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 Post subject: FY6600 sweep generator
PostPosted: Oct Thu 18, 2018 11:19 pm 
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Joined: Sep Tue 12, 2017 3:04 am
Posts: 138
Location: 251 Moon Lane Spring City, TN
I have maybe a dumb question. If my new sweep generator sweeps from 10mS up. What frequency does the SG's channel 1 to channel 1 of the O scope need to be?

I swept a FM radio from 10MHz to 11MHz at .01 seconds to Channel 2 of the O scope, while injecting 60 hz from the 2nd channel of the SG to Channel 1 of the O scope. The result was almost what I'm looking for in the XY mode on the O scope but since The SG will not do a 0.016666 second sweep. So, I'm kind of stuck.
I've done this successfully with my Eico 369, but would like to try it with the FY6600 SG.

Thanks


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 1:16 am 
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Location: Liberty, Missouri
Where does one find information on your FY6600 generator?

Basically with the scope in X-Y mode, the generator's ramp (or AC sweep signal in the case of the Eico) goes to the "X" channel. You adjust the "X" channel controls so you have a horizontal sweep line from the left end end to the right end on the scope's display.

You then apply the detected sweep signal to the "Y" channel, and adjust the "Y" channel controls as needed.

The sweep "speed" doesn't matter to the scope when its in "X-Y" mode.

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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 1:58 am 
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Joined: Sep Tue 12, 2017 3:04 am
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Location: 251 Moon Lane Spring City, TN
Here's the manual http://gotronik.pl/img/FY6600_Series_Users_Manual.pdf

Although I get a good 'S' curve with the Eico, the FY6600, doesn't seem to want to sync up. But I'll just set the X to 60 hz and fiddle with the Y controls a bit more.


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 3:26 am 
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Location: Seattle WA US
Suggest your Eico 369 Sweep Generator is far better suited for radio sweep alignment tasks than your new 6600 Function Generator. If you put the FY6600 on a warm dry shelf, you will find a use for it someday.

-Chuck K7MCG


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 10:55 am 
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Joined: Nov Wed 30, 2016 7:35 pm
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Location: Sunbury, Ohio 43074
Quote:
FY6600 sweep generator

Using your FY6600 to do radio alignments is roughly equivalent to using an atom bomb to dig a fence post hole. Worse actually... with the a-bomb, all you have to do is push one button. With your FY6600, you need a degree in button pushing to get it to do the simple things. I'm sure it handles the complex very well though :)

+1 to using your Eico for the radio... it is much better suited, and more than adequate.

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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 12:25 pm 
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Location: Liberty, Missouri
There seems to be no sweep ramp output, or in their parlance "VCO Control voltage output" on the unit, Therefore you don't have any "X" signal for the scope. As Chuck said, put it on a shelf and use your Eico.

Image

Above is the signal you need to apply to the "X" input of the scope, and the unit you chose apparently doesn't have that signal available. Strange they wouldn't include that output, as its a pretty basic necessity for any sweep display. This is a case where it would have paid to read and understand the user manual before you bought.

If you want to precisely sweep radio IF strips I'd suggest you get an HP-3336C, or a standard signal generator that has provisions for DC control of it's FM modulation function, such as an HP8640, or 8657 or similar.

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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 5:19 pm 
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Joined: Sep Tue 12, 2017 3:04 am
Posts: 138
Location: 251 Moon Lane Spring City, TN
Thanks Mike. The fy6600 will allow you to upload wave forms. I'll tinker with the shape and see if I can make it work. Guys this is just a tinker and learn thing. As said I have an Eico 369, but want to explore other methods. Helps me understand how this stuff works.


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Fri 19, 2018 11:44 pm 
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Bravo JH! I admire your desire to experiment with the FeelTech (BTY, I think the Chinese should have conducted a Western focus group before picking that name ... does not inspire confidence!); it seems like a lot of generator for the $85 bucks, and it's worth putting it to work on your radios. First off, my comments are based on the fact that I have 23 signal/function generators of various vintage in some weird collection, and if you don't consider that some sort of sickness, I assure you that it is. Second, I don't own a FeelTech, so I'm going strictly by the manual. As I see it, you have several ways to set the up for FM alignment:

1) As Mike mentioned, the FeelTech does not have a ramp/sawtooth output corresponding to the start and end of the sweep. The ramp is necessary to provide the X-input sweep signal for your scope when in the X/Y mode. Instead, the generator provides a short sync pulse out the back at the start of each sweep period. However, you can take the scope out of X/Y and put it back into the normal operational mode, put the radio response signal into CH1 and the generator SYNC signal into CH2, with the scope sweep trigger set to CH2. Adjust the scope horizontal timing so that the sync signal appears only at the left and right edges of the display, and you'll be looking at the radio response on CH 1 over one period of the generator sweep, similar to a traditional X/Y display.

2) Set up the generator for your sweep on CH A, and connect the SYNC OUT to SYNC IN to externally trigger a ramp/sawtooth on CH B (set up at the same frequency as your CH A sweep time, external trigger). That way, you should get a ramp output on CH B that corresponds to the start and end of the sweep. Then set up the scope for X/Y mode, as usual. Incidentally, I tried this on a 2-channel Rigol generator, but it turns out that the Rigol cannot be externally triggered or swept on CH B ... I'm not sure if the FeelTech is the same.

