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Today's Topics:
1. Re: Icom IC-9700 and Kantronics TNC (GEO Badger)
2. Re: Icom IC-9700 and Kantronics TNC (Tim N8DEU)
3. Re: Icom IC-9700 and Kantronics TNC (W3AB/GEO)
4. Re: Icom IC-9700 and Kantronics TNC (Tim N8DEU)
----------------------------------------------------------------------
Message: 1
Date: Sun, 6 Sep 2020 18:28:24 +0000 (UTC)
From: GEO Badger <w3ab@?????.???>
To: Tim N8DEU <n8deu@???????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
Message-ID: <2081713883.787830.1599416904133@????.?????.???>
Content-Type: text/plain; charset=UTF-8
Tim,
It seems a modulation issue of some type.
I don't have a 9700 but I do have a 7600 and had a modulation distortion
problem. When using the accessory port insure that "DATA OFF MOD" is set
only to "ACC", not "MIC+ACC". All the others should be set to "USB".
___
Sent from my two way wrist watch
73 de W3AB/GEOOn Sep 5, 2020, at 22:00, Tim N8DEU <n8deu@???????.???> wrote:
I made several measurements with the deviation starting at 0.75 kHz up to
4.00 kHz in 0.25 kHz steps. At each step 10 packets were transmitted and
multiple receivers were used for decoding. At no point did the success rate
go above 50% decoding. At 3.25 kHz and 3.50 kHz the transmit decode rate was
50%. All other settings were less.
?
The Kantronics 9616 cannot drive the IC-9700 any higher than 4.07 kHz
deviation and that level is achieved at XMITLVL = 114. Increasing the
XMITLVL does not produce any additional increase in FM deviation using the
square wave tone from the CALIBRATE mode.
?
I have worked with 1200 baud packet for 33 years and set up quite a number
of systems and this one will require some more observation. The same
Kantronics 9612 connected to a Yaesu FT-736 or and an FT-847 show a 100%
packet decode rate at 1200 baud. Both of these radio?s work fine at 9600
baud which is something not mentioned anywhere for the IC-9700.
?
I was checking to see if others are having issues with the IC-9700. This
started with a friend asking questions for the past 2 months about having
trouble with the IC-9700 connected to a KAM XL and I walked him through all
the logical steps. Finally, I decided I better try hooking my 9612 up to the
Accessory Port to see how it works. This should not be too complicated. My
results were exactly the same poor results he encountered on transmitting
1200 baud packets.
?
Increasing TX Delay does nothing to help as that does not seem to be the
issue.
?
1200 baud packets are decoded through the receiver perfectly fine.
?
The problem is transmitting 1200 baud packets for a successful decode rate
on the IC-9700 through the Accessory Port.
?
?
?
Best Regards,
Tim Cunningham ? N8DEU
?
?
?
From: GEO Badger
Sent: Saturday, September 5, 2020 3:00 PM
To: Tim N8DEU
Cc: amsat-bb@?????.???
Subject: Re: Icom IC-9700 and Kantronics TNC
?
Can you look at the deviation?
?
---?
Ciao baby, catch you on the flip side
??
73 de W3AB/GEO ???
http://www.w3ab.org
You can say "over", you can say "out", you just can't say "over and out".
?
?
On Friday, September 4, 2020, 08:59:04 PM PDT, Tim N8DEU <n8deu@???????.???>
wrote:
?
?
Simplex is the only method I tried at this point to keep it simple.
?
Two different IC-9700 Radio radios, one with a Kantronics 9612 and one with
a Kantronics KAM XL. Both using simplex and both exhibiting the same results.
?
?
- Tim
From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of W3AB/GEO via
AMSAT-BB <amsat-bb@?????.???>
Sent: Friday, September 4, 2020 6:52:05 PM
Cc: amsat-bb@?????.??? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
?
Tim,
Have you tried simplex contacts?
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
On Sep 4, 2020, 14:53, at 14:53, Tim N8DEU via AMSAT-BB
<amsat-bb@?????.???> wrote:
>Has anybody interfaced a Kantronics 9612 or the KM XL TNC to the
>accessory port of the Icom IC-9700?
