DVAP on Raspberry Pi

NOTE – The video above is of the exact hardware configuration (DVAP and the Raspberry Pi), but the software configuration is from a different, albeit reputable source). The software from Robin may prove to be more reliable since he tests all aspects of operation with the DVAP hardware and understands (as you would expect) all the intricacies of the DVAP hardware and software.

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Robin (AA4RC) talked at the Orlando Hamcation about the newly released software for the Raspberry Pi – a $35 self contained computer which only requires a mini-USB for 5vdc power and can connect to various external USB devices, such as the DV-AccessPoint-Dongle. He just recently released the software and we have been successful in personally loading it on a new RPi and testing it.

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The combo-unit (Pi+DVAP) work seamlessly and without need for external User Interface devices – so the keyboard and display are not required for normal operation. The only thing required is either a RJ-45 Ethernet port (if you’re at home, you can connect to your router), or a WiFi connection that can talk to something like a MiFi device with Verizon 4G/LTE. NO COMPUTER REQUIRED..!

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The Raspberry Pi device is about $35 from many sources int he US, including Amazon, Newark and MCM Electronics. I bought the Version-B device which has 512MB of memory plus the Ethernet port and the dual-USB connectors – a cheaper version is available sans the Ethernet port and only has 256MB and a single USB with a price of $25. Didn’t seem prudent to me to limit your options to only save $10.

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The configuration of the software (the Pi boots from an SD card, which needs to be configured) is somewhat of a pain for those who want a plug-and-play system, so we will gladly offer pre-packaged DVAP-PI SD cards to members so that they only have to purchase the device, pop-in the preconfigured FPCARC card with the software, turn the device on to verify that it works, then plug-in their DVAP and GO..!!   Remember, you’ll need to already have (or purchase) a DVAP to use with your DSTAR handheld (any model). Both DVAPs are supported – the original VHF as well as the new UHF models which were specifically developed to support the Icom ID-31 handheld (UHF only).

 

DSTAR Video with Robin Cutshaw (AA4RC)

here is a video from AmateurRadioVideoNews with our friend Robin Cutshaw (AA4RC). Gary (KN4AQ) interviews Robin about the early developments of DSTAR, as well as the future products that he’s working-on. This is from the Huntsville Hamfest in 2012, so fairly current.

Icom 7100 Video by HamRadioNow

I know a lot of you were interested in the new Icom 7100, which is due to be released in the spring of 2013. According to Ray at Icom, it’s still in development and testing and is yet to be subjected to FCC testing, but they’re confident that it will be around the time of Dayton or earlier.

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For those of you who were not able to get close to the unit during the Hamcation, or those who were not able to make it to Orlando, Gary (KN4AQ) has a great video of the unit, with close-ups of the UI (user interface).

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Anatomy of a CubeSat

they seem simple enough..
might we be able to build a rudimentary CubeSat that could be launched by ballon, instead of rocket.. perhaps not orbiting, but to near-space..?  One with live video as well as repeater capability..?   Could it be an educational project for middle/high school students..?  Ohhh the possibilities..

Satellite Ops Video – AO-27 and SO-52

here’s a great video from the UK of Simon (2E0HTS) operating FM through SO-50 (Saudi Oscar 50). The operator is using the same AZ/EL rotator that we used for ARISS (Yaesu G5500), but it is manually controlled, versus our computer controlled antennas for ARISS.

In the video below, Simon operates VO-52, an SSB bird with an inverting linear transponder (increase in uplink frequency results in DECREASE in downlink frequency – by the same amount).

Not DSTAR – What would YOU do..?

 

This video has nothing to do with Amateur Radio – but it goes  to character and compassion. A very touching story about how we SHOULD be in this world.

Rigol DSA-815TG Spectrum Analyzer – WOW..!!

