Remote Control – a Road Warriors Delight

As I mentioned below, I read a very interesting article in QST last week while flying home from Wisconsin. Unfortunately, I left the magazine in the plane, so I don’t have the reference information, but I’ll dig it out and post it ASAP.

As a reluctant road warrior, I’ve been missing out on a lot of operating lately, and particularly miss the regular net checkins etc. So you can understand my interest in remote station control over the internet! It was difficult to sit still on the plane, I was so keen to get home and try out some of the ideas, and began making plans immediately.

I was familiar with Skype, my wife and I use it to chat when I’m away, and for my money, it definitely has the best audio quality of all the various chat programs, and I find it to be very stable in the XP environment.

Audio Setup

I installed the latest version on my shack PC, and using the same cables I use for PSK operation, had radio audio on my remote laptop in no time at all. The audio from the rig feeds directly to the mic input on the sound card, and the headphone jack on the PC is connected to the mic input on the K2 via a 10:1 resistor attenuator.

Rig Control

I had a copy of Ham Radio Deluxe on the desktop and noticed that the latest version does have a remote server option. A quick read of the manual indicated that this would work quite nicely as long as I could access the shack PC remotely from the internet.

The next step was to configure my DSL modem and wireless router to pass through IP traffic addressed to the modem directly to the shack PC. This required setting up a DMZ (a range of IP addresses not protected by the router firewall) and configuring the router to pass through the specific port to the local IP address of the shack PC on the internal network.

This part can be a little tricky if your not at least a little familiar with IP networking, but there is information on the net, and most Ham Clubs probably have a few people who could assist you with this. If you’re a complete Networking Novice, I suggest you try and get some help as you could either hose up your internet connection or open your network to malicious programs and people (which is why I haven’t provided any more details on this post…)

Once this was done, I was able to use the IP address of my DSL modem (assigned by the phone company, and somewhat temporary) to set up the Ham Radio Deluxe remote server. The QST article describes how to set up a domain name that will dynamically track any changes to the IP address assigned by the internet service provder. Before attempting this, I made sure I was able to run HRD in local mode on my shack PC connection to my K2 with the standard serial interface. This was very easy to do, and provided excellent rig control features.

Ham Radio Deluxe Remote Server

There are two steps to setting this up. First, I enabled the remote server service on the shack PC, which starts up with the PC, and essentially runs in the background “listening” for a remote host to connect. So far I haven’t noticed any negative effects of running this service. Clicking on the big “Remote” button in HRD opens a window with instructions on how to edit the configuration file (with a simple text editor) to set up usernames, passwords, ports etc. Simply follow the instructions in the help to edit the file, save it and start the service. At this point the shack PC is ready to accept a connection from a remote PC running HRD.

HRD Remote Connection

On starting HRD, select “NEW” on the initial connection screen to setup a remote connection. On the following screen, select company & radio (Elecraft K2). Choose “Remote” on the drop down list for COM Port and select the appropriate speed (4800).

Press the “Connect” button to pull up the next screen. Here you enter the details for the remote connection, including IP address, port, username and password (I haven’t shown this for security reasons.) I haven’t tried it, but I believe you can either enter an IP address directly, or a domain name of your choice (once you set it up on a DNS as described in the article…) Check the box to save the settings and press the connect button. If all went well, you’ll see a dialog box asking you not to break anything and you’ll be connected to the radio.

Adding Video

As a born skeptic, I wanted to have some positive feedback that the rig control software was working before going on air remotely, so I grabbed my webcam and pointed it at the K2 display, nice and close. It took a little to adjust the light and angles to get a good view of the S meter and display, but the Skype video gave me an excellent view even in a small window as show in the picture above. This gave the added advantage of being able to see messages not normally shown on the HRD interface, like the SWR after tunning the ATU.

Remote PC Control

As indicated in the QST article, initially I used a remote PC application to set things up. Being cheap, I decided to use the free utility built into Windows XP, Remote Desktop Connection. This is relatively simple to configure, once you have access to the shack PC, and again, I just used the IP address directly, but it will also work with a host name.

Remote Desktop works well on a high speed connection, but is a little clunky at lower speeds. I did notice one bug when using it, I wasn’t able to select the correct sound devices on the Skype config – it displayed junk text in the drop downs… As a result of this, I set up Skype on the shack PC to answer automatically, with the video enabled. This alieviated the need for a remote connection for normal operation, but it is handy for trouble shooting should the need arise.

