 |
PM |  | |
Quote | | |
Reply | | |
Full Topic | |
| Joined: | Jun 8th, 2008 |
| Location: | Maine USA |
| Posts: | 74 |
| Status: |
Offline
|
Very kool to see this kind of work...I remember my post and read the info on the coils...I am currently working on cleaning organizing repairing all that good stuff and planning once again to seriously get back into low level signal work.
As you may know I am now live streaming most of my ongoing work - dont really look for ghost pictures in the streams its alot of time consuming work to trudge thru video frames...at some point I will be doing the actual research once I get standards set for signal measurement; it takes more time to prepare than to test !
I will add this circuit to my list - also look at leaving out the use of OPAMPS - try using discrete components like single transistor (and FET) amps and filters - I have not looked deeply into the circuitry here yet - I have a general idea from the beginning of the thread and I will make a device similar as best I can then start comparing and adding here.
Also look at using a bridge circuit for increased sensitivity output into an FET input section - lots of gain and high S/N ratios here !
I will be using this as a possible low level input standard; adding filters etc - I need to verify what is called a-wight and c-wight filter design.
(EDIT:(!): Weighted filters I found were used to test microphones I should know I had to design some for that reason some years back - I totally forgot what the reason was til I read up on them. It was said that as such these filters were best suited for singles tones (to transmit to microphones for testing) due to low distortion (which wasnt mentioned (!); they are not suitable for broad range of freqs - also cant remember how the bandwidth are on them - the idea was to get really low distortion; might be suitable for Spiricom but I dont think that was an issue and probly not necessary.
As for not using OPAMPS - possible mixing of radio frequencies inside or near them...simpler circuits may leave out interference but then again the crystal radio was simple; just my own processing.
I will be doing up streams on power supplies and noise, filtering and such, and building my prototype input amps and filters soon; then I get to hook it all up and start the real research !
As I may have mentioned I only scanned this thread - havnt studied it but I have the idea; I will add this to my list; try it first then start adding here; I happen to have found a large bag of old relays - I knew they would be good for something...)
I will stay tuned here !
Mr Zeta
Last edited on Sep 14th, 2014 06:12 PM by MrZeta