AmateurRadio.com

Archive for February, 2010

	All	80m	40m	30m	20m	17m	15m	Ph	CW	Dig
DXCC	80	2	43	10	66	13	22	52	5	62
WAS	50	28	49	7	48	19	19	43	1	50
WAZ	26	3	21	8	23	9	9	22	5	22

I'm preparing to build my 40m version of Roger G3XBM's XBM80-2 QRPP transceiver into a little box but before I start I have one thing more to do. I have to design an output filter for the transmitter.

Roger didn't bother. Comments from him suggest that he was aiming for a low parts count and assuming that any filtering would be provided by an external ATU. However Alan VK2ZAY comments that the output was more like a square wave. The second harmonic of my 7.030MHz signal would be on 14.060MHz, also a QRP frequency and I can't be sure that my antenna won't radiate this too. So I think an output filter is a good idea.

Alan used a two-stage pi network, each stage consisting of two 820pF capacitors and a 2.2uF inductor. I built this up on my breadboard, terminated the end with a 50 ohm load (actually 47 ohms, the nearest resistor value I had) and checked it with my SWR analyzer. The picture above shows the result.

Out of interest I also checked the response of a single stage of filtering using the same values, shown in the next picture. You can see that the cut-off frequency is a lot shallower than when two stages of filtering are used, so clearly attenuation of harmonics would not be as effective.

My problem is that I need a filter for 40m not 80m. I tried searching the web to see if I could find some online design tools, and I did here, here and here. However when I fed the design parameters for 80m into the calculators the results they came up with were a lot different from each other and also from the values VK2ZAY used.

In the end I decided to use trial and error. I figured that since the frequency is higher the values I would need to use would be lower. The next lower value inductor I had in my parts box was 1uH, so I don't have a lot of choice in the matter. I substituted that for the 2.2uH. The result shown by the SWR analyzer was promising, but there was a big hump below the cut-off frequency and the SWR at 7.030MHz was a bit on the high side. So I then tried lower values of capacitors. The lower I went, the shallower the cut-off but the lower the hump as well.

In the end, I settled on 680pF capacitors with the 1uH inductor. There is still quite a steep hump below the cut-off frequency but I'm only concerned with the performance at 7.030MHz where the SWR is 1.2:1, which I don't think is too bad. The cut-off curve of this one stage filter seems as steep as the two-stage one VK2ZAY used on 80m so I think one stage of filtering will do.

After I'd written the above, the thought occurred to me to try the low pass filter in the circuit while it was on the breadboard. I'm glad I did, because I'd have been disappointed to find after soldering everything into place that the output power had fallen from 100mW to 25mW. After a bit of experimentation, it appears that connecting the low pass filter directly to the collector of the first transistor as VK2ZAY did in his version of the transceiver loads the circuit and reduces both transmit power and receive sensitivity. The solution seems to be to couple the transistor to the filter using a small value capacitor - I found 180pF gave the best results. This removes the need for the DC blocking capacitor on the output. The power is still down quite a lot, but part of this may be due to all the harmonic energy which is now not making it through to the power meter.

Cox and Brockman (1978) said, "People sure like to have a good time. The 1977 CQ WW Contest attests to this fact. In spite of less than normal conditions, interest and activity were never higher." (p 10)

What makes a RadioSport event fun to operate like CQ World Wide franchise?

One answer is DXpeditions according to Cox and Brockman (1978) and another may include antenna system(s) and/or one's receiver. The broader answer maybe active involvement of RadioSport clubs where resources and talent are focused around a specific goal like number one in the Club Box.

Cox and Brockman stated, "Not to be outdone, the Frankford Radio Club (FRC) repaired their antennas, turned their rigs, and walked off with the fierce Club competition title with a total of 62.7 M points. That's alot of work and cooperation." (p 10, 1977).

One senses club strategy beginning to develop with a score target inside the box. Additionally, FRC channeled their knowledge and resources into improving antenna systems-to-radios inside the shack. I believe individual initiative is important in addition to having a stake in the overall success of one's RadioSport club.

If there is a moment when design specifications are pushed to the extreme, it must be during an event like CQ World Wide; when was the last time one thought about their audio gain control (AGC)?

