Modifying MMDVMHost-Dashboard Config Values on a RPi

Posted on January 1, 2017 by robert

Well, as it turned out, I was overthinking the problem.  Sure enough there were NO usernames/passwords assigned to the Dashboard buttons.  Sigh.  However it was a good experience because it lead me to understanding how the Dashboard configuration is carried out, setting the correct timezone, and fixing a typo that prevented the reboot function from working. (Thanks to Kim, DG9VH, who got me going in the right direction.)

A PHP script called “setup.php” needs to be copied from the /home/pi/MMDVMHost-Dashboard directory to the root in the /var/www/html directory.

Once setup.php is there, open the browser and go to http://127.0.0.1/setup.php (assuming you are at the RPi, otherwise substitute your network address).  This will open the setup process. Modify the usernames/passwords as desired and also change to the correct Timezone.

The typo, either in the default config values, or perhaps a mistake made by gigaparts is the “Reboot system command” that needs to be changed from “sudo revboot” to “sudo reboot”.

Since I wasn’t running DMR, I decided to uncheck the “Enable Network-Switching-Function” box turning that feature off. as well.  I also added a URL to my webpage masthead.

After completing the update, you MUST delete setup.php from /var/www/html otherwise anyone who knows your Dashboard address can modify the settings.

 

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Setting up New DVmega-RPi 3B Dual-Band Hotspot

Posted on January 1, 2017 by robert

A friend of mine wanted a Hotspot for his home, which is far enough away from our DSTAR repeater to connect to without resorting to high power and a high gain antenna.  I volunteered to set up a RPi 3B based DVmega for him, and he ordered the kit of parts form gigaparts.

I was expecting to clone my image and change the call signs, but not before checking out the latest build supplied with the kit.  I was pleasantly surprised to discover that they had changed the OS to Raspbian with PIXEL.  It also changed over to MMDVMHost with Dashboard.

In theory gigaparts did all the work on the setup.  That might be the case for their own needs, but it wasn’t working for me.

There were two missing bits of information that would have been helpful on their limited single-sheet instruction:

  1. They claimed the username/password was pi & pi.  That’s not correct.  It is pi & raspberry
  2. They failed to mention that the MMDVMHost setup.php program should be run so that whatever MMDVM usernames/passwords could be modified.

Probably because of #2, I was NOT able to get the RF working.  I checked my older load and everything worked fine, so that meant it had to be a configuration issue.  Eventually I noticed that while I was hearing nothing on my HT, the DVmega was transmitting almost constantly.  Turns out it was repeating DMR signals.

I made the following changes to the MMDVM.ini file (in the MMDVMHost directory) and things started working correctly:

[Info]
RXFrequency=144900000
TXFrequency=144900000
Power=1
Latitude=41.5
Longitude=-71.5
Height=0
Location=Narragansett RI

… … …

[D-Star]
Enable=1
Module=C
SelfOnly=0

[DMR]
Enable=0
Beacons=0
… … …

I REALLY like the MMDVMHost-Dashboard, especially the Buttons that allow updates of the reflector, restarts, shutdowns, etc.  Exactly what is needed to manage a headless RPi.

But at least until I rerun the setup.php program I have no idea what the assigned username/password is for each of the Dashboard buttons.

 

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Goals for 2017 and 2016 in Review

Posted on January 1, 2017 by robert

Four out of seven 2016 goals were completed successfully:

  • 255 Confirmed Countries  YES
  • 1,200 DX Band-Points  YES
  • WAS Completed on 12 Meters (need WV)  NO
  • Successful ARISS Contact at All Saints Academy  YES
  • Teach a Technician Class for Monsignor Clarke Middle School  NO
  • Teach a Technician Class Elsewhere  NO
  • Complete my K1  YES

I made a mistake on two attempted technician classes in 2016 by allowing them to be marketed to professional educators.  The first class was canceled when only 2 students appeared on class day, and the second never got off the ground as nobody signed up. Understandably, teaching professionals are very busy.  Fool me once, fool me twice, no way I get fooled again.

The ARISS contact was a complete success with a record number of questions asked and answered during our contact with Astronaut Jeff Williams.  The crew was excited enough that a second contact for Bishop Hendricken High School is planned for 2017.

DX worked out a bit better than I planned, with 258 confirmed Countries in LotW at year-end, plus 1225 confirmed Band-Points.  However the higher frequency bands are suffering as we are on the downhill side of the solar cycle (which wasn’t that grand to begin with).  I heard painfully few stations on 12 meters at all, let alone a desired West Virginia station.

Other accomplishments for 2016 were writing a comprehensive DSTAR Repeater Supervisor’s Guide for our W1AAD DSTAR machine, along with upgrading the hardware and software. I also installed a DVmega 2m/70cm Access Point in my home.  A visit to ARRL HQ and seeing my father’s memorial brick was a real highlight.

The K1 kit building experience was very positive, reigniting a desire to build more kits.  I have at least two more simple superhet QRP kits ready and waiting for 2017.  Our club will be holding a “Build-Night” for a simple 40m QRP “Pixie” kit that I will help direct.  My acquisition of a Spectrum Analyzer has opened up a world of possibilities as well.

