Tuesday, October 5, 2010

Learning CSS, the hard way...

All of the web pages that I've built look like they were written in 1994; the year I learned to use HTML. As part of the remote receiver project I decided it was high time that I learn a bit more about modern web authoring, and using new techniques like CSS. The very basics of CSS are, of course, easy to understand. Where things get a little tricky is positioning things on the screen. i've been struggling with that.

I found a nice web tutorial that illustrates the point quite well, it's located here.

This, of course, doesn't give me design skills, it just let's me re-implement my 1994-looking-html in a more modern manner ;)

Thursday, September 23, 2010

A long time ago......

In a basement not too far away.....

My friend Dave, KM3T, runs a very cool website called Liveatc.net. Dave has volunteers all over the world with VHF aircraft band receivers that stream live air traffic control traffic to his website. You can select any number of frequencies to listen to. In addition to the normal VHF traffic, Dave has an aircraft HF audio feed. The receiver is a Yaesu FT-817, which I am a proud owner of two. He mentioned to me casually that he changes frequency throughout the course of the day to follow propagation. Now, that intrigued me; how did he change the frequency remotely? Well, it turns out that the Yaesu rig supports CAT commands which is an rs-232 control protocol to change frequency  and modes, etc. Dave used hamlib, which is a set of libraries for linux to provide a common programming interface to various receivers and transceivers.

The concept of having a remotely controlled receiver really caught my attention, and shortly afterwards I started to talk with Jay, AB1II, about how we could do something similar. I quickly set up the streaming audio server on my home linux server and began listening to it remotely from work. The issue of changing frequency and mode was going to take some work, so I asked Jay if he could take a look at hamlib and see if we could come up with some basic utilities to change freq and mode. Jay is a programmer by trade, and within a short period of time he wrote the  utilities to control the receiver remotely via command line!

This was great! Being able to listen to HF while at work was a big bonus, especially when you need to put your headphones on and dig into a project (Coding for Jay, a spreadsheet for me).

Now, at that point we could have been happy and just walked away, but I figured we should push forward and keep adding features. The first feature was fairly obvious; make a web interface so we didn't have to ssh into the machine and have to remember command line arguments. I had been looking for an opportunity to learn PHP programming, so I decided to take this task on. After beating my head against the wall for a bit I had an interface up and running that allowed you to change the frequency via a text input box, as well as change mode.

The original FT-817 interface with shortcuts to well known frequencies
Wow, this is cool!

Some time lapsed and a few new folks started to use the receiver. I had been very busy with other projects and let this project fall by the wayside. Pretty soon I started to get the itch to continue with the project, but I wasn't really sure which direction to move in. I was also thinking at the same time that a Yaesu FT-817 is an awfully nice radio to be relegated to just being just a receiver. I use my other FT-817 on my 10GHz microwave rig. I decided the FT-817 would be replaced with the very nice AOR AR-5000 receiver that I had picked up last year, and hardly used at all. The AR-5000 would receive everything from 10khz up to 2.6GHz.

The AOR AR5000+3 capable of all modes from 10k to 2.6GHz
Ok, that makes sense, it's a receiver that's been sitting on a shelf for over a year, lets give it some use! But what a waste it would be if it were to only be used for HF! Wouldn't it be great if we could switch back and forth between several different antennas and maybe take advantage of the VHF/UHF side of the receiver as well?

Over the years I've been collecting multi-position RF relays for microwave projects, or switching IF lines for my microwave transverters.

6 position RF relay, 28v coil and 5v TTL to switch position
These relays are fairly simple, most of them require +28v @300ma to close the coil and switch to one of the positions. The relay shown in the picture is slightly different, it takes +28v @300ma at the coil plus 5v TTL to switch the position. Now, what would I use to switch positions? I had been poking around on the web and had been seeing lots of information about an open-source micro-controller available called the Arduino. I started looking closer at it and it turns out that it would be fairly simple to get the Arduino to interface with the relay. The Arduino board that I used was called a Duemillenove which has 14 digital I/O pins (TTL), plus 6 analog I/O lines. But.....It would require some software to be written! Now, I didn't exactly write the most elegant PHP code when I did the web interface for the radio, I wasn't sure my programming skills were up to the task to take on this micro-controller.

The Arduino, thankfully, has an extremely easy to use programming language. So, I ordered one and took the plunge. To my extreme amazement, I was able to write a working program in about 30 minutes from knowing absolutely nothing about the language to finish! Ok, proof of concept partially complete.

