Well, I "paid my dues" in the homebrew department over 50 years
ago.? A world war 2 ARC-5 TVI generator for the PA tube &
socket, an old TV set for its power transformer, plate loading
coil wound on a plastic pill vial, an old auto air filter gave the
perforated metal for the PA tube compartment cover, I'm sure you
get the picture.? I stick to operating these days & let the
younger folks do the design & building.
Gerry Sherman
Sent by the Linux Thunderbird
On 2023-03-28 00:43, Siegfried
Jackstien wrote:
toggle quoted message
Show quoted text
yes .. rs918 is mchf clone
but it was our group that included freedv in mchf and it WAS ME
WHO HAD THE IDEA!!
dg9bfc sigi
Am 28.03.2023 um 00:49 schrieb Gerald
Sherman:
The RS918 is the Chinese copy of M0NKA's McHF.
Gerry Sherman
Sent by the Linux Thunderbird
On 2023-03-27 18:40, Siegfried
Jackstien wrote:
nope .. its the second
first is/was mchf (and now its cloned from china)
i brought david and our programming group together ... rest
is history :-)
the guy with the laptop on very right is me ;-)
i have often used freedv with pc on shortwave and i have
found out that the freedv hardware solution .. smartmic ..
sm1000 .. has an stm32 chip and the mchf also has that stm32
inside ... then i brought david rove in contact of our user
group
dg9bfc sigi
Am 27.03.2023 um 01:35 schrieb
Ashhar Farhan:
The digital voice mode that could possibly
replace ssb is freedv. It is actually two things that work
together.
First, the voice is converted into a
stream of very few bits per second. A usual voice stream
like that of telephone uses about 64,000 bits per
second. Freedv codec reduces it to 700 bits per second.
This is at the cost of reduced quality. However, it is
much better that SSB on 80 meters.
The second thing is an HF modem that can
work at 700 bits per second. This is a weird one. On HF
as signals bounce off the ionosphere and arrive at the
rx antenna, you can have a situation where the same
signal can arrive taking different paths and hence at
different times , overlapping itself. This reduces the
number of times you can rapidly change the frequency of
the signal. This is why FT8 works so well, it is so slow
that fading, et al doesnt affect it. So, what the freedv
modem does is that it transmits a number of parallel ft8
like signals as separate tones within the same audio
which when added up give you higher bandwidth. There is
a very impressive name for it that escapes me now.
Our plan is to add freedv into the sbitx,
making it the the first radio to support it natively.
- f
Gordon:
Either RadComm or Sprat
had an article how students in England were
fascinated by Morse code. When asked why, they
replied that "voice" (SSB) didn't interest them
because they could do that with their cell phone.
But Morse was "better" because their parents
couldn't understand what was being said.
Any port in a storm...
Jack, W8TEE
Well, for several years now we have
observed some thing very fascinating among
middle schoolers in our local school.
They are not interested at all in
walkie-talkies
They are not interested at all in HF
radios
Don¡¯t even get me thinking about
digital.
What they absolutely go crazy over,
what they will grab onto and play with
until you have to pull them away kicking
and screaming with their parents,
Is a Morse code key!!!
At every school open house that we hold
we now always provide multiple Morse code
keys and it is a big draw.
We will provide them at this year¡®s
field day
The news media always want a picture of
someone sending Morse code
We have two 6th graders in a very small
school that are already doing about 10
words per minute. I sent 30 minutes worth
of code to them two weeks ago?
It is astonishing the attraction that
Morse code has for these middle schoolers
Meanwhile, across town, at the school
devoted to future police and fire high
schoolers, they have an extremely active
contesting high school I am radio club and
I am told that their best operator can do
over 30 words per minute and they
routinely make hundreds and hundreds of
contacts at voice and CW in contests. ?
Our local ham radio club would have a
hard time beating them!!!!