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Short Takes : Functional Rating=5,   Cost=1  Significant Gripes= NONE

Here’s the deal of a near-lifetime – for a mere $1,525 (with shipping), you can get a serious piece of test equipment for spectrum analysis that has a bandwidth of 9Khz-1.5Ghz, amplitude sensitivity of better than -138dbm with a built-in tracking generator – in a package that weighs about 10 pounds and uses 100-240VAC. The Rigol (pronounced Ree-Gol) DSA-815TG is a DDS/DSP technology with an all-digital IF unit which does everything an amateur could want, at-or-below 1.5Ghz – whether building antennas and using it as an antenna-range receiver, or checking radios for spectral purity, or tuning various filters – including repeater duplexers. This unit can do it all – for a very reasonable cost and with better than needed accuracy for the Amateur Service. It’s very evident that Rigol engineers dove deep into the functionality and user interface of the Rhode and Agilent units – because the Rigol is superior in many ways in its operation to the two stalwarts of the T&M world. Okay – $1,525 is a lot of most amateurs for a single piece of test equipment, but when you consider some folks spend $1,000 for a Power Meter (from Alpha), or other ridiculous and outrageous items, the functionality gained from a quality Spectrum Analyzer cannot be over-stated. Every repeater owner should be required to buy or borrow one of these units to insure that their equipment is operating as it should. It’s an ideal piece of equipment for a club to acquire, since it can be time-shared amongst the more technical members of the group.

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Yes – this is the same unit that was evaluated by QST in the February 2013 issue – it got very favorable narrative and an “AS SPECIFIED” evaluation regarding compliance to the manufacturer’s specifications by the ARRL’s third-party calibration laboratory (not all equipment get’s that certification).

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Yes – it’s made and largely designed in China – but this is not another cheap piece of equipment which we’ve come to associate with Chinese manufacturing – this is, in-a-way, the Apple-like-quality of Chinese test equipment. Compared to my Rhode Schwartz FSH-313 (which goes to 3Ghz), I actually like the Rigol BETTER - ahhh.. if it only had a battery option..!  Cost comparison – $1,525 for the Rigol versus over $14,500 for the Rhode (plus the maintenance contract costs of about $550/year. At that price, I could buy a Rigol every 3 years and end-up with multiple units over time, considering I’ve been buying the Rhode maintenance contract for over 7 years. At this rate, I’ll eBay the FSH-313 for a reasonable amount and pocket the savings.

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High Level Specifications are as follows:

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If you’re interested in details, check out the Detailed Spec Document here:

DSA815_specs-1

Rigol North America – Intro Video for DSA-815TG (Part-1)

Rigol North America – Intro Video for DSA-815TG (Part-2)

Tuning Bandpass and Notch Filters with the DSA-815TG

Teardown Video

 

We’re gonna make some ANTENNAS..!!

okay – a new passion is brewing – I’m getting REALLY INTERESTED in antenna design and construction. You might remember the article about the InnovAntennas that I purchased a month ago. Well, I’m still amazed at the quality of their construction – simple, elegant and very sound from an engineering perspective.

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I was also blown-away by Justin (G0KSC) and his helpfulness = and in all the information that he shared, so I’ve been reading large volumes of material from DUBUS (a great, German publication about antennas) as well as from another subscription source called ANTENNEX.COM – which features a ton of material from L.B. Cebik (W4RNL-SK), one of the world-renown authorities on antennas. My head still swells with all the input and I’m still having constant headaches trying to contain and digest the information.. LOL..

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I also purchased the NEC4 license from Lawrence Livermore Labs, as well as EZNEC Pro/4 which contains a streamlined NEC4 engine within the EZNEC framework. We also installed 4NEC2 from Arie Voors and integrated the NEC4 engine from Livermore labs – so now we have two (2) NEC4 capable modeling packages to do comparative analysis.

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In the meantime, Eddie (KJ4LRB) has been helping me receive a stock of Aluminum that will be sufficient to make about 10 antennas, along with tooling and miscellaneous parts necessary for the assembly.

