Electronics Lab Philippines

455kHz & 10.7MHz stuff

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #60 on: June 29, 2019, 09:58:36 PM »
So in this 74LVC1GX04 circuit, I replaced the caps with 47pF and I got this:





10.7072MHz which is much better.  But increasing the caps to 68pF lowered the freq to 10.669MHz which silenced my radio tuned to DZRJ 3-meters away from my workbench.  DZRJ is at 100.3MHz on the FM dial.

Offline bravokilo

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Re: 455kHz & 10.7MHz stuff
« Reply #61 on: June 30, 2019, 11:27:38 PM »
congratulations!

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #62 on: July 01, 2019, 09:11:42 PM »
This is for you BK.
27.125MHz crystal with 33pF caps on each leg to GND.
Everything else is the same on the circuit.



Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #63 on: July 01, 2019, 09:17:34 PM »
Well lookie here,,,, what have we got!??
I'm surprised to see a very nice sinusoid waveform- 27.1251MHz


Offline bravokilo

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Re: 455kHz & 10.7MHz stuff
« Reply #64 on: July 02, 2019, 05:06:42 PM »
Yipeeeeee!

Offline bravokilo

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Re: 455kHz & 10.7MHz stuff
« Reply #65 on: July 02, 2019, 05:15:21 PM »



Now try this. any NPN tranny will do. For your choke, a 10 uhy will work. If you do not have choke, wind 8 turns on a 8mm coil form and put a 30pf across the coil. That will serve as the choke. Check the F on the collector. Use the 27.125 MHz crystal you have.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #66 on: July 04, 2019, 08:22:18 AM »
Please go to this topic to see BK's 27MHz Oscillator:
http://www.elab.ph/forum/index.php?topic=52171.new#new

Offline bravokilo

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Re: 455kHz & 10.7MHz stuff
« Reply #67 on: July 04, 2019, 09:13:22 AM »
Yahoo!

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #68 on: November 19, 2020, 09:14:18 AM »
I'd like to get back to this topic.  Sad to see that most the photos are gone.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #69 on: November 19, 2020, 03:53:36 PM »
Just received this this afternoon.  Just in time for this topic:



I ordered it from Shopee on Nov 12 so it took only 7-days.  Php507 for this item.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #70 on: November 19, 2020, 03:56:42 PM »
This is the back of the Frequency Counter/Meter.  Darned!  I have no SMA cable to hook up to it....



It runs off of a 9V battery.  Not included, of course.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #71 on: November 19, 2020, 05:18:36 PM »
Ahh.... I found some SMA stuff:



That thing in the middle is an SMA to BNC adapter which I can use with my BNC cable.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #72 on: November 19, 2020, 05:31:04 PM »
Akala ko sira :o

This works from a minimum of 1-MHz with a resolution of 100Hz.  I thought it would go down to 100Hz.  Hindi pala.

But I hooked it up to my Wheeler Function Generator and it was goodly accurate to two decimal numbers to the right, as was in the spec.  What more can we expect.



Here you can see I have a BNC T-connector on the lower-right of the Function Gen.  One cable going to my O'scope to check the waveform and the frequency reading, and the other to the Freq meter.

I was only able to read from 1-MHz to 2-MHz where the Function Gen topped.  The meter has somewhat a high capacitive load that it rounded off the square wave a bit.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #73 on: November 24, 2020, 04:05:18 PM »
One of the not-so-positive comments on the internet about this Frequency Meter/Counter is its lack of sensitivity.  I found that out when I couldn't pick up the transmission of my 433MHz RF remote control switch.

So, I had to revisit my 27MHz oscillator still on the solderless breadboard to check it out.  The oscillator still works but the antenna on the meter wasn't picking up its signal.  I had to directly connect the oscillator's output to the meter's input for this reading:



But it's accurate!  The oscillator's crystal is 27.125MHz.  The meter is reading 27.1253MHz.  For a breadboarded circuit, that can't be beat.

Offline Super zHero

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Re: 455kHz & 10.7MHz stuff
« Reply #74 on: November 24, 2020, 04:13:15 PM »

This is the circuit of that 27MHz oscillator from BK way back last July 02, 2019 (Reply #66 on my counter).




Now try this. any NPN tranny will do. For your choke, a 10 uhy will work. If you do not have choke, wind 8 turns on a 8mm coil form and put a 30pf across the coil. That will serve as the choke. Check the F on the collector. Use the 27.125 MHz crystal you have.

I made this test operating on 3.3 Volts.