Tuesday, March 16, 2010

A Navtex receiver, some tests

Today I am happy, my simple navtex receiver outperformed my TS-50 tranceiver, altough the TS-50 isn't supposed to be a performer at those frequencies neither it was connected to the loop antenna, insted it was to the outside dipole... the inportant is something that I brewed outperformended an appliance!!!
There was a schedule transmission and 1 minute before (Murphy law) it started getting a lot of static. I couldn't hear the signals in the TS-50 but they were visible in the navtex receiver.

Also changed the VFO for varicap control because I have no varicap's spare. Four nice red led's did the job. The led's are connected in pairs catode with catode then we get 3 terminal, one to ground, the other to the top end of the vfo coil, the midle, both catode, are for voltage control. Placed 4 led's at all so I can get enough frequency shift. A variable 47k pot is used to get the variable tension to the varicaps.

Some crappy photos (tm):

I decided the this receiver will be cristal controlled so I must now find a 3168Khz and a 3196Khz cristal to get the 518 and 490Khz reception. Oh well another project waiting for conclusion.

I was looking in some junk electronics boards I use to get some missing/strange parts and in one floppy drive I found an Hall sensor... this could be fun for some future project. Never the less I found no cristal on the frequencies I want.


Anonymous said...

Sorry for my bad english. Thank you so much for your good post. Your post helped me in my college assignment, If you can provide me more details please email me.

Ricardo - CT2GQV said...

Nice it helped :=)
...and where is the email? :]

Anonymous said...

I would like to exchange links with your site speakyssb.blogspot.com
Is this possible?

Ricardo - CT2GQV said...

Shure.... here's one: http://speakyssb.blogspot.com...I have some more to spare if you like! :P