>
>The reason I am asking is there are two IC-9700 users using the same
>firmware who are experiencing the same issue with both of these TNC?s.
>Packets are decoded with little to no issue on the receive side, but
>the transmit side is a different story.
>
>It seems only about 30% of the transmitted packets are decoded by other
>stations using 1200 baud. The deviation of the transmit signal and the
>TX delay are not the issue. The same TNC works with no issue on a Yaesu
>FT-736 and the FT-847.
>
>
>Thank You,
>Tim Cunningham - N8DEU
>
>_______________________________________________
>Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>to all interested persons worldwide without requiring membership.
>Opinions expressed
>are solely those of the author, and do not reflect the official views
>of AMSAT-NA.
>Not an AMSAT-NA member? Join now to support the amateur satellite
>program!
>Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________
Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
to all interested persons worldwide without requiring membership. Opinions
expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
?
------------------------------
Message: 2
Date: Sun, 6 Sep 2020 20:48:55 +0000
From: Tim N8DEU <n8deu@???????.???>
To: GEO Badger <w3ab@?????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
Message-ID:
<BY5PR02MB60827A1F48DD4D65034ED30EFE2B0@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="utf-8"
I stopped guessing and started measuring. The data holds the answer after a
deeper dive into this issue.
The audio is not distorted.
The problem with the ICOM IC-9700 and both Kantronics 9612 and KAM XL setups
is a very old problem. I knew something seemed familiar about the decode
problem, but it was 33 years ago. After measuring the IC-9700 signals on a
service monitor and viewing the signal on an oscilloscope hooked to a
Kenwood TH-D7a headphone jack, the picture was very clear. I discovered the
old twisted audio problem where the higher 2100 Hz tone is much lower in
amplitude than the lower 1300 Hz tone. Why does this matter? The XR2211
demodulators had immense trouble decoding packets with this condition and so
does the TH-D7a with a Tasco modem, but the Tasco modem decodes ~50% of
something where the XR2211 does not decode anything.
When (Amplow*cos(FreqLow)) is close to the same value as
(Amphigh*cos(FreqHigh)) the performance is not good on an XR2211 decoder nor
a Tasco modem chip. Early in the days of 1200 baud TAPR packet modem designs
it was discovered the higher tone needed to be 20 dB higher. In other words,
you at least need some pre-empahasis on the transmit signal for it to be
decoded and obtain some noise reduction. There is no pre-emphasis on the
transmit signal from the IC-9700 Accessory Port based on the results I
measured. The low tone is about 1.47 times higher than the high tone
relative to the deviation measured. When I measure the two tones levels with
an oscilloscope tied to the TH-D7a headphone jack, I measure the low tone is
1.29 times higher than the high tone.
Both of the audio tones output from the Kantronics 9612 are the same level
at roughly 50mV. Thus, the 9700 clearly alters the signal levels on the two
tones in a less than desirable fashion!
I have not tried sending audio through the microphone connector yet, but I
would hope it would at least have pre-emphasis for better results on
boosting the high tone.
Before I pass judgement, I will present the data to ICOM on the topic.
Hopefully, the response I get will be better than what my friend received
from them. They claimed to him the TNC keys the radio and it passes the
audio as if they have no problem in the equation. In their defense, they did
not understand the problem, but they did not pursue it either. Their
response was correct from a simplistic view, but what their radio does or
does not do with the audio can break everything. Pete, N4YOT, found if he
sent 2 duplicate packets back to back with his KAM XL, the transmitted
packet would be decoded. This raised the possibility the TXDelay might be
the culprit initially from his results. However, that gets into the 50%
packet decode rate.
