#1
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I need a sweep generator
I was looking at sweep generators on eBay. I need one that
covers the 22 Mhz band as well as more moderm 42 Mhz. I don't need anything great ... I can use my synthesizer for markers if needed for accuracy. What's good, cheap, and (if tube, recapped) reliable? Good is relative. Doug McDonald |
#2
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eico 368 or 369. I use a modern freq counter to confirm the freq from the unit.
they are pretty cheap, but will need recap and prob calibraion of the markers. For 44mhz I like the BK 415 http://www.youtube.com/watch?v=MOnXtzeAePE Last edited by DaveWM; 06-06-2014 at 02:27 PM. |
#3
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I bought a 368. I figured I could convert it to post-injection for nothing, using a dual-trace scope. I was right.
However, getting it to work was a bitch. This particular gizmo must have been a very adequate tool in its day ... it has been very very heavily used up until the late 70's, as it had a couple of Nichicon electolytics in it and the areas around the dials were worn. Recapping the rest was easy. One vernier mechanism was broken and the front had to be removed to get to it. Then it worked. But the AGC system didn't work and the marker generator was flaky on the top band The AGC problem was a completely open 4.7 meg grid resistor. The flaky markers were caused by poor solder joints on the wires connecting the variable cap and its coils. To make a post-injection output I reversed the flow on the coax that connects the sweep output to the marker generator panel jack and made the circuit I attach. It works OK. You connect it to the second channel of your scope. Values are quite non-critical, but you need very fast low capacitance diodes. Last edited by dtvmcdonald; 07-01-2014 at 09:24 AM. |
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