Where to find schematic of 315MHz receiver module ?

[Externet]

Hi.
It is exactly like this one :
----> https://robu.in/product/rf-transmitter-receiver-module-315mhz-wireless-link-kit-for-arduino/
The 8 pin IC on it is LM358.

Had no luck.

 

[davenn]

Hi.
It is exactly like this one :
----> https://robu.in/product/rf-transmitter-receiver-module-315mhz-wireless-link-kit-for-arduino/
The 8 pin IC on it is LM358.

Had no luck.

I would be surprised if one is available

you may have to trace it out

 

[73's de Edd]

Sir Externet . . . . .

WHASSAMATTAHNOONEWANNAHEPSYOUOUT?
Re:
Your link shows me nothing extraordinary in its schematic as to prevent other (nearby) frequencies from performing.

Are we left to guess-try-and-learn ?

Out of that HUGE treasure trove of linked . . .(plural) . . . info that I gave you . . .you weren't able to seeeek it out ? (seeeek, with that being HEAV-EE on the SEEK aspect )

What ? . . . . am I now getting rebuked and rebuffed ?

At that EARLY instant in time you had given me NOTHING as to what was wanting to be done and only a cryptic suggestion as to modification of freq range, so I submitted just built units that would fall within the ISM bands, such as any " Joe Public" would be able to buy and use on those ISM frequencies.

NOW with your further fill in of just the mere "144 Mhz " . . . . . Do you now think that an advanced amateur extra class licensee with 30 wpm code proficiency PLUS an additional FCC First Class Commercial license with its supplicated radiotelegraph and radar endorsements . . . . doesn't qualify me to know what you are now trying for . . . . .PLUS . . . do YOU have a two letter callsign ?

The info I did send you, is probably the most amassed receiver schematics of that specific type that you have ever seen in one referencing assortment.

it has been said
you may have to trace it out

and there it is, being all laid out for you , right in the board components . . . if you know what you are looking for and what that amalgam of parts are being ?

Now, in looking at the selected two receiver options that you chose , and JUST now seeing your SELECTED one ( from INDIA ? ) . . . let me fill you in to its aspects and its particular points of interest.
I have given you three board views, with the first ground plane shot bordering on useless, the final 2 . . .are definitively more usable.

My markups are using YELLOW flagged boxes for the RF stage and and Superregeneative detector stages. That then refines on down to using RED for the RF stage transistor and L&C tuning components and PURPLE color coding for the Superreg Detector stage.
The inductors are being DIAMOND flagged and the capacitors are STAR flagged.
Now, with you wanting to squegg the frequency of the present state receiver on down to 144, you will be wanting to tweak the L1 coil and its companion C4 downwards in frequency.
Simultaneously, the real receiver tuning is being done with the L2 C14 detector stage tuned elements which also need their resonance freq lowered.

Now I'm going to give these maunfactured products some validity for their performance and stability of the receiver by the solidly wound and supported HEAVY wire inductors . . . . with a little bit of leeway permitted to the lesser critical air wound, magnet wire input coil of the RF stage.
That detector stage coil,frankly, I don't think that you want to mess with . . . . .INSTEAD . . . . pad it with a shunting capacitor across C14.
You need to physically inspect the board to find the two caps . . . . C4 and C14 . . . . that are shunting the respective coils for making parallel resonant circuits.
I take them as being the whitish colored SM's . . . . however I have never -ever bought a SM type of silver mica . . .which is the precise type you want to use for tuning stability in a circuit like this . . . . .since I always had a bushel of wee brown epoxy dipped Cornell Dubilier or Sangamo wire leaded Silver Mica type units.

Calculating 315 Mhz + 2 picofarads for its tuning is revealing a value of 128 nanohenry since its for the L1 resonating coil.
Meanwhile, in using the same coil and adding capacitance across C4, reveals the need of an extra 7.4 pf of capacitance be added, or use one 9.4 pf (10pf) silver mica cap instead.

Over at the detector stage the L2 is untouched ( since its built, supported and wound as solid as a rock) while the C14 cap gets some added capacitance..
Calculations reveal a 30 nanohenry value present for L2 and 5 pf to resonate it to 415 Mhz.
For use at 144, with that same L14 coil being used, will need the use of an additional 35 pf across the existing 5 pf C14. Or put in a 40 pf SM cap alone

The L14 inductor uses diminutive inductance variance for its tuning . . . . . by that I mean that in NO way could it use a ferrite slug . . .or even a low density high frequency powdered iron dust as its slug. Instead, it is using a non ferrous alumininny-ninny-yum-yum . . .or brass slug . . .I am seing brass . . . so that its movement into the coil, will minimally shift its inductance downwards in value, yielding an upward frequency shift.That's creating a desirable, desensitized vernier action tuning shift with the slugs adjustment.

The audio is outputted at the emitter of the detector and is dependent upon that RF choke to isolate the RFpassing from the RF stage to the detector stage, while letting the audio pass thru it and down thru series R4-C8 and past the high pass filter to ground that is using C9-R6, where the continuous bubbles of ultrasonic bursts are being extracted, giving you clean audio into the #3 of one of the dual op amps in LM358.
The LM358 second stage puts out a squared digital quality signal at pin 7 . . . . . but you might not need that degree of processing . . . that audio ? digital ? aspect still seems to be your little secret..

Now I think that in the past, that I perceived your daytime job as being in audio instrument ? equipment ? manufacturing / testing . . . . BUT some of that specialized technolology sector has gone BOOM-BOOM , so you might now be shoeless.

But . . . . . your past mentioned two way and communications signal analyzer might let you generate a signal of the frequency of , 150------300 mhz, so that you can initially FIND your received frequency with that receiver, and then tune on down frequency in making the tuning mod.

FINAL . . . .
The Schematic . . . .
Modify and change actual parts values to your units, to create your units precise schematic . . . . at least . . .I have now given you a basic superregen design to work with.

My first acquaintance with superregenerative receivers . . . . . and no, I don't mean the common REGENERATIVE or REFLEX / FEEDBACK receivers, I mean the real superregenerative receivers which go back to the 30's as TUBED circuitry and then low power peanut TUBED battery powered receivers in the 40's . Then solid state versions creeped in.
They have been used as Ham receivers, particularly 6 and 2 meters, in Garage Door Opener's , Model plane, radio control receivers and you now see them STILL being used in this very application.

Now . . . what, if anytthing, did I short change you on ?

Le Schéma de l'information . . . . .

73's de Edd . . . . .

My wife said that if I don't get off my computer and do my honey do's for her, she'll grab me by the ears and start slamming my head on the keyboard, but I really think that she's just jokinfjreoiwj . . . . . . . . . . rtwe4to8rkljreun8f . . . . . . . . . . 4ny84c8y4 . . . . . . . . . . t58lym4wth . . . . . . . . . . lmhawt4mylt4amla . . . . . . . . . . thnatynohdfhk . . . . . . . . . . ihewshligvsdfrew.

.

 

[Externet]

what, if anytthing, did I short change you on ?

Superb response Edd. Thanks again. Edd, you NEVER short change me or anyone.
-The 'India' is just as found that image on the web matching exactly my modules numbering-

 

[Martaine2005]

Wow, expensive web site considering the same item with exact same components.

Martin

 

[Externet]

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