The Arduino Duemillanove mounted in a Hammond aluminium enclosure

Next, how to send data from the linux machine over to the Arduino? The Arduino has a built in USB-serial chip that you use as the main programming interface, but it can also be used to communicate directly with the processor as well. There are some basic serial commands in the programming language that allow you to send and receive data. I found a little command line utility that let me send data over the USB-serial connection, and before long I could now switch antenna positions from the command line.

Next, I discovered there was actually a serial PHP class that would allow me to access the serial port from within my PHP script. Cool!

So, now the web interface allows you to change frequency, mode and now Antenna. Of course, I've been so busy getting the code working I now need to make up a number of cables to the receiver can have access to array of receive antennas on my roof.
Remote control app with antenna selection

In a future post I'll send a URL for my code, once it's been cleaned up.

In the end, I'm amazed at how easy it was to accomplish the task of interfacing a relay to the web interface. Working with the Arduino is very easy, and it's really opened a number of doors for me. Two other projects that I plan on doing are making a beacon keyer for my future 10m beacon, plus it should be simple to make a basic electronic keyer! I just read about a MP3 shield that is available now for not much money, so I could also think about building an external voice keyer.

The options are endless with this little board.....

System Schematic

Thursday, September 9, 2010

September Contest Season begins....

This weekend is the ARRL VHF September QSO Party, I'll be operating up at K1WHS in Maine. Next weekend is the second weekend of the ARRL 10GHz cumulative contest. I don't have a set plan yet, but I'll likely be driving all around Cape Cod one of the two days. There is talk about going up to Mt. Washington, but that's a lot of driving for a single weekend!

After the second weekend of the 10GHz contest we have the fall sprints:

* 144 MHz - Monday, September 20, 7 pm to 11 pm local time
* 222 MHz - Tuesday, September 28, 7 pm to 11 pm local time
* 432 MHz - Wednesday, October 6, 7 pm top 11 pm local time
* Microwave - Saturday, October 16, 6 am to 12 pm local time
* 50 MHz - 2300 UTC Saturday, October 30 to 0300 UTC Sunday, October 31.

Full rules can be found here.

Get on the air, even if it's only one contact!

Monday, August 23, 2010

First weekend of the 2010 ARRL 10GHz Cumulative Contest

It's that time of year again, this weekend I started off up in New Hampshire on top of Mt. Kearsarge in FN43bj. I was joined by W1FKF, W1EX and N1ZZN (who was there to climb the peak). We got into the park a little early, and were up top and setup by 9:15. The WA1VVH 10GHz beacon was on and VERY loud on Saturday, which was very helpful. We could hear the Mt. Greylock beacon, but it wasn't very loud (I think it's lower power).

We had a great day, I broke my previous records of 22q's with a grand total of 27 for Saturday. My best DX was down to WA2FGK in FN21, who was there, but very weak.

Sunday W1FKF, W1EX and I met up at the Westborough water tank at FN42fg. The weather forecast was for heavy rain, so we knew it wasn't going to be a long operation. I got there a little early and got the liason system up and running. There weren't many people on 2m, which wasn't a good sign. W1FKF and W1EX showed up shortly afterwards and the three of us had our systems up and running within 5-10 minutes. We managed to work about 6-7 stations, the best DX was K2KIB at Highpoint New Jersey, in FN21. That was actually impressive since all three of us were looking through a tree and a bus!

Shortly afterwards the rain started, we made the last 2-3 contacts then called it quits around 9:30. When I got home I brought the 10GHz rig into the house and decided I might try doing some rain scatter. There was a lul in the rain, so I set up on the back porch which faces N-NW. Once the LO was somewhat stable I tuned around and didn't hear the VVH Beacon. I added about 15 degrees of elevation, and boom! There it was! I was hearing WA1VVH/B very strong, about S5 on rainscatter. I could hear it in about a 15 degree arc on the azimuth and about 20-30 degrees in elevation.

I went into the house and tried to get the guys up on Kearsarge to run with me, but they were in a heavy rain period and decided to wait a little while. About 20-30 minutes later we tried sending to each other, but never managed to complete. When I went back to the beacon, it had almost disappeared.

I then downloaded the rainscatter program by K0SM, and learned how to use it. I could see the storm in Eastern New York state that was causing the scatter, it was in the same 15 degree arc that I was hearing the beacon on.

I never ended up working anyone, but it was a good lesson in learning how rain scatter works. I'm more equipped to take advantage of it next time it happens....

