Thursday, May 30, 2013

Creating an Android App with the MIT appinventor

Next step to modifying the control app was to look at the MIT AppInventor. This tool is described at  To install the software on my winxp computer I followed the steps from

Having got it installed I decided to try the "HelloPurr" demo app at which makes a cat noise when the Nexus 7 screen is tapped.  All was well, following along with the directions until I tried sending the app to the tablet. Initially I tried using the apb method through the usb cable. The computer recognised the Tablet but I could never get the adbdevices command to show the device was other than offline.  I tried the wifi method but this was doomed if you have no control of the hotel router (I couldnt ping the android from the pc).

Looking around the tool, I noticed a "Package for the phone" "download to this computer" option which generated an .apk file, which by now I had learnt was the install file on an android. I also remembered that when I installed Google_Nexus_7_ToolKit v5.1.2 (needed to unlock the tablet so i could install non Google approved apps) It had an option to install an application from an .apk file through the USB cable. So I tried this method and the app installed.

For interesting reading material see the .pdfs at

Next task is to see if I can modify the control app!

Wednesday, May 29, 2013

Remote Controlling with an Arduino Uno and a Nexus 7

The local Radioshack was selling off some Arduino shields, as they were being discontinued as they were preferring the Seedstudio versions. I got an ethernet shield and an sd card shield, and was initially attracted to get the androidsdk shield until I realised that it needed a cable connection to my Nexus 7.  I wanted to do it by wireless so ultimately I could control things across the shack remotely

Searching the internet I came across a writeup which used an Arduino UNO and a bluetooth board to control the state of an LED. I already had a revision 3 UNO so I looked on ebay and found a cheap Bluetooth module. This arrived today

Following the writeup everything seemed to be working. I could see the RX led on the Uno flashing as it got data from the BT receiver but the LED stayed off. I was intrigued why the writeup said connect the LED to pin 2 of the UNO but defined the LED as pin 7 in the Arduino code listing. I moved the LED to pin 7 and everything worked great.

I tried voice commands but as usual the google voice recognition software could not cope!

I noted that a link to the source code for the android for the appinventor tool is available to "modify". That could be tomorrow nights Project

Tuesday, May 28, 2013

Holiday weekend Expedition Monday

Starting in Marshall, TX I could have driven straight up I20 to Dallas. This would be boring so I looked to see if there was a state park nearby, Searching the Internet I found Martin Creek lake state park. This lake was made to supply water to the Luminant 2.25GW power plant which can be seen on the West shore. The trains bringing Lignite from the local mine can be seen in the marshalling yard. Lots of boating and some nice woodland walks on the shore. Got to see some fish being caught and an intersting demonstration of how to get a boat out of the water and onto its trailer when you are out of fuel!

CQWWWPX had finished but i threw a wire into the trees and had a look around. 18MHz had the activity and P40A was worked and I had a rag chew with KS7D. I called GS4FOC many times. He got part of my call a few times but we never completed before he eventually faded out. Grid is EM22RG

Left the park at 1600, back in Plano by 1915, just in time for dinner

Statistics of the three day tour are interesting

860 miles driven cost $0.06 per mile
Cheapest gas Shreveport $3.19/gal dearest West OK $4.09/gal 
For 807 miles I saw no roadside starbucks (mckinney, TX to Terrell TX)!
22 Tortoise, 2 Racoons, 1 (live ) Armadillo, 1 roadrunner and a skunk were seen.

Holiday weekend Expedition Sunday

Today started in Texarkana, AR. The aim was to drive South to Shreveport, LA. The drive was interesting with regions of oil wells and regions of nothing. Arriving in Shreveport downtown was even more chaotic than normal with streets closed and diversions for a memorial weekend Fair. Took a quick look at the red river then decided to go elsewhere.

I noticed that lake Caddo was NW of the city, straddling the TX/LA border and is the only natural lake with waters in Texas. It is also the location for the worlds first offshore (over water) oil rig in 1911!

