On Wednesday, October 20, 2021, 09:44:48 AM EDT, Dean Souleles <dsouleles@...> wrote:
20 watts clean!?
I put the transmit amplifier chain together yesterday - two 2N2219A stages followed by an IRF-510 stage to get the drive level where I needed it for the dual RD16HHF1s.? After adjusting the RF gain stage I am getting 20 watts clean out - which is a bit more than I expected.? The input drive level range seems to be fairly narrow and the amp runs a bit warm. Skelton has the bias on the RD16s at 500mA.? I may try reducing the bias and see how things shake out.
?
?
73,
Dean
KK4DAS
-- Jack, W8TEE
|
20 watts clean!?
I put the transmit amplifier chain together yesterday - two 2N2219A stages followed by an IRF-510 stage to get the drive level where I needed it for the dual RD16HHF1s.? After adjusting the RF gain stage I am getting 20 watts clean out - which is a bit more than I expected.? The input drive level range seems to be fairly narrow and the amp runs a bit warm. Skelton has the bias on the RD16s at 500mA.? I may try reducing the bias and see how things shake out.
?
?
73,
Dean
KK4DAS
|
Re: HF Digital Voice Modulation modes
Hi Tom,
I'm preparing a new paper in English to send for a conference soon. I
let you know!
; )
Also, for images, HIFIC, for example, provides significant better
compression than traditional non-AI based image encoders.
Rafael
PU2UIT
toggle quoted message
Show quoted text
On 10/19/21 3:49 PM, Tom, wb6b wrote: On Tue, Oct 19, 2021 at 04:34 AM, Rafael Diniz wrote:
With 1.6 kbit/s you get very good voice with state-of-the-art AI-based
voice encoders
Hi Rafael,
I see you have an interesting paper covering some experiments with the
new trained neural net voice encoders/encoders used on HF radio links.
'adio_de_longa_distancia_utilizando_a_banda_de_HF
<'adio_de_longa_distancia_utilizando_a_banda_de_HF>
For those interested, the pdf can be uploaded to google translate and
it will spit back a translated version.?
Tom, wb6b
|
TSW Firmware for ourTeensy 4.1 Raduino Kit
Just finished uploading some needed small bug fixes to our current firmware ?V1.59. ?Anyone who has downloaded it in the last few days should download it again. ?I also updated the software operating manual to reflect the new, improved display screens and correct some very minor typographical errors that could possibly caused some confusion.
The latest software manual is included in the firmware zip file and can also be found in the documentation directory of the TSW home page, ?.
Jim, W0EB
TSW Project Coordinator
|
Ismo, ?Hans Summers of QRP-Labs did a pretty comprehensive set of tests on the MS5351 and published his results on the QRP-Labs home page.
I¡¯ve been using them in TSW¡¯s Teensy 4.1 Raduino Clone with excellent results. ?On the air tests with 2 different uBITX rigs, one using the genuine Si5351a and one using the Chinese MS5351m in the T4.1 Raduinos showed no noticeable difference in signal quality, RX sensitivity and TX performance. ?I¡¯m out of the Si5351a¡¯s now but have sufficient MS5351 chips on hand that I won¡¯t run out anytime soon.
Jim, W0EB
TSW Engineer/Project Coordinator
|
Randy,
Evan asked all the right questions.
However, without yet knowing the answers, I'd say you need to first determin
somehow if the VFO and BFO are working.
If you have access to a shortwave receiver, you should hear the BItx40 BFO at
12.0 mhz when that receiver's antenna is near the BItx40.
A finger around L5 and C102 should cause a small frequency change.
A modified Bitx40 may have disabled the 12mhz crystal oscillator at Q10,
obtaining that 12mhz BFO signal from CLK0 of the Raduino instead.
On a very old Bitx40, the varicap diode at D9 and the coil at L4 were used
to tune that oscillator at Q9 with a potentiometer across the TUNING1 connector.
When the Raduino was added in December 2016, the oscillator at Q9 was
disabled by removing L4, and then driving the DDS1 connector with CLK2
from the Raduino for the VFO.? On a stock Bitx40 tuned to 7.00 MHz the VFO
should be within 3 khz of 12-7.00=5mhz.? On some?modified Bitx40's?
the Raduino's VFO may be operating at 12+7.00=19mhz instead.
