BK Precision Dynascan Corporation 2005

[saturated]

Hello gentlemen and ladies hope you are having a wonderful evening.

Being an (OLD) noob I wanted to get a signal generator that presumably (sorry still learning) would modulate rf with af.

I already had this af unit and it has been rock solid



However delving into the realm of rf I began googling and reading tons here and well ya know wow I love all the old boat anchors and toob stuff but i wanted to try to give myself some advantage (I still drool over looking at pics and videos of HP-606 units and may still get one some day )

However back to the present I wanted something simple and solid state for sure. Of course I also drooled over the big HP-8640 and consecutive technology but I didn't want to get stuck with something big heavy expensive and in need of repair.

So here we are.

Just trying to comprehend fundamentals I was like man just try to get an rf signal on your scope and then modulate it and then revel in your technological achievements while eating a burnt grilled cheese

So I got this for a pretty good deal (I think) yes I know it's not NASA or FCC certified it's just something I can play with

It looked hella nice in the pics I asked the seller if they had the power cord because the socket looked weird they said no then made me an offer so I took it

When I got home from work it was on the porch and I went to my stash of power cords and found one that fit and it powered up.



So maybe this ain't right (neither am I) I took the easy way out and just connected it BNC cable straight to the scope. With everything turned down low

Anyhow I couldn't get a damn thing out of it finally just touching and switching the range knob I got some signal (woot)

So I put it on 10.7 Mhz



So I thought oh hell yeah envelope here we come I started to add modulation but all it does is add little pointers to the peaks dag nammit



Anyhow I don't know anything this is kinda where I'm at with all of this



But it's a start at least I have something real and actually putting my hands on it

Down the road I'll probably see this and go hmm yeah the reason you don't have a nice pretty modulated envelope...

 

[saturated]

Meanwhile I tried some external modulation



Still not being rewarded with a (wave packet ?)



EDIT
went back and read the manual (ya think?!?)
I think I need something called a 50 ohm termination

 

[nomadradio]

To look at the audio modulation envelope you need to turn the sweep speed down to a more audio-friendly speed. It has to be really fast to see the RF waveform. To see the modulation envelope try 20 mS per div. The RF will just be a blur, but the modulation will be more legible.

73

 

[saturated]

Yes sir thanks nice to hear from you this will be a nice project

 

[Cable Guy]

They show you, in the books, what the rf looks like being modulated, but they seem to show a very low rf frequency being modulated so you can see how the amplitude of the carrier changes at an audio rate. I'd guess if you looked at a 5-10 Khz carrier modulated with a 1 Khz tone, you would see what the book shows. If looking at 27 megahertz rf signal, the carrier is a blur but the modulation is highly visible with the slower timebase. Increase the timebase to see the carrier clearly, the modulation becomes blurry.

 

[saturated]

Hi guys just a bump to shout out for Mr Nomad and Mr Cable
Because they were right....not that I doubted them

Anyhow finally got back to this and got some results

Honestly mostly twiddling knobs until I got what I wanted which isn't perfect but oh well



The above was internal modulation one kHz I was still disappointed I couldn't see the wavy lines inside the packet so I hooked up some external modulation and tried a lower audio frequency but really to no avail



I took pics of what looked acceptable because wow I could get some really weird looking stuff

Another benefit of doing stuff for real what was crazy while I had the generator switched to internal modulation I went to hook up the external af generator (which wasnt even turned on) and when I made the connection the picture on the scope went to complete crap again.
Which I really have no excuse for but maybe it points out to me the rf is all around and is gonna escape or get in no matter what or do it's damnedest

 

[Cable Guy]

Hi guys just a bump to shout out for Mr Nomad and Mr Cable
Because they were right....not that I doubted them

Anyhow finally got back to this and got some results

Honestly mostly twiddling knobs until I got what I wanted which isn't perfect but oh well

View attachment 77104

The above was internal modulation one kHz I was still disappointed I couldn't see the wavy lines inside the packet so I hooked up some external modulation and tried a lower audio frequency but really to no avail

View attachment 77105

I took pics of what looked acceptable because wow I could get some really weird looking stuff

Another benefit of doing stuff for real what was crazy while I had the generator switched to internal modulation I went to hook up the external af generator (which wasnt even turned on) and when I made the connection the picture on the scope went to complete crap again.
Which I really have no excuse for but maybe it points out to me the rf is all around and is gonna escape or get in no matter what or do it's damnedest

That looks about right to me, the generator isn't modulating that rf to 100%. It's looks only about 30% modulated. To see the rf portion, crank that right-hand knob to the right. Some generators allow you to select the modulation percentage.