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Today's Topics:
1. Re: Which gplEDA tools? (Kieran Sullivan)
2. Re: Which gplEDA tools? (George Shaiffer)
----------------------------------------------------------------------
Message: 1
Date: Sun, 12 Aug 2018 19:14:06 +0100
From: Kieran Sullivan <[email protected]>
To: Bdale Garbee <[email protected]>
Cc: Kieran Sullivan <[email protected]>, Altus Metrum
<[email protected]>
Subject: Re: [altusmetrum] Which gplEDA tools?
Message-ID: <[email protected]>
Content-Type: text/plain; charset=utf-8
Thanks. I think my main issue is the lack of accurate frequency counter. I had
hoped to get close with an SDR radio receiver as my o’scope doesn’t quite
manage 435Mhz with a great deal of accuracy. The frequency I measured and
calibrated to at least got me to the point that the tele-dongle flashed red
when receiving packets, but obviously there was a problem with the
reception/checksum so nothing valid received. I will get this cracked and I do
know someone with a spectrum analyser/frequency counter that I can get hold of,
just a matter of doing this.
Good to know about the bring-up script too, I think I missed that.
Regards,
Kieran
On 10 Aug 2018, at 19:59, Bdale Garbee <[email protected]> wrote:
Kieran Sullivan <[email protected]> writes:
Oh, and when someone figures out a good way to calibrate the radio on
the Telemega, please let me know. I’ve been trying to get it right for
a couple of years on and off… :-)
Oh, sorry, I thought we had the process documented but apparently in
manual section 11.8.2 we basically just tell you not to do this
yourself. We should probably add a new appendix to the manual
explaining how to do it with suitable caveats about "don't try this
unless you have the right gear and know what you're doing, or are really
desperate".
In the meantime, if you want to cal a board, you need some way to
accurately measure frequency near 435 Mhz (Keith and I both have
high-end frequency counters locked to GPS disciplined reference
oscillators on our benches). Once you have that, there are two ways you
could go:
First, the ao-bringup/turnon_telemega script in the ao-bringup
subdirectory of our fw/altos repo is our current production script. The
relevant bit is that it calls cal-freq with a device argument and the
SERIAL environment variable set to the board serial number to do the
frequency cal.
The other option is to do it all by hand. Connect to the board over USB
with a terminal program, and the 'c s' command will show you the
currently configured frequency and PLL calibration factor. Use the 'C'
command to generate a steady carrier, measure the actual frequency the
board is transmitting on, and then you can calculate an updated cal
value using the equation:
<desired frequency> / <measured frequency> * <current cal value>
Use 'c f' to set that new cal factor, and 'c w' to write the updated
value to flash. Then use the 'C' command to confirm the board is now
transmitting on the desired frequency.
Hope that helps!
Bdale
------------------------------
Message: 2
Date: Sun, 12 Aug 2018 19:30:33 +0000
From: George Shaiffer <[email protected]>
To: Bdale Garbee <[email protected]>, Altus Metrum
<[email protected]>
Subject: Re: [altusmetrum] Which gplEDA tools?
Message-ID:
<cy4pr2001mb17524e4f87d091d64a312bd9a6...@cy4pr2001mb1752.namprd20.prod.outlook.com>
Content-Type: text/plain; charset="windows-1252"
Kieran Sullivan
I remembered seeing this a couple of days ago.
Don't know if they would be stable enough for your measurements, specs included
below
George Shaiffer
http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz-Red/productinfo/34279+TE/
[Frequency Meter. 8Digit.
100KHz-2.4Ghz]<http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz/productinfo/34112+TE/>
[http://www.mpja.com/images/5note.gif]
Frequency Meter. 8Digit.
100KHz-2.4Ghz<http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz/productinfo/34112+TE/>
Item #: 34112 TE
$18.95
[Frequency Meter. 8Digit. 100KHz-2.4Ghz
Green]<http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz-Green/productinfo/34280+TE/>
[http://www.mpja.com/images/clear.gif]
Frequency Meter. 8Digit. 100KHz-2.4Ghz
Green<http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz-Green/productinfo/34280+TE/>
Item #: 34280 TE
$18.95
[Frequency Meter. 8Digit. 100KHz-2.4Ghz
Red]<http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz-Red/productinfo/34279+TE/>
[http://www.mpja.com/images/clear.gif]
Frequency Meter. 8Digit. 100KHz-2.4Ghz
Red<http://www.mpja.com/Frequency-Meter-8Digit-100KHz-24Ghz-Red/productinfo/34279+TE/>
Item #: 34279 TE
$18.95
PLJ-8LED is a cost-effective microprocessor based, eight-digit digital
frequency display. It can be used for conventional frequency measurement.
