AmateurRadio.com

I had the opportunity of a lifetime to traverse through the nation’s most RF dense mountaintop towersite, and possibly reduce my chances of having children by a large amount…in any case, today’s work was bucket loads of fun.

Towers lining the crest. [Wikimedia user Skoch3, Photo]

The work at the site was simple — some regular maintenance to the W5MPZ D-STAR repeater and gateway.

So, I got up early and headed off to Ed’s (KA8JMW) place to pick up the caravan to the peak. We packed the truck with some server rack shelves and tools, and headed to pick up Brian (N5ZGT), then Chris (NB5T).

And then, the 10,768 ft (3,255m) summit.

The road was blocked by the Forest Service since the park was closed due to fire danger. Thanks to some prior planning, we had no trouble getting past.

And not two turns in to the curvy mountain road, we meet our first deer, head on. Thanks to Ed’s quick foot on the break (maybe he was practicing for QLF?) the deer zipped across the road, perhaps only with a bruised tail.

We were warned that with the lack of humans, nature tends to take over a bit

The one thing I though of going up the road is, what if you had this road all to yourself (like we did then) with a nice, fast rally car?

I think deer would have a problem with that.

Anyway, we got to the top, and met the first obstacle:

Chris dispatched the lock on the well-signed gate and we were in. At that point, we had entered the danger zone; the steel forest. With at least 26 FM stations, almost half being over 20 kilowatts, 33 TV stations, more than half over 100 kW, and an uncountable number of microwave dishes, log periodics, yagis, verticals, radomes, funny looking phased arrays and dipoles supported on dozens of massive towers, I swear I could hear KOB in my teeth.

After driving through the entire site, we arrived at our final destination: the Sandia Nat’l Lab’s personal radio  playhouse.

The guys began working on equipment, while I snapped photos and gazed in awe of the city of Albuquerque all within my field of view.

Chris, Ed, and Brian “working.”

Brian took the job of tightening the D-STAR antenna, which he did adamantly, without falling, thanks to his fancy harness. It’s funny how dinky that antenna seems, but being over 3,000 ft ( 914m) above the rest of the world, it can see almost 100 radio miles (150km). With my 40w mobile radio, it comes in full signal in Socorro, NM, 75 miles (50km) away.

The team was successful of getting things done, cleaning up the shelves of an obtrusive monitor, keyboard and mouse (by going SSH only) and installing a NetIO internet-controlled AC power killswitch.

Before…

After. Notice the new black box on the top right. That controls power for the whole thing via the web.

The work was complete right on the dong of noon, and we had ribs for lunch. YUM! After that, Chris’s wife treated us to some homemade ice cream at his place, and we toured his shack, nestled on the edge of a HOA-restricted subdivision. That doesn’t stop him from loving ham radio!

Next on the list is to move this stuff to its permanent home on server racks. Sadly, I won’t be here, with only two weeks left in my VLA internship. I don’t wanna leave! 🙁

I would like to thank Ed James KA8JMW, Chris Aas NB5T and last but not least, Brian Mileshosky N5ZGT for taking me on this mighty heighty outing. Perfect timing for knocking another thing off my New Mexico to-do list.

The only part I forgot on that list was to bring a spectrum analyzer up there. It would have probably blown up in my hands.

Me, Ed, Chris and Brian on the edge of the crest.

If you’re coming from sotawatch.org, welcome!

—Details—
Peak: W5N/BA-005 – 7284 [Socorro Peak]
Location: Socorro, NM, DM64mb
Time: 20 July 2013, 1700 UTC
Bands: anything I can manage. Likely 20m and up, and 2m
Mode: SSB preferred, but I want to try to muddle through some CW. I’ve never done CW without a computer (shame on me) so PSE QRS!

