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Volume 3 Issue 3
IN THIS ISSUE
DX PROPAGATION PRIMER P.2
SDR DONGLE BASED RADIO P.4
WED. NITE NET P.5
RFM22 RADIO P.6
MARCH MINUTES P.7
President: Al, VE3TET
Vice-President: Johan, VA3JBO
Secretary: Bob, VE3IXX
Treasurer: Reg, VE3RVH
QSL Manager and Lighthouse: Bill, VE3WBJ
Repeater manager and maintenance person: Carl, VE3FEF
Website Admin: Johan, VA3JBO
VE3QB, Bruce’s antenna system. The white shed just behind the evergreen tree is his dedicated “ham shack”.
Now that many more amateurs can now use the HF bands, I thought it might be useful to explain the most basic elements of DX propagation.
The sun emits electromag-netic radiation and matter as part of the nuclear fusion process. Electromagnetic radiation in the ultraviolet region ionizes the F region, radiation in the soft x-ray area ionizes the E region, and radiation of the hard x-rays ionizes the D region.
The F region (made up of F1 and F2) is the prime region for ham radio DX operation.
SUNSPOTS (not to be confused with Solar
Flares) are areas on the sun emitting ultraviolet radiation. Thus they are tied to the ioniza-tion of the F region. The spot in the centre of the picture would swallow the earth. The Smoothed Sunspot Number (SSN) is calculated using six months of data before and after the desired month, plus the data for the desired month. Because of this amount of smoothing, the official SSN is one-half year behind the cur-rent month. Unfortunately this amount of smoothing often masks any short-term unusu-al solar activity that may enhance propagation, and so the eSSN (effective SSN) is more useful on a daily basis.
A DX PROPAGATION PRIMER
Or HOW YOUR SIGNAL GETS FROM
YOU TO ANOTHER HAM
Part 1 Compiled by
Bill Graham VE3ETK
SOLAR FLARES are guided into the ionosphere along magnetic field lines and thus can only impact high lati-tudes where the magnetic field lines go into the earth. Solar matter (which includes charged particles—electrons and protons) is ejected from the sun on a regular basis, and this comprises the solar wind. On a “quiet” solar day the speed of this solar wind heading toward earth aver-ages about 400 km per sec-ond and so there is a delay between the happening and the effect. The sun’s solar wind significantly impacts
Earth’s magnetic field. Instead of being a simple bar magnet, Earth’s magnetic field is compressed by the solar wind on the side facing the sun and is stretched out on the side away from the sun (the magnetotail, which ex-tends tens of earth radii downwind). The sun’s electromagnetic radiation can impact the entire ionosphere that is in daylight.
There are two measurements of this effect: the daily A index and the three hour K in-dex. The A index is an average of the eight three hour K indices, uses a linear scale and goes from 0 (quiet) to 400 (severe storm). The K index uses a quasi-logarithmic scale and goes from 0 to 9 (with 0 being quiet and 9 being severe storm). Generally an A index at or below 15 or a K index at or below 3 is best for propagation.
SDR Dongle-based Radio by Terry VE3XTM
At our February meeting I gave a talk as well as a demonstration of “dongle” based Software Defined Radio (SDR). These dongles are devices that plug into your computer’s USB port. They were originally designed for DVB-T which is for receiving European digital television. The dongles do not work for North American TV as we use a different digital standard here.
However, SDR for these dongles began when DVB kernel developer Antti Palosaa revealed that an ecnomical USB EzTV 668 DVB -T/FM/DAB USB dongle based on the RealTech RTL2832U chip, could be used to stream raw I/Q samples to most PC’s. Since that time enterprising amateurs and software developers have written several programs to present this digital data in a very versatile open source software defined radios that are available for a free download on the Internet.
A recent article in QST titled, Cheap and Easy SDR, by Robert Nickels, W9RAN, outlined how to get SDR up and operating on your PC.
Basic USB dongles such as the Terratec dongle are capable of receiving radio frequencies from about 54MHz up to about 2GHz. There are some that are capable of going lower in frequency down to 24MHz. The dongles will receive all modes, AM, FM, FM stereo, USB, LSB, DSB and CW. These dongles cost about $20 and with the proper antenna one can listen in on the VHF, UHF and microwave portions of the band, including stereo broadcast FM .
The article by Nickles outlines how to download and install the software using a simple batch file install procedure. The soft-ware version that most are using is the SDRSharp or SDR#.
SDR# screen shot showing the panadapter and waterfall screen Source http://sdrsharp.com/
The software allows the setup and frequency correction calibration of the radio, as well as adjustments to sampling rates, sen-sitivity and a range of other features, including the storage of favourite frequencies and a recording/playback of band activity, all in the VHF and UHF bands.
But all is not lost for those who prefer to work in the HF bands. Recent development have seen the design and availability of reasonably price up-converters that allow the use of the dongle in our favourite amateur bands. The up-converter boards are available for about $50. A few SMA adaptor cables are all that is needed to complete a basic SDR radio that will cover the range from the AM broadcast band up to the lower part of the microwave spectrum. For a review of the various up-converters available see the link below.
