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WANTED: Yaesu TCXO-9
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Matt,
I experienced in the past the tcxo failed to oscillate due to component aging. I corrected the issue adding a smd resistor at emitter of oscillator transistor, doubling the bias current. Another possible cure is to play a little with the two cap values of the colpitts feedback network. I know it is small? but with a little of pacience you could succeed. Giuliano IV3DLW? Ps: the clones I have seen contains? ?a PLL inside? and put out a dirty signal with visible harnonics and maybe also? phase noise. Impact on tx purity and rx dynamic range is not unknown, not measured. |
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You can get a knock-off from Aliexpress, probably not as good as the Yaesu one but I'll bet better than the original one that came with the 857. John VE7KKQ On Sat, Oct 28, 2023 at 7:08?AM Mike <mjtdk@...> wrote: Matt, well sorry to hear that they are no longer supporting those parts for the 857 as I have 3 of them. If you are having problems with yours's I would try one of the crystal-controlled ones as I use them in my radios with no problems at all. |
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The issue with the Chinese TCXOs is that they are actually programmable PLL oscillators and have more distortion to the waveform than a single crystal would.?
This means that the RMDR or mixer noise might be higher and cause an issue under some specific conditions. Personally I have used these a good bit and I am not smart enough to figure out how they affect the signal nor how to detect the difference if I knew. The idea is that these are more stable than the original reference oscillator and they are. I have been happy with these installed in a Yaesu 857D and a Kenwood TS590SG. They are cheap enough to not lose much sleep over it and keep the old crystal if you want to put it back in. |
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This is a guess on my part as I've no interest in delving into the "how it works", but I'm pretty sure that the TXCO improves the stability of frequency generation circuits, I do know that for time sensitive modes like FT8, a TXCO for any rig is not wasted money and only improves communications/enjoyment. I have yet to put my 817/57 (a Chinese TXCO in each) on FT8, but once I get my "mobile Hustler 6BTV" installation up and running, I'll be giving it a go. A brief description of my "mobile Hustler 6BTV". I live in what you folks down south call an HOA, we call it a Strata, similar but not quite the same but in common, no visible antennas save for sat dishes. I have been eyeing up the rain gutters... Anyway, you can probably figure out what I am doing, I bought a used bike carrier that fits the 2 inch receiver on my vehicle, I cut the bike carrying part off and now left with a vertical post. The 6BTV will be mounted to this post, I got a very good deal on about 100 feet of aluminum window screen, this will be cut into a few 12 ft lengths to act as a ground plane. I'm really looking forward to operating again, I'm just not looking forward to tuning the antenna as it is getting pretty cold out of late and snow has already made an appearance. John VE7KKQ On Sat, Oct 28, 2023 at 7:54?AM J.D. Barron <jeter.d.barron@...> wrote: The issue with the Chinese TCXOs is that they are actually programmable PLL oscillators and have more distortion to the waveform than a single crystal would.? |
¿ªÔÆÌåÓýIf you're going to all that trouble, why don't you just buy an ATAS so you can automatically tune it?? I replaced Hustlers after 50 years on my mobile and wish I had done it sooner!? Ron Jakubowski, K2RJ? Tab? S9 |
¿ªÔÆÌåÓýIf you want a good mobile antenna get the Little Tarheel ll they tune from 80 meters to 6 meters. ? tarheelantennas.comBest Regards Hanford R. Wright ? WA4LZC CCA # AC11-12590 On Oct 29, 2023, at 08:08, Ron Jakubowski via groups.io <k2rj@...> wrote:
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HIRO, JJ1FXF
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