"DW Holtman" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
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Hello,
Thanks to everyone for all of the information. I'm going to fix it, the
wording about fixing was is not exactly what I was thinking. I planned on
repairing it all along. It is not too complicated, at least the schematic
looks doable, but it has been a long time since I worked on solid state
circuits. It will be a challenge that I'm looking forward to.
Hopefully it will help my signal on this noise 40 meter band.
Best,
DW Holtman
WB7SSN
----- Original Message -----
From: "Jim Shorney" <[EMAIL PROTECTED]>
To: "drakelist" <[EMAIL PROTECTED]>
Sent: Thursday, October 04, 2007 3:47 PM
Subject: Re: [drakelist] SP-75 Speech Processor
"Jim Shorney" <[EMAIL PROTECTED]> made an utterance to the drakelist
gang
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On Thu, 4 Oct 2007 11:11:26 -0600, DW Holtman wrote:
Will a SP-75 Speech Processor really improve my signal, so in situations
where I'm barely heard, my signal will be easier to copy? How does it do
this? Dosen't increasing the audio cause splatter? Why didn't the original
manufactures use the most optimal audio modulation?
To expand on what Evan said, the SP75 is a true RF speech processor that
offers clipping as well as compression. It does this by converting the
audio
to double-sideband RF, processing and filtering it, and converting it back
to
audio. If you do some Googleing, you will probably find some good
information on RF speech processing as the most effective type of
processing.
It does not increase splatter because of the built-in filtering (as long
as
you don't overdrive the radio, that is). It also has a noise gate circuit
on
the input to help keep unwanted background noise from being processed.
On the practical side, I've used my SP75 with my TR7 at the LARC Field Day
the past two years and gotten rave audio reports. The clipping action
allows
me to keep the audio peaks just below the ALC threshold (further reducing
the
possibility of splatter) while maintaining good average output.
I'm sure an on-air demo could be arranged for you to actually hear one,
since
many list members use them.
Fix it. Or sell it to me cheap, I'll fix it and use it... :)
73
-Jim
--
Ham Radio NU0C
TR7/RV7, TR6/RV6, T4XC/R4C, L4B, NCL2000, SB104A, R390A, GT550A/RV550A,
HyGain 3750, IBM PS/2 - all vintage, all the time!
HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/
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