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2013 is going to be an experimentation and learning year – exploring new horizons and MAKING things, versus just operating… gonna be fun..!!

Operating from the Philippines (again)

I’m back in Manila – was just here in late September, but was only able to stay for about a week due to a very hectic schedule. This time, it’s for a longer stint, and I also have a new End-Fed-Dipole for 20/40 meters with me from the folks at LNR Precision (wonderful antennas). I just finished putting the end of the antenna into a tree across the street (using a 2L Coke bottle filled with water as the projectile), so the antenna is acting like an inverted-L, since the feedpoint is on the 3rd floor of this condo unit, with the flat-top being about 50-feet long an about 35-feet in the air, then slanting from the tree branch towards the ground.

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Must be working, since I’ve already made contacts with VK-land (Australia), New Zealand, Indonesia, Hong Kong, Taiwan and Japan – all in just 20+ minutes.. not bad.!!

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The Philippine ARES Traffic net meets in about 15 minutes, so I’ll be listening for emergency traffic from the hurricane area from 3 weeks ago.. hopefully, things have improved in that part of the country..

Elecraft K2 Station – SOLD… but you won’t believe this story

I had been contemplating selling my Elecraft K2 for quite a while – probably almost a year. My first preference was to sell it locally and I had a couple of bites in the Daytona area – both of which fell thru. But no worries, I was in no hurry – and seldom need the money (except to buy other toys), so the trusty and beloved K2 stayed on the shelf in the “shack”, just gathering dust – besides all the prep for ARISS basically took me away from HF operations for quite a long time.

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Now many of you will remember that I spent the better part of 6 weeks putting together each part of the K2, with all of the major options. It was a wonderful experience and one that I will cherish for a long time – the trusty girl also had a trip to Don (W3FPR) in North Carolina for a “tune-up” and some minor diagnosis (assembly error on my part) – but after the initial shakedowns, she was an old-reliable. She even went with me to the Philippine Amateur Radio Association “hamfest” in Subic Bay in early 2012 and made quite a few contacts with my AlexLoop WalkHam Magnetic Loop antenna (a fantastic antenna). Both were the center of a lot of attention at the hamfest.

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But time is precious – and I already have access to the dream station of a pair of Elecraft K3′s with P3 Panadapters and amplifiers on both – so why keep another HF station..?  QRP..? – SURE – but I also have the KX3, which is even better than the K2 – so it was time to find a nice home for the girl and let her stretch her legs.

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That opportunity came on 14-December 2012, when Ervin Kolar (S51ZX) emailed me about interest in the K2. At first, I thought it was a hoax or a scam, so I immediately looked up the call in QRZ.COM – SURE ENOUGH, things started to match. Ervin was inquiring on behalf of Ed (S56X) a significant contester. Another check of QRZ.COM and  there’s Ed’s picture, with his trusty Elecraft K2 on his station table – WOW..!!  I might have just found the new home for my K2..!!  Now, I gotta tell you, there is nothing better than finding a great home for your baby – especially when it will become part of a TWIN station.

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A few emails back and forth and the deal was done – Ervin PayPal’d the funds to me within 24 hours (well within his promise) and I subsequently had the box shipped to him by USPS International Priority Mail to SLOVENIA. He should be receiving it within the next couple of days, since it was sent the day that I left for Manila by my trusty friend Eddie (KJ4LRB) – don’t worry, I packed it, not Eddie, so things should be fine.. LOL..!!

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thanks to Ervin and Ed for a friction-free, painless transaction – I know that the K2 will provide many years of enjoyment. And thank you both for providing my “baby” with a loving home – it was tough to let her go, but I know she’s in good hands.

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to all reading – a Merry Christmas and closing to 2012 – what a fast year it has been. I trust that 2013 will bring many new and wonderful experiences for all of us. Stay Safe, Be Well..!!

73,

Mike – WB6RTH