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Re: MTT4BT Installation on ATV/Motorcycle

 

Ha, yeah, arguably the mini DIN 6 was the worst choice for a device intended to go mobile.

I've had good results putting the unit in a good Tupperware container. I zip tie the mini DIN cable to the TT box. Consider foam etc to pack the TT, and how to grommet the cables going out of the plastic box.

Cliff K6CLS CM87


On September 16, 2021 3:29:51 PM PDT, toy4trax@... wrote:

Looking to do an install on my ATV and/or Motorcycle. While the unit itself is going to be in a waterproof location, I'm looking for cabling thru to the battery which will be exposed to water. I'm not having much luck with finding waterproof mini-din 6 connectors.

Ideally, I have the MTT4BT's Mini Din 6 cable routes to a central location where i can split off to power, and Serial cable to the GPS.

Thoughts?


MTT4BT Installation on ATV/Motorcycle

 

Looking to do an install on my ATV and/or Motorcycle. While the unit itself is going to be in a waterproof location, I'm looking for cabling thru to the battery which will be exposed to water. I'm not having much luck with finding waterproof mini-din 6 connectors.

Ideally, I have the MTT4BT's Mini Din 6 cable routes to a central location where i can split off to power, and Serial cable to the GPS.

Thoughts?


Re: TT4TrackerConfig software.?

 

A great deal of Byonics dated material is available on the Wayback machine:?https://web.archive.org/web/20100416075947/http://www.byonics.com/microtrak/ I use it myself pretty often.

73,

Allen AF6OF

-----Original Message-----
From: Steve (KS1G) <ks1g04@...>
To: [email protected]
Sent: Sat, Sep 4, 2021 8:14 pm
Subject: Re: [TinyTrak] TT4TrackerConfig software.?

Thank you, gentlemen. ?I have a copy of the config software from when I purchased the TT4, so I should be ok. ?But good to know where it¡¯s available on the bionics site and elsewhere.

73 Steve KS1G?


Re: TT4TrackerConfig software.?

 

Thank you, gentlemen. ?I have a copy of the config software from when I purchased the TT4, so I should be ok. ?But good to know where it¡¯s available on the bionics site and elsewhere.

73 Steve KS1G?


Re: TT4TrackerConfig software.?

 

Hi Steve,
As far as I know Tiny Track Alpha Config 0.68 is still the newest application. It is on the Byonics website. If you can't find it let me know and I will e-mail it to you.?
Good luck,

Matt Stanton?
VK3ABC/W3FUG


On Sun, 5 Sept 2021 at 10:28, Steve (KS1G) <ks1g04@...> wrote:
Thanks.? I was wondering, as I am resurrecting an old TT4 (2012-ish?) and TinyTrak4 Alpha Config v0.68 is what I used at the time.?

Are there any issues using it with the v0.72 firmware? (I flashed the TT4 a few days ago and am trying it with YAAC).? Also, where on the Byonics site are they hiding the config software - I found the TT3 config software, but can't locate a current copy for the TT4, glad I hung onto the earlier copy (storage is cheap).? Plan B would be one command at a time using TeraTerm or Putty.??

73 Steve KS1G



--
Matt Stanton
0430340317 mobile


Re: TT4TrackerConfig software.?

 

On Sat, Sep 4, 2021 at 08:28 PM, Steve (KS1G) wrote:
Are there any issues using it with the v0.72 firmware? (I flashed the TT4 a few days ago and am trying it with YAAC).? Also, where on the Byonics site are they hiding the config software - I found the TT3 config software, but can't locate a current copy for the TT4, glad I hung onto the earlier copy (storage is cheap).? Plan B would be one command at a time using TeraTerm or Putty.??
I can't say I've heard any 'issues' with 0.72 firmware.? A few questions, but no one complained about issues.

The zip file has the old firmware and configuration application in it.
I believe the only altered (added) parameters since v0.68 are for the MTT4B(T) .? The PORTB config menu is very handy though.
? So if you had an MTT4B or MTT4BT, you would have to use TerTerm or the like to change the radio parameters (which are pretty much preset.

Robert Giuliano
KB8RCO


Re: TT4TrackerConfig software.?

 

Thanks.? I was wondering, as I am resurrecting an old TT4 (2012-ish?) and TinyTrak4 Alpha Config v0.68 is what I used at the time.?