Goals for 2017:

  • Teach a Technician Class
  • 265 Confirmed Countries
  • 1250 DX Band-Points
  • Successful ARISS Contact at Bishop Hendricken High School
  • Complete at least one QRP kit
  • Convert from HRD to DXlabs

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K1 30-meter Emissions, Revisited

Posted on December 16, 2016 by robert

So I decided to open up my K1 and recheck the 30-meter bandpass filter alignment, guessing that the simple “peak coils for maximum” in the manual might also tend to peak the spurious emissions for maximum as well.  Sure enough that was the case.  I was able to find coil settings that favored a lower 6th harmonic value without negatively impacting the output power.

In the above graph, there was 40 dB of external attenuation.  So the carrier on 10.120 MHz is 40-6.90 dBm, or  33.1 dBm (which is 2 watts — the value used for alignment).  At this setting, the greatest spur was the 6th harmonic, and it was -49.1 dBc, a passing value.

Life is good!

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Elecraft K1 Emissions

Posted on December 14, 2016 by robert

After completing the internal tuner add-on for my K1, I wanted to run emission tests on it as well.  My unit is two bands: 30-meter and 20-meter.

FCC Limit:  For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission.

Test Setup:  UUT feeds a 50 dB Power Attenuator, the output of which is feeding a Siglent SSA3021X Spectrum Analyzer.  The SA calibration is valid through November of 2017.

Test Settings for Carrier Noise:  For close in viewing, span is 10 KHz, centered on transmit frequency.  RBW/VBW 100 Hz.  On 10.125 MHz, 30-meters, Input Power to SA was 50 – 13.36 dBm, or 36.74 dBm (4.72 watts).  TX noise is -73 dBc.

On 14.050 MHz, 20-meters, Input Power to SA was 50 – 12.35, or 37.65 dBm (5.82 watts). TX noise is –  76 dBc.

Worst Case Spurious Emission 30-Meters:  The worst-case emission on 30-meters was the 6th Harmonic.  This was -54.20 dBm, or -41.1 dBc which does not pass.  However, this was with the antenna tuner bypassed, which would add additional harmonic rejection, especially at higher frequencies.

Worst Case Spurious Emission 20-Meters:  The worst-case emission on 20-meters was actually 630 KHz above the carrier at -58.84 dBm.  This is -46.6 dBc, passing.  The second harmonic was at -64.76 dBm, or -52.5 dBc.  Higher harmonics were not visible.

 

 

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Kenwood TH-F6A Passes Spur Test

Posted on December 12, 2016 by robert

Running a spectral purity check on my Kenwood TH-F6A tri-band radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz.  Since that is not coming from the UUT, it can be ignored.

The power from the TH-F6A was -3.68 dBm + 40 dB for the external attenuator = +36.32 dBm = 4.29 watts.

The worst case spur the second harmonic at -74.69 dBm, which (adding back the 40 dB from the external attenuator) is -34.69 dBm or 0.3 microwatts, a passing value.  It is also 71.0 dB below the carrier.

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Kenwood TH-D72A Passes FCC Spur Limit

Posted on December 12, 2016 by robert

Running a spectral purity check on my Kenwood TH-D72A APRS radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz.  Since that is not coming from the UUT, it can be ignored.

The power from the TH-D72A was -3.66 dBm + 40 dB for the external attenuator = +36.34 dBm = 4.31 watts.

The worst case spur the fourth harmonic at -77.49 dBm, which (adding back the 40 dB from the external attenuator) is -37.49 dBm or 0.2 microwatts, a passing value.  It is also 73.8 dB below the carrier.

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BaoFeng UV82 Fails FCC Spur Limits

Posted on December 12, 2016 by robert

BaoFeng sells more radio models than you can shake a stick at.  Another handheld dual band unit that fails FCC spectral purity is the UV82.  This is somewhat larger than the UV5R, sells for a premium, but has an odd dual PTT button that confuses the heck out of users, as it will transmit on different channels depending on which PTT is pressed and how it is programmed.

The identical test setup used for the UV5R was used to test this radio, including the 100 KHz bandwidth setting.

The power from the UV82 was -3.87 dBm + 40 dB for the external attenuator = +36.13 dBm = 4.10 watts.

The worst case spur the third harmonic at -52.48 dBm, which (adding back the 40 dB from the external attenuator) is -12.48 dBm or 56.5 microwatts, a failing value.  It is also 48.6 dB below the carrier.

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Icom IC-80AD Spectral Purity

Posted on December 12, 2016 by robert

Running a spectral purity check on my Icom IC-80AD DSTAR radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz (#2 in the photo below).  Since that is not coming from the UUT, it can be ignored.

The power from the IC-80AD was -4.03 dBm + 40 dB for the external attenuator = +35.97 dBm = 3.95 watts.

The worst case spur the fourth harmonic at -74.51 dBm, which (adding back the 40 dB from the external attenuator) is -34.51 dBm or 0.4 microwatts.  It is also 70.1 dB below the carrier.

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Icom ID-51A+ Spectral Purity

Posted on December 12, 2016 by robert

Running a spectral purity check on my Icom ID-51A+ DSTAR radio, I found that it passes FCC requirements as you would hope it would.

The test setup used for the UV5R was only slightly modified to change the bandwidth so that the noise floor was lowered.  This uncovered a spur that is in the SA itself, at 344.8 MHz (#2 in the photo below).  Since that is not coming from the UUT, it can be ignored.

The power from the ID-51 was -3.48 dBm + 40 dB for the external attenuator = +36.52 dBm = 4.49 watts.

The worst case spur the third harmonic at -68.15 dBm, which (adding back the 40 dB from the external attenuator) is -28.15 dBm or 1.5 microwatts.  It is also 64.7 dB below the carrier.

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