Monthly Archives: June 2016

Amateur Radio, ARRL Ohio Section, Ohio Section Journal

Ohio Section Journal – The Technical Coordinator – June 2016 edition

One of the responsibilities of the Technical Coordinator in the Ohio Section is to submit something for the Section Journal. The Section Journal covers Amateur Radio related things happening in and around the ARRL Ohio Section. It is published by the Section Manager Scott – N8SY and articles are submitted by cabinet members.

Once my article is published in the Journal, I will also make it available on my site with a link to the published edition.

You can receive the Journal and other Ohio Section news by joining the mailing list Scott has setup. You do not need to be a member of the ARRL, Ohio Section, or even a ham to join the mailing list. Please sign up!

If you are an ARRL member and reside in the Ohio Section, update your mailing preferences to receive Ohio Section news in your inbox. Those residing outside the section will need to use the mailing list link above.
Updating your ARRL profile will deliver news from the section where you reside (if the leadership chooses to use this method).
Go to www.arrl.org and logon.
Click Edit your Profile.
You will be taken to the Edit Your Profile page. On the first tab Edit Info, verify your Email address is correct.
Click the Edit Email Subscriptions tab.
Check the News and information from your Division Director and Section Manager box.
Click Save.

Now without further ado…

Read the full edition at: http://n8sy2.blogspot.com/2016/06/june-edition-of-ohio-section-journal.html

THE TECHNICAL COORDINATOR
Jeff Kopcak – TC
k8jtk@arrl.net

DSCF5081 K8JTKHey Gang,
You’re reading this so you survived another Dayton. My dad N8ETP and I went down on Thursday. We stopped at MCM Electronics. It was actually on the way because we stayed south of Dayton this year. My dad was looking for some parts. I ended up buying another Raspberry Pi 3 on a Dayton weekend special and an Arduino Uno board. The Arduino was cheap and a lot smaller than I expected. Don’t have much lined up for it but I did want to try a project I saw on AmateurLogic.TV some time ago.

Raspberry Pi 3The difference between the Raspberry Pi and Arduino Uno boards is the Pi can run a full operating system (usually Linux) while the Arduino Uno runs instruction sets uploaded to memory. Variants of the Arduino can run entire operating systems. Both have General Purpose Input/Output (GPIO) pins for interfacing. I haven’t mentioned it in this space – Raspberry Pi 3 is the latest addition to the line of cheap micro-computer devices. The Pi 3 has all the features of the Pi 2 with an upgraded CPU to 1.2 GHz 64 bit, built in Wireless N LAN, Bluetooth 4.1 and Low Energy (LE). All of this goodness (still) at $35 in the same form factor. I ran a compile of Fldigi/Flmsg for comparison. The Pi 2 compiled the programs in about 22 minutes, the Pi 3 compiled in about 13 minutes.

This year I really didn’t have a lot on the Dayton shopping list. I wanted to take a look at the new ICOM IC-7300. That is a very nice radio and a huge improvement over my IC-7000. I didn’t pull the trigger on that for some reason. I’m reluctantly holding off. The newer radios are coming with built in USB. For someone looking to get into HF digital check out the newer radios. You won’t need a SignaLink type device because the sound card is built in!

Tytera MD-380I did attend Dayton with the intent of purchasing a DMR radio. From the amount of people I heard on DMR repeaters and podcasts afterwards, it sounds like they were the popular item this year. For good reason, I picked up a Tytera MD-380 for a little over $100. It included the radio, battery, charging base, 2 antennas, programming cable, and software.

DMR LogoDMR stands for Digital Mobile Radio and is a standard published in 2005 that came from our friends in Europe. It is an open standard (publically available for adoption and modification) and widely adopted for commercial use. In practice manufactures have introduced proprietary features into DMR and created marketing buzzwords like MotoTRBO. With enough surplus hardware available in the market, the price dropped low enough for hams to adopt the standard and setup DMR repeaters. I have a lot to learn about how all this works. There aren’t DMR repeaters in range of my QTH. Couple on the opposite side of town and to the south. There are some repeaters in Toledo and Columbus. The greatest concentration is between Dayton and Cincinnati. Thanks to the folks at the Dial Radio Club in Middleton, Ohio, I had a DMR repeater easily accessible from my hotel room during the show.

