Field Day 2015

  • Posted on
  • by
  • in

Field Day this year was a little different this year since we were road tripping to Orlando.

On Saturday, we ventured out to the Orlando EOC to check out the Field Day operation there. They had a pretty impressive set up going with a big air conditioned tent and 10 transmitters running. We got there kind of late in the afternoon, and they were nice enough to set up a 10m GOTA station for us to get on the air with, but the band was kind of dead by then. We were able to give my sister, brother-in-law and nieces a good introduction to what Field Day and amateur radio is about though.

Sunday we hit the road back to Charleston after watching the SpaceX launch. Fired up the radio and started tuning around on 20m for the last few hours of Field Day. Got 3 contacts in the log which was good enough for me.

This was also our first Field Day together. Maybe next time we'll do it again when one of us doesn't have to drive.

More cards from the buro

  • Posted on
  • by
  • in

Received my second batch of QSL cards via the buro today. 6 cards total from Hungary, Russia, Slovenia, Mexico, Germany and Brazil. Most were from contacts from about a year ago, but a couple of them were for 2013 QSOs.

Always exciting to receive QSL cards in the mail :)

An RF probe

  • Posted on
  • by
  • in

I camee across N5ESE's site and started browsing around some of his projects. He's got quite the list of them. In his Gizmos section is an RF probe which looked pretty easy to build.

I had a set of those springyy hook-y grab-y DMM leads that were broken, so I cut off the spring-y hook-y grab-y part to use for the DMM side.

On the work bench was a perfectly sized piece of PCB from when I was experimenting with cutting and scoring PCB. From the RXTX build, I just happened to have some extra 0.01 μF SMD capacitors which were perfect for the job. A 1N34A diode and 4.7MΩ resistor finished off the parts.

I used a small hacksaw to score the PCB and divide it into three sections, cut out a notch for the diode and cut the head off a brass nail to serve as the probe. Soldering everything in place was pretty easy.

RFProbe01.jpg

Soldered on the leads and a ground wire with alligator clip and put everything into a shrink wrap tube.

RFProbe02.jpg

The full probe, with all the leads ready for some RF to measure. I still need to find a decent enclosure to shield the probe with.

RFProbe03.jpg

Review: ARRL Satellite Handbook

  • Posted on
  • by
  • in

The book is split into two parts. The first part covers some history of amateur radio satellites, software and terminology, and some of the gear you'll need.

The second part consists of several QST articles describing simple antenna and rotor controller projects that can be used for satellite contacts.

Two appendices let the reader get down and dirty with the math and physics of satellite orbits and the various components and subsystems that go into satellites.

There's a good discussion of Keplerian orbital elements ("Keps"), which are essential to figuring out where and when to look for a particular satellite. Fortunately you don't need to use them yourself, software takes care of all of that. Unfortunately the discussion about Keps is made a little bit confusing by using three completely different sets of numbers in the tables showing different Keps formats and the text describing each of the elements.

One of the projects is titled "Work OSCAR 40 with cardboard box antennas!", a great example of how you don't need fancy expensive gear to hear satellites.

I think I'd call The ARRL Satellite Handbook more of a primer than a handbook, which implies something more comprehensive. Still, it does a pretty good job of covering what you need to know to start working the "birds".

4 stars out of 5.

Review: Radio Science for the Radio Amateur

  • Posted on
  • by
  • in

Radio Science for the Radio Amateur is one of the more recent ARRL publications that I added to the bookshelf.

At a couple hundred pages or so (it follows the ARRL's annoying chapter-page numbering rather than using regular page numbers), the book is pretty light reading and should be pretty easy to get through in one or two reading sessions.

The concept behind the book has a lot of potential, but this attempt doesn't go deep enough into anything to be all that useful. I'm left with the feeling of "Oh, that's pretty neat" but then end up grasping at air because of the lack of substance.

One significant flaw in the book is the lack of references and other resources that readers can go to for more information. For example, the circuit simulation chapter mentions SPICE and tells you it can be used to simulate circuits, but that's it. You're left to go find additional information on your own. A list of resources (books, websites, etc) at the end of each chapter would be immensely useful for such an introductory level book.

2 stars out of 5.