When I hooked up my Kantronics 9612 on my end to the IC-9700, I experienced
the same problem as Pete and he worked on this for the past 2 months getting
nowhere and little help from ICOM. I finally hooked up the 9612 to the
IC-9700 to take a look for myself. It quickly became obvious there is a lack
of pre-emphasis on the high tone when the data is transmitted. In fact, the
emphasis is on the low tone or the high tone is being attenuated!!! The end
result is poor decoding of that transmitted signal when the low tone is
higher in amplitude than the high tone. There is indeed a problem with the
ICOM IC-9700 using the Accessory Port with 1200 baud packet.
This requires a hardware modification on the 9612 to implement a filter to
reverse these effects unless ICOM can provide some insight on how it can be
accomplished with their radio where the problem exists.
Let's see what ICOM has to say with the detailed measurements I collected.
Best Regards,
Tim Cunningham - N8DEU
From: GEO Badger<mailto:w3ab@?????.???>
Sent: Sunday, September 6, 2020 1:28 PM
To: Tim N8DEU<mailto:n8deu@???????.???>
Cc: amsat-bb@?????.???<???????????????@?????.???>
Subject: RE: Icom IC-9700 and Kantronics TNC
Tim,
It seems a modulation issue of some type.
I don't have a 9700 but I do have a 7600 and had a modulation distortion
problem. When using the accessory port insure that "DATA OFF MOD" is set
only to "ACC", not "MIC+ACC". All the others should be set to "USB".
___
Sent from my two way wrist watch
73 de W3AB/GEO
On Sep 5, 2020, at 22:00, Tim N8DEU
<n8deu@???????.???<????????????@???????.???>> wrote:
I made several measurements with the deviation starting at 0.75 kHz up to
4.00 kHz in 0.25 kHz steps. At each step 10 packets were transmitted and
multiple receivers were used for decoding. At no point did the success rate
go above 50% decoding. At 3.25 kHz and 3.50 kHz the transmit decode rate was
50%. All other settings were less.
The Kantronics 9616 cannot drive the IC-9700 any higher than 4.07 kHz
deviation and that level is achieved at XMITLVL = 114. Increasing the
XMITLVL does not produce any additional increase in FM deviation using the
square wave tone from the CALIBRATE mode.
I have worked with 1200 baud packet for 33 years and set up quite a number
of systems and this one will require some more observation. The same
Kantronics 9612 connected to a Yaesu FT-736 or and an FT-847 show a 100%
packet decode rate at 1200 baud. Both of these radio?s work fine at 9600
baud which is something not mentioned anywhere for the IC-9700.
I was checking to see if others are having issues with the IC-9700. This
started with a friend asking questions for the past 2 months about having
trouble with the IC-9700 connected to a KAM XL and I walked him through all
the logical steps. Finally, I decided I better try hooking my 9612 up to the
Accessory Port to see how it works. This should not be too complicated. My
results were exactly the same poor results he encountered on transmitting
1200 baud packets.
Increasing TX Delay does nothing to help as that does not seem to be the
issue.
1200 baud packets are decoded through the receiver perfectly fine.
The problem is transmitting 1200 baud packets for a successful decode rate
on the IC-9700 through the Accessory Port.
Best Regards,
Tim Cunningham ? N8DEU
From: GEO Badger<mailto:w3ab@?????.???>
Sent: Saturday, September 5, 2020 3:00 PM
To: Tim N8DEU<mailto:n8deu@???????.???>
Cc: amsat-bb@?????.???<???????????????@?????.???>
Subject: Re: Icom IC-9700 and Kantronics TNC
Can you look at the deviation?
---
Ciao baby, catch you on the flip side
73 de W3AB/GEO
http://www.w3ab.org
You can say "over", you can say "out", you just can't say "over and out".
On Friday, September 4, 2020, 08:59:04 PM PDT, Tim N8DEU <n8deu@???????.???>
wrote:
Simplex is the only method I tried at this point to keep it simple.
Two different IC-9700 Radio radios, one with a Kantronics 9612 and one with
a Kantronics KAM XL. Both using simplex and both exhibiting the same results.
- Tim
From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of W3AB/GEO via
AMSAT-BB <amsat-bb@?????.???>
Sent: Friday, September 4, 2020 6:52:05 PM
Cc: amsat-bb@?????.??? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
Tim,
Have you tried simplex contacts?