Putting It All Together

 At this point, I had the audio connection into and out of the K2 with Skype and HRD running remotely to control the rig. It was time for some on air testing… I called on the local 2m simplex frequency, and a little while later had a volunteer (Keith, K5YCM) to help with on air HF testing. The moment of truth was here!

As with any worthwhile project, it didn’t work the first time… Keith reported a lot of echo, and what sounded like an audio loop of some kind providing long delay reverb. Basically, the signal was unintelligible! Keith was able to make a recording and email it to me for further analysis. (For someone first licensed in 1959, Keith sure knows his way around a 21st century ham shack…)

So, it was head scratching time… I listened to the audio file and it sounded like there was some kind of feedback loop between the transmit and receive audio on Skype, with about a 1 second delay. It turned out that using the remote desktop software had corrupted the sound device settings in Skype (as mentioned above) and once these were reset, the audio jumped into life.

• Another call to Keith for a report and we were away. I had a remote station working with effective audio and full rig control! This stuff is SO cool when it works…

Next Steps

At this point, I’m not transmitting unless I’m in the house, or my wife is available to switch off the trasmitter if anything goes wrong. In order to comply with FCC regulations, I’ll have to set up a more positive control of the transmitter, and I’ll include a dedicated hardware time out timer in case I lose communications. The QST article details some methods of achieing this, and that will be the topic of a future article. In the mean time, Mendy will have to be my fail safe when I’m on the road…

Comments and Questions

Please feel free to leave comments on questions below, and I’ll see what I can do to help you out if you’re interested in trying this out – it’s great fun even if you don’t travel…

Jim

The Wonders of a Resonant Antenna!

     Dennis Burton, N5DRB, and me.

Dennis, N5DRB, and I finished vertical number two today, in the cold and rain… But this time it didn’t go quite as smoothly!

First of all – I couldn’t find anything… Between a quick tidy up of the shack before receiving visitors, moving all of my tools and parts out of the truck so it could be repaired, and an amazing series of memory lapses on my part, I couldn’t put my hands on anything we needed. If it weren’t for Mendy’s help in finding all the stuff, we may never have finished it.

Then there was the weather to contend with. It sprinkled on and off all morning, but about the time we decided to put it up outside, it really started to come down steadily, and the temperature started to drop. Towards the end, our fingers were starting to freeze.

Despite all this, we finally got it all up and started tuning. Poor old Dennis went up and down the ladder a few times, mainly because my “cheap and nasty” whip design (6ft aluminum rod inside a 6ft aluminum tube – I was going for better efficiency…) made it much harder to adjust the top section, cause the adjustment is too high off the ground. So he had to unscrew and remove it each time.

  Isabelle is helping me tune the antenna…

Finally we got it set up for 20m, spread some make some make shift radials and plugged it into the K2 (now moved to the guest room to reach the back yard…) Following the excellent results of antenna one at Dennis’ house. We had high hopes, but alas we couldn’t get the K2 to tune it! Best we could get was about 4:1. I re-attached the analyzer to check and it was spot on resonant at 14.050Mhz, and had a 50 ohm resistance.

By then it was time for Dennis to head home, and I was very disappointed, but kept on feeling we were missing something – was it a bad coax joint, not enough radials? Anyway, I went and dried off a little, grabbed a chair and the K2 manual and sat down to see what was going on. Sure enough, I finally noticed that in all the rush, I had switched the K2 to antenna 2! So we were trying to tune an open circuit the whole time… I guess I didn’t have my Wheaties today.

On pressing the antenna 1 switch, the speaker just about jumped out of the case as signals came pouring in like I’d never heard before on my short wire over the roof. Oh the wonders of a resonant antenna! Sure enough, on hitting the tune button, it immediately set to 1:1 and stayed that way over most of the 20m band without the tuner even switching once.

I listened around on the CW sub band and signals were coming in really well, so I wondered how it would go on SSB. I’d never had much luck with that and the microphone hadn’t been plugged in for months, but sure enough signals were booming in – mainly from the west coast. Fortunately, the North American SSB QSO party was in full swing and there were people calling from everywhere – Nice!

I was getting out great and worked about a dozen stations from California to Alabama, all with only 10Watts. And the noise floor had dropped drastically compared with the long wire. You should have seen the smile on my face!

Later on that night, I braved the sleet to run outside and set the loading coil tap for 40m and it tuned up really well again. The load resistance wasn’t quite 50 ohms, but maybe with the whip fully extended it will be better, and I may try a base shunt capacitor later as well.  The QSO party was still running, and though the signals were a little weaker, I was still able to work California, South Dakota and Texas on SSB with 10 Watts. Tried tuning 80m, but even with the full loading coil I could only get down to around to about 4.5MHz. Tomorrow, I’ll extend the top whip to its full length and try again.

