Planning & Preparation ..

Well, despite my intentions, I am not able to operate /M using digital modes. On our way up to Webwood, ON. I tried to make a few PSK31 contacts while Julie drove but the radio indicated no ALC while in TX!

See, I should really have tested the whole setup prior to our road-trip but we’ve been exceedingly busy this holiday season. It is a poor excuse, I know, however it is a fact of life. So let this be a lesson to you! If you change your station setup in any way, it s a good idea to test it prior to intended (or emergency) use.

This afternoon, I tried some basic troubleshooting to see what was going on. I am able to receive just fine, and the PTT is working as it should, the problem is that in the “DIG” mode of the radio, there appears to be no audio being fed to the radio (as indicated by no ALC at even high audio levels w/ the digital gain set to 100/high).

So now it boils down to a couple of possibilities – neither of which I am presently equipped to test. The first being that the sound card interface cable I made is faulty – I saw a pinch in the cable and it is possible (though unlikely) that one of the conductors developed an open. The other leading likelihood is that the 6-DIN connector is not making good contact with the socket of the radio. In either event, more testing will be required to determine the cause.

More to follow …

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Mobile Operating ..

Well, time to pack up the radio gear and make the long trek out to Webwood once again this year. Tomorrow morning, we are off to visit Julie’s mother & her family to spread some Christmas cheer and so this means I once again have the opportunity to operate /M (mobile).

With any luck, I will have a chance to operate some PSK31 and JT65A while Julie takes her turn at driving. Traditionally, I have had great results – I can only hope that the propagation is good for our trip. If you are tuning around the frequencies in the usual digital mode spots (ie: 14.070 & 14.076 for 20m PSK31 and JT65A respectively), you may very well hear me!

Wishing you all the best!

73

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80′ tower

.. so I’ve been at it again. I purchased an 80′ mast kit from the Fed. for a cool $357.91 which as far as I’ve seen is substantially less than a similar kit could be found elsewhere.

80' mast kit in a shipping crate

In total, there were six auctions for 80′ tower kits which ranged in finishing prices of $318 through $503 which meant that my winning bid of $357.91 was just below the average price of $380.39 – a win in my books! While it is true that I might have won with a slightly lower bid, I feel that what I paid was well justified considering the timeline I was essentially forced to work with.

 

12' utility trailer

The antenna mast was located in Montreal, so this meant renting a 12’x6′ cargo trailer from a local moving company for $35 which meant the purchase of a 2″ drop ball-mount and 2″ ball which only cost another $25 and I wanted to have for the FJ anyways since it has a class III hitch & required wiring already. As it turned out, the choice of trailer was a very good one – the shipping crate just fit inside the walls (more on this later).

With the winning bid paid for and the “authority to release” documents printed and checked, my trusty ally and I headed out for our long journey to retrieve the tower. At approximately 13:00 we were on our way to Montreal – and the Crown Assets depot we were driving was expecting us for 15:00. Yikes!

Mast section showing the construction

After a long drive, spending some quality bumper-to-bumper time with the proletariat of Montreal, we arrived just in time to have our contact meet us at the loading dock. I backed the trailer up to a waiting forklift which was holding the crate aloft. After an initial inspection, it was determined that we were exceptionally lucky that the crate was just going to clear the rear gate / door of the trailer.

We weren’t sure that we’d be able to transport the whole kit in one piece – the backup plan was to demolish the crate and move the sections by hand onto the trailer for transport. We were both glad to not resort to this tactic.

So there we were at 15:45 ready for peak Montreal traffic, hauling a 12′ trailer with a ton of steel behind us. We stopped in at a fast-food joint as neither of us had eaten all day, and it was well deserved by this point. A few minutes later, we were back in traffic, headed west-bound back to Ottawa, albeit at a much more relaxed pace!

Mast kit hardware

Being an apartment dweller, I had to arrange for temporary storage of my acquisition which meant asking my very loving parents if they would be so kind as to store my future antenna mast until Julie and I find a home of our own (which we are actively, and with great anticipation seeking). I feel a bit bad having the tower stored at my parent’s place – they put up with a lot of crap of mine, and so I am extremely grateful. Love you Ma&Pa!

Upon arrival at my parent’s house, it was originally planned for the tower sections to be hand-delivered to a predesignated storage area – that is until my sympathetic father saw the scope of the work ahead. In typical Buck fashion, a seat-of-the-pants plan was hatched which involved the following aspects:

  • 4×4 low-gear
  • tree-saver strap & tow chain
  • momentum & some leverage

Mercifully, we were able to unload the crate in excellent time with minimal headache (save for a few bald-ish patches of grass which I have to attend to in the spring).

For now, the great tower will lie in wait – eager to be thrust high into the sky (okay, maybe not 80′ high – maybe). More on this adventure later …

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Raspberry Pi & Soundmodem for APRS

So I’ve been tinkering with my Raspberry Pi board, and one of the most recent additions is a pair of heat-sinks to offset the addition of additional thermal loading due to over-clocking. In an effort to get soundmodem working on the pi, I’ve increased the clock frequency by a moderate margin to see if I can alleviate some bottle-necking in the decoding of AX.25 packets.

Raspberry Pi with heatsinks & USB sound card

I am using two different USB soundcards in an attempt to see if the sound devices themselves are part of the resource management issues the Pi seems to be having. In addition, I’ve added a powered USB hub to rule-out power issues for the USB back-plane on the Pi.

Despite my best efforts, the CPU load still seems to be pegged out while running soundmodem, which means that the packet capture rate will be extremely poor at best. This is very frustrating considering that the CPU on the Raspberry Pi should (on paper) be able to handle the task fairly easily.

Now I could take the easy road like many others and use a dedicated hardware TNC but that completely misses the point of this exercise. My objective is to create a $35 TNC/digipeater/igate/tracker module – all exploiting the Raspberry Pi’s hardware. In theory, this task should be relatively straightforward, I mean heck, a fricken’ Arduino is capable of encoding AX.25 packets! (I’ve made a transmit-only position reporter using an ATMega 328)

I haven’t given up on this project, but I am a little dismayed. I’m by no means a software expert and so my attempts at trimming the fat on the Pi have been fairly fruitless. I am hoping that someone a bit more talented has a look at the resource issues and make some headway on the soundmodem implementation on the Pi.

I’ll keep poking and prodding, perhaps I’ll uncover one of the root problems. I’m wondering how better to utilize the Pi in the meantime.

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