The best and simplest informative demo and explanation I have seen online as of yet. Sweep alignment is the most impressive technique I’ve seen , but cumbersome and complicated for the beginners. Over the years fir me the best and quickest method used a 455 kc modulated signal and a Simpson 260 VOM on the output function in the AC mode. The difference in final results is very small with no reception level of the radio. Your explanation was excellent ! I am old timer at this and the sweep dem does give one a much better understanding of the heterodyne concept. Thanks once again for showing is how.
Thank you. I agree with your assessment yet I get asked time and again to demonstrate sweep alignment. It has been quite a while since I touched on this topic and I hope to record an update soon. Perhaps when I get my Radiola 60 going. I think it's very worthwhile to go over the basics periodically.
You have just answered two of my questions in one video. How to get a marker up How to make a demodulator probe. As always a great explanation. Cheers mate!
@bandersentv Thanks for answering all my dumb questions. I read them all, appreciate it.. Only complaint, could have used these videos 2 yrs ago, ha ha; when I was learning there was almost no info on it. Saw the Wavetek on the shelf. I had a 1080A, nice but two issues: 1) Built-in proprietary markers (in mine) were no where near what I needed for radio or TV. 2) Only goes down to 1 Mhz as you say. My "A" model was good, but 1080B models have a history of bad "black" caps. It can be repaired.
I'm dumbfounded how nice your WR50B is working. Mine did not have linear amplitude. The sweep rate (line) was not linear either or in sync with scope. You have a great presentation. BTW I call the pip a BIRDIE marker, since it looks like a bird flying at you flapping it's wings (at least how artist draw it as a squiggly line). You don't use a FREQ COUNTER? I found old tube signal gens are kind of out of calibration from the dial, ie very approximate. Again nice vids. Want to see the WOBBULATOR!
I use 10.7mhz and 455khz crystals in my RCA WR-50B. When used in the 455khz or 10.7mhz sweep mode, you see a perfect little blip right in the center of the trace. I paid $30 for the 455khz crystal. These are like gold now. Although the WR-50b accepts external modulation, it does not have an input for an external marker. Too bad!
Nice explanation. Good clean video presentation. I agree with gmcjp. The sweep is perfect. Better than my Sencore. That unit must have been rebuilt recently. The scope is nice as well. I only work solid state FM units. I would like to get a new scope as my old Hitachi is only 60mhz. What do you think about the new digital scopes?
By the way I looked in the manual for the RCA for the specs in the crystals and found a guy on eBay who had several and made me the others including the 555. Cost was like $10
@bandersentv I recently acquired a WR-50B and I have a few questions: 1.) I'm getting about 55VAC between the WR-50B's ground clip and anything grounded. (Highlighted with the fact that any time I clip it to something I see sparks). I've recapped it, and replaced the 1N3756 rectifier with a 1N4007 and nothing has changed. Is this normal? 2.) when I have it on sweep mode, the wave form is uneven. The beginning of the sweep is bent up, and the end is bent down. But, interestingly, when I connect the scope probe to the wiper pin of the RF attenuator (effectively eliminating the .001uf capacitor in the plastic shell), the waveform stabilizes and looks like what's in your video. Any thoughts?
+X5Industries There are .01 uF caps between either side of the AC line and the chassis. That's likely causing the voltage and sparks. You could try disconnecting them and see if the sparks stop. If so, reconnect the caps and don;t worry about it. I'm not sure about that .001 cap. It's been over five years since I made this video and my memory is a bit foggy. Try asking on the antique radio forum.
@umajunkcollector Don't waste your money on a PC scope. If you just want to GOOF they have some semi free share ware deals. If you want to get serious, find a used analog scope if working on radios. For digital a storage scope might be better. You get what you pay for, and those PC scopes have low bandwidth; when you add up the cost they are expensive for what you get. Get a used scope for $50-$200, very nice. Do some research or PM me.
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The best and simplest informative demo and explanation I have seen online as of yet. Sweep alignment is the most impressive technique I’ve seen , but cumbersome and complicated for the beginners. Over the years fir me the best and quickest method used a 455 kc modulated signal and a Simpson 260 VOM on the output function in the AC mode. The difference in final results is very small with no reception level of the radio. Your explanation was excellent ! I am old timer at this and the sweep dem does give one a much better understanding of the heterodyne concept. Thanks once again for showing is how.
