Its all pcm (pulse Code Modulation).
One channel is 64 KHz, 8 bits, 8KHz sample, that is two samples at 4000 Hz.
The digital phone encoding has more resolution in the center of the
amplitude range to help improve things (or lower bandwidth).
So the digital part of the network does pass to 4000 H
The digital stuff actually goes out to 4000 Hz.
In the past, my company did the network for the FAA, and we had to test the
lines out to 3400 Hz to pass what was needed.
That was often at the end of a lot of copper
Sorry, but I think some rigs just sound nasty, although part of it might be
t
I always thought the fun part was improving things.
I have KT88's as modulators in my 32V3, no driver transformer, and VR tube
regulated screen voltage.
I guess a lot of the sound is in the operators voice, the best stock audio I
ever heard was an old sure 55s plugged into a stock 32V.
If I did
Grant has this correct!! for those that doubt, ask youself this. How often
do I use phonetics when speaking face to face? And why not? Ans. BECAUSE
YOU ARE HEARING THE FULL SPECTRUM! Bernie W8RPW- Original Message -
From: "Grant Youngman"
To: "Discussion of AM Radio in the Amateur Se
"We now fully accept glitchy, noisy and
totally unreliable service at an absurd price as the norm .. :-)"
Amen Grant!
Cellular handsets with no side tone, and sometimes severe latency issues make
for inefficient and unsatisfactory telephony!
Frank/W9FM
Grant Youngman wrote:
> On Sep 15, 2
On 15th September, Grant wrote:
"...Bad just sounds bad, not to mention the fact that all cellular has
really done is kill our "old fashioned" expectations of what phone service
should be. We now fully accept glitchy, noisy and totally unreliable service
at an absurd price as the norm ..."
*
Joe wrote:
> I really don't care whether people chose to modify their old AM
> transmitters to "improve" sound quality, as they can do whatever they
> want with their radio. What does bother me a little is when people use
> words like "nasty" and "awful" to describe the audio quality of some
> cla
On Sep 15, 2009, at 2:05 PM, Charles Ring wrote:
>
> While modern telephones can produce better audio (no carbon mics),
> modern phone exchanges don't. Th e old exchanges passed whatever audio
> was fed into them at least for local calls, but digital switching
> has a
> brick wall cutoff. I
It
Grant Youngman wrote:
> On Sep 15, 2009, at 1:11 PM, Joe Hankins wrote:
>
>
>> I
>> operation was effective radiotelephone service. Human speech falls
>> into
>> the range between 300 and 3000 Hz. There are sounds outside this
>> range,
>> but they do not contribute to intelligibility.
>>
Jim,
You stole my thunder. Negative feedback is a very effective way of reducing
distortion and smoothing frequency response. It was used in the Ranger to
reduce the effective plate resistance of the 1614's so that it would work
well as a speech amplifier for a larger modulator (such as the 810
The method of negative feedback in the audio section of the Ranger is
unique and very effective.
Jim/W5JO
- Original Message -
>I wonder why the Ranger would be among the best stock audio and the
> Valiant among the worst? Same maker, same vintage, etc.
>
> 73 de W3NU
>
>
__
On Sep 15, 2009, at 1:11 PM, Joe Hankins wrote:
> I
> operation was effective radiotelephone service. Human speech falls
> into
> the range between 300 and 3000 Hz. There are sounds outside this
> range,
> but they do not contribute to intelligibility.
That's actually a complete myth. There
I really don't care whether people chose to modify their old AM
transmitters to "improve" sound quality, as they can do whatever they
want with their radio. What does bother me a little is when people use
words like "nasty" and "awful" to describe the audio quality of some
classic transmitters,
Maybe because the Valiant was *better* engineered. Remember the era -
people were trying to get "talk power" out of AM, not hi-fi. So the
clipping, compression, and restricted frequency range were all
intended to enhance communications.
Nick K4NYW, running a 4-400 modulated by 807's.
On Tue, Sep
Bill,
Are you ok?
I think that you may have had a brain fart right there in the middle of your
message.
I am redoing the Par-Metal cabinet that my 50's 813 rig goes in and sprayed
the base with Rust-oleum 7220 textured black paint.
It came out looking like the finish on my 32V2 cabinet. Darker
I wonder why the Ranger would be among the best stock audio and the
Valiant among the worst? Same maker, same vintage, etc.
73 de W3NU
Larry Szendrei wrote:
> Concerning the discussion of audio modifications to commercially designed
> amateur AM transmitters:
>
> A lot of these rigs from the 19
Concerning the discussion of audio modifications to commercially designed
amateur AM transmitters:
A lot of these rigs from the 1950s (Viking I, Viking II, Valiant, DX-100)
did, in fact have pretty nasty audio in their stock state, and there are
good reasons to go in and engineer improvements in t
Bill,
Absolutely. I used a space heater to heat each side since I ended up
working the bulk one side at a time anyway. The Sun has not been out of the
clouds in several days, or that's exactly what I would have used. I'm going
to wait until Saturday (next forecast for sunshine) and finish it up
Not to be argumentative, but Krylon wrinkle does work on primered surfaces.
I always paint aluminum rack panels first with a self etching primer and then
the wrinkle paint. With aluminum you must absolutely use primer either self
etching or Zinc Chromate (which by the way the state of Californi
Brian, a technique that I use is to dip a sponge into a shallow dish of
finish coat cut with paint thinner so it is almost the consistency of water.
It is like applying a wood stain using a brush and then wiping off. I would
let the wrinkle paint dry for at least several days - a week would be bes
Great info David. Thanks!
I was really surprized the Krylon worked as well as it did. The finsh
everywhere except the lid wrinkled very nice and smooth. The lid wrinkled,
but at an angle you can see some areas of defect, but you have to really
look to see it. I had overspray mixed and rattle c
Brian, I have had good luck with Krylon Black Wrinkle 3370. I buy mine from
Advanced Auto. Unfortunately, WalMart does not sell it.
For a finer wrinkle finish try Rustoleum Stone Creations paint. Overspray
with the correct color match. I believe that Lowes carries this line.
David Knepper, W3
David, I don't know about the primer issue with wrinkle paint. I've heard
people have done it both ways. Main reason I primed it was the fact I took
it down to the bare metal when I prepared the surface and primed it just to
keep it from rusting before I got the wrinkle paint in the mail. Took 2
Jim,
Thanks for your graciousness when you said, "it is your radio to do as you
wish and one thing we try to do as operators of AM equipment is preserve the
equipment and mode." I greatly appreciate your comment. Fields like that
of the electronic technician represent a very small selection
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