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Re: Schematics?
A very quick look at diagram,? you should have? 8 volts tx on UHF, pin 1 of J4007 You should have some voltage, less than 8, on Pin 2 of the module.? You should have 13.8 on pin 3 of the module, and RF out on pin 4. Check with handheld at varying distance/without antenna to see if it is amplifying. Check what voltages you have on base and collector of final transistor, Q4006. Should be around 0.65 on base SSB tx, and 13.8 on collector. On Tue, 12 Jul 2022 at 16:01, Max Donoghue <ve3tmt@...> wrote: Yes I can hear the UHF signal quite well on my handheld. But no output power shows on the 847's meter. This is probably the pre-drive signal I'm picking up. |
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Re: Schematics?
Do you have a vhf/uhf handheld? Use on same frequency, with a carefully positioned screwdriver tip on the input of the driver block. Will give a rough idea if you have drive to module. By going on the output of module, you should be able to see if? it is working. On Tue, 12 Jul 2022 at 14:53, Andrew Lenton <a@...> wrote:
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Re: Schematics?
¿ªÔÆÌåÓýNo That is a network analyser, as it has reflection ports and through ports, it is not a spectrum analyser, they are different. ? 73 ? Andrew ? From: [email protected] [mailto:[email protected]] On Behalf Of Max Donoghue ? Looks about the same as what I have... |
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Re: Schematics?
¿ªÔÆÌåÓýAh in that case, buy one of the those small software defined Spectrum analysers, and a few SMA adapters so you can put a scoop probe on it! Look at the single input on the VHF side the UHF will or should be a similar level! ? 73 ? ? ? ? Andrew ? From: [email protected] [mailto:[email protected]] On Behalf Of Max Donoghue ? I don't have a lot of test gear. Multimeter, small portable scope from Amazon and a NanoVNA. |
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Re: Schematics?
¿ªÔÆÌåÓýTrace the signal paths, to the TX PA ? From: [email protected] [mailto:[email protected]] On Behalf Of Max Donoghue ? Thank you Andrew, will do. |
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Re: Schematics?
¿ªÔÆÌåÓýAh That Kingston, not the one 12 miles from me here in Hampshire ! ? This should help, check the drive and the VCO locking they do drift out of lock ? 73 ? Andrew ? ? ? From: [email protected] [mailto:[email protected]] On Behalf Of Max Donoghue ? Hi Andrew, |
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Re: Schematics?
Howdo. When you say you resoldered the leads, was that the leads on to PCB, or taking the top off the module and resoldering internally? I had a problem with a VHF PA that turned out to be a bad solder connection on an inductor. DC one side of inductor leg one side of PCB, but not the other. It was a bad connection to copper.? On Tue, 12 Jul 2022 at 12:59, Max Donoghue <ve3tmt@...> wrote: Hi Andrew, |
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Re: Couple of questions
Any external speaker should sound better than the internal speaker. In the old days radios were designed with large speakers pointing forwards towards the users earholes. Nowadays they fit tiny speakers anywhere they can. Or is that just a ploy to get owners to buy? overpriced extension speakers. I use a bookshelf speaker, that is around the same size as 847, it was one of two off Ebay at ?25 the pair.? If I was really worried, I would put a Yaesu sticker on it. On Sun, 10 Jul 2022 at 14:09, Max Donoghue <ve3tmt@...> wrote:
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Re: File /FT-847 Mods/TCXO_9 mod FT847 ON6AB.pdf uploaded
#file-notice
I tried this mod with a chinese TCXO. The HF? stability was better, but on VHF transmit I had a very large buzz with my signal.I tried decoupling, different regulator, everything I could think of. I ended up removing it. You would be better to wrap the crystal in some foam, as it sits in the air stream from fan. Andy On Sun, 10 Jul 2022 at 21:45, rafael_mota via <rafael_mota=[email protected]> wrote: It is not clear in figure 5 where's Q1022, also description says to solder Gnd from the tcxo into pin 1 of Q1022, but also says to solder it to pin 4 of the same Q1022Can''t do the mod. |
Andy Bosworth
Andrew Lenton