Next I’ll try it with only the 4’6” base section and see how it goes. Stay tuned…

Home Brew Loading Coil for AD5X Vertical

This weekend, Dennis (N5DRB) and I made a loading coil for the second of our AD5X portable vertical antennas. The coil is also based on the design of Phil Salas, and you can see his article for making it at http://ad5x.com/images/Articles/CoilRevB.pdf .

We used a piece of 3 inch PVC pipe as the core, however we screwed 6 inch lengths of edge stip onto the pipe to hold them a little more securely while we wound.

 

We unwound about 6 feet of wire at a time and stretched it as straight as possible before winding it onto the form, trying to keep the tension even. This was definitely a two man job. Once the coil was wound, we masked the former with tape and filled the edge strip with 5 minute epoxy and let it set up overnight.

Next day, Dennis removed the coil from the form, which took a little effort cause we wound it on pretty tightly. He tapped gently on each of the four spacers to slide it off. He then fabricated the coil supports as described in the article using the 3/8″ fibreglass rod.

The final step is to solder the coil onto the brass rods and it’s ready to go…

PCB Layout and Prototyping

For those that might be interested in designing and building your own PCBs, here’s a couple of links which may interest you.

Cadsoft Eagle Layout Editor

This is a comprehensive layout editor which is available as freeware! Some of the advanced features (more than 2 layers etc.) and the max layout size are limited in this version, however you can do double sided boards up to 4 x 3.2 inches. If you need more layers or a bigger board, and your not intending use it commercially, you can upgrade to a Non Profit license for US$125.00, which is very reasonable compared to some of the fully featured products out there. You can download it directly from the web site, and there are comprehensive manuals and tutorials to get you going.

If you’re having trouble getting stated with it – post a comment below.

Olimex Fast PCB Prototypes

This is the lowest cost prototype board manufacturer I’ve been able to find. The catch is they’re in Bulgaria. Not to worry though, they are quite easy to deal with, and 2 week shipping is only US$9.00. The whole transaction can be completed with s credit card by email and fax. I have used them a couple of times and I have friends in Australia who use them exclusively for prototype and commercial boards.

They will run one 6.3” x 3.9” double sided proto board, with plated through holes, 2 side solder mask and silk screen on one side cut to order for US$33.00. They will “panelize” the boards any way you like for the same price (e.g. you could get two 3” x 3.9” boards on the same panel for the same price…)

Even with the shipping, I haven’t been able to find a better deal than that. There are some restrictions, mainly minimum track widths and limited drill sizes, but for prototypes this is usually not a problem. You can also pay extra to get what you want. They accept Eagle board files (saves you generating all the Gerber’s) even tell you how to configure it to meet their design requirements.

Again, if you need a little help getting started with this – please post a comment.

Here is a link to a sample board I layed out with Eagle and had manufactued by Olimex. Sample Board

AD5X Portable Vertical Antenna

Saturday, January 6th, Dennis (N5DRB) and I complete the first of our AD5X portable vertical antennas. Using an MFJ antenna analyser, we were able to tune the antenna all the way from 80m to 10m, with low SWR and close to 50 ohms on all major bands (after careful adjustment of both top whip length and coil tapping below 20m.)

After that we couldn’ wait to get the K1 hooked up and start operating. We chose 20m initially, and as soon as we powered up, the band came to life. Our first contact was with a HI station in the Dominican Republic (about 2000 miles) and later we had a brief exchange with an 8R station in Guyana (3000 miles). Also worked a station in Virginia at 3 watts using a PAC12 vertical. Needless to say, we were both pretty pleased and there were plenty of smiles…

Here’s another picture of the center loading coil, looking up. You can also see the 4 guy ropes clearly.

This version has two x three foot sections of 1/2″ tube making up the lower vertical section, the full lengh MFJ coil with the fibreglass rod, and the MFJ 10′ whip as the top section. Dennis added some brass screws to secure the brass couplings, and crafted a nice four point guy ring which fits neatly over the top of the coil section.

While the extra length has enabled the antenna to tune down to 80m, it also made it a little tricky to assemble and tune, as the top of the coil section is at about seven feet! A step ladder was required! So we may have to rethink the extra length for it to be truly portable…

Can’t wait to get mine finished and running!

You can get more information on the original construction here:

http://ad5x.com/images/Articles/VerticalRevH.pdf

And Phil Salas has lots of other interesting articles and presentations on his web site http://ad5x.com/