Posts Tagged ‘Experimentation’

DVAP + Pi

I’ve owned my Raspberry Pi for a while now.  I purchased it around the time they were first introduced (early 2012).  Not having a lot of knowledge in the Linux OS, the most I ever really did with it was set it up and play around with it.  However, my reason for purchasing the RPI was to some how use it for amateur radio purposes. 

As I have mentioned before on my blog, I also own a D-STAR Digital Access Point Dongle (DVAP).  I purchased it in 2011 and had been using it connected to an older Windows XP machine.  I wrote a “first look” post as well as one where I was experimenting on the DVAP range away from my QTH.   However, in following my own advice given in my podcast, The Practical Amateur Radio Podcast episode 64 about the Microsoft Windows XP End of Life, I decided it was time to explore how the DVAP might be used with the Raspberry Pi.

In most situations, Google truly is your friend.  Just doing a simple Google search for DVAP and Raspberry Pi led me to more information than I had time to read.  However, the very first search result happened to provide all the information I needed to setup my Raspberry Pi to work with my DVAP dongle.  Special thanks to Bill, AB4BJ who had blogged about his experience in setting up his Pi for DVAP purposes. 

If you have a Raspberry Pi, a DVAP Dongle and a D-STAR radio sitting around your ham shack, it’s very easy to set it all up just as I have done.  In the below picture, I have my ICOM ID92-AD, the DVAP Dongle and the Raspberry Pi setup.  Once configured, the Raspberry Pi will function stand-alone (without keyboard, mouse and monitor).  I can access the RPI via VNC from my iPad if needed. 

2013-11-24 13.39.52

Raspberry Pi running Debian Linux and the DVAPNODE and IRCDDB software.  DVAP is connected to REF001A in Aurora, Illinois.  Screenshot from iPad VNC session.

photo

For now, my setup will remain in my ham shack.  I know many build this setup for mobile/portable use.  At the present time I do not have wireless capabilities for the RPI.  I also want to see just how stable this setup is before making any additional changes.   I was pleased to wake up this morning and find the RPI was still running and the OS was stable.  Time will tell…

Until next time…

73 de KDØBIK

More KX3, iPad and PSK-31 Experimentation

Last week I created a YouTube video to document some experimentation I had completed with the KX3, my iPad and the iOS PSK-31 app called PSKer.  This week I made some modifications to my setup.  This included adding a USB extension cable and I experimented with the VOX settings of the KX3. 

Watch this video on YouTube.

 

Thank you for watching!

73 de KD0BIK

An iPad, PSKer iOS App and KX3 = FUN

As I briefly mentioned in my blog post titled KX3 – The First 24 Hours.  I spent a little bit of time experimenting with the iOS App titled PSKer.  This experimentation included operating it in an over the air method.  Meaning I have no audio cables running between the iPad and the KX3.  I’m simply relying on the iPad built-in microphone to pick up the audio signal from the KX3 speaker for receive and using the iPad speakers and the KX3 microphone for transmit.  The image below is a snapshot from the PSKReporter website.  I’m running 5 watts into a ground mounted Hustler 6BTV.  My transmitted audio IMD is –34 as recorded by my KK7UQ IMD Meter in the shack.

image

Of course, an optimum setup would include some sort of audio interface to directly connect the KX3 and the iPad.  While I’m still looking into these options, I’m fairly pleased with the performance in the testing.  Also, while I had always envisioned this process to be a bit awkward by having to hold in the PTT mic switch and fumble with typing on the iPad.  The KX3 makes this much easier with an XMIT button.  I can press the XMIT button on the front of the KX3 and the rig will switch into transmit mode until I press it again.  I think this is better than using VOX.  All I need to worry about is making sure the microphone is positioned near the iPad speakers and the iPad is near the KX3 speaker.   More about the KX3 speaker in just a bit.

