Loggings > North American Shortwave Pirate

Wolverine Radio 6925u

<< < (2/3) > >>

Zoidberg:

--- Quote ---Lex, what program do you use to copy SSTV off the air?
--- End quote ---

MMSSTV, one of the world's great freebie programs.  Should be available from several sites.

Very easy to use, only takes a little work to set up.  Once the program is calibrated to your sound card's clock, it runs in auto mode with little or no user intervention.

Other than the calibration step (easy to do and explained with the program, mostly using a WWV freq), the only other step is probably to use a ferrite choke or isolation transformer on the cable between the receiver and computer, since connecting the receiver to the computer will probably generate some hash.  I use an ordinary shielded mono audio patch cord - RCA on the receiver end, mini jack on the sound card end - with Radio Shack ferrite chokes on either end.  One choke cuts the RFI about 95% and the second cuts the rest.  Some folks prefer an isolation transformer but so far I haven't found that necessary.

Most folks will get better reception than I do, especially from Wolverine.  I'm just using a passive indoor shielded magnetic loop, and when conditions are good my SSTV reception from Wolverine is nearly noise-free.

Fansome:
I have had pretty good results just holding a microphone up to my receiver's speaker.

SW-J:

--- Quote from: Lex on July 01, 2010, 1920 UTC ---
--- Quote ---Lex, what program do you use to copy SSTV off the air?
--- End quote ---

MMSSTV, one of the world's great freebie programs.  Should be available from several sites.


--- End quote ---

Thanks Lex, I'm going to give that a try ...

.

Zoidberg:

--- Quote from: Fansome on July 01, 2010, 1935 UTC ---I have had pretty good results just holding a microphone up to my receiver's speaker.

--- End quote ---

Not all of us can decode SSTV in our heads.   :o

Seamus:

--- Quote from: SW-J on July 01, 2010, 2006 UTC ---
--- Quote from: Lex on July 01, 2010, 1920 UTC ---
--- Quote ---Lex, what program do you use to copy SSTV off the air?
--- End quote ---

MMSSTV, one of the world's great freebie programs.  Should be available from several sites.


--- End quote ---

Thanks Lex, I'm going to give that a try ...

.

--- End quote ---
Over the years, I have used several different programs for SSTV reception of both amateur and pirate material, and MMSSTV remains my favorite.  It may not be as polished as some of the others, but it's robust, flexible, and quite functional.

The "quick and easy" way to hook it up is, as mentioned above, to place your computer's microphone next to your receiver's speaker.  It will pick up the squawks and warbles and magically turn them into images.  It will also pick up other noises in the room, and be subject to some of the oddities of going through an acoustic link, but it's a perfectly usable method, and one that we used to get many people on the air with SSTV back when I was in Florida.

Another method also mentioned above is the direct audio line, though also as mentioned, you may need to choke out some noise with ferrite beads or toroids.

The method I prefer is to use a 1:1 transformer in the line, to isolate the radio and the computer from being directly connected to each other.  This also lets me throw an attenuator into the mix so I can adjust the levels easily with a knob instead of having to mess with onscreen volume controls all the time.  I also have another isolation transformer going the other way, from the computer to the radio for sending SSTV on the ham bands.  This is part of the interface that I made, which also has an outgoing attenuator (again, no fiddly onscreen controls), manual/off/auto TX switch (using the computer's serial port to kick the radio into TX mode), and a level meter to avoid splatter. 

That's a whole hellofalot more than the basics required to work SSTV though.  For the isolation cable approach, all you really need is an audio cable with a 1:1 transformer in it (you can use other values too if 1:1 isn't available - I've seen people use all sorts of wacky values and work fine - it just needs to be an audio transformer).

Then again, for full transmit-receive capability, a mic and speakers work just fine - just hold the one up to the other, depending on which direction you're going, and the sound goes through.

Navigation

[0] Message Index

[#] Next page

[*] Previous page