Re: Creating Gerber files for pcb construction
Gordon Gibby <ggibby@...>
Thanks for yet another great suggestion.
I have now created a "flying jumpers" breadboard version using a couple of different resistive bridge designs --- the K6BEZ design driven by the Si5351 directly didn't produce enough voltage to make the reverse measurement accurate and I gave up after several
hours on that. Would need to add an amplification stage I believe... The easy swr indicator kit from http://www.qrpkits.com/ezseries.html#ezswr (no LED, just take the rectified voltage and run into
an op amp with a gain of about 6) produced a voltage that seemed to work. My circuit is sorta haywire (with egloo jumpers everywhere) and the pcb version would be FAR MORE STABLE but I'm able to measure shorts, 25 ohm, 50 ohm, 100 ohm, 220 ohm and open
circuit and get "sorta close SWR" measurements at frequencies up to maybe 30 MHz. There is so much haywiredness to the breadboard that I can't make any better observations at the moment. The PCB should be a ton more mechanically stable. Earlier today
I put it on a real antenna and it did find the resonance.
A friend is working on the "single meter" SWR version using a toroidial swr measurement head (which I also have built and should also work). The goal there is to emulate the $129 LDG big meter display of SWR..... The pcb that I cranked out (and now
being built in China, fingers crossed!) should work with both. (2 different inputs).
You folks are a lot brighter at this stuff than I am but it has been a ton of fun just getting this much to work! I think this is going to be a great building project for our ARES group.
From: BITX20@groups.io <BITX20@groups.io> on behalf of William R Maxwell <wrmaxwell@...>
Sent: Saturday, January 20, 2018 5:02 PM
Subject: Re: [BITX20] Creating Gerber files for pcb construction
Another to consider is www.jlcpcb.com. I have just received 10 boards for a mere $2 total, including DHL shipping. Note the there is a sixe limit of 100mmx100mm, and two layers, green solder resist and 1.6mm material.
This offer I think is limited to your initial order. A subsequent set of 3 boards, 10 copies each, cost me $29, including shipping.
On 21/01/2018 12:38 AM, Gordon Gibby wrote:
Wow!!! Thank you for that wonderful tip.