AmateurRadio.com

One of the reasons I’m not endlessly filling my log with DX contacts is because I actually get more enjoyment and interest out of trying new things or just tinkering about. On Sunday I decided to try using my K2 – which has been redundant since the few mobile excursions I made earlier in the year when Olga was away – for HF 30m APRS. I connected it up to the magnetic loop. I didn’t have a spare sound card I could use for the packet modem, but the microphone input of the USB dongle I use for computer audio playback was free, so I set it up for receive only.

When I previously tried to use that USB audio device to decode HF packet via the AGW Packet Engine I had no luck at all. At the time, I concluded that this was due to 300baud packet being a higher speed mode than PSK31 and the USB device was somehow losing the information necessary to decode it. However it now appears that the reason it didn’t work before is because the AGW Packet Engine opens the device at a higher sample rate than most digital mode programs. For the last few weeks I have been using TrueTTY as a packet decoder and this uses a 11025Hz sample rate. I used TrueTTY to decode the audio coming from the cheap dongle and it appears to be just as sensitive as it was when the audio was coming from my best sound card.

This morning I tried listening on 14076kHz, the JT65A frequency, and decoded several stations despite the high noise level on 20m. So it seems to me that it is possible to use these cheap USB dongles for sound card digimodes as long as the software you use samples at 11025Hz. Some programs unfortunately don’t let you set the sample rate and may use a rate as high as 48000Hz. This is unlikely to work if my experience is anything to go by, so I still don’t recommend that you buy one of these cheap devices for digimode use unless you have a specific application in mind that you know it will work with.

I have now ordered another of these cheap USB dongles which I plan to make into a “DIY SignaLink USB” with the aid of the digital VOX circuit developed by Skip Teller, KH6TY. This will allow me to use the K2 for HF APRS, WSPR or other QRP activities using the magnetic loop, and free up the K3 for other purposes using the multiband dipole. In fact I will then be able to use four amateur bands and four different radios simultaneously if I want to!

As a bypass survivor, each morning when possible, I go for a brisk walk. We are blessed to live in a nice development in Orlando which has a bit of lakefront and also has some irrigation and flood prevention ponds. This water attracts a good selection of wildlife which makes it fun to be outside and exercising even though the heat and humidity are often both above the 90 mark.

We have ducks, baby ducks, coots, turtles, snakes, eagles, hawks, osprey, sand hill cranes, storks, cormorant, anhinga,  raccoon, possum, squirrels, armadillos, feral cats, foxes, geckos, lizards, frogs, toads and all sorts of other neat critters to entertain us at various times of the year.   This morning I spent some time watching the water birds fishing on all the new fingerlings from this year’s hatch of bass, bream and tillapia that gather in the grass along the water’s edge.

Learning S & P from a Heron

Today a heron demonstrated how to do catch fish and I realized that the heron could teach me some things about operating QRP style search and pounce.

The heron has a particular style… they spread their wings like this great photo demonstrates so well (thanks Chris Harshaw and http://www.wikimedia.org). So what’s that got to do with ham radio? Like a karate master who learns from the world around him, a good QRP op can learn from the birds! The heron shades the target with its wings to take the glare off the water so it can see better. It also causes the fish to become confused and they can pick off the loner or easiest target.

Same thing with QRP… we need to spread our wings by tuning around a bit more agressively and listening for the ones we can snag. Not always the strongest, but a signal that is decent and an op that genuinely wants to make a contact. When we find that contact we need to pounce on it and not waste time.

Yes, I learned a bit from watching that heron this morning. He caught quite a few fish in a short time using his form of search and pounce. That heron was quick and moved from spot to spot gingerly and didn’t miss his target very often. No wonder he’s grown so large! I want to be more like that heron when I am on the air.

Still time to cast your vote in the poll for the best ham radio location in the USA.

72,

Kelly K4UPG PB #173

Charles Preston, a member of the Buddipole User Group email reflector has just posted links to two clear and useful guides to using the A123 Battery Packs available from Buddipole. While the Buddipole site links to documents about the batteries there’s very little practical information available about how to nurture these batteries. Similarly the Cellpro Multi4 charger documentation is more geared to the primary market – radio controlled airplane enthusiasts – so it’s great to see advice directly relevant to our intended use.

The first document is a Guide for Buddipole A123 Battery Packs and it explains how to maintain them and likely operating times for popular transceivers. The core of the document is how to charge the A123 Packs using the Multi4 charger (also available from the Buddipole site). There’s also mention of how to approach charging the Battery Packs with a solar panel and mention of the Genasun GV-4 Li 14.2 V MPPT controller. BatterySpace.com also sell a version of this charger designed for LiFePO4 batteries. Prices between US$110-119.

It’s great to have all of this information available.

The second document is Charging a Buddipole 4S2P or 4S4P A123 battery pack with a Cellpro 10s charger and focusses on the larger charger.

Three cheers for Charles Preston!

