Ripples in the Ether

As I mentioned on the Avnet Spartan-3A Eval Kit Google Group, I’ve created a C program that will allow you to configure the FPGA via your Linux box. I don’t have a lot of time to elaborate on how to use this program, but the basic steps are listed below. These instructions assume that you are at least moderately familiar with using the shell in your distribution and building a program from source code. This code is in an alpha state and I have only tested this on my Ubuntu Hardy Heron box, so your mileage may vary. I’m sure there’s much I can do to improve it (clean up, refactor, etc.), but it seems to do what it needs to for now.

Right now, the program is controlled by three command line switches. I’ve created these options with a mind for expansion in the future (at least the serial flash part). Here’s the help printout from the program:

Usage: avs3a [options]
Options:
  -b, --bitstream=BITSTREAM	Bitstream used to configure FPGA
  -p, --port=SERIAL-PORT	Serial port connected to eval board
  -s, --slaveser		Configure FPGA in Slave Serial mode

1. Download the source code here.
2. Unpack the archive in the location where you intend to use the program.

   tar xzvf avs3a.tar.gz

3. Change to the avs3a directory.

   cd avs3a

4. Build the program from source.

   make all

5. Make sure that your eval board is plugged into a USB port.
6. If you don’t know the serial port of the eval board, then find it. I’m not sure what you will see, but on my Ubuntu Hardy box, my board enumerates as /dev/ttyACM0 or /dev/ttyACM1

   dmesg | grep tty

7. Make sure you have a bitstream file to use.
8. Issue the command to program the board

   ./avs3a -s -p /dev/ttyACM0 -b sample_bitstream.bit

If you try this and find it useful, or find a problem with the program then please, please, let me know in the comments below (or e-mail me). Thank you for testing this!

The big move is nearly here and I’m getting excited now. I’d say at least 2/3 of our belongings are packed away (not to mention the large amount of stuff that we threw out/donated to Goodwill). Nearly the entire second floor is packed, save for our bed, a small amount of clothes, and a few things from the office/shack. Friday at 5 PM is when we get the keys, so we plan on starting to move some stuff over immediately after that. The big push will be on Saturday morning, when we will move all of the big stuff and the rest of the boxes that we don’t get on Friday. This week has been dragging by agonizingly slow, but you know that’s going to change once the moving starts. Wish us luck!

And now for some loldogs of the Yellow Lab variety…

I couldn’t help but think of Rooster & Peanut when I saw this.

Since the ham shack is now mostly packed up in cardboard boxes and plastic totes, the only ham radio activity that I’ve been working on lately is research on antenna options for the new QTH. I’ll have a fairly good-sized lot at the new QTH with tall trees on opposite corners. The problem is that there’s a nice CC&R which restricts any kind of external antenna or wire drop to the house. So if I want to keep my new neighbors on my good side, I had better plan for a stealthy antenna installation to get me started.

Right now I’ve got my options narrowed down to two: an attic antenna or a steath longwire in the tree. There’s a nice, tall oak in the back yard where I could probably get a wire up vertical about 60 feet or so, and let it hang down through the limbs. The biggest problem that I see with this plan is that problem of deploying the antenna. There’s another house very close to the back side of the tree, which means that I stand a good chance of hitting it if I try to shoot a weight with a leader up to the top. And there’s no way that my fat carcass is going to climb up more than 20 feet or so.

The attic antenna option is a bit more appealing for it’s ease of installation, but not so much for the performance factor. I still think it’s what I’m going to try for first, just because it won’t attract any unwanted attention from the neighbors. The house is a typical one-story 70s ranch-style, so the antenna won’t be any higher than about 15 feet I’m guessing. Not very appealing, but it should work OK for local contacts. I’ve been leaning towards the linear loaded dipole, or more specifically a variant called the Cobra Jr. There’s not very much information about this antenna on the Interwebs, but I found a pretty good site by N4SPP. The antenna found on this page is more like a “Cobra Jr. Jr.”, since it seems to be cut for a lowest frequency of 40 meters. I’ve decided to try to lash up a version of this antenna using 450Ω window line with another wire threaded down the middle of the insulation to give three conductors. I’ll give an update when I get a chance to finish the antenna and maybe try it out temporarily here before we move.

A brief update to let you know that I expect that posting here will be fairly light for the next few weeks while we gear up for our big move. I don’t think that I will have the time for much more experimentation or ham radio stuff in general. I’ve already started packing away some things in the shack, so even if I wanted to work on a project, it’s going to become very difficult to do so as my equipment gets boxed up. I won’t be neglecting the blog completely, just having a bit of a slowdown. Things will be sure to pick up quite a bit once we get settled in at the new QTH.