On 20 July, I plan to activate a nearby mountain for SOTA. This isn’t any regular mountain – the some parts of the road up to the peak is owned by EMRTC, or, simply speaking, its a bombing range. Therefore access is permit-only and this plan is tentative at the moment [edit — It’s a go!!]. However, at last night’s Socorro ham club meeting, I met a guy willing to be my escort, so I don’t get blown up, and to make sure I don’t steal anything, I suppose.

Map of the area and the Summit. [http://sotamaps.wsstvc.org/]

BA-005 is known as 7284 on the SOTA map, but the peak is commonly referred to as M-Mountain or Socorro Peak. A nearby peak which has a large, limestone M on it isn’t included in the database because it’s too near the taller peak.They only differ in elevation by about 60 feet.

This shorter peak is the home of the famous Elfego Baca Golf Shoot, where participants tee off at about 1500ft above and 2 miles awaythe hole. I think it’s a par 36 😀

Instead of golf, we’re going to shoot for some QSOs.

I’ll be using my new fangled End Fed Half Wave coupler and some conveniently placed towers. If those don’t work, then I’ll revert to some hamsticks. Stay tuned for more on the antenna project, and the summaryof the activation!

Our station was active for almost 24 hours, minus a lull at about 1:10 am Sunday morning. Our backup arrived at around 2 am, which included Brian (N5ZGT, Rocky Mtn Division Director), who just got back from a Turks and Caicos island vacation (or DXPedition, you might say), and Scott (N5SQR) who worked PSK and SSB.

Setup and Operation 

Beam

TA-33 with the 80m windom in the background

Dipoles

On my first shot, I got over this tree and the line sat perfectly on the brown number post.

The perfect shot.

Old Glory on our 80/40 trap dipole

RPi camera

Operation

We were 2A, so we had 2 stations on the air, all supported by batteries. We operated SSB, CW and PSK31.

Scott, N5SQR working SSB

No field day station is without its problems. We were lucky to only have minor issues, like the logs not syncing or the digital station computer interface not working. These were easily and promptly fixed. Everything else (except for the band conditions) was perfect.

Our ops came from all areas of the hobby. Brian, for example, just got back from Turks & Caicos, and worked hordes of stations from VP5-land, while Seth never worked a contest before being a technician.

Brian and Seth teaming up to send Radiograms for bonus points

Seth taking names and gettign mults on the voice station

Seth quickly caught the Field Day bug and worked the 12-1am shift by storm, and eventually took both working and logging on the voice station on solo.

It was very cool to see him warm up to the air and get excited to work stations. It reminds me of my first Field Day, where I was thrown into the action and started racking up QSOs as fast as any other operator after only having a few hours to figure it out.

A visitation by the local sheriff

  Satellites

The Arrow LEO-SAT yagi and other antennas in the background

Sat Station Setup — FT-817 for RX and an 897 for TX

My job at W5MPZ was to bring a satellite QSO to the log for an extra 100 points. Unfortunately, this didn’t happen.

I had several attempts at SO-51 (the only FM satellite), VO-52, FO-29 and the zombie AO-7 (all SSB/CW transponders). I had most luck with the SSB satellites but had problems in being able to hear myself.

To work the SSB satellites (all but SO-51) you need to know where your signal ends up after it gets translated to the other band. For example, FO-29’s uplink band is 145.8-145.9 MHz, while the downlink is 435.9-436.0 MHz. One would think the 100 kHz passband would be linearly related, e.g. I transmit on 145.85, and hear myself on 435.95, but this isn’t the case. The doppler effect causes the frequency to differ by up to 500 kHz on UHF, so you need a way of calculating doppler, or simply finding yourself.

My technique was to spin a carrier through the passband until I heard it on the downlink, and switch to SSB to call CQ and tune into myself. Upon the switch, I lost myself.

