Author Topic: LuLu Style Tx's 10W carrier, 40W Peak, with Modulator, Mod Tranny + 6925 XTAL  (Read 11998 times)

ThaDood

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When I noticed some FM on the Radio Systems, I Am Radio (a.k.a. updated Talking House), TX, I grounded the case of the main crystal to chassis ground and that reduced the FM to better than 1/2 of what it was. The 13.560MHz AM Pixie-like TX I have, the main crystal is 13.560MHz (Thank you Fearless Fred on that one!). That crystal is also tied to chassis ground. On FM listening, I really have to crank the volume all the way to just hear it. It's better than any commercial AM TX gear that I have. You might want to give that I try. Where did I get the idea from? Before ICF (International Crystal Manufacturer.), closed up, I asked their engineers if that was a good practice to ground crystal cases, and they recommend that indeed. 
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Stretchyman

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It's grounded already. I've already explained the fming is due to an inductor used to pull the Xtal L.F.

All future LuLus will use an AD9833, hopefully immune from any fming issues.

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