The next weekend of the contest I'll be down on the Cape for at least 1 day, and I might spend some time down in CT and RI along the coast line.

Perseids a bust for me...

The peak of the Perseids meteor shower was back on 8/12 and 8/13. I ended up not really having the time to work anybody and from my location wasn't really hearing many burns at all. I monitor the WA1ZMS 2m beacon on 144.285 and can frequently hear pings, but I wasn't hearing any more than the normal amount during the meteor shower. Also, my station is still in the state of dis-repair. My main 2m Antenna is a real POS, and needs to be replace badly. The 6m Antenna is OK, but it's only 3 elements. Both antennas are slated to be replaced this fall, and as it turns out, I found the exact 2m antenna I wanted for sale used locally. Now I just need the 6m antenna and a new rotor.

The other issue that I've wanted to fix is RF power. On 2m I've been using an external 170w power amp, that puts out more like 130w peak (It's old and tired). On 6m I have 100w from the FT-847, but on both bands I run at 50% power since the WSJT protocols run at 100% duty cycle. So, that puts me at 65w on 2m, and 50w on 6m, not really Ideal power levels for meteor scatter.

The good news is that I have lots of power available for 6m! I bought a used 1Kw tube amp a number of years back that's been sitting Idle in the basement. I don't plan on running anywhere near 1Kw, but I think I could run 250w full duty cycle with no problems. That should be more than enough power to get the job done. The real issue I face right now is getting the amplifier integrated into the system. When you start having to worry about switching relays and sequencing, it gets more complicated.

For 2m, I recently picked up a 350w amp from a friend and have been working to get that integrated as well. I built a new sequencer from a kit and completed the enclosure last night. I just need to work out the relay wiring and I'll be all set.

Of course, both amplifiers will require lots of power to run, and at the moment, I only have a single 15 amp circuit in my office, so I have more things to work out.

So, work continues on improving the meteor scatter station, I should be ready for the next shower, at least on one band....

Saturday, July 24, 2010

I've found my stride with JT6M

The 6m Sporadic E season ended up well for me this year. I worked a number of double hops to the west coast and managed to get some DX in Bermuda, Spain, Portugal and Cuba this year. Now that things are slowing down, I'm re-focusing back on the digital protocols.

I had played around with FSK441 on 2m meteor scatter, and had made a few other JT6M contacts, but I never really got the hang of it. This morning, that all changed.

I woke up early and spent a few hours hanging out on Ping Jockey (site for scheduling meteor scatter contacts). Finally, around 9am I worked WA4CQG in Alabama, the onto other guys in Oklahoma, Indiana and Illinois. Now, unfortunately, these were not likely meteor contacts, but rather terrestrial via sporadic E. But it was still a good exercise to get the rhythm of the QSO. I still had some questions on which reports to send, and whether I should run first or second.

That's all worked out, and I now look forward to completing my first FSK441 Meteor Scatter QSO on 2m. I've decoded other peoples pings, and (via ping jockey) know that other people have decoded my pings as far out west as Missouri. So, now it's just time to wait for the right conditions...

Tuesday, April 20, 2010

W1RJA EME event with Arecibo

The EME event at the Eastern VHF Conference was a big success! We participated in the Echoes of Apollo on the air event and successfully made contact with KP4AO at the Arecibo Observatory. I put together a 10 minute video that shows the station and our contact. I also has some comedic relief towards the end!

Thursday, April 15, 2010

Arecibo Moon Bounce this weekend

This coming weekend (April 16-18th, 2010) is the Echos of Apollo EME event. A group of hams will be operating EME from the world famouse Arecebo observatory in Puerto Rico.

This weekend is also the Eastern VHF Conference hosted by the NEWS group. I will be in attendace at the conference doing some video taping.

A bonus for anyone attending the conference, Dave, K1WHS, has been hard at work building a 432MHz EME station that will be assembled Saturday morning. This station is complete with a 1500w amp and dual long-yagi's on an Az-el rotor. Should be a fun time for anyone in attendance, hopefully we'll have some video sometime next week.

Monday, April 12, 2010

WA1MBA Plays with Lasers!

Tom Williams gave a little demo of what various consumer lasers are capable of at the March NEWS meeting in Longmeadow, MA.

Thursday, March 25, 2010

2007 NEWS Video

I came across some video I had taken back in 2007 at the Northeast Weak Signal Groups annual cookout and 10GHz MDS test session. I edited together the more interesting bits, enjoy!