For example, Richard Norton, N6AA operated from Trinidad and Tobago, as 9Y4AA in 1977 and logged 1400 Qs on 20m that year. He moved from third place in 1976 to winning first place in 1977 while establishing a world record. Undoubtedly, he understood the design specifications of his radio, inside and out.

An on-going conversation on CQ Contest Digest reflector inspired researching how-to improve my receiver and/or decrease listening fatigue. Admittedly, I set controls at near maximum, according to Eric, K3NA many operators run their gain controls too high, and I'm one of them.

His suggestions are straightforward and easy to implement to include adjustments for a specific set of headphones.

Additionally, when considering a DXpedition designed for an event like CQ World Wide, understand point structuring as part of one's decision tree.

Cox and Brockman (1978) stated, "The Sochi Radio Club decided that 3 points per QSO would be better than 2, so they took a trip down to the Black Sea coast to UF6. It was well worth it, because their crew set a new world multi-single record with an incredible 4058 Q totaling out at 6M points." (p 10)

Several fun factors contribute to the overall success of an event like CQ World Wide such as 1.) An active RadioSport club focusing resources and talent on specific achievable targets, 2.) Learning design specifications of one's radio, and 3.) Understand an event's point structuring and maximize operating time and/or operating location to that of the point structure.

Believe in your signal!

Reference: Brockman, L. N6AR, Cox, B. K3EST (September, 1978). CQ Magazine: 1977 CQ World Wide DX Contest: C.W. Results. pp. 10 - 12, 14 - 24.

My QRP crystals finally arrived. Murphy worked overtime on this eBay purchase: the first batch apparently got lost in the post and the replacements were sent by mistake to another customer with the same surname. But I have at last been able to try out the little QRP CW transceiver built to G3XBM's design on the QRP working frequency.

The transceiver is still on the breadboard as I was waiting to try it on both 40m and 80m before deciding which band to make it up for. Certain components need to be optimized for the band in use, and even the crystal in use, since to save space I've hand picked a fixed capacitor to set the transmit frequency instead of using a trimmer. I need also to decide how much power output I want because that is governed by other components. I have had over 200mW out of it but I'm not sure if a 2N3904 without a heat sink could really handle that, so at the moment it is set up to give 100mW output when powered by a 9V rechargeable PP3 battery.

I'm leaning towards 40m as this would make a nice little fun portable rig and the antenna being half the size of 80m would make things much easier. 40m generally has more activity during the daytime, too. I have never found 80m an easy band to work with limited antennas and low power, so it has always surprised me that the lower band is so popular with QRPers.

Of course, it being the weekend there is a contest on today, so not much chance of being heard with 100mW. Even if someone did hear me and reply, it's doubtful if I could pick them out using a receiver with no selectivity whatever! This tiny, simple transceiver is amazingly sensitive, as you can hear in this 1 minute audio clip recorded on 40m this afternoon using my MFJ magnetic loop for an antenna. How many different stations can you copy?

This evening I may put the 80m crystal in and see what it sounds like on that band. Unfortunately the little receiver has no tools for fighting the terrible QRN that comes on during the evening when all the neighbourhood plasma TVs are switched on, and sometimes 80m is all but unusable.

The 2010 ARRL International DX CW event was my first operating experience when the solar flux indice broke through the 80 barrier. I watched A- and K-index steadily fall and marveled at our G4 class star. I imagined our ionosphere is much like the surface of an ocean. Each successive day reminding me of the local surf report.

Is there another sport as dependent on cosmological mechanics as RadioSport?

Friday night did not produce spectacular results, basically, the first evening is tough. My signal rarely scores on the first, second, or third call. It is however an opportunistic moment at logging multi-multi stations on spaces such as 15m or 20m at sunset using gray line enhancement.

I operated from N1MM's band map with good effect while hopping between each space after loading needed multipliers. Additionally, I entered the high end of the spectrum into the dialog box then pressed enter for example; 14.080, 21.075, or 28.065 MHz then clicked downward.

I practiced moving through each space as fast as possible while loading or unloading the band map. The swarm network of spotting stations has little bearing in relationship to my location, the influence of propagation, and type of antenna system. I'm not spending expensive time ciphering through the cloud of information, pertinent or not, because of the variability of station configurations.

