Category Archives: Activities

Nashua Area Radio Society activities. Included is Field Day, our Annual Picnic, Tech Nights, On The Air Activations and much more.

Activities, Antennas, Featured, General, Homebrewing, Newsletter, Station Equipment

Small Software Defined Radios ~ Part 1: Hardware

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There are some exciting things going on in the software defined radio (SDR) world. In December (2018) I’ll be doing a Tech Night SDR workshop encouraging everybody to get familiar with these little gems. Use this article as a shopping guide to prepare for that meeting.

The SDR Stick

The workshop will concentrate on the USB stick style SDR. The most popular is probably the RTL-SDR unit based on the DVB-T TV tuner and the RTL2832U chipset. Sure it can be used to decode digital TV, but some innovative soul recognized that it could also be a general purpose receiver with a range of about 25 MHz to 1.5 GHz. Figure 1 shows that USB device along with a kit of handy parts to get started. This is available from Amazon here for about $28.

 

Figure 1. The starter kit for the RTL-SDR

 Figure 2 shows the circuit board inside the little dongle.

 

Figure 2. Inside the RTL-SDR stick

With this and your computer you can have a bunch of fun and learn about pan adapters, SDR tuners, and even watch for aircraft data.

Antennas for the Sticks

The starter kit comes with collapsable whips, a suction cup mount, a small lightweight tripod mount, and feed line. You can do quite a bit with just these parts. If you wanted to use this for a particular purpose (like monitoring aircraft) you can get an antenna specifically for that band or frequency. For example, this antenna is used for doing ADS-B aircraft monitoring. It is available from Amazon here for $8.

 

Figure 3. ADS-B monopole

Then again, you can make your own antennas easily enough for this purpose or others. See another article I wrote Homebrew ADS-B Antenna for Airplane Tracking for more information on that.

It is possible to use an existing antenna as well. The RTL-SDR dongle accepts an SMA type connector. A converter from SMA to BNC can be handy. Amazon has a set of two here for $11. See Figure 4.

Figure 4. SMA to BNC connectors

No Computer? No Problem!

An excellent way to explore these small SDR devices is with an inexpensive Raspberry Pi computer. I recommend getting one of the higher end models of these single board computers with a little extra horsepower. Processing SDR signals takes a lot of CPU power and that generates heat. My first Raspberry Pi unit was underpowered and it overheated within minutes. I’ve switched to a newer and faster model that handles the task easily. And, I’ve put it in a case with a small fan to increase airflow. See Figures 5 and 6.

Figure 5. Raspberry Pi 3 B+ motherboard

Figure 6. Kit with case, power supply, and heat sinks

These two items are available from Amazon. The Raspberry Pi 3 B+ board is $39 here. The kit that includes a case, fan, heatsinks, and power supply can be found here for $16.

Amplifier

A small device called an MMIC is a broadband RF amplifier that can bring signals up 30 dB. One of these is available on Amazon mounted on a board with two SMA connectors (in and out) here for $11. See Figure 7.

Figure 7. MMIC amplifier for RTL-SDR use.

You’ll also need a jumper to go between the amplifier and the SDR. An SMA to SMA jumper (set of 2) is available here for $4.59. See Figure 8.

Figure 8. SMA-SMA jumper

Aircraft Tracking

If you enjoyed the aircraft tracking talk given in the regular meeting by Thomas R Kavanaugh, KC1ELF, then you might be interested in the SDR stick sold by Flight Aware specifically designed for this purpose. It has an amplifier built in, and a filter centered around the ADS-B frequency. It is available here for $20. See Figure 9.

Figure 9. The SDR bundled solution for flight tracking

Smile!

Don’t forget to use the Amazon Smile feature when buying your equipment to support NARS!

Next Time

I’ll cover software options for these SDR sticks in the next installment. I hope you’ll purchase an SDR kit and bring it to the Tech Night meeting in December. It is a workshop intended to help everybody get something running. See you there!

Activities, Field Day, General, Newsletter

RV’s and Hams – Winter Field Day Needs You!

Hello, fellow RVers and Hams!

We all know that Amateur Radio is a great crossroads where many hobbies and interests intersect.  I’ve been slowly building a station in my travel trailer, some of you may have seen it during Field Day last summer:

N1SFT RV Camper in winter
N1SFT/P During Winter operations

That’s N1SFT/P at its winter operating position, in Freedom NH grid square FN43kt.

The trouble is, once the camper is in place after Thanksgiving, the snow is relentless!  I won’t be able to extract it from the campground until mid-April.

With Winter Field Day looming, I was wondering if any other club member would donate the use of their RV “Portable” during Winter Field Day.

The club will operate from a temporary tent structure, and it will be plenty warm… but to have a dry RV standing by with a furnace for safety would be appreciated.

If you or you know of someone who would be willing to bring their camper to Winter Field day, please contact Craig Bailey.  Keep ’em winterized – we’re just looking for a warm place to sit and take a break from the action.

And as always, we are looking for as many operators as we can get to come out and operate during the event.  If enough folks sign up, we could ensure seat time would be plentiful and efficient.

Craig, N1SFT

Activities, Field Day, General, Newsletter

CW Operators Wanted for Winter Field Day 2019

CQ CQ DE N1FD/WFD K

Winter Field Day 2019 is about two months away. A few of us hardy NARS members are planning to setup an outdoor multi-op station for this event. If you are curious about WFD, Craig, N1SFT, has an excellent summary article. The primary goal of WFD is to gain some hands-on experience with emergency communications in winter conditions. And although our objective is to be safe while having fun during the doldrums of winter, it is a contest nonetheless. And as is the tradition for NARS, we are in-it-to-win-it! Thanks to Charlie, W1CBD, we have a mathematical model for using the allowed band/mode multipliers to take first place. But we’re missing a key ingredient: solid CW operators willing to commit to a few hours to help get the needed QSOs.

Okay, okay, I know what your thinking… are you nuts! It’s cold in January, and snowy too! But not to worry. We have a solid plan for a heated pavilion sheltered from the wind. It’s a short walk on a cleared & treated path from a plowed parking lot. I guarantee you’ll be colder doing holiday shopping than operating from our cozy camp.

We are looking for CW operators who are willing to commit to a few hours starting on January 26, at 2 pm EST. Our goal is at least 12-hours of CW coverage during the 24-hour event. If you’re interested in operating CW for WFD, please contact Jerry, K1OKD (email to ‘jerry at okdoty dot com‘). If you want to help participate with event planning or setup, we can always use more volunteers.

Even if you’re not interested in operating CW, please stop by, make a few digital or phone QSOs, and have some hot cocoa with us. You’ll be glad you did.

73!

Jerry, K1OKD

Radio Amateurs Developing Skills Worldwide