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
On Sep 4, 2020, 14:53, at 14:53, Tim N8DEU via AMSAT-BB <amsat-bb@?????.???>
wrote:
>Has anybody interfaced a Kantronics 9612 or the KM XL TNC to the
>accessory port of the Icom IC-9700?
>
>The reason I am asking is there are two IC-9700 users using the same
>firmware who are experiencing the same issue with both of these TNC?s.
>Packets are decoded with little to no issue on the receive side, but
>the transmit side is a different story.
>
>It seems only about 30% of the transmitted packets are decoded by other
>stations using 1200 baud. The deviation of the transmit signal and the
>TX delay are not the issue. The same TNC works with no issue on a Yaesu
>FT-736 and the FT-847.
>
>
>Thank You,
>Tim Cunningham - N8DEU
>
>_______________________________________________
>Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>to all interested persons worldwide without requiring membership.
>Opinions expressed
>are solely those of the author, and do not reflect the official views
>of AMSAT-NA.
>Not an AMSAT-NA member? Join now to support the amateur satellite
>program!
>Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________
Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
to all interested persons worldwide without requiring membership. Opinions
expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 3
Date: Sun, 06 Sep 2020 14:22:58 -0700
From: W3AB/GEO <w3ab@?????.???>
To: Tim N8DEU <n8deu@???????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
Message-ID: <0f73522b-d06f-43be-b765-2b91b2d1b3f3@?????.???>
Content-Type: text/plain; charset=UTF-8
Very good Tim. Thanks for diving in so deeply.
BTW, have you tried the TX audio EQ?
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
On Sep 6, 2020, 13:48, at 13:48, Tim N8DEU <n8deu@???????.???> wrote:
>
>I stopped guessing and started measuring. The data holds the answer
>after a deeper dive into this issue.
>
>The audio is not distorted.
>
>The problem with the ICOM IC-9700 and both Kantronics 9612 and KAM XL
>setups is a very old problem. I knew something seemed familiar about
>the decode problem, but it was 33 years ago. After measuring the
>IC-9700 signals on a service monitor and viewing the signal on an
>oscilloscope hooked to a Kenwood TH-D7a headphone jack, the picture was
>very clear. I discovered the old twisted audio problem where the higher
>2100 Hz tone is much lower in amplitude than the lower 1300 Hz tone.
>Why does this matter? The XR2211 demodulators had immense trouble
>decoding packets with this condition and so does the TH-D7a with a
>Tasco modem, but the Tasco modem decodes ~50% of something where the
>XR2211 does not decode anything.
>
>When (Amplow*cos(FreqLow)) is close to the same value as
>(Amphigh*cos(FreqHigh)) the performance is not good on an XR2211
>decoder nor a Tasco modem chip. Early in the days of 1200 baud TAPR
>packet modem designs it was discovered the higher tone needed to be 20
>dB higher. In other words, you at least need some pre-empahasis on the
>transmit signal for it to be decoded and obtain some noise reduction.
>There is no pre-emphasis on the transmit signal from the IC-9700
>Accessory Port based on the results I measured. The low tone is about
>1.47 times higher than the high tone relative to the deviation
>measured. When I measure the two tones levels with an oscilloscope tied
>to the TH-D7a headphone jack, I measure the low tone is 1.29 times
>higher than the high tone.
>
>Both of the audio tones output from the Kantronics 9612 are the same
>level at roughly 50mV. Thus, the 9700 clearly alters the signal levels
>on the two tones in a less than desirable fashion!
>
>I have not tried sending audio through the microphone connector yet,
>but I would hope it would at least have pre-emphasis for better results
>on boosting the high tone.
>
>Before I pass judgement, I will present the data to ICOM on the topic.
>Hopefully, the response I get will be better than what my friend
>received from them. They claimed to him the TNC keys the radio and it
>passes the audio as if they have no problem in the equation. In their
>defense, they did not understand the problem, but they did not pursue
>it either. Their response was correct from a simplistic view, but what
>their radio does or does not do with the audio can break everything.