As the CQWWWPX contest was still in motion the wire was thrown into a tree in the car park where the empty boat trailers are stored and the KX3 activated. 34 stations were worked with one European. Grid is EM32AR


The night was spent in Marshall, TX

Monday, May 27, 2013

Holiday weekend Expedition Saturday

For many years the locals in NTMS have activated a site near Mena, AR on the microwave bands. As it was a holiday weekend I thought I would drive up there and take a look

Leaving Plano at 0900 the route took me north through Texas to Eastern OK and to Mena, which is only just into AR. I was surprised at the number of Tortoises ambling across the road in OK (22!) I arrived in Mena at 1330, having stopped to admire Satis Dam. There is a ridge that runs E/W near the town so I headed up there  along Skyline drive to the Queen Wilhelmena State park (where the NTMS expeditions camp)

First surprise was the full size steam engine at the park gates, the nearest railway is 12 miles away! There is also a miniature train that takes people round the park, but this was not operational. A short walk produced the following view. The path to Dallas is over the ridge on the right of the horizon

Next I went a walk down the lovers leap trail which was pretty and the downhill / uphill gave my daily exercise. The lodge at the park was being rebuilt so no refreshments, good job I had the emergency rice pudding

I then travelled back towards Mena and visited the fire tower. It was possible to climb up the metal structure to the top and admire the view

Exhausted after all this exercise, and having remembered I had the KX3 and a length of wire with me I decided to activate AR. I found another parking area with a good southerly takeoff and WW2R/5 proceeded to work 17 stations on CW , including 10 on 10m (it was CQWWWPX contest)  The long wire can be seen leaving the right of the car into the bushes! Grid is EM24TQ.

  I also had WA5YWC flex1500 with 2m transverter so I hooked it up to my 902 Transverter and could hear the W5HN beacon on 902.380MHz with a cloverleaf antenna on the roof of the car. Seems to be working

I then drove 50 miles south and stayed in Texarkana, not many hotels around Mena.. Texarkana as its name suggests is a split state city, the hotel was in AR, the restuarants were 100 yards away in TX!

Thursday, May 23, 2013

W5HN 902/1296MHz Beacons

Last Friday I went with WA5TKU and AA5C to the TWU dormitory roof to maintain the W5HN beacons on 902 and 1296MHz. THe frequency and power had not been set/measured in a couple of years so the visit was overdue.
The 902.370MHz beacon was still producing 10W and was within 200Hz of its nominal frequency, not bad for an unovened crystal. The 1296.370MHz beacon was down at 1296,349MHz and had low power output. 2mW in fact, 30dB down on nominal. I tuned up the oscillator chain and got 2watts back, but it went again. The decision was made to remove the beacons and take them home for maintenance on test gear. While there AA5C removed his old microwave beacon package

The 902/1296 beacon was taken to Bobs, WA5YWC, as he was the closest available spectrum analyser. Investigation revealed that one of the airwound coils had moved and broken the connecting PCB track. Resoldering it produced a stable 3W. Both beacons were left at Bobs on soak test over the weekend.

On Monday morning the power was still the same, just needed to set the receiver. The beacon was taken to W5LUA's shack as he has receivers on both bands. Just in case the 1296 beacon's crystal was bad I dropped by the storage unit and retrieved the spare crystal. Installing the crystal we got back to 1296.380MHz (the original frequency from 2000) and the FSK was still good. The 902 beacon was moved to the matching 902.380MHz frequency

On Wednesday Wes and I  returned to the site and reinstalled the beacons, We also commisioned the Z3801 GPS locked reference which will be used as part of the upcoming 50MHz 6m beacon. We also investigated methods to integrate a 1W 10GHz amplifier into the 2/3/5/10GHz roof mounted beacon package

Sunday, May 19, 2013

Working G100RSGB by 5760MHz EME

At the Martlesham Round Table it was announced that GB100RSGB would be activated over the weekend of May 18/19 on 5760MHz EME to coincide with the DUBUS 6cm EME contest. It would be nice to work the call, but now my USA EME station is dismantled it would be impossible. I mentioned the activity to K5GW and asked if I could operate his station to work them, Sure was the response, and if you want to operate the contest, as I don't do it,  you can see what else you can work.

Arriving at the site at 1400 local on the Saturday, the equipment was quickly activated.  The station runs 125W to a 6.9m dish. The TWT is located at the feedpoint so feeder loss is not an issue. No immediate sign of  G100RSGB but CQ calls produced a pileup.  GB100RSGB was worked at  1018z .A little later I was called by G4CCH which was a suprise as I did not know he was QRV on the band. G3LTF was the third English station worked. Activity went quiet at 2300z (1800 local) so the opportunity was taken to work on the Doppler tracking software for my KX3 while waiting for the VK/JA window to open. At around 0500z  (0000 local) three JA stations were work before the moon set. I got back home at 0300 local, having worked a total of 22 stations, all of them on CW. The only getaway was LX1DB.

Monday, May 6, 2013

Ubuntu on the Beaglebone Black (2)

Next I searched for a desktop. I spent 6 hours installing gnome-desktop. Upon reboot it showed promise, by showing a desktop screen but ignored the mouse and keyboard. So I rebooted and after the 3rd time I managed to get the mouse and keyboard working. I managed to add a new document to the desktop, but after much searching and experimentation I could not add any apps to the desktop, even they were on the machine.

