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  1. Miguel Lopez

    Help with aerial for channel 38

    Hello everybody. Hope all of you had had a nice time last week. Happy new year for everybody!!! Well, the antenna worked!!! I built a 25cm round loop and positioned on the roof of my sister house. The antenna is for my sister as I have not acquire the digital decoder yet :(. The reception is...
  2. Miguel Lopez

    Help with aerial for channel 38

    It is not intended to see TV Azteca. It is to see Cuban Digital TV broadcastings that began with Channel 38. Thank you very much. I will consult that site
  3. Miguel Lopez

    Help with aerial for channel 38

    Hello everybody I need some help to build an aerial to tune the channel 38. In Cuba, digital TV has started with this channel and althought I can tune it with the legacy aerial (wide band), I find that sometimes reception is not good, so I thought to build, a specially-built antenna for the...
  4. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Such as Titanic's :D
  5. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Yeah, yeah, but anyway I'm not interested on going back to the future. :D Yes, not funny anymore. That's why I love vintage. Best Regards
  6. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    And finally this is how it looks like on its place of work, on top of my bench. http://www.imagebam.com/image/363e08350684653 http://www.imagebam.com/image/bbfaf7350684654
  7. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Soviet had good scopes, not so good scopes, bad scopes and then the C1-99. I never saw any C1-99 working, despite being the lucky one who extracted about five from the crates (brand new). They showed the beam for a while, and then the beam vanished a few minutes later. Some friends of mine has...
  8. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Indeed it is rotated cause when I took that picture the correction coil was not connected yet. The mu-metal cone has a coil around the neck to correct the trace horizontality against deviations due to the CRT tolerances and the Earth magnetic field. I connected this coil to the 18,9V for heater...
  9. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Here is the front panel. I used the same as in Version 1.0. The markings are made of a photograph, designed in Photoshop and then covered by a transparent plastic piece. Ranges in voltage are [V/div]: 50m, 0.1 0.2 0.5 1.0 2.0 5.0 10 20 50 100 and 200; plus two adittional fixed ranges of...
  10. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    With PSU, CRT, X sweep generator and Y amplifier on their respective places, there's nothing else to do but adjust both time and voltage ranges. On Version 1.0 I used point-to-point wiring and there was a lot of wires eager to get induced noise on them, so this time in order to reduce that mess...
  11. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Thank you very much for your kind words. As somebody would say: "When need must". Now a picture of the scope with both the Y and X circuits on their respective places. Finally I removed one of the valves of the PCB cause X output doesn't need to be simmetric.
  12. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    The sweep generator is triggered by a flip-flop circuit which delivers a pulse synchronized with the input signal. Without signal (DC mode) the flip-flop oscillate at 70Hz (+/-) so starting the sweep on this condition too. The tube is an ECC81 twin triode...
  13. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    The next step is the X amplifier and sweep generator. As said before I used the Telequipment Serviscope Minor circuit with minor changes. The X sweep generator is to the left. Sorry, I took no pictures of the X section alone.
  14. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    We (the Cubans) are friends of everybody who wants to be a friend. Well, the Version 1.0 of the scope was a mess regarding the CRT wiring. That is something I corrected this time, using a PCB. I placed all of the CRT circuit on a PCB located besides the mu-metal cone. I placed directly on it...
  15. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Here are a couple of pictures of the Y amplifier. http://www.imagebam.com/image/6e427d350660247 http://www.imagebam.com/image/fcf075350660309
  16. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    Hi all. Remember that I'm using a cabinet from a Soviet C1-99 oscilloscope, and that the mu-metal cone shielding the CRT is from a C1-83 Soviet oscilloscope. I did not build the cabinet. I just built the chassis, the PCB and the front and rear panel (we will get there) @Steve I didn't used the...
  17. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    The mains transformer is mounted at the last compartment of the chassis; while the other two are intended for the Y amplifier and X sweep generator. The transformer is a Soviet TCA-70 core with factory-made primary and several home-made secondaries. The three big capacitors seen behind the...
  18. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    This is the basic circuit that I used for the HT PSU. I did some changes. Instead of LM317, I used LM7815, and instead of LM329, I used a 15V Zener diode with a 1N4007 in series, for temperature compensating. Resistors are adjusted for my purposes. The circuit is supplied with 340 to 355V DC...
  19. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    The next step, was to build the PSUs. As said before, they are S-S based and mounted on PCB. Here a picture of the PSUs mounted on the chassis. http://www.imagebam.com/image/27db07350660373 And a close-up for more details http://www.imagebam.com/image/953ba0350660208
  20. Miguel Lopez

    Home made valve oscilloscope. Version 2.0

    All rigth, let's go on The first problem to solve was induced noise. To solve this I built a steel chassis, with shielded compartment for the diferent sections. Y amplifier, X Sweep, and Transformer-rectifier-filter are in the upper part of the chassis, shielded from each other by a steel wall...
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