>Pete, N4YOT, found if he sent 2 duplicate packets back to back with his
>KAM XL, the transmitted packet would be decoded. This raised the
>possibility the TXDelay might be the culprit initially from his
>results. However, that gets into the 50% packet decode rate.
>
>When I hooked up my Kantronics 9612 on my end to the IC-9700, I
>experienced the same problem as Pete and he worked on this for the past
>2 months getting nowhere and little help from ICOM. I finally hooked up
>the 9612 to the IC-9700 to take a look for myself. It quickly became
>obvious there is a lack of pre-emphasis on the high tone when the data
>is transmitted. In fact, the emphasis is on the low tone or the high
>tone is being attenuated!!! The end result is poor decoding of that
>transmitted signal when the low tone is higher in amplitude than the
>high tone. There is indeed a problem with the ICOM IC-9700 using the
>Accessory Port with 1200 baud packet.
>
>This requires a hardware modification on the 9612 to implement a filter
>to reverse these effects unless ICOM can provide some insight on how it
>can be accomplished with their radio where the problem exists.
>
>Let's see what ICOM has to say with the detailed measurements I
>collected.
>
>
>Best Regards,
>Tim Cunningham - N8DEU
>
>
>From: GEO Badger<mailto:w3ab@?????.???>
>Sent: Sunday, September 6, 2020 1:28 PM
>To: Tim N8DEU<mailto:n8deu@???????.???>
>Cc: amsat-bb@?????.???<???????????????@?????.???>
>Subject: RE: Icom IC-9700 and Kantronics TNC
>
>Tim,
>
>It seems a modulation issue of some type.
>
>I don't have a 9700 but I do have a 7600 and had a modulation
>distortion problem. When using the accessory port insure that "DATA OFF
>MOD" is set only to "ACC", not "MIC+ACC". All the others should be set
>to "USB".
>
>___
>Sent from my two way wrist watch
>73 de W3AB/GEO
>On Sep 5, 2020, at 22:00, Tim N8DEU
><n8deu@???????.???<????????????@???????.???>> wrote:
>
>I made several measurements with the deviation starting at 0.75 kHz up
>to 4.00 kHz in 0.25 kHz steps. At each step 10 packets were transmitted
>and multiple receivers were used for decoding. At no point did the
>success rate go above 50% decoding. At 3.25 kHz and 3.50 kHz the
>transmit decode rate was 50%. All other settings were less.
>
>
>
>The Kantronics 9616 cannot drive the IC-9700 any higher than 4.07 kHz
>deviation and that level is achieved at XMITLVL = 114. Increasing the
>XMITLVL does not produce any additional increase in FM deviation using
>the square wave tone from the CALIBRATE mode.
>
>
>
>I have worked with 1200 baud packet for 33 years and set up quite a
>number of systems and this one will require some more observation. The
>same Kantronics 9612 connected to a Yaesu FT-736 or and an FT-847 show
>a 100% packet decode rate at 1200 baud. Both of these radio?s work fine
>at 9600 baud which is something not mentioned anywhere for the IC-9700.
>
>
>
>I was checking to see if others are having issues with the IC-9700.
>This started with a friend asking questions for the past 2 months about
>having trouble with the IC-9700 connected to a KAM XL and I walked him
>through all the logical steps. Finally, I decided I better try hooking
>my 9612 up to the Accessory Port to see how it works. This should not
>be too complicated. My results were exactly the same poor results he
>encountered on transmitting 1200 baud packets.
>
>
>
>Increasing TX Delay does nothing to help as that does not seem to be
>the issue.
>
>
>
>1200 baud packets are decoded through the receiver perfectly fine.
>
>
>
>The problem is transmitting 1200 baud packets for a successful decode
>rate on the IC-9700 through the Accessory Port.
