EMRFD Message Archive 10256

Message Date From Subject
10256 2014-09-15 17:30:12 Phil Sittner WA7EXM Power Meter
A couple of young hams have expressed interest in building this excellent meter but I'm unable to find a source for the PC boards. I have a copy of the PIC compiled code that I can share with them but need to source the boards, or get my hands on the gerber files so some can be produced. FAR circuits does not list the boards and it appears that Kangaus is not fully operational. Does anyone know where either boards or the gerber data can be acquired?
10257 2014-09-15 22:03:47 Ed Manuel Re: WA7EXM Power Meter

Consider the board set that was produced by the Poor Hams Scalar Network Analyzer (PHSNA) Yahoo Egroup.  Rather than using the PIC code that Roger did, it uses an Arduino Uno.  The power meter is a separate board for use with the system of generator (an AD9850 or 9851 module), and processor.  Contact the group, or Jim, emrfd@yahoogroups.com for current status of boards available.  As useful as the power meter is, in a system forming a SNA, it's really a powerful tool.

I do have one set of boards for the WA7EXM power meter that I once planned to build, but have moved on to other instruments for the same purpose.

I'll pull it out if you want it, but I have only one set, un-built.

Let me know if I can help.

73, Ed - N5EM

10258 2014-09-16 11:22:20 mosaicmerc Re: WA7EXM Power Meter
I can help develop the gerber etc. if you have the schematic. Also, a clean scan of the existing PCBs (both sides)  can be used to manufacture the boards using the toner transfer approach. PCB etching using laser printer


10259 2014-09-16 11:58:15 mosaicmerc Re: WA7EXM Power Meter
Also this looks interesting
Fox Delta PIC18F4550 Graphic LCD 500MHZ Dual Channel RF Meter By Tony/I2TZK, Frank/k7sfn, Dinesh/VU2FD


10260 2014-09-16 13:16:35 Phil Sittner Re: WA7EXM Power Meter
Thank you for your response. I'd be interested in buying your set of boards if they are available. You can respond directly to me sittners@sbcglobal.net. I can likely generate a duplicate layout for other some of the other guys.
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10261 2014-09-16 13:17:47 Phil Sittner Re: WA7EXM Power Meter

Both of these look interesting and I'll show them to the new guys. Thanks.
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10262 2014-09-16 19:37:38 ka7exm Re: WA7EXM Power Meter

I believe WA7EXM is very responsive, if you just contact him directly.  Last time I checked, he had a few more sets of boards available.

The boards were drawn and fabricated by ExpressPCB.  So there are no gerber files for the boards.  With the relatively low demand for the boards, and the cool alternative choices out there, it probably doesn't make sense to re-draw this project and do another board run.

All of the design information (article re-prints, source code, hex files ready for programming) as well as the ExpressPCB files are at KA7EXM DOT NET



    Roger Hayward

10263 2014-09-16 20:05:25 Phil Sittner Re: WA7EXM Power Meter

I've tried contacting the ka7exm site and the power meter file section faults to "not found". Is there another way to access the information?
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10264 2014-09-16 20:52:33 ka7exm Re: WA7EXM Power Meter
Try again....I had to nudge it back to life.  Sorry for the confusion.


10265 2014-09-17 08:40:49 Phil Sittner Re: WA7EXM Power Meter

Everything down loaded fine. Thanks for the friendly help and cooperation.
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10266 2014-09-17 11:58:52 arfghans Re: WA7EXM Power Meter
Roger's PIC-based version is definitely the Cadillac of this type of meter. If you want a simpler one that still has a digital display, here's the one I built, based on a small digital panel meter.

Gary NA6O

10267 2014-09-17 12:48:19 Phil Sittner Re: WA7EXM Power Meter

Nice job. I originally built mine using a PIC 16F676 and a standard 16x1 LCD display. It's a bit convulated because you need to custom format the A-D conversion to match the performance of your AD8307 (they're all just a little bit different in their performance). There's a potentiometer to set the reference voltage for the A-D and you scale the offset to match the low end output of the 8307. Each step equals .1dBm. My unit is actually more linear than the WA7EXM version that was also constructed. I do like your approach. Thanks for sharing it with me.
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10268 2014-09-17 14:16:04 kerrypwr Re: WA7EXM Power Meter
Very nice kits are being sold by Lou VK3AQZ;


Similar circuitry to the Bob Kopski design I guess.

The cost is very reasonable but postage to overseas could be high; it might be worth contacting Lou.

Lou's noise bridge kits are also interesting; he sells quite a few of these "old-fashioned" (but very useful & educational) instruments I believe.

Kerry VK2TIL.