Kenwood APRS DSTARNew things I saw include scanners from Whistler with DMR (expected June 2016). Following quickly behind was Uniden with the same announcement (no release dates set). If you have a public service agency utilizing a DMR system, you’ll soon have scanner options available. Kenwood showed off their 2m/220/440 radio with APRS and D-STAR (and hopefully DPRS). My dad and I both noticed how incredibly crisp and clear the color display was. Standing about 5-6 feet away we could easily read it. DV4mobile Wireless Holdings showed off a new digital all-in-one radio, the DV4mobile. This thing has ALL the features: 2m/220/440, DSTAR/DMR/Fusion – with P25/NXDN/NEXEDGE coming next year, LTE (as in cellular connectivity), remote programming, remote operation, Ethernet/WiFi, SMS (text messages). Will this thing do my dishes too? Wow. Both Kenwood and Wireless Holdings are expecting release dates in about 6 months.

Thanks to everyone who stopped by the Field Services table at the ARRL Expo. I had a great time chatting with hams from England and exchanging ideas. It was fun meeting those in Newington who administer the programs we know and love. A lot goes into these programs and there’s a lot of technical research happening. The table was staffed by representatives from the Ohio Section including moi. Scott and his wife Jane spent most of the show at the table making sure everything went smoothly. Huge thanks to them for getting everything organized. It was nice to meet all of you. I picked up a couple books in the store on the way out. More stuff to do!

Windows 10Reminder about Windows 10: Don’t forget the free upgrade offer to Windows 10 is set to expire July 29th. You still have about a month to decide on the upgrade. If you missed my April article, I went into great detail about Windows 10 and the push to upgrade users. Check it out on my site or on the Ohio Section Journal site. There is no indication from Microsoft if the upgrade will become a premium option or if they will extend the offer. Some analysts think it will become a pay upgrade others think the upgrade offer will be extended indefinitely. One change, Microsoft is becoming even more aggressive in forcing the upgrade. Didn’t know this was possible but they’ve succeeded. I mentioned in April that clicking the red “X” to close the upgrade pop-up will delay the upgrade. This is no longer true. Microsoft’s new interpretation of clicking the red “X” is an AGREEMENT to the upgrade. This whole upgrade thing is ridiculous. I have no defense for this behavior. If you want to disable the Windows 10 upgrade, run Never10 (https://www.grc.com/never10.htm). Many users are disabling Windows Update to prevent the upgrade. Please don’t. If you have, run Never10 and disable the upgrade. Reboot. Check it’s still disabled by running Never10 again. Run Windows Updates and let it do its thing. Then run Never10 again to verify the upgrade is still disabled. I’ve been upgrading my machines to Windows 10. It takes some finessing to disable the crap. I do keep coming back to a single question: “why?” Not ‘why did I upgrade’ but ‘why is this useful setting now burred and takes fifteen clicks when it used to be three’ or ‘why would you change things (color schemes, color contrasts, move things around for the seventh time) just to change things?’ Haven’t yet taken the plunge to wipe-out my machine in the shack.

Technical Specialist report:

With summer and projects gearing up, requests have been coming in. Bob K8MD and a good friend of his Dave NF8O traveled to the Ohio Veterans Home station, W8OVH, in Sandusky. They have a sideband station and wanted an upgrade to run digital modes. Bob and Dave spent a few hours working with them to get the station up and running. They trained the club members how to use Fldigi and helped them make their first PSK31 contact! The guys reported it was a humbling experience talking to Vets who served in major conflicts from WWII to Grenada.

Dave KD8TWG has been busy with presentations for ARES groups. First was a presentation on APRS for Cuyahoga ARES. The presentation touched on history, uses, settings and what they mean, and systems built on the APRS network. There is a lot to APRS and I learned a lot. Soon after he did a “program your radio without a computer” for Geauga ARES. Interesting concept. Most groups bring computer programming in to help newbies program their radio. Knowing how to program a radio without a computer is useful during an event or public service activity where improvisation is likely needed. Could you change PL tone on your radio and save it in memory though the front of your radio? Programming a temporary repeater that has a 1 MHz split? DCS, anyone? It’s good to know and practice changing transmit, receive, PL frequencies, and power settings on-the-fly through the front of your radio.

PCARS (Portage County) club members contacted me about a moon bounce (EME) presentation. This is an area I wasn’t familiar with or knew anyone who operated. I reached out to the assembled mass of Technical Specialists. Tracey – W8TWL came through with a couple contacts. Got PCARS in touch with one of them and they are working out the details for the July 11th meeting. I’m hoping to make this meeting and see a great presentation on Earth-Moon-Earth.

