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.

4 comments:

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Ricardo - CT2GQV said...

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...and where is the email? :]

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