regenerative receiver

[adnan012]

i need a 27MHz regenerative receiver for R/C model airplane.
This circuit will work.

 

[Nigel Goodwin]

No, that's for picking up commercial aircraft voice radio on VHF.

You should really use a professionally build radio for an RC aircraft, it's essentially a 'flying bomb' and losing control of it could be very dangerous. They cost very little these days and are incredibly small, you mustn't attempt to use a regenerative receiver they aren't reliable or selective enough, professional ones are superhet and crystal controlled.

 

[adnan012]

Actually this is my university project.
I construct my transmitter,CHANNEL encoder,decoder,ESC etc

I reverse-engineered the regenerative receiver from a kit.I measured the range for more than 300 meter.

My transmitter is 27mhz PPM MODULATION.
i measured the pulses by using the o-scope.They were perfect.
There is also a LCD that shows the width of each channel.

the problem i am suffering is that my servos starts vibration

1)when i touch the aerial of the receiver.

2)when the receiver is too close to the receiver.

( however there is no problem with speed controller.)

4) receiver is affected by the direction of of the receiver.

5)what type of antenna should i use for receiver.
a flexible wire or a hard one

6)there are two amp stages in the receiver one is common emitter amp and the other which i added my self is an op-amp. whose gain controlled by a variable resistor.

when the variable resistor is at its lowest position no signal goes to the decoder section as i vary the variable resistor the signal start going to the decoder. at this point if i switched off the receiver than the receiver shows no signal.Here the problem is that the amplification.

When the potentiometer value is increased more then the reviver becomes noisy.And the decoder section receive signals even when the transmitter is switched off.


Can i make a super-hetrodyne receiver by using ne612 mixer ic, it use a overtone crystal.
I don't have much knowledge to use crystals in overtone modes.

is there any simple hetrodyne design.

 

[Nigel Goodwin]

Presumably the 'kit' was for a toy car (not a model car), it's not suitable for a plane, and shouldn't be used for one.

There are plenty of superhet circuits about, just google for them - but they are obviously much more complicated than regens - but that's why they are so much better.

To be honest though this doesn't sound a very 'exciting' university project, trying to duplicate a cheap commonplace item of equipment?.

 

[jpanhalt]

We don't know what country you are in, so it is a little hard to make specific suggestions about sourcing. Search on Park Flyers. They often use cheap 27 MHz radios. Harbor Freight in the US has one for about $12 complete. Here is a site from my search that also has inexpensive Park Flyers: **broken link removed**

John

 

[stevez]

You might do some research in amateur radio literature and publications. The 10 meter amateur band is close to 27 mHz. The amateur radio hobby does include people who play with R/C models.

 

[adnan012]

recently i construct am (500khz to 1600khz) hetrodyne receiver as a small project of my "analog communication" course.

i know very little about crystal controlled oscillator.
i need some tutorial about crystal controlled oscillator in designing point of view.