Sunday 14 June 2015

Patriot Games

I came home from Dayton to be presented with a TenTec Patriot, all thanks to my friend and benefactor, g6ybc...

The Patriot is a QRP CW and sideband rig for 40 and 20 metres, built on the ChipKit UNO 32 platform which, although it is based on a Microchip PIC processor, is approached through a Development Environment compatible with that of the Arduino. This makes the system more accessible for amateur programmers and - obviously - has some significant links to the work I've been doing with my Occam's Microcontroller project.

The Patriot is a development of TenTec's earlier "Rebel" CW rig. Both the Rebel and the Patriot are genuine Open-Source projects; both the hardware schematic and the code are published on-line and there are active user groups supporting these products. Indeed, without the user group, it is difficult to see that the product would be viable...

The Patriot is delivered with just a simple printed user guide - no connectors or accessories of any kind. Fortunately, all the connectors are pretty standard, as seen on the photo of the front and rear panels below...

Regular readers will know that microphones are about as rare as rocking horse poo here at m0xpd, so finding a mic for the new rig was always going to be a problem. Harder still was the 8-pin plug it is connected with (a TenTec standard, apparently). Sideband operation would have to wait - I would try CW first.

The rig has the usual stereo (tip-ring-sleeve) 3.5mm jack socket for a paddle input but the code supplied with the Patriot (as delivered) only supports a straight key or external keyer.

I was disappointed to measure that the power output on CW was only around 1.5 Watts, despite the 5 Watt claim in the specification. Ever since getting back to the UK, the bands have been in pretty poor shape and I have been dogged by QRM - so I wasn't too surprised to find it difficult to make an initial contact with this 1.5 W. But I WAS able to connect with other rigs of similar power - so, obviously, something was wrong...

On investigation, I found that something was, indeed, very wrong. The code as delivered appeared to have completely ignored the CW offset, such that when I was tuned to a station calling CQ, my reply was so far off as to be inaudible to the far-end station. The only way to get the situation close-to workable was to have the RiT control at maximum offset (full clockwise on 40, full anticlockwise on 20, I think it was - I can't now remember!). Even this didn't quite get to a "zero beat" - but, at least, I could make some contacts.

I decided to look into the code, so I downloaded the development environment, MPIDE, delighting at how compact it was compared to the ludicrously long downloads we are now being offered from the various offshoots of Arduino.

The IDE is familiar to anybody who has played with an Arduino before - so I quickly made modification to the band limits to make sure I didn't offend the terms of my license...

I also confirmed that there was indeed no attempt at sorting the CW offset and wrote a modification to include it. It took me an age to get this modification to work (because of another "blooper" in the code, which took me a while to spot), but eventually I had the CW offset sorted to my satisfaction.

These code changes are programmed into the rig through the USB connection on the rear panel, seen in the photo above.

Despite the terrible band conditions, I've now been able to have QSOs on 20 and 40, best of which was to Bandi, ha5aek, in Budapest.

The Yahoo users group, who I've now joined, seem to have spotted the CW offset issue and (no doubt) have a fix for it in their code.

After a few days' wait, a bag of three 8-pin plugs (technically they are line sockets, but we all know what we're talking about) arrived from Jan and Sandra of The Norfolk CB Shack...

No affiliation - other than the pleasure of trading with people who will send me three plugs for pretty much the same price everybody else seems to be asking for just one.

I was soon able to knock together a little microphone with a junk-box electret insert and a tactile switch...

A whistle into the mic causes the rig to put out a measured 4 Watts on 40m (although I haven't made any adjustments to the little "Mic Level In" preset on the side of the case).

Again, the bands haven't been collaborating since the arrival of the microphone - but I did manage a quick exchange with Sergey, ra1any, in St Petersburg on twenty metres yesterday. He gave me 5 and 5.

There's a lot more to be done, of which the priorities must be to hook up some kind of frequency display, to implement a keyer and to get the power on CW up to closer to the full gallon. But my first impressions of this little rig are positive enough.

Hardly surprising - they are preaching to the converted!

...-.- de m0xpd

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