The commonly-held wisdom goes that an “ounce of prevention is worth a pound of cure.”  As things typically go around the K8GU station, 50% of problems are solved by prevention and 50% by cure.  Today, it was a cure.  Readers of the blog are no doubt aware that I have a recently-discovered problem with QRM between my radios when they were on the 20- and 40-meter bands.  (I didn’t notice this problem until I got both of the TS-930′s up and going again; so, it’s probably the result of the “new” station location and arrangement.)

I pulled the 20- and 40-meter W3NQN filters out of the circuit and measured them.  They benefited from a little tweaking, but nothing that would have caused the problem.  I put them back in and was rewarded with much lower VSWR in across both bands.

It didn’t matter which of the radios was on 20 and which was on 40, the interference, a popping hash that followed the leading edge of my keying, was there.  The next step was to put a dummy load on the output of one radio, then both radios.  Even when transmitting into the dummy load, the interference remained.  This suggested to me that the problem was very close by.  All of my gear is bonded together with heavy straps.  So, I wasn’t too worried that it would be difficult to find.  I noticed that the 40-meter LED flickered on my KK1L band decoder box following my keying.  It became the prime suspect.

I found some split beads that AD8P and I bought from AA1K in the Dayton flea market a few years ago.  I’m not sure what mix they are, probably 43 or possibly 77.  Winding a few turns of the band data lines from each radio through the beads knocked down the interference a good bit.  I slapped some more on the audio lines going to the Heil HCS that I use for SO2R audio and the interference disappeared.  But, I was using the dummy load on one of the radios.  As soon as I went back to the external antennas, the inteference came back.

Next, I dug out a couple of the 2.4-inch diamater mix-31 toroids that I purchased in the first K9YC “group buy” of these parts back in 2005 or 2006.  I wrapped the DC power supply line to the KK1L box and the AC supply to the HCS.  And, the problems pretty much disappeared.  At least one of these is due to what K9YC calles “the pin 1 problem.”  Basically, if the shield is brought through the metal enclosure to the circuit board, it conducts (noise) current that’s riding on it into the enclosure.  So, I need to dissect the HCS and KK1L boxes to see if I can find a deeper fix than just slapping ferrite on the outside.

But, there’s hope for SO2R in this week’s NSL!

Logging Qs this afternoon in the Salmon Run was a lot of ham radio fun
inside the shack relaxation zone. Signals ranged from arm chair copy
to light with more than one unique call going into the database. I
listened on 15 and 10m yet Cycle 24 needs a little more punch for my
low profile, low power station. Admittedly, there are a few of us
local ops, wishing upon a sunspot where the high bands are fully
juiced.

A few locals either upgraded their antenna systems or performed
maintenance chores like treating for corrosion or added a new antenna.
Sunspots or the lack thereof has not stopped anyone from having fun
with ham radio. Fred has nearly completed his Route 66 award and his
VUCC received its certification.

Traditional cards continue arriving in the mailbox with countries like
Chile and Galapogas Islands now confirmed in addition to blogger AE5X
and longtime RadioSport operators. My approach is crafting fun out of
our tradition of exchanging cards like KB6NU who collects a callsign
that makes a word.

I came back from a nice walk through the countryside, having picked a lovely amount of blackberries, damsons and sloes and popped into the shack. Earlier today, I’d started up my APRSIS client (APRSIS32 by Lynn, KJ4ERJ) and left it running.

I noticed there was a message waiting from Julian, G4ILO-6. I opened it up and to my surprise, it said ‘Hi via ISS’. Julian had launched a packet on 2m, it had been digipeated by the International Space Station and then come back to earth where it had been received by other iGates on the APRS network and found its way to me.

Thanks Julian for a really interesting message!

If you want to read about how this works and see the stations that have been heard by the International Space Station have a look here.

Over the last few days Lynn, KJ4ERJ has been adding some very cool features to APRSISCE/32 which I’ve been helping to test. The ISS packet digipeater is still operating so as there were several good passes during the daytime I’ve been playing on it as well.

Today I managed to hear my own beacon repeated back by the space station, and this time it was also gated to the internet by TF8TTY so my call showed up on the map of stations heard through the ISS at ariss.net. I also managed to send a couple of messages through the bird. Tim, G4VXE was impressed to receive a greeting relayed via the space station. I also managed a two-way exchange with Marc, PD4U, which I think counts as an actual satellite contact.

Of course, whilst it’s fun to bounce radio waves off a satellite it isn’t a very practical method of communication. The ISS is the best QTH ever and it can hear all the activity on a frequency at the same time, so communication is only possible if not too many people use it. Lots of messages never get anywhere because they are sent at the same time as messages from other people which you can’t avoid transmitting over because you can’t hear them. The space station decodes only the strongest, so turning the power up improves your chances of success quite a bit. You can get through the ISS using a hand-held VX-8, but only at 4 o’clock in the morning when most sane people are asleep, unless you are incredibly lucky.

The new feature in APRSISCE that I mentioned is the ability to open separate windows so you can track individual stations at a more detailed mapping level. Lynn has called this Multi-Track(TM) and he thinks it will be very popular with emergency communications teams who will be able to see the entire area of the event in the main window and see exactly where individual team members are at the same time. It’s only available in the development (beta test) versions at the moment, though.