Are there any issues using it with the v0.72 firmware? (I flashed the TT4 a few days ago and am trying it with YAAC).? Also, where on the Byonics site are they hiding the config software - I found the TT3 config software, but can't locate a current copy for the TT4, glad I hung onto the earlier copy (storage is cheap).? Plan B would be one command at a time using TeraTerm or Putty.??

73 Steve KS1G


Re: MTT4BT Digipeater, weather station, Beacon, and Message issues....

 

There is provision for a local time stamp tht indicates it is not real-time
but CPU clock time. I instead of ending with DDHHMMz it ends (I think)
with HHMMSSh from the last time the CPU was started. THe "h"
indicates it is CPU time. (Alll this from memory since I dont have
the energy to look it up).

In any case the original post was correct in that time stamps should
usually be ignored in systematic use and the TIME OF RECEPIT
should be used for accuracy.

Bob, WB4APR (forgetting a lot these days)...

On Wed, Aug 25, 2021 at 11:46 AM AC1DW <KC1HEP@...> wrote:

The APRS weather without location seems to require a time stamp.

Looking at raw data on aprs.fi for w1bst; it appears that way.


Re: MT4BB Voltage Accuracy

 

If the TVOLTTWK adjusts the reading by 27mV, it implies an offset (not a gain change).
That was why I asked the question.

Next point:
As I read the TT4 firmware manual, the telemetry output is either 255 (8-bit) or rescaled (in firmware) to 999 bits FS, not true 10-bits because the protocol only allows 3 digits in the message.?
So on TELHIRES TRUE, the reported value at 5V would be 999, not 1023 (or 1024).
Enables sending of high resolution telemetry data. If false, telemetry reports range from
0 for 0V to 255 for 5V. If true, telemetry reports range from 0 for 0V to 999 for 5V.

Although between 999 and 1023 would probably be very high battery voltages:
??? 999 / 1023 * 5 / 0.18 = 27.13 to 27.78 Volts, so I guess it could be truncated.

Robert Giuliano
KB8RCO



On Wednesday, August 25, 2021, 08:40:06 AM EDT, AC1DW <kc1hep@...> wrote:


Rob, you really get me going with your posts. Thank you.

What we know:
Vin is voltage divided: 2.2/12.2 = 0.180
Vin has diode protection dropping it ~0.2 V

Vadc = 0.180*(Vin-0.2) = Vin*0.180 - 0.036

The Atmega ADCs are 10 bit with programmable gains of x1, x10, x200
bits = 1024/5*Vadc (0.00488 Volt/bit) [999*0.00488=4.878 or a -2.5% FS error)
?????? divide by 4 (255 bits or 0.0195 Volt/bit) is simply dropping the last two bits. (bit shift)

Combining the above I get:
bits*5/(0.18*1024)+0.2 = Vin
or
bits*0.0271+0.2 = Vin

I think "the TELVOLTTWK has a resolution of 0.27v / bit," is a typo. I am guessing it is 27mV/bit.

Your "bits + (128 - TVOLTTWK)" is probably the correct answer.
I don't have a TT4 here to test this out.

Thoughts?
btu, AC1DW

PS> So I went to the TT4 firmware manual to see where the 0.27V/bit came from.
???????? Yup; typo. From the manual "Default is 128 and each adjustment unit up or down will tweak the reading by 27mV"
???????? But I had fun reverse engineering it just the same.


Re: MTT4BT Digipeater, weather station, Beacon, and Message issues....

 

The APRS weather without location seems to require a time stamp.?

Looking at raw data on aprs.fi for w1bst; it appears that way.?


Re: MTT4BT Digipeater, weather station, Beacon, and Message issues....

 

Any system that does not have an active GPS should not use an APRS
protocol that includes a time stamp.

There should be a non-time-stamp version of every packet type. (I hope)
Bob, WB4APR

On Wed, Aug 25, 2021 at 2:21 AM Gil Smith <tinytrak@...> wrote:

Some time back I corresponded with a fellow in the aprs-is (group/provider...?) system when I was formatting wx packets to be posted via the net. I recall something about the aprs-is system ignoring times in packets and adding a real timestamp when packets arrived -- something about them not trusting any other times given to them, since they would often be bogus (or just off, as in the case of a battery-backed rtc or such). Makes sense to me. I was sending incorrect times in packets when I was first playing around, those incorrect timestamps were ignored by the system. I would guess that the radio side of aprs would do the same thing as those packets get added to the system.

