Hey Garey, did you mean uF or pF. Richrd is quite certain you really meant pF.
Chuck, K1OM On Thu, Feb 25, 2010 at 2:38 PM, Garey Barrell <[email protected]> wrote: > Richard - > > OK. That 0.005 cap isn't particularly critical. The 1000 ohm resistor is > the load, the cap is just to prevent shorting the DC to ground. Any disc > ceramic from 0.001 to 0.01 uF at 500V or more would work just fine. > > I wouldn't worry too much about the calibrator. As long as someone hasn't > twisted on the trimmer cap it's plenty close enough. > > > 73, Garey - K4OAH > Glen Allen, VA > > Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs > <www.k4oah.com> > > > Richard Palmer wrote: > >> Garey, >> >> I have cleaned my eBay TR-4. Replaced two tubes, V1 &V20. Along with >> tightening up the ps connector pins and probably some other small forgotten >> stuff it seems to be working nicely. Although I still have yet to make >> "first contact". I thought I'd go through the complete alignment procedure >> to check and adjust as necessary. >> >> ( I thought I had a source for two 0.01pF capacitors from Allied but their >> web site ordering is worse than crap. I called them and to my disbelief >> still more crap. So I'm still looking for some caps to get the 0.005pf for >> the alignment procedure.) >> >> That's why I asked about calibrating the calibrator. I don't suspect any >> problem... just want to check all the settings. >> >> Richard Palmer >> KB8NXO >> >> >> Garey Barrell wrote: >> >>> Richard - >>> >>> Do you have ANY receiver aside from your TR-4? It doesn't have to have a >>> BFO or be particularly stable or sensitive. >>> >>> If all you have is a Broadcast Band table radio, see if you have a >>> commercial station on an even 100 kHz frequency such as 700, 800, 1200, etc. >>> It doesn't have to be local, in fact best if it isn't too strong, and the >>> higher the better. Get it close to the TR-4, and possibly wrap a turn or >>> two of wire around the calibrator tube, bringing the other end near the >>> broadcast receiver antenna. Turn on the calibrator and adjust your wire >>> until the calibrator signal is about the same strength as the BC station, >>> then adjust the calibrator until the signal is at zero beat. Adjust as >>> carefully as you can, if the signals are near the same strength you'll >>> actually be able to hear a slow variation in amplitude when you're within a >>> few Hz of zero. >>> >>> This is far from ideal, but BC stations are very accurate. When you >>> calibrate at 10 MHz, you are comparing the 100th harmonic of the calibrator >>> to a known frequency, whereas with a broadcast station you're only at the >>> 10th harmonic on a 1 MHz BC station. But plenty close enough for our >>> purposes. >>> >>> Better still is if you can borrow a receiver that covers 10 or 15 MHz, >>> and if you can resist adjusting the calibrator, they stay correct for a LONG >>> time. In fact, unless someone has been "adjusting" it, it's probably close >>> enough! >>> >>> 73, Garey - K4OAH >>> Glen Allen, VA >>> >>> Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs >>> <www.k4oah.com> >>> >>> >>> Richard Palmer wrote: >>> >>>> The manual says to tune to WWV ect.ect. I'm assuming this is 10Mc. . Can >>>> I use a signal generator set to 10Mc. and accomplish the same desired >>>> result? I have neither of these and must buy what I need to skin this cat. >>>> Any suggestions? One caveat... it must be inexpensive. >>>> >>>> Thanks in advance, >>>> Richard Palmer >>>> KB8NXO >>>> >>> >> > _______________________________________________ > Drakelist mailing list > [email protected] > http://mailman.zerobeat.net/mailman/listinfo/drakelist >
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