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

Jerry Taylor, KD0BIK, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. He is the host of the Practical Amateur Radio Podcast. Contact him at [email protected].

3 Responses to “DVAP Tests–Range”

  • Tom Kb3hg:

    Outstanding Jerry,
    Its good to hear how well they work, now the sticky question, did you leave it open to anyone or only to your call? Please update h0ow it works in the winter.

    73,

    Tom Kb3hg

  • Fred W0FMS:

    One of the local clubs here in Cedar Rapids just put up a couple of D-STAR repeaters. I wanted to participate.. I really did! I just don’t get $500 for a ICOM radio that is really only slightly better than a $80 Chinese HT otherwise and I really don’t get $200-300 for the Dongles. And when someone states that to a D*Star fanatic you always get back that you can buy an AMBE chip for $25 and use open source stuff otherwise. (Where?) Yeah I suppose I could build a D-Star *repeater* with bits from the garage and open source stuff– but then not have end user access! That stupid low quality CODEC is still the fatal flaw with D-Star.

    I suppose that it’s cool to play with that stuff as toys, but a 20+ year old CODEC that is proprietary modulating a 1980’s grade 4800 bps GMSK modem to me just seems so… I don’t know… DEAD.. in late 2011. I guess ICOM can just not love me…

    And BTW, I heard ARISSAT-1 on a rubber duck on a Yaesu FT-50R the other day, so don’t be too impressed with that antenna! Lots of QSB but it was strong at times. Copied 2/3 of the telemetry without trying..

    Still you can see 10mW is fairly powerful with gain at 2m… keep experimenting. Hopefully you’ll get more out of the $800 you spent on D-Star than I would…

  • Arpad ( VA3VAD ):

    I live on the 29th floor.
    When I tested My DV access point dongle( 2m )with my 3 element beam antenna.
    I attached the DV access point dongle directly to the antenna.
    In that way I had no cable loss. The receiving site was on the 28th floor roof top, line of sight.
    The distance was 10 km or 6 Miles. I used My 92AD, the signal was full scale.
    I live in Toronto facing to the City.
    On 145.670 MHz I have about S4 noise level on the beam, but only if my antenna is in vertical position, if I turn the antenna horizontally I have S0 noise. For the test the beam was horizontal position. I had to hold the 92AD horizontally to receive the full signal. If I held the radio vertically there was no signal at all.

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