While I would not opt to use this setup in the ham shack.  I’m thinking this will be perfect for SOTA activations.   Again, I think a direct cable solution is optimum, I’ve not seen any schematics or plans anyone has designed to date.  At a minimum I believe the iPad needs to receive audio from the KX3 via a cable.  During the maiden SOTA activation for the KX3, I realized just how weak the KX3 speaker is in an outdoor environment. 

With a light breeze and the KX3 sitting on a foam pad on the ground, I had difficulty hearing stations on SSB.  I had to use my ear buds and even those proved to lack the quality when connected to the KX3 (as compared to my 817).  Of course, what do you expect with a $2 pair of cheap ear buds.  I will look into other alternatives before the next activation.

Final comment on the KX3 speaker.  I don’t fault Elecraft.  As I mentioned in my blog post titled KX3 – The first 24 hours, Elecraft has stated from the beginning that the quality of the built-in speaker will be compromised due to size and recommended either external speakers or earphones/headphones when using in a noisy environment.  I’ve done a little research on the Chill Pill mobile speakers.  These have been discussed on the Elecraft Yahoo reflector with mostly positive reviews.  Weighing in at a mere 7 ounces, they won’t break my back or take up much room in my pack.  

I did some testing earlier to see if I could feed audio from the KX3 into the iPad and the PSKer app.  The picture below is the setup I used.  The white piece is the iPad Camera Connection kit.  This connects to the bottom port on the iPad and provides a standard USB connection.  Connected to this (via USB) is a Plantronics USB soundcard adapter.  I plugged a short stereo patch cable into the KX3 headphone jack and the other end into the microphone input of the Plantronics USB adapter.  I connected a second stereo cable from the KX3 mic jack and the other end to the headphone jack on the USB adapter.This does work.  But….

photo

The weak link in this is the connection at the iPad.  The iPad Camera Connection kit (the white piece) with the added length (approx. 3 inches) of the Plantronics USB soundcard device makes it hard to keep it all plugged into the iPad.  On a SOTA activation I am sitting on the ground and will have the iPad in my lap.  I can easily see where the connector will get unplugged. But as you can tell it does work.  In the picture below I have my iPad running the PSKer App connected to the Elecraft KX3 via the Apple iPad Camera kit and the Plantronics USB sound card device. 

photo

I recently created a YouTube video where I discussed this setup and the items I used to connect the iPad to the KX3.  I’m going to continue to experiment with other options and will blog about these findings at a later date.   You can watch the video below.

 

Watch this video on YouTube.

 Until next time…

73 de KD0BIK

DVAP Tests–Range

As I recently blogged, I purchased the DV Access Point Dongle a few weeks ago.  It really came down to trying to do something to enhance my interest in D-STAR or sell my ICOM IC-92AD.  I was first introduced to D-STAR back in early 2008 and purchased the IC-92AD in the fall of 2008.  I spent the first several months having QSO’s on the local repeaters with the growing number of D-STAR users in the Rocky Mountain region.  But I’ll admit I did get a little bored with just speaking with the same group of guys.  I mean no disrespect, but I never really got into the local VHF/UHF repeater scene.  I think I would have more interest in local repeater operation if I had a longer commute.  But with less than 5 minutes in the car, there’s just no time to try. 

Anyway, a few months ago I grabbed the D-STAR radio and re-educated myself on how to use it and connected to the local Denver repeater and connected to the REF005 London repeater. I really enjoyed just listening with that reflector dialed up in the background.  Not wanting to tie up the local repeater just for my enjoyment, I began looking into the DV Dongle and the DV Access Point Dongle.  I was first leaning towards the DV Dongle as I figured I would do more listening that actual talking and it could just play in the background.  I could use my IC-92AD when I wanted to QSO.  But as I began comparing the two dongles (no dongle is created equal) I began leaning more towards the DV Access Point Dongle with the ability to still use my radio. 

It didn’t take long before I had a short list of ideas on how the DVAP would come in handy around the house and in the office.  In the office I work in a lab which is a RF black hole.  Nothing comes in and nothing gets out.  I could take the DVAP and my IC-92AD to the office and either just listen or perhaps even strike up some QSO’s during lunch.