Knowing that 13.04 was experimental, I decided to install 12.10 again  This took a while, as usual.  I then installed ubuntu-desktop and this showed the same results as installing it under 13.04

So I made another card with 12.10 and then searched for another desktop. I found one at the lxde desktop.  /bin/bash /boot/uboot/tools/ubuntu/ took the whole of the Anaheim v Detroit hockey NHL game to install. It did however end up with a desktop with mouse and keyboard. 

I installed wspr without incident, but the big issue was that the screen flickered any time the cpu had to do something AND the cpu usage hit 100% and stayed there. Obviously more work to do!

Saturday, May 4, 2013

Ubuntu on the Beaglebone Black (1)

After spending the afternoon over in Fort Worth doing a presentation on the 1.3GHz UK Activity Contest to NTMS, this evening was spent installing Ubuntu on the BBB

Initially I tried the procedure using a prebuilt image  at and eventually, after solving some issues due to priveleges I got a USDHC card produced. Unfortunately, after powering up the BBB with the reset button near the uSDHC pressed as instructed and waiting, it produced lots of flashing blue lights but no video output. Time to try something else.

Next I searched for any other prebuilt images and came across (a later version of Ubuntu) I followed the instructions on my ubuntu laptop which did not need any corrections and built an uSDHC card

Booting the BBB with the reset button pressed it was reassuring to see a penguin appearing on the screen and a demand for login and password

Flushed with success, I decided to try and install WSPR. I used the process of the previous WSPR blog. However all commands had to be typed in letter by letter, as, not having a desktop or browser I couldnt go to this blog and cut and paste!) It built way faster than it ever did on the RPI.

Launching WSPR it complained as usual about having no display to export to, so the next step is to install a desktop, find a sound card (and a browser!)

Visit to Mouser Electronics

The last few days I have been working on the replacement w5hn 50MHz beacon. Testing the N1JEZ board showed i needed a replacement Fox 10MHz Crystal oscillator, which I needed to get from Mouser Electronics. I was going to get it shipped, then I thought "its a nice day let me go and get it". By nice (for Dallas) i mean i was not going to roast in the car; it has been cool lately. Having ordered from them for 20 years it would be nice to see the source of all the goodies

Went online, exchange with there online help who said "will call" wasnt an issue, just choose that box when choosing shipping method. I choose the components needed then got to shipping page. No "will call" box. Had to resort to calling the ordering line and a helpful lady said you need to put will call and a time in the special instructions box, even though it warns putting anything there could delay the order processing. You still have to choose a carrier for delivery , even though you wont be using one,  to get to the next page and complete the order!. She stayed online till the order was placed then intercepted it and changed it to will call; not an efficient process.

Drove to Mansfield, TX which took an hour. GPS said I was there and I suspected the big concrete building was Mouser but found no signange. Went to the reception (still no sign) who said willcall was round the back near the fedex trucks. The order was there, waiting and while there I got a paper catalogue. On the way out I found THE  sign, the only one on site,  at the intersection outside. All the entrances just say "No Trucks"

As WA5VJB was on my route home I  had lunch at the Mongolian BBQ with him, returning just in time to beat the Friday afternoon rush hour

Thursday, May 2, 2013

Beaglebone black is here

As promised, I got an email from Mouser on May 1 saying the Beaglebone black board had been despatched. It arrived may 2 and looks nicely made, apart from the (yellow) RT1 component standing 12mm off the board with the resultant risk of shorting out on the ethernet connector

Following the instructions at I updated the software. Its slightly different from the rpi. You put an image on the microsdhc card, plug it into the BBB,  reboot it and it installs it onto the BBB (40 minutes). You remove the card, reboot and off you go. You dont need the card inserted to run the OS. It all came up nicely with the mouse and keyboard on the powered USB hub but connecting to the internet via the WNCE2001 access point or the wifi dongle from the RPI did not succeed after many attempts

Good job I had got all the previous experience editing /etc/Network/interfaces as I needed to edit eth0 to be dhcp. I needed that as clicking the box and the top right of the desktop that looks like an ethernet connector,  and checking the two ethernet ports (one for usb and one for the rj45) said they were already dhcp, but the ifconfig did not agree

Having connected to the internet I expected that like the RPI it would ntp to set the clock. NO it does not but i found at the way to set it up. I need to automate the process as it needs to be done every restart

I have noticed there is a UBUNTU image for the BBB which I want to have a try with as I have had more experience with that than the supplied BBB OS