On 10/08/2017 10:42 AM, dwight via cctalk wrote: > One wonder how many SW hams were active in the Caribbean. Most hams today > seem to be into 2 meter and not so much long range SW. The HF 3-30 mhz spectrum has propagation that makes long range possible at modest power. The Caribbean hams have to get back on the air first. Their priority is family, home, and security. As it is many have recovered some and are moving health and welfare messages.
Before the two hurricanes there was a good deal of activity on hf. > I would suspect it was still quite important. It still is as it provides the longer range link that VHF generally cannot. With the addition of digital modes Winlink,Pactor, and others it give the supplemental connections that can out reach a broken infrastructure area and provide connectivity to the Internet at some point where that is functional. Like networking you have layers of communications. VHF is local and can be very portable. For longer wide area communications you resort to lower frequencies for the ability to reach beyond the horizon. The reason ham radio is important is not unlike adhoc networks, they can setup and do useful communications independent of infrastructure. An example is a group of volunteers went to PR to provide radio support for agencies and utilities there that are out of the range of working cells (last heard 1300 out of 1600 cell sites are down) and land mobile systems that often shares the same towers or resources like back up power. Doesn't hurt that lowering costs of high performance batteries (LiFePo) and solar panels make off the grid radio at moderate power (100W) on HF very doable. I know this because that how my station and a few computers are run without connection to the grid. > As a fun project, a number of years ago, I used a modem card with a DSP chip > to decode radio weather fax. I used to DSP to be a narrow band filter and to > digitize the signal, when connected to a receiver. As far as I know, they > still transmit weather fax on SW. Wefax is still there, PCs or even RaspberryPi/Beaglebone and other ARM platforms make it easier to do and continue to lower the power and space needed to do this.. Its easy to do now using PC as the processing platform and sound cards as the baseband IO. Many of the newer radios even have the sound card and USB IO built in to make the physical connection easier. Computers and communications have been married for many decades and well before PCs. An example was a friends VHF packet node that relied on a Commodore to do store and forward back when Internet was called Arpanet. Way off topic I know but computers are a part of communications,and have been for a long time. Allison/kb1gmx > Dwight > > > > ________________________________ > From: cctalk <cctalk-boun...@classiccmp.org> on behalf of Jon Elson via > cctalk <cctalk@classiccmp.org> > Sent: Saturday, October 7, 2017 7:51:14 PM > To: Brent Hilpert; gene...@ezwind.net; Discussion@ > Subject: Re: OT: the death of shortwave / Re: Hallicrafters S-85 > > On 10/07/2017 06:46 PM, Brent Hilpert via cctalk wrote: >> SW is dead. The internet killed it. You can fix your S-40B >> but there won't be much to make it fly with. There are a >> couple international broadcasters left, but nothing like >> it used to be. I was an SWL'er as a kid in the 70s, >> learned a lot about the world. Voice of America, Armed >> Forces Network, Radio Japan, Radio Hilversum Holland, >> Deutsche Welle, HCJB Voice of the Andes, Radio Prague, >> Radio Moscow, Radio Peking, BBC, etc., etc., etc. >> Listening to the Cold War play out on the international >> airwaves. Pretty much all gone. Left between the static >> are a few religious broadcasters. > I used to do a lot of RTTY receiving. I copied RCC in > Washington DC. That was the Soviet embassy! They'd send > some clear test stuff for a while, then go off the air for 5 > minutes and start sending 5 digit code groups. > > I also figured out how to decode a binary synchronous > transmission that turned out to be a police net among the > French-speaking Caribbean islands. It was standard ITA2 > (5-level teletype code, often called Baudot) with the start > and stop bits removed, and blocked into groups. > > Only hams seem to use RTTY any more. There are a plethora > of digital modes used by hams, though. > > Jon > >