If you’re not familiar with the DV Access Point D-STAR Dongle, it is a simple looking little device that connects to your PC via USB and allows you from your D-STAR radio to connect into the D-STAR network via the Internet.    The DVAP has a small antenna and transmits at a mere 10mw.  But the nagging question was just how far will 10mw travel?

I had read many blog postings from other hams who were enjoying the world of D-STAR from their DV Access Point.  They were finding out they could successfully operate from other rooms, the back deck, the back yard and even to the henhouse as in the case of my friend, Tim Kirby G4VXE in the United Kingdom.

Now before I go any further, allow me to type out some fine print.  The DV Access Point Dongle is truly designed to provide a licensed ham the ability to connect to the D-STAR network from inside and around their home or location.  It is not intended to be used as a neighborhood D-STAR repeater and send RF signals across the neighborhood or across town. 

Having said all of the above, I still wanted to know the range.  My ham shack is in my basement.  With the DVAP setup and using the little stubby stock antenna, I tested by walking all around my basement, then going upstairs to the ground level, then upstairs to the second floor and then finally on my back deck and courtyard.  No issues.

Like many, the experimentation aspect of the hobby is something I enjoy.  I don’t have a lot of time to build radios and living in such an antenna restricted neighborhood, I don’t have a lot of need to build and experiment with antenna design.  So my eagerness to know just how far I could move away from my QTH really excited me.  I know I’m a nerd…but if you’re reading this so are you. Smile

So I decided to connect the DV Access Point Dongle up to my Diamond X-30A external VHF/UHF antenna.  This antenna is attached to the side of my house where a Directv satellite dish once was mounted.  The antenna works great for working the front range repeaters (including the D-STAR repeaters) and I’ve also managed to hear ARISSat-1 via this stationary antenna.  As a point of reference, the antenna is approx. 16 feet off the ground and it does not stick up above the roofline.  It is totally hidden from view of neighbors and as such it not as efficient as it could/should be.

With no other modifications to the DVAP, I connected it to the external antenna and hopped in the car to go to the grocery store.  From my QTH to the grocery store parking lot (based on Google Earth measurements) as the crow flies or the RF travels, it is .75 miles, 1.20 kilometers, 3,941 feet, 1201 meters…I think you get the idea.  I honestly figured I wouldn’t make it out of my neighborhood.  As I reached the end of my street I was able to do a successful echo test.  I continued up the road and to the exit of my neighborhood.  Another echo test proved successful.  I then proceeded down the street towards the grocery store and with IC-92AD in hand and in the car I did another successful  echo test.  I reached the grocery store parking lot, stepped outside and conducted the final echo test….yep successful.  I was .75 miles from my QTH and had solid copy on the echo test to the DVAP dongle.

Again…let me add the fine print.  The DV Access Point Dongle is intended to provide the licensed amateur radio operator access to the D-STAR network in and around their house/yard.  It is not intended to provide connectivity at 3/4 of a mile away. 

I was short on time this particular day and plan to conduct further testing to determine the limit.  The neighborhood I live in is relatively old with tall, mature trees.  Another test in the dead of winter might also prove to provide additional range since less foliage on trees will get in the way.  A final testing to just fulfill my interests will be as far as I take the range experiment.  I’m not interested in trying to amplify the 10mw signal as I believe that is taking the DVAP in a direction not intended by its developer.  However, the next time I go to the community pool which is located just about 100 yards from my QTH, I believe the IC-92AD might just come along.

Look for an updated blog post on the additional range testing to see if I can go a full mile.  I’ve read reports from hams in the NY area who have been successful at one mile in all directions (N, E, S, W).  I may just wait until winter to try this as I stated above. Finally, I do want to do a little testing to see just how this setup could perform in a portable setup using an AT&T 3G data card.  I’ve certainly read blog posts from other hams stating they have had no issues with a configuration like this.  Again, it’s more to fulfill my experimental interests. 

Until next time…

73 de KD0BIK


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