Saturday, August 23, 2008

More Digital Contacts on 30 and 20 Meters

I've been having a lot of fun lately on the HF bands. Of course, I've operated SSB before, both at my own station and at numerous Field Days. But over the past couple of weeks I have operated nothing except for the digital modes, including PSK31, MFSK16, Olivia, and Hellschreiber. Many of my earlier contacts were on 40 meters. Lately I have been using 20 meters or even the fairly unique 30 meters. I would eventually like to try a mode such as PSK31 on 80 meters, and when the sunspots return, I'll definitely be using 15 and 10 meters. 30 meters, as I mentioned, is a fairly unique band. In the U.S., amateur radio operators use 30 meters on a secondary basis to a fixed service. I wonder what fixed service that is. Every evening when I turn the radio on to 30 meters at around 2000Z on roughly 10.130 MHz, I hear a signal that sounds a little bit like RTTY, but this transmission has a fairly wide shift. By playing around with MixW, I can determine that the shift is 850 Hz, but I apparently don't have the baud rate set correctly, because nothing meaningful ever decodes. If anyone knows what this is, let me know. I routinely hear other digital transmissions, including one that I guess is PACTOR. In the U.S., we are limited to 200 watts PEP on this band (presumably to avoid interference to the primary users of the band), and although I haven't looked at the Part 97 FCC rules lately, I know that you cannot use phone or image transmissions. They are just too wide. On the other hand, I have read about people trying Olivia 1000/32 on 30 meters, so I presume that at least 1 kHz bandwidth is allowed; at least in certain segments. I just checked my meager log (I've been operating the digital modes less than a month): I've got five QSOs on 30. Four are PSK31 and one is Olivia (which I assume is Olivia 500/16 since I've never tried 1000/32 and only tried 500/8 once).

20 meters has been somewhat more productive for me. I currently have 13 QSOs in the log for 20 meters. All of those contacts are using PSK31, except for one which was PSK63 (very similar to PSK31 but with double the baud rate and, I believe, double the width). As I suspected 20 meters works better for DX than 30 meters, and 30 meters may be slightly better than 40. Of course, I believe the reason is simple. My antenna is a fixed height above ground and is not particularly high to begin with. Many hams realize that an antenna needs to be a certain fraction of a wavelength above ground in order to have the lower takeoff angles (for the RF energy), in order to work good DX. When the antenna is too close to the ground for the band in question, you have what many refer to as a "cloudwarmer". Going back to my log (which has less than 50 entries, because I have only been doing this less than a month), I have no problem working the eastern provinces of Canada, and I can easily work 500 miles out or so in the U.S. I have no other DX on 40 meters. On 30 meters, I only have seven log entries, but I have Cuba. Station CO8LY is located in Santiago de Cuba, which is 1430 miles from me. Not too bad. On 20 meters, my DX gets even better: Mexico (Cancun), Venezuela, and Colombia. The Venezulean station, YV4OW, is located on Margarita Island (which happens to be SA-012, one of the Islands On The Air). Margarita Island is 2300 miles from me. I can also hear TG9AHM in Guatemala and TI2CCC in Costa Rica. It's just a matter of time before I work them.

I can't wait until the sunspots return, because I suspect that my workhorse DX bands will be 15 meters and 10 meters.

As a final note, I started working on this post about a week ago, after I first worked a station on 30 meters. In the meantime, I received a comment on my post entitled "The Internet and Radio Propagation". David, K2DSL, left a comment for me about another web-based propagation tool (which I plan to take a closer look at and blog about), but he also left me an email where he indicated that he has an amateur radio blog, and that he had similar radio equipment to mine. I was encouraged by his post about the SARTG RTTY Contest that was recently held. David has very similar gear and was able to work all sorts of DX. Good job, David, and it's certainly encouraging for me.

Until next time,

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