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I visited the ROS Digital Modem Group on Yahoo! and found the following message:

ROS ULTIMATUM

Several hours ago I posted about the news that the FCC had reversed its decision regarding the legality of the use of ROS in the US. Is that not good enough for him?

A week ago, when I posted that ROS was illegal in the US, that was what the FCC believed and what I wrote was true at the time. I am not in the Soviet Union and I am not rewriting history to suit someone else’s convenience. Moreover, if someone has an issue with me or anything I write, would not the correct way to proceed be to send me an email, not issue an ultimatum in a public forum that I may or may not read?

I am so angry I can barely type.

Update: Jose has now seen my post of this morning and issued an apology. He wrote:

I apologize and I hope you put yourself in my place and understand my indignation.

I don’t wish to have any ill-feeling so I have accepted his apology. But I am still pretty angry and upset about the manner in which he chose to express his indignation. Even if I hadn’t yet written about the changed ruling, an email would have been all that was needed to obtain my assurance that I would as soon as I could.

I will not be using the ROS digital mode any more.

José Alberto Nieto Ros, the developer of the new ROS digital mode, has submitted the technical specification of the mode to the FCC, as a result of which they conclude that ROS can not be viewed as Spread Spectrum and would be encompassed within the section 97.309 (RTTY and data emissions codes).

Now, all that needs to be resolved is the issue of where to use it without causing complaints from users of existing nets and other modes. Anyone with experience of getting quarts into pint pots please apply now.

Today is the 10th anniversary of me getting my first ham radio license, which was officially issued by the FCC on March 1, 2000. My original callsign as issued was KC2FZT, though I changed to the current vanity callsign (K2DBK) later that year, just before I upgraded to my General license. At the time I was licensed, I had to take both the old Novice and Technician written tests to receive a Technician class license. (Major license restructuring occurred on April 15, 2000, when they reduced the number of license classes from 6 to 3 (Technician, General, and Amateur Extra). I didn’t take a Morse code test at the time (which would have given me “Technician Plus” privileges), but I did take a 5wpm test later that year as part of the General Exam. And no, I didn’t have to go to the FCC office in New York City as used to be the process, I took my exams in Joyce, KA2ANF‘s basement from a dedicated group of Volunteer Examiners.

I first got interested in getting onto the HF bands after participating in Field Day that year. Alan, KG2MV, helped me work the 15m phone tent (and yes, the bands were a whole lot better then, so we were pretty busy) and I got hooked. In addition to friends in my radio club (the 10-70 Repeater Association), I also had a lot of encouragement from a co-worker Jim, WK8G, and of course from my good friend Larry, N4VA, who continues to encourage me today.

Reflecting back on 10 years as a ham, there are a number of things that I’ve come to realize are why I so enjoy the hobby. There is always something new to try, be it a new digital mode, a new contest, or operating from a new location, although you can always go back on something you already know well and with which you are comfortable. The hobby is there when I’m ready for it; I don’t have to depend on good weather or some particular location. And of course, there are good friends and good times for those of us drawn together by a common avocation.

East of Mississippi.

• N4OGW | 64 Qs | 45 Mults | 2,880 Points [ACG].
• W9RE | 58 Qs | 40 Mults | 2,320 Points [SMC].
• N8EA | 55 Qs | 39 Mults | 2,145 Points [Thumb Area Contester].

n = 24 scores submitted in this division.

West of Mississippi.

• N3BB | 55 Qs | 40 Mults | 2,200 Points [CTDXCC].
• W0BH | 51 Qs | 38 Mults | 1,938 Points.
• WD0T (@KD0S) | 48 Qs | 39 Mults | 1,872 Points.

n = 14 scores submitted in this division.

NCCC Member (CA/NV).

• N6RO | 52 Qs | 32 Mults | 1,664 Points.
• N6ZFO | 47 Qs | 30 Mults | 1,410 Points.
• K6VVA | 45 Qs | 28 Mults | 1,260 Points.

n = 5 scores submitted in this division.

A shout out from the shackadelic on the beach to Tor, N4OGW and his great effort while leading the Alabama Contest Group to its banner position until next winter! The fastest 30-minutes in RadioSport experimented with its winter version of NS Sprint and scored a resounding success.

Now, if my work schedule permits, I want to join the fun this summer at least on one band before bedtime.

Contest on.

Kevin, GW0KIG, has just written in his blog about struggling to brush up his Morse. He first learnt the code at the age of 19 and has “memories of a Morse code tutor program on a borrowed ZX81 computer (remember those?)”

I remember the ZX81 and its wobbly 16KB RAM pack very well. In fact, a Morse tutor was one of the first programs I wrote for it. I wrote an article for Short Wave Magazine which described the program, together with a Morse keyboard with programmable memory and a high-speed Morse sender for meteor-scatter work. It is amusing today to read my conclusion that “it is possible to program the ZX81 to create sophisticated memory keyers.” These primitive programs would hardly seem sophisticated today.

The article was published in the August 1982 issue of Short Wave Magazine. I kept a copy and you can see it here. I wonder if my program was the one Kevin used to learn Morse when he was 19? One of these days I might try downloading a ZX81 emulator and see if these old programs will run on it.

I have been browsing for information about various circuits recently. Two books that are often recommended are “Solid State Design for the Radio Amateur” (which is now quite old) and its successor “Experimental Methods in RF Design”. I decided to get a copy of the latter and was gobsmacked to find on Amazon.co.uk that only used copies are available, priced from £557.14. No, that’s not a misprint, it’s about 800 bucks in real money.

I clicked over to Amazon.com and found the same book listed as available new for a slightly more reasonable (joke) $600.00, or I could buy a used one for a whisker under $500.00. Who are these sellers kidding? Do people really pay $600 for a book that was published by the ARRL in 2003 with a cover price of about $40? I wish I’d invested in a pile of them – they would have been a better return on my investment than my shareholdings (sick joke.)

I browsed down the Amazon.com page to see the usual stuff Amazon tells you about a book and found that 37% of people (rich or insane people, presumably) buy the item featured on the page, while 36% buy “Experimental Mathods (sic – not a joke) in RF Design” for a mere $42.70. That’s 36% who can’t spell, I guess, but I can live with a misprint in the title if it saves me $550.

But seriously, what’s going on here? Is “Experimental Mathods” a pirate copy using a mis-spelt title to avoid copyright infringement? Is a joke being played on somebody? If I buy it will I receive something other than what I expected, like searching for “mammaries” instead of “memories” on Google? I’m off to confused.com.

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.