If the Raduino is working, you should be able to hear that 7mhz or 19mhz
signal on the receiver as well.
Of course, if you have access to an oscilloscope or spectrum analyzer,
those could be used to check the BFO and VFO as well.
A good high resolution schematic should be available here:
? ??
under the tag "Download the circuit diagrams".
Unfortunately that link is broken, so I am attaching the schematic for the Bitx40 to this post.
That is the only version of the Bitx40 schematic with Raduino that was ever made available.
There are some minor corrections to be made to that schematic:
All transistors labeled BC849 are actually stuffed with MMBT3904's (the surface mount version of the 2n3904)
C93, C103, and R105 are not stuffed, R105 has all three terminals shorted together.
D15 and D16 are packaged together in one BAT54S surface mount part.
I would recommend not exceeding 12 volts dc.
At 13 or 14 volts there is a risk of burning out some of the parts.
Be sure you have a good enough antenna to capture signals on the air.
This radio is designed to work best with a resonant 50 ohm transmitting antenna.
With at least 10 meters of wire laid across the floor for an antenna, you should start hearing signals.
In some cases, the BNC connector was not machined precisely enough, and the center pin
did not make contact.? Make sure you really do have a connection to the antenna.
If you bought this used, it may have been sold for a reason.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Tue, Oct 19, 2021 at 08:19 AM, Evan Hand wrote:
Hi Randy,
It sounds like you have a calibration issue or a component(s) INSTALLED that should not be there when using the Raduino as the VFO/LO.? The one other possibility is the BFO may not be aligned correctly.
Let's start with what test equipment do you have to work with?? An oscilloscope, DMM, and frequency counter are tools that make diagnostics easier.
Can you also verify that L4 is not installed?? That is for the analog VFO/LO and should be removed when using the Raduino.
Are there any modifications to the board?
Last on the list is the software that is installed in the Raduino.? Is it original or one of the updates/upgrades that are available that include things like CW options.
I do not have a BITX40.? I have e different version of the ?BiTx that is based on the design of the BITX40, so know a little bit about the operation.? Here is the circuit description on HFSignals web page:
You will use this to trace the signals through the rig.
Let us know what you find out about the points above.
73
Evan
AC9TU
|
Re: HF Digital Voice Modulation modes
Wow!
Things have advanced considerably.
Those 1.6 kbps voice samples were better than I expected.
At 5 GMAC/s, the computational load is significant but within easy reach.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Tue, Oct 19, 2021 at 04:34 AM, Rafael Diniz wrote:
With 1.6 kbit/s you get very good voice with state-of-the-art AI-based
voice encoders (eg. LPCNet or SSMGAN). Please take some time to hear:
And try also with FreeDV 2020 (with LPCNet).
1.5kbit/s with audio barely intelligible was 25 years ago with some
second generation vocoders... which were indeed pretty good for the
time. Codec2 in standard version go down to 700 bps, and down to 450 bps
with data-driven reconstruction techniques.
Cheers,
Rafael
|
Hi Randy,
It sounds like you have a calibration issue or a component(s) INSTALLED that should not be there when using the Raduino as the VFO/LO.? The one other possibility is the BFO may not be aligned correctly.
Let's start with what test equipment do you have to work with?? An oscilloscope, DMM, and frequency counter are tools that make diagnostics easier.
Can you also verify that L4 is not installed?? That is for the analog VFO/LO and should be removed when using the Raduino.
Are there any modifications to the board?
Last on the list is the software that is installed in the Raduino.? Is it original or one of the updates/upgrades that are available that include things like CW options.
I do not have a BITX40.? I have e different version of the ?BiTx that is based on the design of the BITX40, so know a little bit about the operation.? Here is the circuit description on HFSignals web page:
You will use this to trace the signals through the rig.
Let us know what you find out about the points above.
