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Self Osc Problem
On May 25, 2:31 pm, Jack Schmidling wrote:
I thought the "Masonite shielding" would suffice for a smiley. It did - I just didn't want to spend the next 3 weeks figuring out how to put one in.....(bloody computers) And thanks for the explanation - I didn't see the 807 socket, and didn't know there was a VR150(was it?) in there as well. And the extraneous tuning stuff to the left, well, now I know its for a VFO. (Gee, voltage regulation - thats getting fancy - yes, the dropper resistors do run stinking hot, don't they....) Strangely enough, theres a fault in human design in that the nerve endings that detect heat are a lot bloody slower than everything else - by the time we figure out its too hot, the damage is done.... And must admit to wallowing in nostalgia - mine attempts were similar, and probably oscillated all over the place as well - BUT without virtually any test gear, (or knowledge) it didn't seem to matter - there was no one to complain anyway, the bands were virtually empty except for other manic experimenters, TV was black and white, and broadcast was AM. Nothing else to get into - and the bands were harmonically related so we we're QRM other hams anyway....2m was the outer frontier anyway, there was NOTHING used above that.... How about a photo of the latest metal attempt? - remember, if it looks nice and neat, it doesn't really matter if it don't work too good.... I have things here I am not game to connect to the spectrum analyser - don't want my dreams shattered toooo quickly.... but getting back, more and more, into the older stuff - partly fading eyesight (I cant see u-mini smd ic's) and besides, theres something comforting about the warm glow of valves in a dark room, the crash of static from the other side of the world, the thrill of hearing someone on air from an exotic National Geographic land...the reasons we got into amateur radio in the first place.. The bands here at the moment are a total write off everywhere - 80m is S9 noise, the rest not much better. QRM, QRN wall to wall. So, I sit here and type on a keyboard, I guess its still "hamming" after a fashion... That was my first attempt at a wooden chassis and it became obvious why metal is better and I abandoned it a few weeks ago. Yep. Tubes with gain killed wooden chassis..... It started out xtal controlled but then I got the bug to add a VFO which is the crap on the left. The 807 turned into an 866 so I substituted the 6146 till I got another 807. The missing meter was a hamfest special that bounced so much it was useless and then crapped out completely. Hah! - silly man - NOW you have to get the VFO stable, as well as all the other problems. And as for 807's - I think about 90% of the people reading this will have some sitting around, just waiting for the "magic moment" of inspiration. Good On Ya Jack - your doing it - good luck! And the magics still there, even after 30 plus years of experimenting........cant be killed by the internet, store bought gear, mobile phones - all those glittering toys that didn't even exist exist when we started out..... And I got boxes of hamfest meters that are probably crappy too - haven't tried to use them yet, so don't know. Finally built myself a rough tube tester a few weeks ago (I had to, trying to find working tubes for a VERY elderly Yaesu FTDX400) It's been a challenge. I made a simpler version of this as a kid and am sort of re-living my childhood. It's like a Mr Wizzard Science project for me. I am now plagued with real test equipment and can't play "ignorance is bliss". Yep. Its a real PITA that - we cant delude ourselves our home brew QRM generators are not what they are.....still, its an excuse to use some time creatively....... 73 de VK3BFA Andrew. |
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