----- Original message -----
From: "Rob Giuliano via groups.io" <kb8rco@...>
To: "[email protected]" <[email protected]>
Subject: Re: [TinyTrak] MTT4BT Digipeater, weather station, Beacon, and Message issues....
Date: Tuesday, August 24, 2021 4:27 PM

You have a TEXT port and a PEET port, so no GPS port.

I am curious how the MTT4BT gets a time and date with no GPS attached?
As far as I can tell, there is no RTC and no means of setting the time.
The timing appears to be either from delta time between TX, or time from the GPS.

I cannot say I've ever investigated this, but I see 3 scenarios:
1. No GPS. Assume poackets sent without timestamp
2. With GPS -> GPS provide time
3. Start with GPS attached, then remove GP.
Does the MTT4BT keep time from last acquired information - that would likely get out of date fairly quickly.

Robert Giuliano
KB8RCO



Re: MT4BB Voltage Accuracy

 

Rob, you really get me going with your posts. Thank you.

What we know:
Vin is voltage divided: 2.2/12.2 = 0.180
Vin has diode protection dropping it ~0.2 V

Vadc = 0.180*(Vin-0.2) = Vin*0.180 - 0.036

The Atmega ADCs are 10 bit with programmable gains of x1, x10, x200
bits = 1024/5*Vadc (0.00488 Volt/bit) [999*0.00488=4.878 or a -2.5% FS error)
?????? divide by 4 (255 bits or 0.0195 Volt/bit) is simply dropping the last two bits. (bit shift)

Combining the above I get:
bits*5/(0.18*1024)+0.2 = Vin
or
bits*0.0271+0.2 = Vin

I think "the TELVOLTTWK has a resolution of 0.27v / bit," is a typo. I am guessing it is 27mV/bit.

Your "bits + (128 - TVOLTTWK)" is probably the correct answer.
I don't have a TT4 here to test this out.

Thoughts?
btu, AC1DW

PS> So I went to the TT4 firmware manual to see where the 0.27V/bit came from.
???????? Yup; typo. From the manual "Default is 128 and each adjustment unit up or down will tweak the reading by 27mV"
???????? But I had fun reverse engineering it just the same.


Re: TT4 with Peet Ultimiter Troubleshooting

 

From my observation of PEET serial data; 0 is a reported value.?

Non- reported values are a dash "-".?
Values are in HEX.

Fwiw


Re: MTT4BT Digipeater, weather station, Beacon, and Message issues....

 

Gil, that is what I read too.?

Rob, the PEET data has a date (MM/dd) and time (hh:mm) in the packet it sends (data or packet modes).

The TT4 is decoding like this is a leap year. It is a day behind now. Don't know what January would look like though.??

I'm going to do a reset to factory defaults and start from there. I haven't been able to recreate some of the anomalies I've observed. One being; when both ports were in TEXT mode, the decoded received packets were being transmitted as "UI" input.?
2021-08-22 13:34:02
>APTT4,WIDE2-1,NH4-4,qAR,:W1IMD>APN391:!4350.15NS07049.05W#PHG3464


Re: MTT4BT Digipeater, weather station, Beacon, and Message issues....

 

Some time back I corresponded with a fellow in the aprs-is (group/provider...?) system when I was formatting wx packets to be posted via the net.? I recall something about the aprs-is system ignoring times in packets and adding a real timestamp when packets arrived -- something about them not trusting any other times given to them, since they would often be bogus (or just off, as in the case of a battery-backed rtc or such).? Makes sense to me.? I was sending incorrect times in packets when I was first playing around, those incorrect timestamps were ignored by the system.? I would guess that the radio side of aprs would do the same thing as those packets get added to the system.

----- Original message -----
From: "Rob Giuliano via groups.io" <kb8rco=[email protected]>
Subject: Re: [TinyTrak] MTT4BT Digipeater, weather station, Beacon, and Message issues....
Date: Tuesday, August 24, 2021 4:27 PM

You have a TEXT port and a PEET port, so no GPS port.