I figured out the solution on the last pass of the weekend. The FT-897 has a feature in SSB mode that allows you to send CW at your tone frequency. So if I’m on 145.000 and have a 700 HZ CW pitch, it would send it at 145.000.70 MHz. Therefore, if you were tuned into 145 MHz on another rig, you’d hear that same pitch. All I had to do was zerobeat on the flipped bandpass, and call away. I finally heard myself repeated by the satellite, but didn’t have any replies within the last 5 minutes of the pass.

It was worth the effort (and in hindsight I should have just worked the ISS’s message system via packet)!

Summary

The underlying point of Field Day (aside from preparedness) is to have fun. W5MPZ did exactly that. Our support team of family members kept us well fed, watered, sheltered, and our batteries charged. One could not ask for a better place to set up and operate from, and the weather (despite being cold in the mornings) was amazing – not having wind and the 100°F temperatures to contend with was a huge relief.

I’m not sure of the final QSO count or score, but we only missed a few sections in Canada – NT, MAR, and ONN I believe — like we expected. Field Day isn’t a contest, so the score isn’t important to me or any of the operators aside from personal club goals and whatnot, so that wasn’t a worry. What matters is the coming together of like-minded people to getaway from the daily grind, have a ton of fun, share stories, and work stations.

It’s always been a dream of mine to put on glasses that allow you to see only waves of RF emitting, reflecting and illuminating the world around you…this would make my job so much easier too!

Well, there just so happens to be such a thing that allows you to see RF…it only requries about 3 acres and 250 antenna elements, a supercomputer and a fast internet connection.

The LWA near the VLA

The Long Wavelength Array is a seemingly random assortment of crossed dipole pairs with a frequency response of 10-88 MHz. Every antenna is separetly fed into a giant computer that correlates and beamforms the array into a giant RF eye looking at the sky.

LWA Dipole Detail with the VLA in the background

And by eye I really mean it sees the RF world above it in real time:

Above is a real time view of the sky above the LWA (hit F5 to refresh, I dare ya!). During the day you can see the sun and several radio sources like Cas A, Tau A, and Cyg A which are galaxies, pulsars, and other nebulae of ridiculously “loud” RF emitters. Also, at the top and top left, you can see RFI from the VLA site, which is one of the things we’re working to alleviate.

Another cool thing it can do is plot spectrum over the whole day:

This shows the intensity at all frequencies between 10 and 90 MHz over a 24 hour period starting at 17:00 PST 11 July 2012. You can watch the nighttime MUF drop between 00:00 and 06:00 PST, and surge again at sunrise. Other strange and interesting patterns exist as well — check out the index at http://lwalab.phys.unm.edu/lwatv/ovro and see what you can find.

Ckeck out their website at www.phys.unm.edu/~lwa/lwatv.html and read technical information about the LWA here, and an even more technical dissertation here.

73!

New Mexico is dry. I was floored when it rained three days ago. But for 11 months out of the year, the air is dry, the sun is bright, the clouds are facetious, and everything’s on fire. 

Smoke plume from the 30,000 acre Silver fire

Smoke fills the horizon

 Such is life in NM. The 10% humidity caused me some pain and suffering for a while, but I seemed to got used to it. I used a lot of normal lotion, which wasn’t the best idea for being out in the sun so much.

Currently, a large chunk of the Gila mountain range is on fire, but thankfully few people live in the area. The Silver fire (named because its near Silver City, NM) is currently at 32,000 acres, making it the biggest fire in the US. From atop a VLA dish, you can see the smoke plume and the long trail of smoke being carried by 30-40 mph surface winds. It’s quite dark in Truth or Consequences.

Aside from the fire, the plains of central New Mexico have a variety of weather, typically involving some kind of dust and lots of wind:

Dust carried aloft by 40 mph winds

We even have tornadoes of dust! (Seriously, some of them are big enough to cause damage):

A particularly strong dust devil with a well defined center column

Then, all of a sudden, it storms:

A snowstorm to the north…it’s a rare event to see precip actually get to the ground.

