[ARDF] Re: ARDF Digest, Vol 38, Issue 4

Thu Feb 16 15:10:00 PST 2006

I am at work so I don't have my fox controller info in front of me but I wanted to respond before I forgot.  I am doing so from memory so things might be a little fuzzy.

The PCBs that FAR circuits sold back when Albuquerque put on the first event (and I suspect are the same PCBs they are selling now) has a pretty deadly flaw that the newer version of the fixes.

The "old" version when used with our 80 meter transmitter could key up the final with the oscillator un-keyed -- which would make the final transistors catch on fire pretty quickly.

The problem as I recall had to do with how the LED was engineered into the circuit and how the LED was accessed by the firmware when the firmware detected an illegal DIP switch setting.  At power on, if the firmware would see, for example, a fox set as MO5 with a 3 minute cycle time it would start flashing the LED.  Problem is the same PIC line that flashes the LED also keys up the 80 meter final.

We discovered this a week or so before the event and had to make some quick changes.  We did a little PCB rework and I modified the firmware.  The easiest thing for us to do at the time was to re-route one of the PIC I/O lines used to access the DIP switch and use it to drive the LED (or maybe it went to the 80 meter transmitter).  I then modified the firmware to decode the DIP switch a little differently (fewer delayed start options) and modified the firmware to control the 80 meter transmitter in a safe way.  I also modified the firmware to change the xmit speed.  The change increased the amount of time we transmitted energy.  We wanted to make it a little easier to grab the 80 meter signal.

The hardware mod was not difficult.  I think I only had to cut one or two traces and solder on a couple of jumpers. I can provide details on the hardware changes and provide source / hex files for the new software if that is of interest.

After discovering the problem I contacted FAR circuits and suggested they either update their PCB or at lease issue a warning.  Looks like they did neither.

The old firmware will not work with the new design and the new firmware will not work with the old design.

The original fox source was written in assembly and a free assembler can be downloaded from Microchip.  It is pretty easy to modify the source and re-generate a HEX file.

The new firmware is written in CCS C.  CCS does not offer a free version of their compiler.  To make changes, one would either have to buy a CCS C compiler or port the code to High-Tech C (they do offer a free version of their 16F84 compiler).

I have the CCS C compiler so I could compile / make changes if that is needed.

I hope I remembered right and this all makes sense.