73
Evan
AC9TU
|
Re: HF Digital Voice Modulation modes
On Tue, Oct 19, 2021 at 04:34 AM, Rafael Diniz wrote:
With 1.6 kbit/s you get very good voice with state-of-the-art AI-based
voice encoders
Hi Rafael, I see you have an interesting paper covering some experiments with the new trained neural net voice encoders/encoders used on HF radio links. For those interested, the pdf can be uploaded to google translate and it will spit back a translated version.? Tom, wb6b
|
In need of troubleshooting help with my bitx40 with Raduino.
I hooked everything up per the instructions and all appeared to be working.
Unfortunately for several days, I could only hear white noise while tuning through the 40 m band.
Finally, I heard a commercial broadcast.
?I attempted to tune away from the broadcast. While the Raduino still appeared to be working, the radio was locked onto the commercial broadcast.
What parts of the circuit could be causing this, and what can I do to get the radio to tune properly?
Thanks K5UTM
|
Re: HF Digital Voice Modulation modes
With 1.6 kbit/s you get very good voice with state-of-the-art AI-based
voice encoders (eg. LPCNet or SSMGAN). Please take some time to hear:
And try also with FreeDV 2020 (with LPCNet).
1.5kbit/s with audio barely intelligible was 25 years ago with some
second generation vocoders... which were indeed pretty good for the
time. Codec2 in standard version go down to 700 bps, and down to 450 bps
with data-driven reconstruction techniques.
Cheers,
Rafael
toggle quoted message
Show quoted text
On 10/18/21 10:59 PM, Jerry Gaffke via groups.io wrote: Yes, that all sounds right.?
You can do a lot with 1 carrier, but the more you do the more
susceptible it is to noise.
I am curious how much more bandwidth 2 tone GMSK needs over something
using?
the most sophisticated multiple tones, multiple phases, multiple
amplitudes scheme
for equal performance in the presence of typical HF noise.?
I'd guess not much, but could be wrong.? Regardless, on HF we would be
forced
to do that stuff if we must follow this absurd max symbol rate of 300
baud.
D-Star on VHF gets by with choosing between just two tones, has a
bandwidth of 6khz
for fair voice quality.? Bitrate is higher than what Codec2 can do,
Codec2 should get it down to 3 or 4 khz for the same voice quality.
At 1500 bps, I'd guess Codec2 is just barely intelligible,
everybody sounding like a 50 year old TV robot.
Jerry, KE7ER
On Mon, Oct 18, 2021 at 10:58 AM, Ashhar Farhan wrote:
The codec2 with packet overheads will come to approximately 1500
bps. With the 300 baud limit, we are looking at 1500/300 = 5 bits
per baud.?
We slice this many ways. The easiest way is to have five tones.
One for each bit. Further, you can reduce it to half, or lets say
3 bits with each bit having four values at 0, 90, 180 and 270
degree phase shift from the previous phase, thus conveying two
bits. Further, you can add two amplitude levels double from four
to eight different? values, bringing the bits per tone to eight.
These are usually plotted on a phase/amplitude graph as a
constellation.
These higher bits per baud accordingly need better cnr to resolve
the exact phase or amplitude.
Wspr/jt set of modulation schemes limit themselves to a single
frequency modulated tone. It achieves remarkable relience by
averaging the carrier frequency over tens of cycles
- f
|
Re: HF Digital Voice Modulation modes
On Mon, Oct 18, 2021 at 12:59 PM, Jerry Gaffke wrote:
max symbol rate of 300 baud.
The regulations are as clear as mud, but one interpretation may be that is perfectly OK to transmit digital voice at baud rates high enough for digital voice. And doing so with GMSK as well as other digital modulation modes. Just as long as you transmit digital in the voice part of the HF bands. If you want to transmit digital anything in the parts of the HF bands reserved for RITTY/Data then the 300 baud limitation come into play. Interesting, they don't even mention CW anymore. It is all data now.?
"(2) No non-phone emission shall exceed the bandwidth of a communications quality phone emission of the same modulation type. The total bandwidth of an independent sideband emission (having B as the first symbol), or a multiplexed image and phone emission, shall not exceed that of a communications quality A3E emission."
Above paragraph cut from this document:
Tom, wb6b
|
I long forgot that stuff, I still have several of the Z80 chips in my parts boxes never been used for the project they were intended for.