Saturday produced an entirely different set of results. I submit the existence of station configuration stratification where optimal stations are first logged through the competitive funnel leaving signal space during the last 24-hours of a major for modest stations.

Experience suggested following a Day Two type strategy and log data supported my conclusion 80% yield on day two versus 20% on day one.

Consequently, I logged (Japan = 19), (Hawaii = 17), and (Netherlands Antilles = 5) across five spaces within 24-hours. I'm optimistic as Cycle 24 actually stimulated 10m last weekend with a few South American 100-watt stations (Argentina and Brazil) going into the log.

It is exciting to learn my vertical antenna system is sensing low power stations on the high bands.

Raw Results.
80m | 2 Qs | 1 Mults.
40m | 28 Qs | 11 Mults.
20m | 17 Qs | 8 Mults.
15m | 16 Qs | 10 Mults.
10m | 7 Qs | 3 Mults.

Total = 70 Qs.
Total Multipliers = 33.
Total Raw Score = 6,831 Points.

I have one more antenna system that will complete my coverage of available competitive bands within a home owner association regulated community. Admittedly, those sunspots added additional fun to an otherwise stellar event sponsored by the ARRL's Contest Branch.

73 from the shackadelic on the beach.

P.S. Thank you Japan and Hawaii for making the difference in my log!

I hate to use a Cavuto-style question as a blog title, but to borrow a Beckian phrase this week I'm feeling like the "question needs to be asked".

Here's an inquiry to the FCC that was posted on the digitalradio 'flector regarding the new ROS rigital rode:

Summary* : Request for clarification of new amateur radio digital mode

Description* : Within the past week, a new digital mode - called ROS - has surfaced on the HR amateur bands. Its creator refers to it as spread spectrum, but there is some debate over whether the mode truly represents spread spectrum as defined by the FCC. I am writing to request a review of the creator's documentation, which I have attached, and a formal ruling on whether this mode is legal for use below 222 mHz by licensed U.S. amateurs. It would be very helpful if the FCC, upon completion of this review, would distribute a public announcement of its determination to appropriate amateur radio and media outlets. Thank you very much in advance for your time and prompt attention to this request. I look forward to hearing from you soon.

Sincerely,


Timothy J. Lilley - N3TL

There's been a ruckus over the new ROS digital mode going on in radio amateur blogademia and on radio ramateur reflectors. (Rut-ro!) Apparently ARRL has advised someone that ROS is spread spectrum and therefore is illegal below 222 Mhz in the US. The manual for ROS describes it as "a digital communications software based on a FSK modulation of 144 tones".

Welcome to Handiham World!

If there is any theme that runs through publicity about amateur radio these days, it is generally one about the reliability of our communications in an emergency situation. In story after story that I see ferreted out by Google News, ham radio operators tell the press and the public about the way amateur radio operators can stay on the air to provide vital communications when cellular phones are overloaded or down altogether and other communications infrastructure has failed. The training and volunteerism of amateur radio operators are also highlights of these articles, and the very best of these stories also include some human factor - a volunteer operator who has helped the community, a team of operators who have worked in tandem with emergency personnel to provide backup communications, and sometimes even a victim who owes a debt of gratitude to amateur radio. These are themes that the ARRL has taken a leadership role in promoting, and the evidence is that the strategy has worked. More new hams than ever joined the ranks of amateur radio here in the United States last year.

Quoting from a story on ARRL's website, "A total of 30,144 new licenses were granted in 2009, an increase of almost 7.5 percent from 2008. In 2005, 16,368 new hams joined Amateur Radio's ranks; just five years later, that number had increased by almost 14,000 -- a whopping 84 percent! The ARRL VEC is one of 14 VECs who administer Amateur Radio license exams."

Of the many reasons people become interested in amateur radio, the one I have heard most often in recent years is that new hams want to earn a license so that they will have the means to help in emergencies and to be of service to the community. This, among the other themes, has been expertly promoted by ARRL in special websites, publicity releases, articles, and videos. Taking on the erroneous image of ham radio as an "outdated technology" that has been all but replaced by the internet, ARRL answers the questions of why we are relevant in the 21st Century on its Wordpress "We Do That Radio" and "emergency-radio" websites.