Sunday, February 14, 2010

Hot Amplifier

With my recent experimentation with the WSJT protocols on 2m, I've run into a new problem. The FSK441 protocol is effectively 100% duty cycle while it's transmitting, and with the sequencing it's 30 seconds of transmit, 30 second of receive. This has the side effect of creating a very warm amplifier, to say the least. I'm currently using an old RF Concepts amp, 45 watts in/170 watts out.

To reduce the chances of melting your amplifier, it's recommended that you drive the amp at reduced power. That past week I've dropped my input power to about 20watts PEP. Even at that rate, the heat sink on the amp was very warm to the touch. I figured the easiest solution to solve this problem would be to put some fans on top of the heat sink to try and draw away the heat, create some constant airflow.

I went down to the work shop and rummaged through some old junk boxes and pulled out 3 working 12v fans that were pulled from an old PC (it occasionally pays to be a pack rat). So, now I just needed a mounting method. Over the course of the week I had time to think about it, and after a trip to the hardware store I came up with an overly complicated mounting bracket that would hold the fans down to the amp. I'm not sure where the quote came from, but i've always subscribed to the thought "Anything worth doing, is worth OVER-doing!".

I found I had some small aluminium strips that I had purchased at the local home center, it seemed to be the right material for the job, but I didn't quite have enough of it, so off to the store I went. Luckily for me they recently built a big box home center 2.0 miles from my house. Said company now extracts money out of me on a weekly basis.

So, with crude measurements, a few whacks of a hammer, some drilling and I have a basic bracket. I simply tied the lead wires together and crimped them into an Anderson Power-Pole connector, which is the standard low-voltage connector in my shop.

The three fans together draw about 350ma at13.8v. Ideally I'd like to find a small circuit that would detect the amp keying and would turn the fans on for a set period of time. Normal voice operations doesn't really require it, but extra thermal protection never hurts. For WSJT modes having the timer be longer than the typical sequence would effectively keep the fans on constantly, which is a good thing.

The whole assembly is currently sitting snugly on top of the amp, but it's not permanently attached. I think I can get away with not having to drill any holes into the heat sink since it's fairly tight.

Now, the dangerous thoughts are running through my mind. Since I've greatly increased the thermal dissipation, how much harder can I run my amp? Could I run at full power?

I don't currently have the ability to measure the surface of the heat sink, but I'm guessing I could probably run closer to 30w input, maybe 130w output. I think it might be time to look for an inexpensive IR thermal sensor, like I saw at show-n-tell at the last NEWS group meeting. I'm guessing Harbor Freight probably has something that will do the trick.

Monday, February 8, 2010

JT65b Digital mode on 2M SSB

Over the course of the past year I've been working on getting my home VHF/UHF station permanently on the air. I've had various antennas up in temporary configurations, but never with any sense of permanence. Recently, while reconfiguring the workshop, I also reconfigured all my feedlines and radios. I now have a permanent 2m ssb radio, 2m 160w amp and 12 element yagi up around 25'.

Part of the reconfiguration also got me back on HF again, something that I've been missing since I moved to Colorado back in '04. With the big feedline re-shuffle I re-routed my 75m inverted vee up to the same radio that is the permanent 2m ssb station (Yaesu FT-847).

One of the main HF modes that I enjoyed was PSK-31. I really enjoyed watching the DSP work wonders with nearly completely in-audible signals. Part of the new station configuration included purchasing a Tigertronics Signalink USB soundcard/radio interface. This is a nice little unit that greatly simplifies the whole radio interfacing, in my case, eliminating the need for overly complicated wiring schemes.

While working PSK-31 one day it occured to me that now that I had this digital interface I could also try some of the new WSJT modes on 6m and 2m. Since I didn't have a 6m up in the air, 2m it was! This all happened during the weekend of the ARRL January VHF Sweepstakes, so it was a good time to test it all out.

Well, Saturday night of the contest weekend I listened on the meteor scatter calling frequency of 144.140, but I wasn't hearing any pings at all. I decided to leave the program running over night to see if I heard anything. In the morning I was very happy to discover that I had decoded a couple of pings! Wow, actual reflections off of meteors! Over the course of the next couple of weeks I didn't have much time to play, but this past Saturday afternoon I found myself on Ping Jockey talking to other folks. I actually heard some pings, but unfortunately had the WSJT program in the wrong mode. D'oh! Russ, K2TXB, asked if I'd like to try some JT65b over tropo, I was excited to try!