Thanks for reading and 73… de Jeff – K8JTK

Img: VA3XPR, raspberrypi.org

Amateur Radio, Tutorials

APRS RX IGate with RTL-SDR and Raspberry Pi

For sometime I wanted to experiment with an APRS IGate. Coverage was spotty at best in my area. There is an IGate in my city but it doesn’t receive so well. Recently there have been more IGates blanketing the area.

APRS stands for Automatic Packet Reporting System and has been developed since the late 1980s by Bob Bruninga – WB4APR. It’s a digital communication mode amateur radio operators use to primarily broadcast location information, though this wasn’t the intended use. It handles text messages, alerts, announcements, bulletins, and information of interest like weather station reports. APRS operates typically on a single frequency.  A system of relay stations and digipeaters repeat messages over a wide area. APRS Internet System (APRS-IS) are Internet connected receivers (IGates).

Any ham can add an icon or information to the APRS map.  The information is available on the Internet or to users on the local RF network.  Data is automatically tracked over time. APRS is frequently used to track mobile stations in a public service event or volunteers in a search and rescue event to visualize locations and track progress.

This project will utilize the Raspberry Pi and RTL-SDR dongle. The Raspberry Pi is a credit-card sized micro-computer intended for teaching computer science to students but became popular with the makers. RTL-SDR dongles are DVB-T (European standard) TV tuner dongles. It was found the signal data could be accessed directly which allowed them to be converted into wide band software defined radio receivers. The Pi costs about $35 and RTL-SDR about $20.

Since the RTL-SDR dongles are meant to receive high power wide bandwidth TV signals, they are not as as sensitive or frequency stable as a ham radio or scanner. Receiver performance will be a little less than an equivalent radio performing the same task but depends on the usual variables: amount of APRS activity, antenna height, antenna gain, propagation, etc, etc. With my antenna about 15 feet high, I get about 5+ miles of coverage. With band openings I’ve heard stations on the opposite side of town and across Lake Erie into Canada.

Even though this IGate will be non-transmitting (cannot relay packets from the Internet), packets are forwarded to APRS-IS. The higher profile – higher power Digitpeaters in the area will relay packets received by your IGate to the local RF network.

Assumptions

This guide is step-by-step in nature, meant for beginners, with brief explanations of the steps. It will help to have an understanding of Linux commands and scripting. Capitalization is important in Linux!

My setup is on my home LAN. The IGate could be installed at a remote site using a shared Internet connection. Be aware that firewalls that might block connection to the APRS-IS network on a shared connection. You may want to request or have port 22 open on your router for SSH to establish a remote connection.

If all wired options fall through, look for a cellular hotspot device such as a MiFi to install along with the Pi. Use the built in WiFi on the Pi 3 or approved WiFi dongles for earlier Pi devices. Associate the MiFi with your Pi (turning on WPA2 so no one else piggybacks on your connection). Test the setup before installing it. Don’t find out after leaving the site that the MiFi times out after a few hours.

Program versions

Applications and versions used in this writeup:

  • Windows 10 64 bit
  • Raspbian Jessie 2016-05-27
  • Win32 Disk Imager 0.9.5
  • PuTTY 0.67
  • SDR Sharp 1.0.0.1444
  • RTL-SDR 0.5.3
  • Multimon-NG ?
  • Pymultimonaprs 1.3.0

Parts list

Listed below are all the parts needed to get this project working. It is noted when items can be left out or substituted.

That’s all the parts needed for this project. Check out the AdaFruit Raspberry Pi page for other hardware that might be useful, like the USB to PS/2 adapter for example. Many of these parts are included in the Raspberry Pi Starter Pack.

Pages: 1 2 3 4 5 6 7 8 9
Amateur Radio, Tutorials

Use Soundcard Oscilloscope to understand DSP features of an HF radio

As I continue to use Soundcard Oscilloscope in the shack, I find new uses for it.  In a previous post, I showed how to use it to calibrate receive levels for Ham Radio digital modes.  I’ve used Soundcard Oscilloscope to understand DSP (Digital Signal Processing) features of my radio.  I have an ICOM IC-7000 which doesn’t have any of the features the newer/larger radios: waterfall display, frequency display, or oscilloscope.  As a substitute, I’ll fire up Soundcard Oscilloscope to set filters eliminating loud adjacent stations or set a manual notch filter for annoying stations that tune up on frequency.

Soundcard Oscilloscope is a program that emulates an oscilloscope from signal data received from a sound card. It also has a frequency graph which will be used for this tutorial.