Well, with all of that in mind, we turn to the large cardboard envelope I received from Matt Arthur, KA0PQW, this week. Matt had told me he was sending me an article, but I was surprised and delighted to see that it read:

Honored by President Obama

Local ham radio hobbyist recognized

The story appeared in the February 18, 2010 edition of the Star-Eagle newspaper, and featured a photo of Matt, KA0PQW, in his well-equipped ham shack. In the article, staff writer Jody Wynnemer explained that when a letter arrived from the White House, Matt had learned that he had been selected to receive a President's Volunteer Service Award.

"Congratulations on receiving the President's Volunteer Service Award, and thank you for helping to address the most pressing needs in your community and our country", the letter began.

Matt was recognized for his work with the Community Emergency Response Team in Steele County, Minnesota. He recalled how he volunteered and handled communications during a flood in 2007. It had been nine hours until the National Guard could relieve him, and in the meantime he handled traffic in and out of the flood zone, passing messages to authorities in Winona.

Those of us who know Matt as a Handiham leader and volunteer understand what a great spokesman he is for amateur radio. To paraphrase a familiar saying about politics, all good ham radio work is local - at least that's how it begins. Local ham radio classes, local Skywarn training, local ARES exercises, local club meetings and programs - and local news stories, just like the one that features Matt. Of course ham radio is worldwide by its nature, but getting the word out about the things we can do really does begin right at home.

Congratulations to Matt, KA0PQW, on this wonderful honor!

For Handiham World, I'm...

Patrick Tice, wa0tda@arrl.net

Hot from the K3UK Sked page. "Breaking news from ARRL. They concur that ROS is a spread spectrum mode and as such is not allowed by the FCC on bands below 222 MHz."

I had just been giving ROS another try with my K3 and 40W this time, and managed to complete contacts on 20m with Alabama and Washington State. Neither of these are locations I would expect to work under current conditions using another mode. As soon as the announcement was posted on the site it all went quiet.

My sympathies to my fellow digimode enthusiasts in the USA. It has always struck me as ironic that hams in the land of the free have to operate under more rigid controls than those of us in "socialist" Europe.

Attempts to use the newly developed ROS weak signal mode are resulting in more chaos and frustration this morning as an increasing number of people pile on to the same frequencies. And attempts to decide frequencies to use with the mode seem to indicate total ignorance of other band users and modes. The latest list of recommended frequencies includes:

7.040 - which is going to interfere with the now long-established WSPR weak signal mode
10.140 - which will also interfere with WSPR's established frequency on that band
14.100.9 - which does not avoid the long established 24/7 packet network which has already complained about interference by this mode, and is also within the range reserved for beacons.

There are a total of three frequencies suggested for 30m, in ignorance of the fact that 30m is supposed to be used only for narrow band modes.

Someone responded to my earlier comment that a body like the IARU should decide which modes can work where, by saying that the IARU does not recommend frequencies for specific modes as that would interfere with experimentation. However I still think they should. When left to individual amateurs you simply get a fight between one group of people who don't have a clue and another group, users of existing modes, who have strong views about where they should NOT go. Without some overseeing arbitrator this will just end up as a mode war.

I think it is arguable that there just isn't room for a 2.2KHz wide weak signal mode on the HF bands at all. But if true, who is going to make that decision?

On February 23rd 2007, amateur radio in the U.S. was liberated from the tyranny of a minority of radio amateurs. They said amateur radio would be destroyed. The foundations of amateur radio were being dismantled, eliminating all that was good and wholesome, ruining decades of innovation and service. Hiram would be turning over in his grave. Cats would be sleeping with dogs. Rupaul would be sleeping with women. The bands would be silent as a long cherished traditional would be outlawed. The CBers would be dancing in the streets and invading our bands, polluting and pillaging our precious frequencies. Old men would have to talk about something other than the early dinner specials at Dennys. It was a grim and apocalyptic picture they painted in those days leading up to the great event.

Single Operator All Band.