>
>
>
>
>
>
>
>Best Regards,
>
>Tim Cunningham ? N8DEU
>
>
>
>
>
>
>
>From: GEO Badger<mailto:w3ab@?????.???>
>Sent: Saturday, September 5, 2020 3:00 PM
>To: Tim N8DEU<mailto:n8deu@???????.???>
>Cc: amsat-bb@?????.???<???????????????@?????.???>
>Subject: Re: Icom IC-9700 and Kantronics TNC
>
>
>
>Can you look at the deviation?
>
>
>
>---
>Ciao baby, catch you on the flip side
>
>
>73 de W3AB/GEO
>
>http://www.w3ab.org
>
>You can say "over", you can say "out", you just can't say "over and
>out".
>
>
>
>
>
>On Friday, September 4, 2020, 08:59:04 PM PDT, Tim N8DEU
><n8deu@???????.???> wrote:
>
>
>
>
>
>Simplex is the only method I tried at this point to keep it simple.
>
>
>
>Two different IC-9700 Radio radios, one with a Kantronics 9612 and one
>with a Kantronics KAM XL. Both using simplex and both exhibiting the
>same results.
>
>
>
>
>
>- Tim
>
>From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of W3AB/GEO via
>AMSAT-BB <amsat-bb@?????.???>
>Sent: Friday, September 4, 2020 6:52:05 PM
>Cc: amsat-bb@?????.??? <amsat-bb@?????.???>
>Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
>
>
>
>Tim,
>
>Have you tried simplex contacts?
>
>?___
>Sent from my two way wrist watch
>73 de W3AB/GEO?
>
>On Sep 4, 2020, 14:53, at 14:53, Tim N8DEU via AMSAT-BB
><amsat-bb@?????.???> wrote:
>>Has anybody interfaced a Kantronics 9612 or the KM XL TNC to the
>>accessory port of the Icom IC-9700?
>>
>>The reason I am asking is there are two IC-9700 users using the same
>>firmware who are experiencing the same issue with both of these TNC?s.
>>Packets are decoded with little to no issue on the receive side, but
>>the transmit side is a different story.
>>
>>It seems only about 30% of the transmitted packets are decoded by
>other
>>stations using 1200 baud. The deviation of the transmit signal and the
>>TX delay are not the issue. The same TNC works with no issue on a
>Yaesu
>>FT-736 and the FT-847.
>>
>>
>>Thank You,
>>Tim Cunningham - N8DEU
>>
>>_______________________________________________
>>Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>>to all interested persons worldwide without requiring membership.
>>Opinions expressed
>>are solely those of the author, and do not reflect the official views
>>of AMSAT-NA.
>>Not an AMSAT-NA member? Join now to support the amateur satellite
>>program!
>>Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>_______________________________________________
>Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
>to all interested persons worldwide without requiring membership.
>Opinions expressed
>are solely those of the author, and do not reflect the official views
>of AMSAT-NA.
>Not an AMSAT-NA member? Join now to support the amateur satellite
>program!
>Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 4
Date: Sun, 6 Sep 2020 22:00:34 +0000
From: Tim N8DEU <n8deu@???????.???>
To: W3AB/GEO <w3ab@?????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
Message-ID:
<BY5PR02MB6082EAE02430006BE4E0E48EFE2B0@?????????????.????????.????.???????.??
?>
Content-Type: text/plain; charset="utf-8"
What audio EQ?
9612 or IC-9700?
If you are talking about the Treble and Bass settings on the IC-9700, they
had no significant impact in decoding the transmitted signal.
Best Regards,
Tim Cunningham - N8DEU
From: W3AB/GEO<mailto:w3ab@?????.???>
Sent: Sunday, September 6, 2020 4:23 PM
To: Tim N8DEU<mailto:n8deu@???????.???>
Cc: amsat-bb@?????.???<???????????????@?????.???>
Subject: RE: Icom IC-9700 and Kantronics TNC
Very good Tim. Thanks for diving in so deeply.
BTW, have you tried the TX audio EQ?