I am curious how the MTT4BT gets a time and date with no GPS attached?
As far as I can tell, there is no RTC and no means of setting the time.
The timing appears to be either from delta time between TX, or time from the GPS.

I cannot say I've ever investigated this, but I see 3 scenarios:
1. No GPS.? Assume poackets sent without timestamp
2. With GPS -> GPS provide time
3. Start with GPS attached, then remove GP.?
??? Does the MTT4BT keep time from last acquired information - that would likely get out of date fairly quickly.

Robert Giuliano
KB8RCO



Re: MT4BB Voltage Accuracy

 

Although I understand these are just "indicators", I would have guessed the resistors would be 5% or 1% (typically not a big cost hit).

I always wondered how the TVOLTTWK value worked.? Is it an offset or a gain?
???? Gain:??? bits / (TVOLTTWK * 2) *5 /0.18
?? Offset:??? bits + (128 - TVOLTTWK) /255 *5 /0.18?????????????????????????? (I used 255 since max ADC value is 255 at 5V)
The gain would be more of a compensation of resistor tolerances.
The offset would be 0.11 V per bit.
Neither formula gives a 0.27V per bit delta.

As for the EQNS values using reading of 13.1 Volts):
??? Voltage with TELREAD TRUE???? 0,0.100,0????????(0x^2 + 0.100x + 0)?? so if x=131 => 0 + 13.10 + 0 = 13.10 Volts
??? Voltage with TELHIRES FALSE?? 0,0.109,0 ?????? (0x^2 + 0.109x + 0) ?? so x = 120 => 0 + 13.08 + 0 = 13.08 Volts ???
??? Voltage with TELHIRES TRUE??? 0,0.005,0 ??????? (0x^2 + 0.005x + 0) ?? so x = 471 => 0 + 13.08 + 0 = 13.96 Volts ??
Where 'x' is the value reported in the telemetry packet.? NOTE: with TELREAD TRUE, this is not the ADC value.
? Otherwise, it depends on the TELHIRES setting.?

Robert Giuliano
KB8RCO



On Tuesday, August 24, 2021, 12:01:40 PM EDT, vhsproducts via groups.io <vhsproducts@...> wrote:


Gentlemen,

Your understanding of these issues is an order of magnitude beyond my own, but being ignorant of something never caused me to stop chiming it! I just wanted to point out a few things: The Voltage Sampling on the MTT4BT is as Robert pointed out, derived from the 10K and 2.2K Voltage divider. Note please that these are 10% value resistors, and you might do well to keep that in mind when estimating derived values. ( I am not sure what the tolerance of the resistors used in the standard TT4) Also, keep in mind that the Voltage sample is taken AFTER the polarity protection series input diode. In every version of the MTT4BT, this is a Schottky Diode, and you will see nominally .20 Volts of drop on the sampling part of the circuit. Although this may not be idea for Voltage Telemetry, is does keep the TT4 chip from being blown to smithereens by transient reverse polarity power supplies or plain old accidents. As Bob supposes, I discussed the issue of when sampling occurs with Byon some years ago, and I believe that the Voltage and Temperature values are both read immediately before a scheduled transmission. Both values are essentially derived from an analog Voltage of 0-5 Volts from Voltage dividers. In the case of the temperature sensor, that's an LM335Z biased with a 2.2K resistor.?

Somewhere in my notes is a explanation of how to modify the EQNS values to trim up these values, but if you figure it out, you would do us all a great service in posting it!?

73,

Allen AF6OF
( The Micro-Trak hardware guy)?


-----Original Message-----
From: Rob Giuliano via groups.io <kb8rco@...>
To: [email protected] <[email protected]>
Sent: Tue, Aug 24, 2021 5:17 am
Subject: Re: [TinyTrak] MT4BB Voltage Accuracy

Although the TELVOLTTWK has a resolution of 0.27v / bit, so you should be able to do the math and get it close in 1 shot (1.5 / 0.27 or 4 - 5 bits.
? Since you said "almost", I set TELVOLTTWK 124 and see what happens.

As for sending the voltage in Telemetry packets, you may have to change the coefficients, depending on your settings of TELREAD and/or TELHIRES.
Post questions, and we can help sort that out if needed.? First step is to get the voltage read properly.