Thank you. I agree with your assessment yet I get asked time and again to demonstrate sweep alignment. It has been quite a while since I touched on this topic and I hope to record an update soon. Perhaps when I get my Radiola 60 going. I think it's very worthwhile to go over the basics periodically.
Thanks again for another of your excellent teaching videos. You have no idea how appreciated they are.
You have just answered two of my questions in one video.
How to get a marker up
How to make a demodulator probe.
As always a great explanation. Cheers mate!
You answered most of the question I had. Very informative video, also enjoy you restore projects.
Good information. Thank you.
Very informative and very well done.
Thanks, I'm glad you enjoyed it.
Thanks, I'm glad you enjoyed it.
@bandersentv
Thanks for answering all my dumb questions. I read them all, appreciate it.. Only complaint, could have used these videos 2 yrs ago, ha ha; when I was learning there was almost no info on it. Saw the Wavetek on the shelf. I had a 1080A, nice but two issues: 1) Built-in proprietary markers (in mine) were no where near what I needed for radio or TV. 2) Only goes down to 1 Mhz as you say. My "A" model was good, but 1080B models have a history of bad "black" caps. It can be repaired.
I'm dumbfounded how nice your WR50B is working. Mine did not have linear amplitude. The sweep rate (line) was not linear either or in sync with scope. You have a great presentation. BTW I call the pip a BIRDIE marker, since it looks like a bird flying at you flapping it's wings (at least how artist draw it as a squiggly line). You don't use a FREQ COUNTER? I found old tube signal gens are kind of out of calibration from the dial, ie very approximate. Again nice vids. Want to see the WOBBULATOR!
I use 10.7mhz and 455khz crystals in my RCA WR-50B. When used in the 455khz or 10.7mhz sweep mode, you see a perfect little blip right in the center of the trace. I paid $30 for the 455khz crystal. These are like gold now. Although the WR-50b accepts external modulation, it does not have an input for an external marker. Too bad!
Great video thanks
Very nice info. How will be to know the bandwidth for a Crystal ssb filter???
Nice explanation. Good clean video presentation. I agree with gmcjp. The sweep is perfect. Better than my Sencore. That unit must have been rebuilt recently. The scope is nice as well. I only work solid state FM units. I would like to get a new scope as my old Hitachi is only 60mhz. What do you think about the new digital scopes?
Very interesting! Could the Heathkit probe schematic you showed be suitable for use in a Eico 150 transistorized circuit tracer?
excellent
By the way I looked in the manual for the RCA for the specs in the crystals and found a guy on eBay who had several and made me the others including the 555. Cost was like $10
@bandersentv I recently acquired a WR-50B and I have a few questions:
1.) I'm getting about 55VAC between the WR-50B's ground clip and anything grounded. (Highlighted with the fact that any time I clip it to something I see sparks). I've recapped it, and replaced the 1N3756 rectifier with a 1N4007 and nothing has changed. Is this normal?
2.) when I have it on sweep mode, the wave form is uneven. The beginning of the sweep is bent up, and the end is bent down. But, interestingly, when I connect the scope probe to the wiper pin of the RF attenuator (effectively eliminating the .001uf capacitor in the plastic shell), the waveform stabilizes and looks like what's in your video. Any thoughts?
+X5Industries There are .01 uF caps between either side of the AC line and the chassis. That's likely causing the voltage and sparks. You could try disconnecting them and see if the sparks stop. If so, reconnect the caps and don;t worry about it.
I'm not sure about that .001 cap. It's been over five years since I made this video and my memory is a bit foggy. Try asking on the antique radio forum.
@umajunkcollector
Don't waste your money on a PC scope. If you just want to GOOF they have some semi free share ware deals. If you want to get serious, find a used analog scope if working on radios. For digital a storage scope might be better. You get what you pay for, and those PC scopes have low bandwidth; when you add up the cost they are expensive for what you get. Get a used scope for $50-$200, very nice. Do some research or PM me.