___
Sent from my two way wrist watch
73 de W3AB/GEO
On Sep 6, 2020, at 13:48, Tim N8DEU
<n8deu@???????.???<????????????@???????.???>> wrote:
I stopped guessing and started measuring. The data holds the answer after a
deeper dive into this issue.
The audio is not distorted.
The problem with the ICOM IC-9700 and both Kantronics 9612 and KAM XL setups
is a very old problem. I knew something seemed familiar about the decode
problem, but it was 33 years ago. After measuring the IC-9700 signals on a
service monitor and viewing the signal on an oscilloscope hooked to a
Kenwood TH-D7a headphone jack, the picture was very clear. I discovered the
old twisted audio problem where the higher 2100 Hz tone is much lower in
amplitude than the lower 1300 Hz tone. Why does this matter? The XR2211
demodulators had immense trouble decoding packets with this condition and so
does the TH-D7a with a Tasco modem, but the Tasco modem decodes ~50% of
something where the XR2211 does not decode anything.
When (Amplow*cos(FreqLow)) is close to the same value as
(Amphigh*cos(FreqHigh)) the performance is not good on an XR2211 decoder nor
a Tasco modem chip. Early in the days of 1200 baud TAPR packet modem designs
it was discovered the higher tone needed to be 20 dB higher. In other words,
you at least need some pre-empahasis on the transmit signal for it to be
decoded and obtain some noise reduction. There is no pre-emphasis on the
transmit signal from the IC-9700 Accessory Port based on the results I
measured. The low tone is about 1.47 times higher than the high tone
relative to the deviation measured. When I measure the two tones levels with
an oscilloscope tied to the TH-D7a headphone jack, I measure the low tone is
1.29 times higher than the high tone.
Both of the audio tones output from the Kantronics 9612 are the same level
at roughly 50mV. Thus, the 9700 clearly alters the signal levels on the two
tones in a less than desirable fashion!
I have not tried sending audio through the microphone connector yet, but I
would hope it would at least have pre-emphasis for better results on
boosting the high tone.
Before I pass judgement, I will present the data to ICOM on the topic.
Hopefully, the response I get will be better than what my friend received
from them. They claimed to him the TNC keys the radio and it passes the
audio as if they have no problem in the equation. In their defense, they did
not understand the problem, but they did not pursue it either. Their
response was correct from a simplistic view, but what their radio does or
does not do with the audio can break everything. Pete, N4YOT, found if he
sent 2 duplicate packets back to back with his KAM XL, the transmitted
packet would be decoded. This raised the possibility the TXDelay might be
the culprit initially from his results. However, that gets into the 50%
packet decode rate.
When I hooked up my Kantronics 9612 on my end to the IC-9700, I experienced
the same problem as Pete and he worked on this for the past 2 months getting
nowhere and little help from ICOM. I finally hooked up the 9612 to the
IC-9700 to take a look for myself. It quickly became obvious there is a lack
of pre-emphasis on the high tone when the data is transmitted. In fact, the
emphasis is on the low tone or the high tone is being attenuated!!! The end
result is poor decoding of that transmitted signal when the low tone is
higher in amplitude than the high tone. There is indeed a problem with the
ICOM IC-9700 using the Accessory Port with 1200 baud packet.
This requires a hardware modification on the 9612 to implement a filter to
reverse these effects unless ICOM can provide some insight on how it can be
accomplished with their radio where the problem exists.
Let's see what ICOM has to say with the detailed measurements I collected.
Best Regards,
Tim Cunningham - N8DEU
From: GEO Badger<mailto:w3ab@?????.???>
Sent: Sunday, September 6, 2020 1:28 PM
To: Tim N8DEU<mailto:n8deu@???????.???>
Cc: amsat-bb@?????.???<???????????????@?????.???>
Subject: RE: Icom IC-9700 and Kantronics TNC
Tim,
It seems a modulation issue of some type.
I don't have a 9700 but I do have a 7600 and had a modulation distortion
problem. When using the accessory port insure that "DATA OFF MOD" is set
only to "ACC", not "MIC+ACC". All the others should be set to "USB".