Good luck!

Robert Giuliano
KB8RCO


On Tuesday, August 24, 2021, 12:42:48 AM EDT, Bob Holowenko <holowenko@...> wrote:


Thank you Robert!

I am just using the ^V method, however I will turn on the telemetry?option as well since it will likely produce a sexy graph in APRS.fi that is something I can check from anywhere instead of the private Cacti instance ingesting APRS-IS packets and slicing them in perl....It's not pretty.

The current source is roughly 2000Ah of batteries?and is not significantly restricted. We only see a drop of a few 10ths of a V under transmit. When we measured the voltage we checked it at the source (actually a fused bus bar) with the unit powered up, and again at the DIN connector with the unit not powered. Neither showed any voltage differential.?

My assumption is that the AtoD reads the result of the divider, does the math mentioned above, and turns that into a V string, stuffs that into the packet, THEN transmits that packet it crafted in memory. I would only expect the V to drop at the DIN connector under TX load and cause low voltage as that's the least surface area contact in the power rail, HOWEVER, it should not matter as I suspect the sampling happens pre-PTT activity.

I will certainly play with the "TVOLTTWK" command and see if I can tighten it up again. I am perfectly fine with the lower-res power readings, as I really only care to the tenth of a volt anyway.?

Cheers,

Bob Holowenko
B.Tech & ASC (Computer Forensics), Dipl Technical Studies, CCNA CCNP ASC?
Quesnel Search and Rescue Society, Director?
Quesnel Emergency Radio Communications, DERC - VE7WNK
cell: 250-255-6439
email:?holowenko@...


On Mon, Aug 23, 2021 at 1:38 PM Rob Giuliano via <kb8rco=[email protected]> wrote:
Sent from e-mail but did not seem to post.

Yes, the MTT4BT voltage monitor is a simple voltage divider of 10k / 2.2k.
? So Vread = Vin * 2.2/12.2 or 0.180 Vin.? So reverse conversion would be Vread / 0.18.
If the power source is limited in current, the voltage will drop on TX.?
? You should check (compare) the volyage readings when the MTT4BT transmits.
?
The TT4 line has a means to adjust for variations in parts.
Check TVOLTTWK for adjusting.
???? Allows the supply voltage sensor reading to be adjusted. Default is 128 and each
???? adjustment unit up or down will tweak the reading by 27mV
?
You don't say how you are reviewing the voltage:
?
?? 1. Direct reading value in beacon using ^V????????? This allows direct reading of the voltage in volts (with decimal)
?
?? 2. Telemetry Data (format is important)??????????????? This depends on other settings to convert.
?????? TELHIRES {true or false}? ????????????????????????????? TRUE means 0 - 999 rather than 0 - 255
?????? TELEVOLT {true or false}? ????????????????????????????? TRUE means this data is included in a telemetry packet in either 'Volts' or 'bits'
?????? TELREAD {true or false}? ?????????????????????????????? TRUE 131 is 13.1 Volts in the telemetry packet (TELEHIRES doesn't matter)
?
?
EXAMPLE:
?? TELEVOLT TRUE??????? Data shows 131 so Vin is read as 13.1V? use TVOLTTWK to adjust to match reality
?? TELHIREAS FALSE ??? Data shows 120 so Vin = 120/255 * 5 / 0.18 = 13.072 Volts
?? TELHIREAS TRUE????? Data shows 471 so Vin = 471/999 * 5 / 0.18 = 13.096 Volts


Re: MTT4BT Digipeater, weather station, Beacon, and Message issues....

 

You have a TEXT port and a PEET port, so no GPS port.

I am curious how the MTT4BT gets a time and date with no GPS attached?
As far as I can tell, there is no RTC and no means of setting the time.
The timing appears to be either from delta time between TX, or time from the GPS.

I cannot say I've ever investigated this, but I see 3 scenarios:
1. No GPS.? Assume poackets sent without timestamp
2. With GPS -> GPS provide time
3. Start with GPS attached, then remove GP.?
??? Does the MTT4BT keep time from last acquired information - that would likely get out of date fairly quickly.