Skip Davis, NC9O
|
Re: HF Digital Voice Modulation modes
Yes, that all sounds right.?
You can do a lot with 1 carrier, but the more you do the more susceptible it is to noise.
I am curious how much more bandwidth 2 tone GMSK needs over something using?
the most sophisticated multiple tones, multiple phases, multiple amplitudes scheme
for equal performance in the presence of typical HF noise.?
I'd guess not much, but could be wrong.? Regardless, on HF we would be forced
to do that stuff if we must follow this absurd max symbol rate of 300 baud.
D-Star on VHF gets by with choosing between just two tones, has a bandwidth of 6khz
for fair voice quality.? Bitrate is higher than what Codec2 can do,
Codec2 should get it down to 3 or 4 khz for the same voice quality.
At 1500 bps, I'd guess Codec2 is just barely intelligible,
everybody sounding like a 50 year old TV robot.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Mon, Oct 18, 2021 at 10:58 AM, Ashhar Farhan wrote:
The codec2 with packet overheads will come to approximately 1500 bps. With the 300 baud limit, we are looking at 1500/300 = 5 bits per baud.?
We slice this many ways. The easiest way is to have five tones. One for each bit. Further, you can reduce it to half, or lets say 3 bits with each bit having four values at 0, 90, 180 and 270 degree phase shift from the previous phase, thus conveying two bits. Further, you can add two amplitude levels double from four to eight different? values, bringing the bits per tone to eight.
These are usually plotted on a phase/amplitude graph as a constellation.
These higher bits per baud accordingly need better cnr to resolve the exact phase or amplitude.
Wspr/jt set of modulation schemes limit themselves to a single frequency modulated tone. It achieves remarkable relience by averaging the carrier frequency over tens of cycles
- f
|
Re: HF Digital Voice Modulation modes
The codec2 with packet overheads will come to approximately 1500 bps. With the 300 baud limit, we are looking at 1500/300 = 5 bits per baud.? We slice this many ways. The easiest way is to have five tones. One for each bit. Further, you can reduce it to half, or lets say 3 bits with each bit having four values at 0, 90, 180 and 270 degree phase shift from the previous phase, thus conveying two bits. Further, you can add two amplitude levels double from four to eight different? values, bringing the bits per tone to eight. These are usually plotted on a phase/amplitude graph as a constellation. These higher bits per baud accordingly need better cnr to resolve the exact phase or amplitude. Wspr/jt set of modulation schemes limit themselves to a single frequency modulated tone. It achieves remarkable relience by averaging the carrier frequency over tens of cycles - f
That's a good description of MSK, but there is a second order discontinuity when it switches tones.? The slope of the curve makes an abrupt change there.? GMSK makes the transition more gradual, but still centers the transition on the zero crossing like MSK.
??
A modulation scheme such as Olivia can choose from dozens of different tones sent one at a time, not just two different tones.? With enough different tones to choose from, you can probably have enough bandwidth to meet the needs of Codec2 voice transmissions and still meet the US FCC's 300 baud max symbol rate.? But I'm guessing the total bandwidth occupied would not be much less than a two tone signal switched at a fast enough rate to give the same bandwidth.? Switching between many different tones can probably be done using the GMSK method, but all the basic descriptions of GMSK I've seen so far only tell us about the two tone version.
Most Codec2 transmissions on HF take it a step further, and send multiple tones simultaneously to get even more bandwidth out of that 300 baud max symbol rate.? These transmissions must go through a linear amplifier.
Jerry, KE7ER
On Mon, Oct 18, 2021 at 08:59 AM, Ashhar Farhan wrote:
Gmsk is really very simple.
First, it picks two frequencies that the carrier switches between. Second, the frequency is switched preciselt where the signal hits the zero voltage. Thus, it avoids the abrupt ending of one frequency waveform and start of the next.
- f
|
Re: HF Digital Voice Modulation modes
That's a good description of MSK, but there is a second order discontinuity when it switches tones.? The slope of the curve makes an abrupt change there.? GMSK makes the transition more gradual, but still centers the transition on the zero crossing like MSK.
??
