درخواست: فرستنده ها و گيرنده

این یک گیرنده سوپر هترودین 27 مگاهرتز با فرکانس کاری 25 تا 28 مگاهرتز:

پاسخ : رد: فرستنده ها و گيرنده

reza_476 گفت:

این یک گیرنده سوپر هترودین 27 مگاهرتز با فرکانس کاری 25 تا 28 مگاهرتز:

کلیک کنید تا گسترش یابد...

با سلام :
رضا جون معمولا این لینک ها بعد از مدتی از کار می افتند و جهت ماندگاری در سایت اپلود گردید .
این هم توضیحات متن و تنظیماتی لینک گیرنده 27 مگاهرتز فوق :

To build a good walkie-talkie you need have a sensitive and stable receiver circuit. This is very sensitive and high
selectivity superheterodyne AM receiver on 25 ~ 28MHz range. The heart of the circuit is the famous AM receiver IC, TCA440. It can work up to 30MHz truly. It has a controlled RF prestage, very well implemented large-signal characteristic begins already from 4.5 V supply voltage, terminals for indicating instrument and controlled IF amplifier implementing 60 dB control range. It contains several function units, which enable it to act as an efficient AM tuner.

How does it work?
The received RF signal from antenna couple to input stage of the TCA440 by L2. The internal oscillator of U1 is tuned with (L3, C3, C10, CV1 and varactor diode D1) and build local oscillator signal. These two signals are mixed and after passing through the filter composed by (T1, CF1, C5 and CF2) amplified and the output of IF amplifier is applied to detector circuit formed by (T2, D2, R5 and C18). The detected signal after passing through (C15 and potentiometer P2) is ready to amplify.
Inductors specification:
Prepare two IF coil without the installed bottom capacitor and remove the shield house and wounded wire of them carefully. Build the L1 and L2 using them as follows:
L1: N = 9 turns, Wire Diameter = 0.3mm, Variable Ferrite Core Diameter = 4mm.
L2:
Primary: same as L1.
Secondary: N = 6 turns, Wire Diameter = 0.3mm, Spin: same as L1, On the L1 ferrite core.
L3: 180uH RFC.
T1: White IF.
T2: Black IF.
How to adjust it:
Connect the output of the circuit to an amplifier and turn on the receiver. You will hear a loud HIS sound and the circuit will sink about 100mA. Adjust the T1 and T2 until you hear the loudest sound from the amplifier. If you have access to a 27MHz signal generator, use it as an AM transmitter. Now adjust the L1, L2, P1 and P3 to receive the strongest signal.
[hide] http://www.irantk.ir/attachment.php?attachmentid=36948&stc=1&d=1309861246 [/hide]
موفق باشید .

پاسخ : رد: فرستنده ها و گيرنده

reza_476 گفت:

کلیک کنید تا گسترش یابد...

با سلام :
دوست عزیز میشه توضیح بزارید که این لینک ها چیه ؟؟؟؟ ارسالات خودتون را تست میکنید ؟؟؟؟؟
همه پست ها تون تاریخ گذشته و منسوخ هستند لذا حذف می شوند .
موفق باشید .

[h=2][/h]
[h=2]پاسخ : رد: فرستنده ها و گيرنده[/h]

CB receiver

source: Kyriakos Kontakos

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​

TECHNICAL CHARACTERISTICS:​

Tendency of catering: + 12V DC​

Frequency of reception at AM: ~27MHz​

​

Materially:​

The resistances are 1/4W.​

* Intermediary frequencies mf1-3 you can him find in a old radio AM.​

​

Regulations: ​

For the regulation needs a transmitter or generator in mpa'nta the CB, that is to say in the region 27MHz. If you have a certain friend with CB, you convince you to help.​

1. 1. Connect a piece of cable around in the one metre in the place of aerial.​
   2. Be supplied the receptor with + 12V and turn in half the potentiometer of regulation of sound (R12).​
   3. Turn on the generator or the transmitter CB and you emit in distance of 10 metres roughly from the receptor, in the channel that receives the receptor..​
   4. From the loudspeaker it will be supposed it begins to be heard what you emit and if it does not have big force, you turn the core of inductor L1/L2 until you have a increase of intensity. After this you can continue with the various medium frequencies beginning from black (MF3) until you have the biggest intensity. If it is heard mjkrofwnjsmo's, you lower little the intensity of loudspeaker or you remove the transmitter from the receptor.​

Modification:​

If you cannot find krysta'lloys you can make the modification that shows the form. That is to say, instead of crystal you in joint action put respectively coordinated circuits with LC each one in different channel.​

Notes: ​

The receptor this can combine itself with the transmitter CB in order to you manufacture a complete station CB.
​

http://www.electronics-lab.com/projects/rf/002/index.html

رد: پاسخ : فرستنده ها و گيرنده

CB transmitter
cb مخفف Citizen Band باند شهروند و فرکانس 27 مگاهرتز میباشد:
source: Kyriakos Kontakos

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http://www.electronics-lab.com/projects/rf/003/index.html

رد: پاسخ : فرستنده ها و گيرنده

[h=1]27MHz CB receiver circuit[/h] category: Radio tags: 741 • CB receiver • KXC/K3265 • LM386 • TCA440


This is a simple 27MHz FM-CB receiver built with TCA440 for listening CB ( citizen’s band ) transmissions with FM (frequency modulation). The selection is made with ceramic filters. This 27 MHz receiver works with an intermediary frequency of 455 kHz. The input filter is 27 MF type, so we obtain an acceptable attenuation of the mirroring frequency.



Because the intermediary frequency filter is used without adapting transformer, the selection is at 40 dB. Because of the noise in the transmission pauses, the CB receiver circuit has a squelch circuit which reacts at 4.5 kHz domain noise. [h=2]CB 27MHZ Circuit Diagram[/h]
741 IC datasheet
LM386 datasheet


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رد: پاسخ : فرستنده ها و گيرنده

[h=1]27MHz Fm Narrow Band transmitter[/h] category: Radio tags: cb transmitter • MC2833


NBFM or Narrow Band Frequncy Modulation is used in this 27 MHz fm transmitter circuit schematic. This circuit is an application by Motorola MC2833 – VHF transmitter with FM modulation and narrow band in a single chip.
The output power is 10mW (+10 dBm) and the coverage is 10 – 20m.
P1 is used to adjust microphone amplification and P2 to adjust the deviation. Remember that this 27MHz fm transmitter use NBFM with maximum 5KHz deviation, this mean you have to use an nbfm receiver to obtain enough audio level.



The transmitter is easy to adjust: trim C9, C9 and C18 for maximum output power on a artificial 50Ω load. Then listen on a 27MHz radio receiver and adjust P1 and P2 untill you obtain the best modulation.
X1 = 27.005 MHz quartz


[h=2]27MHz NBFM transmitter circuit schematic[/h]

رد: پاسخ : فرستنده ها و گيرنده

فرستنده 27 مگاهرتز باند باریک
[h=1]27MHz NBFM Transmitter[/h] category: Radio tags: cb transmitter • FM transmitter • MC2833


A 27MHz NBFM transmitter circuit schematic with MC2833 and 2 FET transistors MPF6660. Using a Motorola MC2833 one-chip FM transmitter, a few support components and am MPF6660 RF amp, this transmitter delivers up to 3W into a 50 Ω antenna. It is capable of operation over about 29 to 32 MHz with the components shown.


[h=2]27MHz NBFM transmitter circuit diagram[/h] http://electroschematics.com/wp-content/uploads/2009/01/27mhz-nbfm-transmitter.jpg