Tag: amateur radio

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Amateur Radio CQ WW RTTY contest 9/22-9/23/17: 40m contacts using an end fed wire antenna at 5ft

I worked a few hours in the CQ WW RTTY contest today and logged 30 contacts so far, mostly on 20m, a few on 15m, and then this evening several on 40m.

For 20m and 15m I have homebrew wire dipoles in my attic at about 33ft above ground. They probably don’t work as well as they would at the same height outside in the clear, but I logged contacts (from Davis, CA – grid CM98dn) with Japan, Mexico, Chile, Uruguay, Hawaii, British Columbia, and across the US. I’ve worked my Worked All States (WAS) with these antennas, they’ve been working well for me so far.

I haven’t worked out a 40m dipole that will fit in my attic (without some serious bending back and forth), so for 40m and 80m I have a Maple Leaf 160-6m 60ft end fed, which runs along my backyard fence line. Now at about 5ft above ground a 40m antenna is far below it’s optimal height above ground (at least for a 40m dipole which should be 66ft above ground), and yet this antenna works. Does it work well? Probably not as well as an equivalent 40m dipole up at 66ft, but using this antenna this evening to work some RTTY contacts on 40m, I made 6 contacts all between 500 to 600 miles out to the East and South, and then one slightly further out, up to BC at about 700 miles.

I think at 5ft above ground this antenna probably qualifies as an NVIS antenna, but working contacts out to 700 miles is ok for what I’d consider a compromise antenna, or at least with a compromised installation. Or am I misunderstanding how these end feds work?

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Homebrew contest 1st place: Packet Radio Go-Kit with node.js Packet to Twitter bridge

Super excited (and rather surprised!) to win the 1st place prize in the Homebrew Contest at this month’s River City Amateur Radio Communications Society club meeting last night!

My entry was something I’ve been working on over the past few months on and off to get ready in time for this month’s contest. There were two parts to my entry:

1. A self-contained, portable 2m Packet Radio Go-Kit. I put this together using:

  • 10″ waterproof gear case (from MCM)
  • 2m HT radio
  • Raspberry Pi 3
  • 7″ touchscreen
  • a TNC-PI packet add-on board for the Pi, from Coastal Chipworks (which I assembled as a kit)
  • ax25 apps (for axlisten and axcall)

2. A Packet Radio to Twitter bridge (implemented using JavaScript on node.js). While the goals and benefits of a portable Packet radio kit are somewhat more obvious, writing an app that receives Packet Radio transmissions and then retransmits them as Tweets on Twitter doesn’t have many practical applications. The main motivation for this part of the project was that I thought it would be an interesting blend of old tech and new tech. The popularity of Packet Radio declined with the arrival of easy access dial-up information services and BBSes in the 80s and then access to the internet in the early 90s, so linking the two together seemed an interesting idea. Plus, it’s an interesting stepping stone and talking point from common-place tech used on our wireless devices today, with data communications enabled via Amateur Radio.

I put together a number of articles as I was assembling my project and working on the Packet to Twitter interface. If you’d like to read more, here’s links to my previous posts:

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River City ARCS weekly SSTV Net 8/30/17 9pm

This was my second time joining the weekly River City ARCS SSTV net and it had been a few weeks since the first time, so I had to go back and work out how I setup MMSSTV again. Since MMSSTV is a Windows app, on my Mac I booted WIndows 10 in Parallels and ran it from there. Unfortunately the combination of MMSSTV’s flaky soundcard settings and sharing a USB soundcard device with Windows in a Virtual Machine is probably not the best combination, but for future reference here’s the steps I used that finally worked:

  • Plug in the USB Rigblaster before starting Windows 10
  • From Mac System Preferences, Sound, set in and out to default mic and speakers, make sure Rigblaster not selected for either
  • Boot Windows 10 then from Parallels menu, Devices, Sound, select Rigblaster for both input and output
  • Start MMSSTV, go to Options, Setup MMSSTV, Misc tab, select Default for In and Out – this is shown in screenshot below:

The above steps seemed to work fine. Plugging in the Rigblaster after booting Windows 10 and then assigning it to the Windows 10 running VM when prompted by Parallels didn’t seem to work for me (although probably makes more sense), despite seeing the Rigblaster showup in the MMSSTV soundcard settings. No idea why this didn’t work.

Here’s a selection of the pictures received on the net this week:

Between each of these I was trying different settings and trying to get the Rigblaster selected in MMSSTV. By the time of the last couple of pictures sent on the net, I’d got the setting setup just right.

The River City Amateur Radio SSTV net is held weekly at 9pm, on the clubs 440Mhz repeater (which has coverage of Sacramento, CA and surrounding area). Details are on the club website here.

 

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River City Amateur Radio Communications Society weekly SSTV net (06/21/17)

The River City Amateur Radio Communications Society in Sacramento runs a weekly SSTV net Wednesdays at 9pm local time (following the 2m net on the 2m N6NA repeater, and the 10m net) – I’ve tried to receive the pictures before but on 2m simplex between most of the stations in Sacramento area and out to my QTH in Davis, it’s a bit far to get a good copy, and some of the stations I can’t copy at all.

This week we tried something different and ran the net on the club’s 440MHz repeater. This worked great for me as we’ve got great coverage from this repeater over Sacramento area and surrounding area.

This was my first time to actively check-in on the net so I had a few things to learn on the fly! First, Multiscan 3B, what seems like one of the most common SSTV apps for the Mac, doesn’t seem to run reliably on current OS X 10.12.x versions. Last time I tried to use it I didn’t have any issue, but with the most recent MacOS version it would only start up the first time after it was installed, and every other time it crashed.

 

The first couple of pictures I received I realized I was receiving through the built in mic, and wasn’t even receiving via my Rigblaster interface. Understandably these first few pics were pretty terrible:

Part way through the net I switched to installing MMSSTV on Windows 10 running under Parallels on my Mac. My connection to my radio is through a Rigblaster, so I had to attach the Rigblaster input and output USB device to my Windows 10 guest. Once I configured it to receive and send through my Rigblaster interface, now I was receiving great images from the other ops on the net, and managed to send and get good reports on a couple of pictures myself:

 

 

 

 

 

 

 

Now I’ve got my config setup, I’m looking forward to our next SSTV net!

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