Off we go, I see Russ's signal and I start clicking buttons, quickly realizing that I don't know what I'm doing :) All the reading I had done was on FSK441, not JT65, so the sequencing was a bit different. Then, much to my dismay....WSJT starting crashing! Needless to say Russ and I didn't complete, but Russ was a great sport and gave me some private pointers that really helped me out. I was very appreciative that Russ took the time to elmer me, it really does make a difference, thanks Russ!

I'll skip over the saga of me getting WSJT to work, but it involved downloading the source code and compiling on mutliple machines. The bleeding edge is often a painful place to live. In the end I had a workable system. The "end" was about 11pm that evening.

Sunday morning 5:45 I wake up with hopes of actually completing with someone, I jump on Ping Jockey and to my suprise there are a handful of guys awake and ready to run. My first victim was VE2DSB, Dan up in Quebec, FN35hs. Dan wanted to try QRP first, just to see if we could do it. I figured with me being a complete amateur at the digital modes I would have failed completely, but to my surprise I was able to see his signal on the waterfall! The QSO went very well, no issues at all (other than one operator error, clicked the wrong button). A few minutes later we had a QSO in the logbook! Dan then told me that he was only running 15w into a fairly modest antenna!

Here is a shot of the spectrum with the messages added on top in red.

15 Watts into a 12 Element yagi, and we were able to work each other over a 285 mile path! It's absolutely amazing what can be done with these digital modes.

My next step is to sucessfully work someone on FSK441. I've had some decodes, but never enough to actually make a contact. Saturday, during one attempt, I had several folks out in the midwest report hearing *my* pings, but I never heard any in response. Part of the station improvement that will happen shortly is the addition of a SSB Sp-2000 pre-amp that will be mounted up near the antenna. I just need the weather to cooperate and give me a nice 50-60 degree Saturday afternoon. Wishful thinking?

Friday, February 5, 2010

Work has begun on my new (to me) Elecraft K2

A number of years back I purchased a partially-built Elecraft K2 kit from a co-worker who lost interest in building it about 1/3 of the way into it. I had always planned on using it as an IF rig to drive VHF/UHF/Microwave transverters, since it's very well suited for the purpose.

Well, the kit sat on the shelf for years and gathered lots of dust. Oddly enough, a few years later the co-worker was re-invigorated in his interest, bought and built a new K2 kit! A few weeks back I completely tore apart my workbench and got it finally configured the way I wanted it, with all the test gear powered up and in the right position. I had previously only been able to power up two devices at a time which made it difficult to build anything.

Feeling like I could fix anything, I found a little bit of motivation and dug up the K2 kit. Several layers of dust later and I was into it! When my co-worker had first started building the kit, it was the first major electronics project he had taken on which resulted in a few problems that needed to be worked out. Simple things, like missing soldering a ping on an 8 pin DIP, etc. Simple, but will stop you dead in your tracks if you can figure out why it's not working! At this point the rig is working on 40m CW, and I'm starting the next build phase.

I get the feeling that I'll need to re-visit 40m in the future, I think it's suffering from a lack of sensitivity, but I feel the need to march forward. I figure at the rate that I'm moving (slow) it will take me a couple of weeks to complete. I still also need to build and install the SSB module and I also plan on picking up a KIO2 module.

Thursday, January 28, 2010

I hate PL-259 connectors!

I was down in the shop tonight re-arranging feed lines so I could route the upstairs 2m radio to the bigger 2m beam (I have a 12el and a 6el up) to the 175W brick amplifier. During the shift I came to realize this RF Concepts amp had SO-239 connectors (female PL-259). GRRR! Why does the radio industry insist on using these crappy connectors!

Just then I remembered that last October at NEAR-Fest I had picked up (2) N-female chassis connectors for the express purpose of replacing the amplifier connectors. So, I opened up the amp and was relieved to find that it would be an easy job replacing them. I now have 2 fewer crappy connectors in my world. Here are some snapshots of the excursion:

Here is the first connector installed, the second one was a snap. The whole process took 15 minutes max. Now I'm motivated to go around to all my radios and see how easily they can be replaced!

Where has the time gone?

Oh my, am I behind the times keeping this blog updated. Things that have been accomplished:

- put up 35' mast w/2m,222MHz and 432Mhz antennas
- Holiday time vortex
- worked the January VHF SS, made 104q's for just over 4100 points.
- Decoded my first 2m Meteor scatter frames, looking forward to doing more of that!

I'm back in the workshop mode, we'll have more posts shortly!