3) Use the FeelTech VCO input; it will vary the frequency at CH A according to the signal applied at the VCO. So, try setting up a ramp/sawtooth of say 60 Hz & 0-5 Volts from CH B and feed it into both the VCO input and the scope X-input. Set CH A up for your sweep, but using VCO (this will take some fiddling, I'm sure, as I'm not sure of the exact setup procedure on the generator). Scope in X/Y, with the radio response in Y-input and the CH B ramp into the scope X-input.

Long story short (although WAY too late for that now), I think you can make this work and have some fun doing it. There is some local resistance to using a function generator over a signal generator for radio alignments, due primarily to the former's lack of shielding, comparatively high output levels, and perhaps stability specs. But if you're only working with general broadcast AM & FM radios, my opinion is that the FeelTech is more than up to the task.

Good luck, and check back to let us know how it goes.

Jim


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Sat 20, 2018 1:01 am 
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Joined: Sep Tue 12, 2017 3:04 am
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Location: 251 Moon Lane Spring City, TN
Thanks Jim. Working on old radio's and equipment is fun, but learning what's going on is even more fun for me. Sounds like you're just the one to get me on the right track.
Josh


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Sat 20, 2018 1:54 am 
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Joined: May Wed 31, 2006 6:41 am
Posts: 255
I have the same signal generator. It can do lost of things.
In this case you can internally modulate in frequency the channel a with the channel B. set a ramp on the channel B and a sine on the channel A. connect the channel B of the signal generator to the X channel on the oscilloscope.
With the mod button it give you a a lot of options to modulate channel a with channel B. or to modulate with an external source


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Sat 20, 2018 3:24 am 
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Joined: Sep Tue 12, 2017 3:04 am
Posts: 138
Location: 251 Moon Lane Spring City, TN
DRL wrote:
Bravo JH! I admire your desire to experiment with the FeelTech (BTY, I think the Chinese should have conducted a Western focus group before picking that name ... does not inspire confidence!); it seems like a lot of generator for the $85 bucks, and it's worth putting it to work on your radios. First off, my comments are based on the fact that I have 23 signal/function generators of various vintage in some weird collection, and if you don't consider that some sort of sickness, I assure you that it is. Second, I don't own a FeelTech, so I'm going strictly by the manual. As I see it, you have several ways to set the up for FM alignment:................................Good luck, and check back to let us know how it goes.Jim


Here's a little report on the FY6600:
Sync Out=is a 3.4 vpp square wave that follows Channel 1's frequency setting
Sync In= ????? I've injected several signals and got no change on either channel......................Yet. This might sync the phase, as I now think about it.
VCO In= Using another signal gen, I got it to vary the sweep signal (Channel 1). Amplitude of the signal also changed the sweep some, still sorting that out.

I've tried each of your suggestions, but have failed to get a swept S curve........yet. I'll try again later and see if I misread something. Thanks for the help.
Josh


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Sat 20, 2018 4:00 am 
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Joined: Sep Tue 12, 2017 3:04 am
Posts: 138
Location: 251 Moon Lane Spring City, TN
Well Jim, I rethought the process and the #1 hookup you suggested and this time got an S curve. With no trace blanking, it kind of leans a bit, but is pretty clean. You can even see the stations roll up it as you move the tuner. I'll do a little more thinking and try the other methods that you and alfonsol suggested.
Wonder if a marker can be worked into this?

EDIT: Gosh I'm tired! I meant the #3 method with the VCO. The reason I think it didn't work earlier is I had the voltages too low on Channel 2.


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 Post subject: Re: FY6600 sweep generator
PostPosted: Oct Sat 27, 2018 5:13 am 
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Joined: Sep Tue 12, 2017 3:04 am
Posts: 138
Location: 251 Moon Lane Spring City, TN
Well Jim fueled me with the needed ideas to solve the FY6600 problem to get a S curve to align a FM radio. This took some tinkering, but Jim offered that I reduce the injection voltage into the radio from Channel 1. Here's the settings that worked.
Feeltech Channel 1, Wave=sine, Voltage=0.25 AND connected through a PI resistor network attenuator made of two 300 ohm to ground and one 51 ohm resistors, no other settings adjusted since they will be controlled in the Sweep menu, Channel 1 connected to the antenna of the radio though a capacitor
Feeltech Channel 2, Wave=Ramp, Voltage=15, Frequency=30 to 100 Hz, Channel 2 connected to the VCO on back of the SG and also to the X (ch1) of the Oscilloscope.
Feeltech Sweep Menu, Start=10.3 MHz, End=11.1 MHz, Source=VCO, Sweep=frequency, Mode=linear , Direction=forth (backwards) or set Ch2's Ramp to reverse (gives a clear S curve in my case)
Oscilloscopes Y(channel 2) connected to the output of the radio, in my case the audio amps output. Seems to me an old analog scope works better than the digitals.

This seems like a lot of stuff but actually is easy and quick to setup. My #1 problem with this SG is when you power down, you have to set it all back up again. And you can't change the defaults.

I used it to readjust a FM radio I use for testing on my bench. This radio is a little picky and the FY6600 did a good job. Jim also suggested adding a marker from another none sweeping SG, by just laying the wire near the output to the O'scope. It worked great.


Attachments:
File comment: Before Adjustment showing marker
before adjustment.jpg
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File comment: After Adjustment
Upload to ARF.jpg
Upload to ARF.jpg [ 83.92 KiB | Viewed 1466 times ]
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