___
Sent from my two way wrist watch
73 de W3AB/GEO
On Sep 5, 2020, at 22:00, Tim N8DEU
<n8deu@???????.???<????????????@???????.???>> wrote:
I made several measurements with the deviation starting at 0.75 kHz up to
4.00 kHz in 0.25 kHz steps. At each step 10 packets were transmitted and
multiple receivers were used for decoding. At no point did the success rate
go above 50% decoding. At 3.25 kHz and 3.50 kHz the transmit decode rate was
50%. All other settings were less.
The Kantronics 9616 cannot drive the IC-9700 any higher than 4.07 kHz
deviation and that level is achieved at XMITLVL = 114. Increasing the
XMITLVL does not produce any additional increase in FM deviation using the
square wave tone from the CALIBRATE mode.
I have worked with 1200 baud packet for 33 years and set up quite a number
of systems and this one will require some more observation. The same
Kantronics 9612 connected to a Yaesu FT-736 or and an FT-847 show a 100%
packet decode rate at 1200 baud. Both of these radio?s work fine at 9600
baud which is something not mentioned anywhere for the IC-9700.
I was checking to see if others are having issues with the IC-9700. This
started with a friend asking questions for the past 2 months about having
trouble with the IC-9700 connected to a KAM XL and I walked him through all
the logical steps. Finally, I decided I better try hooking my 9612 up to the
Accessory Port to see how it works. This should not be too complicated. My
results were exactly the same poor results he encountered on transmitting
1200 baud packets.
Increasing TX Delay does nothing to help as that does not seem to be the
issue.
1200 baud packets are decoded through the receiver perfectly fine.
The problem is transmitting 1200 baud packets for a successful decode rate
on the IC-9700 through the Accessory Port.
Best Regards,
Tim Cunningham ? N8DEU
From: GEO Badger<mailto:w3ab@?????.???>
Sent: Saturday, September 5, 2020 3:00 PM
To: Tim N8DEU<mailto:n8deu@???????.???>
Cc: amsat-bb@?????.???<???????????????@?????.???>
Subject: Re: Icom IC-9700 and Kantronics TNC
Can you look at the deviation?
---
Ciao baby, catch you on the flip side
73 de W3AB/GEO
http://www.w3ab.org
You can say "over", you can say "out", you just can't say "over and out".
On Friday, September 4, 2020, 08:59:04 PM PDT, Tim N8DEU <n8deu@???????.???>
wrote:
Simplex is the only method I tried at this point to keep it simple.
Two different IC-9700 Radio radios, one with a Kantronics 9612 and one with
a Kantronics KAM XL. Both using simplex and both exhibiting the same results.
- Tim
From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of W3AB/GEO via
AMSAT-BB <amsat-bb@?????.???>
Sent: Friday, September 4, 2020 6:52:05 PM
Cc: amsat-bb@?????.??? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Icom IC-9700 and Kantronics TNC
Tim,
Have you tried simplex contacts?
?___
Sent from my two way wrist watch
73 de W3AB/GEO?
On Sep 4, 2020, 14:53, at 14:53, Tim N8DEU via AMSAT-BB <amsat-bb@?????.???>
wrote:
>Has anybody interfaced a Kantronics 9612 or the KM XL TNC to the
>accessory port of the Icom IC-9700?
>
>The reason I am asking is there are two IC-9700 users using the same
>firmware who are experiencing the same issue with both of these TNC?s.
>Packets are decoded with little to no issue on the receive side, but
>the transmit side is a different story.
>
>It seems only about 30% of the transmitted packets are decoded by other
>stations using 1200 baud. The deviation of the transmit signal and the
>TX delay are not the issue. The same TNC works with no issue on a Yaesu
>FT-736 and the FT-847.
>
>
>Thank You,
>Tim Cunningham - N8DEU
>
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Sent via amsat-bb@?????.???.
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are solely those of the author, and do not reflect the official views of
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Not an AMSAT member? Join now to support the amateur satellite program!
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End of AMSAT-BB Digest, Vol 15, Issue 369
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