway.
About "jail" or "cage"(as I named it), yes, but it is very narrow and You have to
use a fan. Fan, from the other hand, can produce some noise to input....
It will need some extra electronics to calm down that noise.But in any case,
"jail" is nice too.
Well, what to say more....it seem that if we all put some ideas here(and draws and
some mod's schematics) we can come up to a very nice device. That was my
idea at the begining. Besides, man can learn much more when share with others!
In that spirit I salute You people.
Best regards.
P.S.
I am waiting for more mods. J Player did a great job so far.
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