Robert Giuliano
KB8RCO



Re: MT4BB Voltage Accuracy

 

Gentlemen,

Your understanding of these issues is an order of magnitude beyond my own, but being ignorant of something never caused me to stop chiming it! I just wanted to point out a few things: The Voltage Sampling on the MTT4BT is as Robert pointed out, derived from the 10K and 2.2K Voltage divider. Note please that these are 10% value resistors, and you might do well to keep that in mind when estimating derived values. ( I am not sure what the tolerance of the resistors used in the standard TT4) Also, keep in mind that the Voltage sample is taken AFTER the polarity protection series input diode. In every version of the MTT4BT, this is a Schottky Diode, and you will see nominally .20 Volts of drop on the sampling part of the circuit. Although this may not be idea for Voltage Telemetry, is does keep the TT4 chip from being blown to smithereens by transient reverse polarity power supplies or plain old accidents. As Bob supposes, I discussed the issue of when sampling occurs with Byon some years ago, and I believe that the Voltage and Temperature values are both read immediately before a scheduled transmission. Both values are essentially derived from an analog Voltage of 0-5 Volts from Voltage dividers. In the case of the temperature sensor, that's an LM335Z biased with a 2.2K resistor.?

Somewhere in my notes is a explanation of how to modify the EQNS values to trim up these values, but if you figure it out, you would do us all a great service in posting it!?

73,

Allen AF6OF
( The Micro-Trak hardware guy)?


-----Original Message-----
From: Rob Giuliano via groups.io <kb8rco@...>
To: [email protected] <[email protected]>
Sent: Tue, Aug 24, 2021 5:17 am
Subject: Re: [TinyTrak] MT4BB Voltage Accuracy

Although the TELVOLTTWK has a resolution of 0.27v / bit, so you should be able to do the math and get it close in 1 shot (1.5 / 0.27 or 4 - 5 bits.
? Since you said "almost", I set TELVOLTTWK 124 and see what happens.

As for sending the voltage in Telemetry packets, you may have to change the coefficients, depending on your settings of TELREAD and/or TELHIRES.
Post questions, and we can help sort that out if needed.? First step is to get the voltage read properly.

Good luck!

Robert Giuliano
KB8RCO


On Tuesday, August 24, 2021, 12:42:48 AM EDT, Bob Holowenko <holowenko@...> wrote:


Thank you Robert!

I am just using the ^V method, however I will turn on the telemetry?option as well since it will likely produce a sexy graph in APRS.fi that is something I can check from anywhere instead of the private Cacti instance ingesting APRS-IS packets and slicing them in perl....It's not pretty.

The current source is roughly 2000Ah of batteries?and is not significantly restricted. We only see a drop of a few 10ths of a V under transmit. When we measured the voltage we checked it at the source (actually a fused bus bar) with the unit powered up, and again at the DIN connector with the unit not powered. Neither showed any voltage differential.?

My assumption is that the AtoD reads the result of the divider, does the math mentioned above, and turns that into a V string, stuffs that into the packet, THEN transmits that packet it crafted in memory. I would only expect the V to drop at the DIN connector under TX load and cause low voltage as that's the least surface area contact in the power rail, HOWEVER, it should not matter as I suspect the sampling happens pre-PTT activity.

I will certainly play with the "TVOLTTWK" command and see if I can tighten it up again. I am perfectly fine with the lower-res power readings, as I really only care to the tenth of a volt anyway.?

Cheers,

Bob Holowenko
B.Tech & ASC (Computer Forensics), Dipl Technical Studies, CCNA CCNP ASC?
Quesnel Search and Rescue Society, Director?
Quesnel Emergency Radio Communications, DERC - VE7WNK
cell: 250-255-6439
email:?holowenko@...


On Mon, Aug 23, 2021 at 1:38 PM Rob Giuliano via <kb8rco=[email protected]> wrote:
Sent from e-mail but did not seem to post.