Above, you see it’s snowing. Snowstorms in the southwest isn’t a myth after all! Just last year, a snowstorm dumped 2′ of snow on Socorro, NM.

Typically though, the air is so dry that any precipitation just evaporates before it hits the ground. This phenomena is called virga, and is the sole reason why the clouds are so facetious. What does hit the ground are tendrils of lightning, graupel — basically mini snowballs from the sky — and hail.

A tendril of lightning betwixt two VLA dishes

In 2004, hail fell with a vengeance:

So its dry, its dusty, windy and usually boring (minus the bits of hail, getting caught in a haboob, and waking up to lightning barrages)…but now is the season for rain. And we’re in dire need. NM has been in a 10 year drout, and wells are drying up like int he community of Magdalena, NM, just east of the VLA.

Locals believe that July 4 is the day which marks the start of the monsoon season…don’t take monsoon to seriously though, it’s not like the monsoons of India and Asia. They may dump 2″ of rain, but that gets sucked up so quickly by the dry, absorbent dust and flora of the mountain ranges that it was like it never happened the next day.

We’ll see what the skies bring.

The once famous Jamesburg dish (wikipedia link), located in Carmel Valley, California, was restored and used by hams to do EME experiments and events after its prime mission to capture and relay communications from Apollo 11, Tiananmen Square, and Intelsat came to an end.

The massive 30m wide by 100ft tall Jamesburg Dish

A few weeks ago, the IPG got some curious email from some ABQ-ians asking if they could play Ingress at the VLA to capture some GPS-based portals. If you’ve never heard of Ingress, think of it as geocaching with a Virtual Reality spin. Check out their website here.

Ingress is played on smart devices, which require data connections to operate. These data connections are fine and dandy unless you’re at the world’s greatest radio observatory; here they aren’t so dandy.

RF-EMS

Below is a screencap of our RF-EMS (Radio Frequency-Environmental Monitoring System) which captured two WiFi access points (the darker blotches) from an RV containing a Verizon 4G hotspot and another router for something else.

Your VLA on WIFI

In the last blog I described the 10′ dish for pinpointing RFI. We also have a (usually) 24/7 monitor that uses some pretty nifty antennas and preamps on a 50′ tower, sending it to an HP 70000 Spectrum Analyzer in a RF-shielded room from which we can record and upload plots like the one above, every day for the past 5+ years. 

RF-EMS Tower and Bunker

The biggest downfall is adequate locating of interfering transmitters. Currently, I’m designing a method which will allow the IPG to quickly and accurately pinpoint people with any kind of transmitter, be it a cell phone, hotspot, or vehicle keyfob (if we wanted to locate such things). My idea is based on multilateriation, which uses multiple receivers around the site which compare arrival times to calculate a four dimensional location. Keeping the bill of materials as low as possible, simplicity, ease-of-use and network integration (without causing RFI itself) a prime focus.

It may be overkill, but it gives me something to do in the free time.

Other Doin’s: Testing out and Debugging the 74 MHz System

When I’m not having free time, this is what I’m doing. A new feature of the Expanded-VLA is observations on the 4 meter band. The current system in place uses these simple crossed dipoles hoisted a few meters below the sub-reflector.

The cross dipoles connect to our receiver, which hooks up to the rack that magically digitizes the signal and turns it into pulses of light which the correlator feeds upon.

One of the problems we face are things broken that don’t have to do with our antennas and receivers. For example, the first test we do to examine the receivers performance is a band pass plot. Often times, we see something like this:

A bad bandpass plot caused by a faulty relay in the T301.

This is ugly! What we want to see is this:

A beautiful bandpass! You can see 4 band on the left, and P-band in the middle with RFI spikes all over.

First we go digging in the LO-IF and FE racks for a place to stick a spectrum analyzer to…

And from that we figure its’ this T301 which does the first IF up-conversion from 0-1GHz to 1-2GHz.

We get a new one, stick it in, turn it on and voila, it’s alive!