Station setup

  • HF Radio and antenna.
  • SignaLink USB and correct cable for your radio (pictures).  Any audio interface will work or even 1/8″ male-to-male audio cable between the audio out of the radio and Line-in on any regular sound card.
  • PC computer where the radio interface is connected.

Program versions

  • Windows 7 – 64 bit
  • Soundcard Oscilloscope 1.46

Download and Installation

This will install Soundcard Oscilloscope on your PC.

hf_dsp_features-01_install-01_soundcard_oscilloscope_website

Go to https://www.zeitnitz.eu/scope_en.

Click the link to “Download the latest version.” Save it in your Downloads folder.

hf_dsp_features-01_install-02_installer-01

Launch the installer.

Click Yes.

hf_dsp_features-01_install-03_installer-02

Click Next.

hf_dsp_features-01_install-04_installer-03

Click Next.

hf_dsp_features-01_install-05_installer-04

Click Next.

hf_dsp_features-01_install-06_installer-05

Installation will begin.

hf_dsp_features-01_install-07_installer-06

Click OK.

hf_dsp_features-01_install-08_installer-07

Click Finish.

Soundcard Oscilloscope is now installed.

Configuration

This will setup Soundcard Oscilloscope to capture audio coming from your audio interface device.

hf_dsp_features-02_configuration-01_language

Start Soundcard Oscilloscope by clicking the Start orb.

Click All Programs.

Click Scope.

Click Scope.

The first time the program is run, you’ll be prompted to select a language. Select your language and click Continue.

hf_dsp_features-02_configuration-02_license

The program is not free and will ask for a License key. Not entering a license will display this screen each time the program is started. The program is less than $12.50 US. Please support the developers by purchasing a license. This is made at the download site by clicking the “private donation license” link.

Click Continue if you don’t have a license.

hf_dsp_features-02_configuration-03_audio_interface_selection

Click the Settings tab.

Under Windows Sound Parameters, Audio Devices, Input is where you select the audio interface device. For SignaLink USB, this would be Microphone USB Audio Codec. Other interfaces: Line In, or Mic In would be selected appropriately and known from my audio interface setup tutorial.

Soundcard Oscilloscope is now configured.

Loud adjacent station

An example using notch functions and filters to remove a loud and stronger adjacent station.

hf_dsp_features-ration-03_loud_adjacent_station-01_settings

Click the Frequency tab.

These settings will need to be reset after restarting the program. At this point, my radio is off but it doesn’t matter.

Along the bottom is the Frequency graph, click about 1500 Hz (1.5 kHz) on the graph.

Slide the Zoom control over about 5 ticks so that the frequency graph now shows 3000 Hz (3 kHz) near the right edge.

I unchecked Auto-scale.  This is not required and only keeps the vertical graph at the same scale for this tutorial.

Turn on the radio if it is not already.

hf_dsp_features-ration-03_loud_adjacent_station-02_loud_station_2500-3200

Between 2500 Hz and 3200 Hz is a strong adjacent station to the frequency I’m trying to work.  The station is really coming in between 2100 Hz and 3200 Hz as we’ll see in a moment.

hf_dsp_features-ration-03_loud_adjacent_station-03_manual_notch_function

I try a Notch Filter (Manual Notch Function – MNF) to notch out the signal.  The wide setting it not enough to get rid of the signal.  The signal is still peaking between 1750 Hz and 3200 Hz.  You can see the notch between 2750 Hz and 2900 Hz.  I tried adding in the 2nd notch filter and it didn’t fully notch out the entire signal.

hf_dsp_features-ration-03_loud_adjacent_station-04_manual_notch_function_radio

Notch filter settings on the 7000 radio.

hf_dsp_features-ration-03_loud_adjacent_station-05_filter

I am able to knock out the loud adjacent station by choosing a narrower filter and using pass band tuning to shift the filter.

hf_dsp_features-ration-03_loud_adjacent_station-06_filter_radio

Turn off the Notch Function.  Selected a filter bandwidth of 1.8 kHz (FIL) (SSB-3 default on the 7000 is 1.8 kHz).  I used pass band tuning (PBT) to shift both edges of the filter to the left (on screen).  In this case the Shift Frequency was -650 narrowing the bandwidth to 1.7 kHz.  The filter shape was SHARP.

These settings eliminated the adjacent station as shown in the previous image.  Everything higher than 2000 Hz is completely gone.