Yes, the MTT4BT voltage monitor is a simple voltage divider of 10k / 2.2k.
? So Vread = Vin * 2.2/12.2 or 0.180 Vin.? So reverse conversion would be Vread / 0.18.
If the power source is limited in current, the voltage will drop on TX.?
? You should check (compare) the volyage readings when the MTT4BT transmits.
?
The TT4 line has a means to adjust for variations in parts.
Check TVOLTTWK for adjusting.
???? Allows the supply voltage sensor reading to be adjusted. Default is 128 and each
???? adjustment unit up or down will tweak the reading by 27mV
?
You don't say how you are reviewing the voltage:
?
?? 1. Direct reading value in beacon using ^V????????? This allows direct reading of the voltage in volts (with decimal)
?
?? 2. Telemetry Data (format is important)??????????????? This depends on other settings to convert.
?????? TELHIRES {true or false}? ????????????????????????????? TRUE means 0 - 999 rather than 0 - 255
?????? TELEVOLT {true or false}? ????????????????????????????? TRUE means this data is included in a telemetry packet in either 'Volts' or 'bits'
?????? TELREAD {true or false}? ?????????????????????????????? TRUE 131 is 13.1 Volts in the telemetry packet (TELEHIRES doesn't matter)
?
?
EXAMPLE:
?? TELEVOLT TRUE??????? Data shows 131 so Vin is read as 13.1V? use TVOLTTWK to adjust to match reality
?? TELHIREAS FALSE ??? Data shows 120 so Vin = 120/255 * 5 / 0.18 = 13.072 Volts
?? TELHIREAS TRUE????? Data shows 471 so Vin = 471/999 * 5 / 0.18 = 13.096 Volts


Re: MT4BB Voltage Accuracy

 

Although the TELVOLTTWK has a resolution of 0.27v / bit, so you should be able to do the math and get it close in 1 shot (1.5 / 0.27 or 4 - 5 bits.
? Since you said "almost", I set TELVOLTTWK 124 and see what happens.

As for sending the voltage in Telemetry packets, you may have to change the coefficients, depending on your settings of TELREAD and/or TELHIRES.
Post questions, and we can help sort that out if needed.? First step is to get the voltage read properly.

Good luck!

Robert Giuliano
KB8RCO



On Tuesday, August 24, 2021, 12:42:48 AM EDT, Bob Holowenko <holowenko@...> wrote:


Thank you Robert!

I am just using the ^V method, however I will turn on the telemetry?option as well since it will likely produce a sexy graph in APRS.fi that is something I can check from anywhere instead of the private Cacti instance ingesting APRS-IS packets and slicing them in perl....It's not pretty.

The current source is roughly 2000Ah of batteries?and is not significantly restricted. We only see a drop of a few 10ths of a V under transmit. When we measured the voltage we checked it at the source (actually a fused bus bar) with the unit powered up, and again at the DIN connector with the unit not powered. Neither showed any voltage differential.?

My assumption is that the AtoD reads the result of the divider, does the math mentioned above, and turns that into a V string, stuffs that into the packet, THEN transmits that packet it crafted in memory. I would only expect the V to drop at the DIN connector under TX load and cause low voltage as that's the least surface area contact in the power rail, HOWEVER, it should not matter as I suspect the sampling happens pre-PTT activity.

I will certainly play with the "TVOLTTWK" command and see if I can tighten it up again. I am perfectly fine with the lower-res power readings, as I really only care to the tenth of a volt anyway.?

Cheers,

Bob Holowenko
B.Tech & ASC (Computer Forensics), Dipl Technical Studies, CCNA CCNP ASC?
Quesnel Search and Rescue Society, Director?
Quesnel Emergency Radio Communications, DERC - VE7WNK
cell: 250-255-6439
email:?holowenko@...


On Mon, Aug 23, 2021 at 1:38 PM Rob Giuliano via <kb8rco=[email protected]> wrote:
Sent from e-mail but did not seem to post.