• J88DR (G3TBK) | 3423 Qs | 261 Mults | 34hrs13mins | 2,677,860 Points [Chiltern DX Club].
  
• LU5FF | 2115 Qs | 233 Mults | 29hrs | 1,477,686 Points [LU Contest Group].
• P40LE (K2LE) | 1267 Qs | 224 Mults | 15hrs | 851,428 Points [OBONY].

n = 21 scores submitted in this category.

Multi-Single.

• C6AWL | 4199 Qs | 309 Mults | 48hrs | 3,892,473 Points.
• 5W0OU | 2339 Qs | 250 Mults | 48hrs | 1,754,250 Points [WVDXC].

n = 2 scores submitted in this category.

A thank you to each international low power operator who populated North American logs this weekend. This was a stoked event especially when 100-watt stations were logged inside shackadelic. How about 10 meters? One can accomplish the RadioSport impossible within this spectrum space.

Congratulations Dave Cree, G3TBK who operated J88DR to a 3830 Top Score and for providing a new DXCC counter as well.

73 from the shackadelic on the beach.

US | VE Single Operator All Band.

• N4YDU | 1942 Qs | 330 Mults | 41hrs | 1,922,580 Points [PVRC].
• N9CK | 1768 Qs | 335 Mults | 34hrs | 1,772,820 [SMC].
• VE9DX | 1580 Qs | 317 Mults | 1,502,580 Points.

n = 97 scores submitted in this category.

US | VE Multi-Single.

• N7DS (@NE7D) | 466 Qs | 164 Mults | 25hrs38mins | 228,780 Points [WVDXC].

n = 1 scored submitted in this category.

Cycle 24 provided an activity stimulus package this weekend surprising some and pleasing many. It's not the peak for sure however the long sunspot recession is finally over. Event numbers suggest phenomenal effort and stellar returns within all categories.

Nathan Moreschi, N4YDU leads the low power pack before log adjudication and he is one to watch as an emergent RadioSport athlete. His station configuration is definitely low power Box potential. Congratulations Nathan on a job well done while leading the Potomac Valley Radio Club, to yet, another banner week.

Low power multi-single remains as a category waiting for a few innovators. I would venture to say it is under capitalized with lots of great opportunity for the future of RadioSport.

Believe in your signal!

Late this afternoon I noticed that the ROS website had been updated with a new frequency suggestion for 20m 1 baud operation of 14.105, so I decided to have one more try.

For a while I seemed to have the frequency to myself. However I posted that I was calling there on the K3UK digital sked page. Shortly after, WB2YDS posted that he copied my CQ. I didn't copy anything from him, but I called again and the second time I got his report, though not perfect copy as the meter in the ROS program showed he was 30db down in the noise.

I sent a report, which I know via the sked page he received, but unfortunately a few seconds after he started KB1PVH started calling CQ and the program started decoding his CQ call instead. With two stations on the frequency it was hopeless, and soon after that Olga called me for dinner and that was that.

Normally an almost-QSO wouldn't rate a mention, except that I was using 5W from the FT-817 to a dipole, and WB2YDS was also running 5W to a long wire. I don't think I have ever worked across the Atlantic QRP to QRP before, and indeed I still haven't, but I nearly did, which shows what the ROS 1 baud mode is capable of if you are lucky enough to have a clear frequency for the duration of the contact.

Unfortunately the software has a number of issues that need to be addressed before it can be considered suitable for general use, one of which is the ability to lock on to the replies to you and ignore anyone else who comes up on the frequency.

Another problem is that ROS is still a mode without a home, and at 2.2KHz wide it needs quite a big home and no-one seems to want to make it welcome. There have already been complaints that by settling on 14.101MHz it is disrupting a long established packet network, and while I'm typing this someone seems to be jamming the 40m frequency 7.053MHz with some sort of digital idle signal.

As I said in an earlier post, the issues involved in releasing something like this to the ham populace at large haven't been thought through. Perhaps there needs to be an overseeing body like the IARU that decrees what modes can be used and where, so there can be no arguments. It's a pity that the use of a mode with such promise is being thwarted by so many difficulties, but practical reality often stops you doing what you want to do and ham radio is not immune to this.