[AMPS] ARRL and QST (and CW Relevance)

km1h@juno.com km1h@juno.com
Sat, 30 Jan 1999 19:57:07 -0500




On Sat, 30 Jan 1999 01:47:27 GMT wrt@eskimo.com (Bill Turner, W7TI)
writes:
>
>On Fri, 29 Jan 1999 19:23:17 -0600, Jon Ogden <jono@enteract.com>
>wrote:
><snip>
>>>If you send dit-dit-dit-dah and noise or QRM causes you to
>>>miss a dit and copy it as U instead of V, you have no way of knowing
>>>you got it wrong.
>>
>>Yes, I do.  Let's say the V was the start of the word Very.  When I 
>hear 
>>Uery, I know that I got it wrong.  I have error correction.
>
>Ok, if you're happy with "uery", no problem.  I'm not.



In the real world its called "fill" by experienced ops. Of course its not
applicable to copying code groups ( :


________________
>Yes, it CAN work magic.  It's done with signal averaging.  The DSP
>will record a short piece of signal, say a few hundred milliseconds,
>and analyze it looking for a pattern buried in the noise.  The pattern
>of course, is the tone from the signal you're trying to receive.  In
>effect it "subtracts" the totally random stuff from the non-random
>stuff and what's left is the signal.  If you ever get a chance, watch
>a modern digital storage oscilloscope in action.  Put in a sine wave
>which is totally buried in noise.  In the "normal" mode, nothing is
>visible to the eye except what appears to be white noise.  Turn on the
>"averaging" mode and like magic, the noise fades away and the sine
>wave appears.  The first time you see this happen it will give you
>goose bumps.  At least it did me.


It sure looks good on a lab scope and there are $10K + boxes that are
available but IMO the ham related stuff is mostly useless with a GOOD
radio.

I have bought and sold  just about every ham style DSP unit on the market
during attempts to improve 160M DX and VHF meteor scatter results. The
only item I still have is one of the first DSP on the market, an old JPS
NF-60 automatic notch filter which far outperforms the multiple use boxes
for notching out carriers for those rare times I go on SSB.

Under the best of condx, the NF-60 was used in series with other DSP
units but outside of a lab I found that having only 2 hands really
limited the usefulness. Drift and tune forever which is why many EME ops,
etc choose the DSP between their ears.

73  Carl  KM1H


.



>
>This same technology can be applied to radio.  NASA has used it for
>years to dig spacecraft signals out of the noise.  It works; now we
>need it applied to amateur radio.  It's coming.
>
>
>73, Bill W7TI
>
>
>--
>FAQ on WWW:               http://www.contesting.com/ampfaq.html
>Submissions:              amps@contesting.com
>Administrative requests:  amps-REQUEST@contesting.com
>Problems:                 owner-amps@contesting.com
>Search:                   http://www.contesting.com/km9p/search.htm
>
>

___________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
or call Juno at (800) 654-JUNO [654-5866]

--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm