Hi all, I just finished a build from an Ali Express seller. It seemed to work good, but wouldn¡¯t always find a match and never showed less than 1.17:1 SWR. I saw a post on the GitHub site regarding the RF diodes. It appears many of the Chinese boards came with poorly selected diodes, allowing capacitance across the junction. Or something. I¡¯m not an EE¡
I ordered a handful of 1N5711 Shottkys from Mouser. They arrived today, so I immediately swapped them out. I removed the SMDs and replaced them with traditional through-hole devices. Sure enough, the SWR gets down to 1.04:1, which is close enough for me. The wattage appears to be more accurate as well.?
I have found that the tuner works great, most of the time. I have an 80M end-fed, and tried several hands. It would not match 160M. My Elecraft radios will match it, as will my MFJ-993b. Granted, I¡¯m not getting out great, but it does find a match. On 80M, I reached higher into the band and it could not match a 3:1 SWR. Even my 7300 can match that. Otherwise it seems to match everything from 40M to 6M.?
Can anyone enlighten me on checking the toroids and capacitors? Does the power-on troubleshooting screen show the expected values or the measured values? Would it indicate whether the device was open or shorted??
I like this project a lot. I¡¯m learning a ton and hope someone can teach me more. Thanks!
K9NUD-Steve