Archive for the ‘work’ category

QRL for Sprint and September VHF

September 16th, 2010

As I mentioned previously, I was planning to make the NCJ North American Sprint and the ARRL September VHF contests my kick-off to the Fall/Winter contest season.  When a work trip was scheduled for that weekend, I assembled my portable station.  But, Sarah convinced me not to take it since carrying the ham gear always complicates travel a little bit.  Since the work trip was radio-related, I thought I’d share a couple of pictures and stories.

One of the projects in which I participate is the middle-latitude expansion of SuperDARN (Super Dual Auroral Radar Network).  SuperDARN is a global HF radar network that is used to monitor plasma processes in the polar ionosphere/magnetosphere.  It was recently highlighted on  Last year, we built a pair of radars near Hays, KS.  This year, two radars are under construction in central Oregon.  I went out to assist with the initial phases of the build.

The radars are installed on an old HF over-the-horizon-backscatter (OTH-B) radar transmitting site in Christmas Valley, OR.

Two of these radars were constructed for the U.S. Air Force as an early-warning system for aircraft, one in Maine and one in Oregon/California.  The western portion of the radar was only turned on briefly for testing before being relegated to “warm storage” and then decommissioning.  Typical.  None of the antennas or transmitters are still on site and a lot of the copper wiring has been looted.  Everything left inside the building, including the backup generator, was in essentially mint condition.  As an aside, the transmitters from the Maine site were recently installed at Arecibo Observatory.  I have no idea what happened to the transmitters from this site.  Despite the fact that the antennas and transmitters were missing, there were a number of interesting things to see.

This OTH-B radar was a megawatt class (output, not ERP) system split into three segments/sectors, facing NW, W, and SW, each fed by four transmitters.  Each sector had a separate, dedicated 3-phase power line that came from a substation some 50 miles away—I found it on the way home.  You could follow the poles straight to it if you knew what you were looking for.   Each of the transmitting arrays was surrounded by a fence, for obvious reasons.  The fence was made entirely of wood.  Furthermore, almost all of the washers were a fiber material, not galvanized steel like the bolts.

At first, I thought that the washers might have been an electromagnetic consideration, like the wooden fence, which might have distorted the antenna pattern in the best of cases or simply melted in the worst.  But, I suspect now that it was a mechanical consideration to deal with dramatic changes in temperature and humidity in central Orgeon’s Great Sandy Desert.

The actual construction of the SuperDARN radar is not that exciting at this point, but here are some of the 72 aluminum poles we dressed with cables for the two radars.  Each radar has a 16-element phased-array of folded dipoles mounted in a corner reflector.  I installed a lot of N connectors on LMR-600 and a lot of Preformed end-grips on Phillystran, in addition to some more cerebral tasks.

The site has good optical conditions, too.  So, I’m looking forward to trying some of my optical instruments out there.  Here’s a quick star-trail exposure I took with the camera propped up on a picnic table in the motel parking lot.

So, that’s what I was doing instead of Sprinting and grid hunting!  I should be QRV in the NS Ladder tonight.

Travel with Radios and Antennas

July 23rd, 2010

Every now and then, there is a question on one of the e-mail lists or forums about traveling by air with radios and antennas.  In my experience, most travel headaches can be minimized by adhering to a couple of simple rules:

  1. Make it easy for the security (and Customs, if international) inspectors. Pack everything neatly so it’s easy to search, even if you’re not present (checked baggage).  Label everything.  Include documentation and instructions on how to quickly disassemble things if needed.  Be courteous if searched.  This is not the time to “educate” inspectors about amateur radio.
  2. Carry your radio and computer as hand luggage. I think everyone knows this by now.
  3. Put antennas into a sensible container and check them. I’ve heard of golf club carriers, ski bags, fishing rod carriers, and cardboard boxes.  I use a 4-inch thin-wall PVC drain pipe that’s about 48 inches long.  It has a black rubber cap on one and a drain plug on the other.  This may have problems in the automatic baggage-handling systems of some airports like O’Hare.  The sporting equipment bags are better because the airlines know how to handle them.  It makes sense to use a carrier that might be similar to other baggage going to your destination.  But, in reality if you just call it your “ski bag” or “golf bag” at the counter, the agent will never ask what’s in it (aside from the usual security questions).  Also ensure that this bag is acceptable on all your flights, including island hoppers.
  4. Keep as low a profile as possible, but don’t be weird or break the law. Practice moving fluidly with all of your gear.  Expect to be questioned and prepare for it.

If the trip is international, every country is different.  So, it’s helpful to have either a resourceful, intelligent local fixer or at least to discuss your plans with someone who has been there before.  However, most countries that receive a lot of tourists and have relatively easy reciprocal licensing requirements will not pose any problems.


December 15th, 2008
RSS Feed of JGR

RSS Feed of JGR

A few months ago, I wrote up my own RSS feed generators that scraped the AGU in-press pages.  Today, one of my papers appeared in the feed.  Surreal.  And, gratifying.  In other news, my advisor discovered this week that AGU now has their own RSS feeds.  Geophysics gone Web 2.0.

» Read more: Surreal


October 27th, 2008

Just some miscellaneous news from happenings over the past month…first, the good news…

I passed the oral exam on Tuesday.  So, I’m officially ABD now.  There is a light at the end of the tunnel.

Nikon released the 50mm f/1.4G AF-S SWM prime lens at the end of September.  I guess I wasn’t paying close enough attention.  This is good news for D40 owners such as myself.  But, the price is almost as steep as the Sigma f/1.4 30mm and 50mm HSM lenses.  The 30mm lens would be a better all-around choice.  Perhaps Nikon will come out with something a little shorter by the time I’m ready to buy.  Until then, I’ll keep using the 50mm f/1.4 AF-D that I have on indefinite loan from work.

I managed to destroy the drivers in my recently-repaired TS-930S.  I considered swapping the drivers from my second radio into this one.  But, when I took that radio apart, I found that the capacitors had swollen.  So, I have parts on order to fix that.  UPS says they’ll be here today.  I requested a quote for the NTE236 replacement for the MRF-485 drivers.  They want almost as much for the NTE236 as RF Parts does for the MRF-485.  I think I’ll get the MRF-485s.

We had high winds yesterday (Sunday).  I lost the 80-, 40-, and 20-meter dipoles.  Sarah said, “Do you expect that (80-meter) antenna to last the winter?  It just broke in September.”  She’s right.  I’m not sure I’ll repair it if it breaks again.   It’s less than a week to the CW Sweepstakes and I only have one working radio (FT-840) and antennas for 10 and 15 meters.  The forecast calls for 65 and sunny on Thursday.  So, I’ll probably take the day to work on antennas.

» Read more: Miscellaneous


April 28th, 2008

Cloud on Mount Haleakala

Work sent me on a last-minute trip to Maui at the beginning of April to focus some cameras and collect backup data.  It’s pretty hard to complain about that.  Although, I didn’t get to see much since we had a motherboard fail the last night I was there.  The dead board has two RS-232 ports, which is about impossible to find these days.  Fortunately, we had another computer with the exact same board in the lab.  So, we got that running again and shipped it back.  Hopefully, it will just work.