Yes, the MTT4BT voltage monitor is a simple voltage divider of 10k / 2.2k.
? So Vread = Vin * 2.2/12.2 or 0.180 Vin.? So reverse conversion would be Vread / 0.18.
If the power source is limited in current, the voltage will drop on TX.?
? You should check (compare) the volyage readings when the MTT4BT transmits.
?
The TT4 line has a means to adjust for variations in parts.
Check TVOLTTWK for adjusting.
???? Allows the supply voltage sensor reading to be adjusted. Default is 128 and each
???? adjustment unit up or down will tweak the reading by 27mV
?
You don't say how you are reviewing the voltage:
?
?? 1. Direct reading value in beacon using ^V????????? This allows direct reading of the voltage in volts (with decimal)
?
?? 2. Telemetry Data (format is important)??????????????? This depends on other settings to convert.
?????? TELHIRES {true or false}? ????????????????????????????? TRUE means 0 - 999 rather than 0 - 255
?????? TELEVOLT {true or false}? ????????????????????????????? TRUE means this data is included in a telemetry packet in either 'Volts' or 'bits'
?????? TELREAD {true or false}? ?????????????????????????????? TRUE 131 is 13.1 Volts in the telemetry packet (TELEHIRES doesn't matter)
?
?
EXAMPLE:
?? TELEVOLT TRUE??????? Data shows 131 so Vin is read as 13.1V? use TVOLTTWK to adjust to match reality
?? TELHIREAS FALSE ??? Data shows 120 so Vin = 120/255 * 5 / 0.18 = 13.072 Volts
?? TELHIREAS TRUE????? Data shows 471 so Vin = 471/999 * 5 / 0.18 = 13.096 Volts


Re: MT4BB Voltage Accuracy

 

Thank you Robert!

I am just using the ^V method, however I will turn on the telemetry?option as well since it will likely produce a sexy graph in APRS.fi that is something I can check from anywhere instead of the private Cacti instance ingesting APRS-IS packets and slicing them in perl....It's not pretty.

The current source is roughly 2000Ah of batteries?and is not significantly restricted. We only see a drop of a few 10ths of a V under transmit. When we measured the voltage we checked it at the source (actually a fused bus bar) with the unit powered up, and again at the DIN connector with the unit not powered. Neither showed any voltage differential.?

My assumption is that the AtoD reads the result of the divider, does the math mentioned above, and turns that into a V string, stuffs that into the packet, THEN transmits that packet it crafted in memory. I would only expect the V to drop at the DIN connector under TX load and cause low voltage as that's the least surface area contact in the power rail, HOWEVER, it should not matter as I suspect the sampling happens pre-PTT activity.

I will certainly play with the "TVOLTTWK" command and see if I can tighten it up again. I am perfectly fine with the lower-res power readings, as I really only care to the tenth of a volt anyway.?

Cheers,

Bob Holowenko
B.Tech & ASC (Computer Forensics), Dipl Technical Studies, CCNA CCNP ASC?
Quesnel Search and Rescue Society, Director?
Quesnel Emergency Radio Communications, DERC - VE7WNK
cell: 250-255-6439
email:?holowenko@...


On Mon, Aug 23, 2021 at 1:38 PM Rob Giuliano via <kb8rco=[email protected]> wrote:
Sent from e-mail but did not seem to post.

Yes, the MTT4BT voltage monitor is a simple voltage divider of 10k / 2.2k.
? So Vread = Vin * 2.2/12.2 or 0.180 Vin.? So reverse conversion would be Vread / 0.18.
If the power source is limited in current, the voltage will drop on TX.?
? You should check (compare) the volyage readings when the MTT4BT transmits.
?
The TT4 line has a means to adjust for variations in parts.
Check TVOLTTWK for adjusting.
???? Allows the supply voltage sensor reading to be adjusted. Default is 128 and each
???? adjustment unit up or down will tweak the reading by 27mV
?
You don't say how you are reviewing the voltage:
?
?? 1. Direct reading value in beacon using ^V????????? This allows direct reading of the voltage in volts (with decimal)
?
?? 2. Telemetry Data (format is important)??????????????? This depends on other settings to convert.
?????? TELHIRES {true or false}? ????????????????????????????? TRUE means 0 - 999 rather than 0 - 255
?????? TELEVOLT {true or false}? ????????????????????????????? TRUE means this data is included in a telemetry packet in either 'Volts' or 'bits'
?????? TELREAD {true or false}? ?????????????????????????????? TRUE 131 is 13.1 Volts in the telemetry packet (TELEHIRES doesn't matter)
?
?
EXAMPLE:
?? TELEVOLT TRUE??????? Data shows 131 so Vin is read as 13.1V? use TVOLTTWK to adjust to match reality
?? TELHIREAS FALSE ??? Data shows 120 so Vin = 120/255 * 5 / 0.18 = 13.072 Volts
?? TELHIREAS TRUE????? Data shows 471 so Vin = 471/999 * 5 / 0.18 = 13.096 Volts