Digital Signal Processors DSP

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From: Byron8LCZ@aol.com
Date: Sat Mar 18 1995 - 21:31:46 EST


The Radio Shack DSP filter is just that, a filter. The JPS or Timewave 599+
 DSP's are alot more. They have a peak function, the software in the DSP
reconizes the signal, amplifies it, then surpresses the noise, thereby
increasing the signal to noise ratio by a substantial amount. The Timewave
also has filters from 25 hz to 1.6 khz.
 
the Radio Shack filter is around 70 dollars, the JPS is abt 249 and the
Timewave is 299.00 It depends on what you're looking for. A couple of my
QRP buddies ( WB8E & AA8LZ ) have the radio shack filter and like it.

You'll find the current draw can also be heavy, as much as 500 ma. at 12
volts (JPS). I use the JPS NRF-7 all the time, i've found i depend on the
constant noise reduction, especially on 80 and 40 meters. But its not a cure-a
ll. i still have alot of noise to content with. the 80/40 meter noise must be
a combination of atmospheric, man-made and band noise. No one device seems to
help alot. Using a full wave closed loop antenna seems to do more than any
other single method to reduce. My typical 80m noise level is s-5 and my 40m
noise is s-3 or greater. I live a couple of miles from Detroit and have alot
of noise round the clock. If i could figure out how to get a 80m loop on my
small property, i would do it.

Another option is a SCAF filter, Oak Hills Research has them for abt 60
bucks. They work extremely well.

Some DSP's are designed for the SSB op, like the JPS NRF-10 which includes a
automatic notch filter that handles up to 4 hetrodynes. The NRF-7 is
designed for the QSK CW op, it has fast recovery, two cw filters and a peak
function, but unfortunetly you cant use the cw filter and the peak at the
same time.
The Timewave gives you more options (filters, peak, notch,agc) and lets you
use them together but the peak function is harder to set and needs to be
adjusted often.

A discussion on DSP is directly related to QRP and ham radio, and i'll bet
there are at least a hundred hams out there, that want to hear about it or tal
k about it. DSP is part of the future of ham radio, it will be built into
more and more rigs in the next few years. Its already in the Kenwood TS 950,
The Ten Tec Omni-6 and probably other rigs.
 
On another subject:
Too many people on this list are afraid to say something for fear of
offending the "self appointed QRP-L police". If you are paying for a Internet
connection, you have as much right to speak as anyone else. If you let these
guys silence you, we'll all miss the opportunity to learn more about our
favorite hobby, QRP. Ask questions, make comments, thats what this list is
all about. If the "police" dont like it, too bad. Some of the "very best"
comments I've seen on this list, come to me in private e-mail, bacause the
authors dont want to offend the police. What a shame. Just think of all the
really interesting posts that everyone else has missed.
  
72, Byron WA8LCZ


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