Features: small size and reliable performance.
Settings are automatically saved
Features:
Processor: Microchip PIC16F648A
Power: 9V ~ 15VDC (with reverse polarity protection )
Operating current up to 160 mA
Eight 0.56in. High brightness Red LED Display
8 Display Brightness settings (factory set to the highest)
Zero auto blanking,
2.5ppm Voltage Controlled TCXO Frequency reference
Unique gate control & accurate time algorithm (non-timed interrupt mode).
Multi Gate time:
0.01 seconds
0.1 seconds
1.0 seconds
Measurement Input:
High impedance
Three Measurement modes (Low, High & Automatic)
Low Frequency Mode
Range: 0.1 MHz ~ 60 MHz
Accuracy: ± 100Hz (0.01sec. Gate)
± 10Hz (0.1 sec. Gate)
± 1Hz (1.0 sec. Gate)
Sensitivity:
1 MHz to 60 MHz: better than 60 mVPP
High Frequency Mode
Range: 20 MHz to 2.4 GHz
Accuracy: ± 6400 Hz (0.01sec. Gate)
± 640Hz (0.1sec. Gate)
± 64Hz (1.0 sec. Gate)
Sensitivity : 20 MHz ~ 30 MHz: Better than 100mVPP
30 MHz ~ 60 MHz: Better than 50mVPP
60 MHz ~ 2.4GHz: Not tested
Auto Mode
Automatically selects the High or Low Mode according to the input signal
frequency, The crossover frequency is 60 MHz.
Connections:
DC IN: HX2.54-2P socket
RF IN: HX2.54-2P socket
ICSP: (programming interface) 2.54-6P pin
L: 4-7/8” W: 1” H: 7/8” WT: .12
________________________________
From: altusmetrum <[email protected]> on behalf of Kieran Sullivan
<[email protected]>
Sent: Sunday, August 12, 2018 12:14 PM
To: Bdale Garbee
Cc: Altus Metrum
Subject: Re: [altusmetrum] Which gplEDA tools?
Thanks. I think my main issue is the lack of accurate frequency counter. I had
hoped to get close with an SDR radio receiver as my o’scope doesn’t quite
manage 435Mhz with a great deal of accuracy. The frequency I measured and
calibrated to at least got me to the point that the tele-dongle flashed red
when receiving packets, but obviously there was a problem with the
reception/checksum so nothing valid received. I will get this cracked and I do
know someone with a spectrum analyser/frequency counter that I can get hold of,
just a matter of doing this.
Good to know about the bring-up script too, I think I missed that.
Regards,
Kieran
On 10 Aug 2018, at 19:59, Bdale Garbee <[email protected]> wrote:
Kieran Sullivan <[email protected]> writes:
Oh, and when someone figures out a good way to calibrate the radio on
the Telemega, please let me know. I’ve been trying to get it right for
a couple of years on and off… :-)
Oh, sorry, I thought we had the process documented but apparently in
manual section 11.8.2 we basically just tell you not to do this
yourself. We should probably add a new appendix to the manual
explaining how to do it with suitable caveats about "don't try this
unless you have the right gear and know what you're doing, or are really
desperate".
In the meantime, if you want to cal a board, you need some way to
accurately measure frequency near 435 Mhz (Keith and I both have
high-end frequency counters locked to GPS disciplined reference
oscillators on our benches). Once you have that, there are two ways you
could go:
First, the ao-bringup/turnon_telemega script in the ao-bringup
subdirectory of our fw/altos repo is our current production script. The
relevant bit is that it calls cal-freq with a device argument and the
SERIAL environment variable set to the board serial number to do the
frequency cal.
The other option is to do it all by hand. Connect to the board over USB
with a terminal program, and the 'c s' command will show you the
currently configured frequency and PLL calibration factor. Use the 'C'
command to generate a steady carrier, measure the actual frequency the
board is transmitting on, and then you can calculate an updated cal
value using the equation:
<desired frequency> / <measured frequency> * <current cal value>
Use 'c f' to set that new cal factor, and 'c w' to write the updated
value to flash. Then use the 'C' command to confirm the board is now
transmitting on the desired frequency.
Hope that helps!
Bdale
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