Ensemble RXTX build - Driver/PA

The driver/PA section is the final section of the build.

Three capacitors are the final SMD components left to solder onto the back of the board.

DSC02196.JPG

Two binocular core transformers are part of this section. You might be tempted to do these last, but I suggest making them the first components to install. The top of the board is starting to get pretty crowded at this point and you'll want a bit of room to thread the wires for the transformers through the holes. Same for the RF choke (RFC1, which I noticed I inadvertently left out).

The transformers themselves can be tough to wind. Make sure you pull each wire tightly through the hole or you'll have a hard time fitting all the windings in.

The three BS170 FETs get covered up by a heatsink and pad. The 2N2222 transistor also gets a heatsink treatment. There are a few components that get partially covered up by the heatsinks, so make the FETs and 2N2222 the last parts you work on.

Everything else is pretty simple and should go together without any issues.

DSC02201.JPG

The top and bottom of the (practically) completed board.

DSC02200.JPG

DSC02197.JPG

Ensemble RXTX build - TX mixer

The TX mixer section doesn't have quite as many components as the previous section, but there are a few band specific components including a toroid and transformer so you'll want to make sure you have the right band selected if you're following the WB5RVZ build instructions.

Like the RF mixer stage, the only SMD components are the FST3253 IC and three accompanying capacitors.

DSC02169.JPG

The through hole components consist of a 3904 transistor and a few capacitors and resistors. Watch out for accidental solder bridges between the closely spaced holes of the transistor.

Both the L1 inductor and T2 transformer have a lot of turns to wind onto a relatively small T30 core. If you have some 28 or 30 gauge magnet wire that's a different colour than what comes in the kit, use it for either the primary or secondary winding on T2. That will help make it easier to separate out the T2 wires before soldering onto the board.

DSC02171.JPG

Here's the top and bottom of the board so far.

DSC02172.JPG

DSC02170.JPG

One more section left in the build: the driver/PA section.

Ensemble RXTX build - TX op amps

Lots of parts to solder on in the TX op amp section, but most of them are through hole. No band specific compnents to worry about.

You might be tempted to place them all at once and then start soldering, but with all the dangling leads you end up with, it can make getting around with the solder and soldering iron a bit difficult. I found it easier to place a few components, solder, trim the leads and then repeat with a few more components.

I cross-wired JP1 here instead of jumpering them straight across, based on the notes in the build instructions. May end up having to change this, but we'll see.

DSC02163.JPG

Two SMD op amps and accompanying capacitors go on the bottom of the board. By now, soldering the SMD components should be pretty easy, even if you're new at working with them.

DSC02165.JPG

Getting near the end of the build now. Only two more sections left: the TX mixer and PA. TX mixer section is up next.

Ensemble RXTX build - RX Opamps and Output

The RX op amp/output stage is another relatively easy one. A handful of non-band specific through hole parts, 3 SMD caps and the SMD op amp. Nothing too difficult here, although again, you're dealing with pretty tight quarters with the through hole parts.

The line-in (which goes to the line in port on your computer's sound card) is the largest component to deal with.

The instructions for wiring JP2 in the build instructions were a bit confusing. My interpretation was that if your jumpers crossed over (jumper wires formed an X), then you could use any of the software mentioned (PowerSDR, Rocky, Winrad). In this configuration, you'd need to set a "Swap IQ" setting in Rocky/Winrad. If the jumpers were straight across, you could use Rocky or Winrad, but not PowerSDR.

I chose to jumper them straight across as shown in the WB5RVZ build instructions.

Top of the board for this section.

DSC02162.JPG

Bottom of the board

DSC02161.JPG

Next section is the TX op amp. Lots of parts there.

Ensemble RXTX build - RF Mixer

The RF mixer section is a pretty easy section with only 4 through hole parts and 2 SMD. Nothing terribly complicated here.

If you're doing the build over an extended period of time like I am and following the WB5RVZ build instructions, make sure to double check the band selection before each build session.

Two capacitors and two resistors (band specific) are added to the top of the board.

DSC02159.JPG

On the bottom of the board, the only thing to watch out for is the orientation of the FST3253 IC.

DSC02160.JPG

RX op amp stage is next.