While we cannot expect these dongles to rival commercial radios at this time, they do give amateurs an introduction to SDR and the ability, with the panadapter, to see the signals on the various bands. We are only at the beginning of this new radio technology and the future will hold many more developments through the creative use of software and digital processing of signals.
WEDNESDAY NITE NET CONTROLLERS
APRIL 3 – DOUG VE3CXU
APRIL 10 – CARL VE3FEF
APRIL 17 – BILL VE3ETK
APRIL 24 – M E E T I N G
MAY 1 – AL VA3TET
MAY 8 – RALPH VE3EUC
MAY 15 – HARRY VE3EIX
MAY 22 – M E E T I N G
MAY 29 – WALLY VE3LCR
THE RFM22 RADIO PROJECT
BY JAMES LITWILLER VE3JLC
The RFM22 is a low-cost ISM (Industrial, Scientific & Medical) FSK (Frequency Shift Keying) transceiver module which offers communication at tuneable frequencies in the 70cm band. It has an adjustable output power of up to +17 dBm. The wide operating voltage of 1.8-3.6 volts, plus a low current consumption makes the RFM22 an ideal little project.
This is the 3rd or 5th iteration of my RFM22 FSK radio project proto-type. These are won-derful little radios that can have you dreaming about the wildest software projects. Also the choice of the Arduino Pro mini 3 volt prototype board makes many things quickly possible and can easily enough run two radios at the same time.
I’m not sure yet how this is going to come together, as just a fox hunt radio that makes a little puff sound on the amateur radio 70cm band or other more advanced possibilities. To-day, I thought it might be interesting to try to construct a compact antenna to accompany the radio. Previously, a 1/4 wave length wire was used, which was fine, but opportunities exist for many possibilities.
Two 40mAh lithium batteries are intended to power this project. Connecting them in parallel could have complications, but I don’t think it will cause a power outage (Hi Hi) and some tests have shown that with precautions it can be done safely. Software projects will need to attempt power considerations. The container for an SD memory card (as shown in the photo) works as a god case for the project.
Further information can be found at:
MINUTES FOR THE MARCH MEETING
The meeting was begun with each member introducing their name and call sign. Gord VE3EOS, who was visiting, was warmly welcomed.
The first order of business was the Treasurer’s Report. Reg VE3RVH handed out his annual statement and reminded everyone that the membership fees are due. The ERC has $2,551.68 in the bank. Reg made a motion to accept the minutes and it was se-conded by Bruce VE3QB.
The second item on the agenda was that Al needed some-one to help assess the equipment from the estate of Bing Harris. Ralph (VE3EUC) volunteered to go with him. There will also be a need for volunteers to dismantle Bing’s tower and 4-element beam. Johan VA3JBO, Jim VE3JMU and Terry VE3XTM will set a date with Al to get the job done.
For new business, Bruce VE3QB explained some of the diffi-culties he encountered to re-configure the IRLP on his computer when he changed servers. It took several phone calls to Dave Cameron before he finally got it up and running well again. Our thanks to Bruce for his hard work. Bruce suggested that the club make a cash donation to the IRLP service and made a motion to send them $50.00. This was seconded by Ralph VE3EUC.
Reg VE3RVH giving the Treasurer’s Report.
Al spoke about the fleamarket on June 2 and about the need for more volunteers to run the Ontars net. He said that we will need about five people to cover the hours. Paul VE3PVB, Bob VE3IXX offered to help Al. Rich VE3DCC and Harry VE3EIX may possibly be able to help as well.
Al reminded all members to mark their calendar for the Field Day (June 22 and 23) at Bob’s (VE3IXX) farm. Al moved that the Sunday meal again be the traditional steak or roast beef dinner. This was seconded by Johan VA3JBO.
The final item of business was a discussion of the Lighthouse weekend (in Au-gust) at Point Clarke. Given the difficulties with a decent antenna last year and the fact that the lighthouse was still under re-construction, Al wondered whether it was even worthwhile to participate this coming August. He suggested that if the lighthouse is still not useable this summer, we may just forget this project.
Having finished the business part of the meeting, Al began a discussion of the up and coming ERC projects for this year. The first idea was for an HF pre-selector using a Cascode amplifier. Using schematic diagrams on the board, Al explained how this am-plifier works.
The second project idea was an EH antenna using a cone shape. While the flute shaped EH antenna (which Al and Paul had built a prototype) was more desirable, the cone shape is much simpler to build and works well. The EH antenna is only about three percent of a wavelength (great for smaller spaces), has a low noise level and works like an isotropic antenna.
A special Note of thanks to Bruce VE3QB for his many frustrating hours of work trying to get his computer to run the IRLP for the ERC repeater.
We can all appreciate how difficult computers can be at times. Having the IRLP available to all who use our repeater is a great asset.