Category Archives: Linux

Next step on the rooftop LNA setup

This past weekend I finally started building the ultimate case to house the LNA and FM BCB filter for the rooftop multireceiver project.

Last night I did the final bit of wiring, installed a DC-DC buck converter to take +12 vdc and knock it down to 5.0 vdc.

Here’s some pics of the project.

The two separate die-cast enclosures are the LNA (lower) and the FM BCB notch filter (upper). There’s a LM2596 DC-DC converter in the lower left, and a weathertight Ethernet connection in the center-right wall. All external RF connectors are N. All internal connectors are TNC. All coax is RG316 double-shielded. I used an Ethernet connection to get power to the box and to allow the future addition of either an Arduino or an Raspberry Pi for telemetry purposes.

The overall enclosure with installed components. Got this particular enclosure for about $22 delivered – someone in Santa Maria CA didn’t want it. Was missing the base plate upon which I mounted all the components – fortunately, I had a piece of Al in the garage that was a near-perfect fit! Would have cost nearly $70 new.

The left N connector is the antenna input, the right N is the assembly output to the shack. The Ethernet connector is for future expansion and dc power.

Installed on the roof temporarily (will be mounted on the tripod to right ultimately) with power supplied by batteries in the Tupperware container.

The batteries (Eneloop AA x 10) are charged with a newly modified solar panel install. Again, over the weekend I cut some Al extrusions to replace the old way I’d attached a single 5 w solar panel, now it supports two 5 w panels for a total of 10 w. This almost guarantees sufficient charge for long winter nights.

In addition, the box mounted on the tripod already had a PoE Ethernet connection from the main rooftop unit. I use that 12.6 volt PoE ¬†through a single 1N4001 rectifier to source power to the LNA box when the solar panels can’t provide enough charge to keep the batteries up. I want to add some telemetry (through a future Arduino or similar on the roof) to measure voltages, temperatures, etc.

 

Adding Real Time Clock to Raspberry Pi

Added a Sunfounder DS3231 RTC to my Raspberry Pi 3 running weewx.

The following helped me with understanding how to

https://github.com/weewx/weewx/wiki/Raspberry-Pi

https://github.com/weewx/weewx/wiki/pi-RTC-with-raspbian-jessie

After a reboot before step 9 in the following, I then completed the rest of the steps through 14 and get the following:

pi@raspberrypi:~ $ timedatectl status
Local time: Sun 2016-10-30 14:44:09 MST
Universal time: Sun 2016-10-30 21:44:09 UTC
RTC time: Sun 2016-10-30 21:44:09
Time zone: US/Arizona (MST, -0700)
NTP enabled: yes
NTP synchronized: yes
RTC in local TZ: no
DST active: n/a

I have not disconnected it from the network yet to see if it’s really working, though. Will have to reconfigure my setup to have a console connection rather than an SSH.

ADS-B and PiAware

I’ve been experimenting with PlanePlotter, acarsdec and a bunch of other things recently, and have had to hack my way to a whole new level of incompetence with Linux in the form of Raspbian.

One important thing I just learned was the system flow diagram for dump1090 and piaware.

https://flightaware.com/adsb/piaware/about

At least now I understand better how messages flow within my setup here, and am starting to learn more about the different ports on dump1090 and piaware, and how mlat (multilateration) works using the aggregation of other piaware receivers through the FlightAware servers.

PlanePlotter, however, is a whole new can of worms, perhaps interesting worms, but worms, nonetheless.