A modulation scheme such as Olivia can choose from dozens of different tones sent one at a time, not just two different tones.? With enough different tones to choose from, you can probably have enough bandwidth to meet the needs of Codec2 voice transmissions and still meet the US FCC's 300 baud max symbol rate.? But I'm guessing the total bandwidth occupied would not be much less than a two tone signal switched at a fast enough rate to give the same bandwidth.? Switching between many different tones can probably be done using the GMSK method, but all the basic descriptions of GMSK I've seen so far only tell us about the two tone version.
Most Codec2 transmissions on HF take it a step further, and send multiple tones simultaneously to get even more bandwidth out of that 300 baud max symbol rate.? These transmissions must go through a linear amplifier.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Mon, Oct 18, 2021 at 08:59 AM, Ashhar Farhan wrote:
Gmsk is really very simple.
First, it picks two frequencies that the carrier switches between. Second, the frequency is switched preciselt where the signal hits the zero voltage. Thus, it avoids the abrupt ending of one frequency waveform and start of the next.
- f
|
Re: HELP on Gerber Files of M0YTH
re,
I had put a TDA2030 kit directly on my NJM2073 output, for me it worked fine, but the TDA2030 packed up and fried the NJM2073.
I know that we also need to add filters to the output of the TDA2030 to prevent runaway. here my NJM2073 amplifier  ?
|
Re: HELP on Gerber Files of M0YTH
Hello,
I have a question about the addition of a more powerful amplifier type TDA2030.
For you, what is the best adaptation to connect it to an existing amplifier on its loudspeaker output. Example:  cdt ?
|
Re: HF Digital Voice Modulation modes
Gmsk is really very simple. First, it picks two frequencies that the carrier switches between. Second, the frequency is switched preciselt where the signal hits the zero voltage. Thus, it avoids the abrupt ending of one frequency waveform and start of the next. - f
As I understand it, GMSK as used by D-Star is just two tones.??
In GMSK, the transition from one tone to the other is made as soft as possible
to reduce the bandwidth of the resultant signal, the key click filter on a?
CW transmitter does something similar.
Looking around the web, I don't see much talk about D-Star modulation for HF.
My guess is that anybody using D-Star on HF just uses the same modulation scheme
as on VHF, ignoring the FCC's 300 baud max symbol rate.? ? Does anybody know for sure?
If AM phone is still legal, I suppose they would argue that a 6khz wide D-Star
transmission should be too.? Or perhaps I am wrong about the 300 baud max.
Jerry, KE7ER
On Mon, Oct 18, 2021 at 05:38 AM, Tom, wb6b wrote:
On Mon, Oct 18, 2021 at 05:18 AM, Evan Hand wrote:
I thought that FreeDV was a multiple carrier mode and would require a linear amp.
I was proposing to use the FreeDV codec but use the GMSK modulation type. Or another FSK type it it is better.?
I don't think there's any reason not to mix and match codecs (voice encoders) and modulation schemes.
Tom, wb6b
|
Re: HF Digital Voice Modulation modes
As I understand it, GMSK as used by D-Star is just two tones.??
In GMSK, the transition from one tone to the other is made as soft as possible
to reduce the bandwidth of the resultant signal, the key click filter on a?
CW transmitter does something similar.
Looking around the web, I don't see much talk about D-Star modulation for HF.
My guess is that anybody using D-Star on HF just uses the same modulation scheme
as on VHF, ignoring the FCC's 300 baud max symbol rate.? ? Does anybody know for sure?
If AM phone is still legal, I suppose they would argue that a 6khz wide D-Star
transmission should be too.? Or perhaps I am wrong about the 300 baud max.
Jerry, KE7ER
toggle quoted message
Show quoted text
On Mon, Oct 18, 2021 at 05:38 AM, Tom, wb6b wrote:
On Mon, Oct 18, 2021 at 05:18 AM, Evan Hand wrote:
I thought that FreeDV was a multiple carrier mode and would require a linear amp.
I was proposing to use the FreeDV codec but use the GMSK modulation type. Or another FSK type it it is better.?
I don't think there's any reason not to mix and match codecs (voice encoders) and modulation schemes.
Tom, wb6b
|
Jim Sheldon
Skip Davis
Gerard