-Mike, K5ATM

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> Today's Topics: 
> 
> 1. Montreal fox controllers (Jennifer Harker) 
> 2. Re: Montreal fox controllers (Marvin Johnston) 
> 3. Re: Montreal fox controllers (Dale Hunt, WB6BYU) 
> 
> 
> ---------------------------------------------------------------------- 
> 
> Message: 1 
> Date: Wed, 15 Feb 2006 12:08:32 -0800 (PST) 
> From: Jennifer Harker 
> Subject: [ARDF] Montreal fox controllers 
> To: ardf at kkn.net 
> Message-ID: <20060215200832.7036.qmail at web50804.mail.yahoo.com> 
> Content-Type: text/plain; charset=iso-8859-1 
> 
> For Valentine's Day, I promised my sweetie I'd build a set 
> of Montreal Fox controllers. I had ordered boards from FAR 
> circuits, ordered parts from Mouser, and everything arrived 
> earlier this week. 
> 
> Well, the circuit boards are labelled version 1 rev 4, 
> dated 2/27/98. The parts list, schematic, etc. at 
> http://www.qsl.net/ve2emm/pic-projects/mtfoxctr/mtl_fox.html 
> are Version 3, dated May 00. Based on a quick look-over, 
> the schematics for the two versions are not the same. 
> 
> Luckily, I noticed this while soldering the resistors on, 
> before I got to the more expensive components... 
> 
> So, I have several options: 
> 
> 1) Try to rework the circuit board for version 1.4 to fit 
> the schematic (and parts) for version 3. There's a few 
> traces that I'd have to cut, and several caps (including a 
> variable cap) that'd have to be wired in somehow. 
> 
> 2) Find someone to manufacture 7-10 circuit boards based on 
> the version 3 board layout (which also has the advantage of 
> being smaller, so it might actually fit in an altoids tin). 
> I don't want to do board etching, myself. 
> 
> 3) Try to build version 3 on a radio shack prototype board 
> and hope that it can still function at 4 MHz, and fit with 
> everything else in the ammo case. 
> 
> 4) Ask around for a copy of the version 1.4 parts list and 
> schematic, and build an "obsolete" version. I don't know 
> if the current programmed PIC is compatible with the old 
> hardware, but reprogramming it shouldn't be a problem. On 
> the other hand, I don't know the reasons why the design was 
> revised... 
> 
> 5) Give up and use the PicCons we'd been using (though 
> we're still having problems getting them as stable as we'd 
> need for a championship-level meet). 
> 
> I know that several of you are using the Montreal fox 
> controllers. I'm curious what version of the hardware 
> you're using, whether you needed to make any changes to get 
> them up to IARU championship-level standards, and if you 
> ran into the same problem I did, what you did about it. 
> 
> I'm leaning towards having someone etch some circuit boards 
> for me. A few of these low-quantity quick-turnaround shops 
> have popped up online over the past few years; does anyone 
> have any experience with these (besides FAR circuits)? 
> 
> Thanks! 
> ---Jen 
> 
> 
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> ------------------------------ 
> 
> Message: 2 
> Date: Wed, 15 Feb 2006 12:24:46 -0800 
> From: Marvin Johnston 
> Subject: Re: [ARDF] Montreal fox controllers 
> To: Jennifer Harker 
> Cc: ardf at kkn.net 
> Message-ID: <43F38E0E.30B2BD4F at rain.org> 
> Content-Type: text/plain; charset=us-ascii 
> 
> 
> I've found ExpressPCB to work well for me. They have proprietary 
> software to do the layout, but it is relatively intuitive to use. The 
> price for the mini-board service is about $60.00 for three 2.5" x 3.8" 
> boards with a 350 hole maximum. For the offset attenuator boards I've 
> been selling, I can get 10 of them on a panel, and then cut them apart 
> using a Dremel cutoff wheel. The boards are double sided, plated-thru 
> holes, and the quality is excellent. I usually have the boards within a 
> week of ordering. Ordering is done through the Internet. 
> 
> Marvin, KE6HTS 
> 
> Jennifer Harker wrote: 
> > 
> > I'm leaning towards having someone etch some circuit boards 
> > for me. A few of these low-quantity quick-turnaround shops 
> > have popped up online over the past few years; does anyone 
> > have any experience with these (besides FAR circuits)? 
> > 
> > Thanks! 
> > ---Jen 
> 
> 
> ------------------------------ 
> 
> Message: 3 
> Date: Wed, 15 Feb 2006 21:29:34 -0800 
> From: "Dale Hunt, WB6BYU" 
> Subject: Re: [ARDF] Montreal fox controllers 
> To: ardf at kkn.net 
> Message-ID: <43F40D77.CF33C890 at arrl.net> 
> Content-Type: text/plain; charset=iso-8859-1 
> 
> Jen - 
> 
> I have several controllers wired using the FAR circuits 
> boards, and a couple that I did by hand on perfboard. 
> Yes, perfboard is smaller, and it isn't that hard, just a 
> bit tedious to do all the wires between the chip and 
> the switches. 
> 
> I'll have to look at the new circuit and see what is 
> different. You might email VE2EMM and ask him for his 
> suggestion - Jacques probably knows the circuit better 
> than any of us! He may have changed it to use a less 
> expensive PIC controller. He would also know if FAR 
> Circuits is planning on carrying the new board, and 
> may have copies of the older circuit available. 
> 
> Otherwise, may have the documentation printed out 
> for the controllers, or at least can draw the schematic 
> for you based on the controllers that I have. Looks 
> like you could fit it in an Altoids tin if you mount 
> the DIP switches so they stand vertically with one 
> side soldered into the holes nearest the PIC and 
> a common ground wire connecting the other sides. 
> That should allow you to trim 1/2 off of the board, and 
> I just checked that is enough. (As long as you don't 
> want to put a battery in there also! 
> 
> Which reminds me... I still have a few boards to 
> solder up when I get a chance. 
> 
> Charles NZ0I programmed the PICs for me. His verison 
> has some changes, but PICs are easy to change if you 
> have a programmer. 
> 
> 
> - Dale WB6BYU 
> 
> 
> Jennifer Harker wrote: 
> > 
> > For Valentine's Day, I promised my sweetie I'd build a set 
> > of Montreal Fox controllers. ...Ï 
> --- 
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> 
> 
> 
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> End of ARDF Digest, Vol 38, Issue 4 
> *********************************** 