So I wouldn¡¯t quite give up yet. ?human
nature is the same. And there are certain
number of us who really love the auditory
and tactile tickling that only Morse code
gives¡. And by the way it is the first
digital, the only digital that can be
decoded by the human brain without much
else.? End it enjoys an order of magnitude
or two advantage over voice In terms of
threshold signal to noise ratio!!!?
On Mar 26, 2023,
at 13:23, Dan Eggers N7DE <N7DE@...>
wrote:
?
Thank
you?for the
information.? I see you and I are both
CW old timers.? So far we have lost
about half of the CW people without any
real replacements coming along, but you
and I came along during a certain era.
Best wishes.? ? ?
?73, Dan
Eventually there will be something that
replaces analog single side band voice.
But it¡¯s not yet here. ? And I think I
have been doing CW for 55 years or more. ?
That¡¯s my thought
Gordon Kx4z?
On Mar 26,
2023, at 11:51, Dan Eggers N7DE <N7DE@...>
wrote:
?
I have
been sending Morse code now for
57 years, and I will just
continue to send Morse code, but
since you seem to be very
knowledgeable is there a digital
voice modulation system that
will eventually replace SSB?
Thank
you.? ? ? ? ? 73, Dan, N7DE?
Single side band typically
requires a 10 DB signal to noise
ratio for useful communications in
a disaster.? That is, the
efficient transfer of information
My contrast, using the same
base noise in that bandwidth,
data communications of moderate
speed can tolerate SNR into low
single digits, and still move
efficient communications far
faster than voice
Low data rate redundant
digital communications can
tolerate signal to noise ratios
a couple orders of magnitude
lower SNR
These comparisons are widely
available
It¡¯s no secret why people who
are very involved in the (voice)
national traffic system often
have kilowatt amplifiers. ?
And people who are into JS8
?don¡¯t need them
So there are different
requirements for different parts
of our hobby
On Mar
26, 2023, at 11:33, Dan
Eggers N7DE <N7DE@...>
wrote:
?
I
used 20 watts for a long
time, and I have had a
number of people refuse
to talk to me, because
my signal was too week,
so more power is
needed.? I have written
a booklet about solar
cells, and maybe you use
solar cells and power
conversion, and that is
also a very interesting
area, but I also want to
be able to talk to
people.
?
? ? 73, Dan, N7DE? ?
With respect, Dan,
"need" isn't an actionable
or useful concept,
especially in QRP land.
I live on a sailboat and
am currently in Tampa Bay.
With a couple of meters of
tinn
On Sat, Mar 25, 2023 at
01:55 PM, Dan Eggers N7DE
wrote:
20 w is -7 dB, and that is too far down.? it is
getting close to -10
dB down.? You need
to be at 50 w, and
that is only -3 dB
down.? What I have
used for low cost
has been an MRF455
in an EB63A board
from Communications
Concepts, and it
works very well.
?
However, the Chinese are selling a 100-w
amplifier with a
heatsink that has
had the level set,
and they also sell a
lowpass filter board
XDT LPF200 for 3 -
30 MHz at a
reasonable price
that works very
well, so these days
there really isn't
any reason to "build
your own"
amplifier.?
?
The main thing I am saying is that you need more
power so that you
can be heard.? I
went through enough
Electrical
Engineering courses
that I am now an
Electrical Engineer,
but I do not think I
am going to try
design amplifiers
from scratch myself.
?
I am very grateful for all of the people who
helped produce the
UBITX 6, because I
think that has been
the only low cost
real general
coverage transceiver
that is out there.?
? ? ? ? ? ?73, Dan,
N7DE
?
Hi Ted
Thanks. Incidentally
the FET is? IRFP150?
And Not IRF150 , sorry
for the typo.
I will edit at the end
of the video..
The FET i have used is
Harris IRFP 150
It works great with
not much heat at 35 V
.
Regards
Sunil vu3sua
--
Jack, W8TEE
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