300MHz RF module - Page 4 - Electronic Circuits Projects Diagrams Free

audioguru · 28th December 2006, 12:42 PM

The MAX7030 looks like a nice modern tranceiver IC. It might be a nightmare to get a prototype to work. It would be best to buy a module that is manufactured to work well.

bananasiong · 28th December 2006, 01:09 PM

Hi,
Do you mean, it is too difficult to make one using max7030? Or this is impossible for me? Or I have chance to make one? Or it is a very very scary nightmare?

BTW, the external components determines the operating frequency right? But I see the inductors are not handmade, just wonder if it is working. Then why maxim manufacture this product?

Thanks

audioguru · 28th December 2006, 01:47 PM

An expert might make 5 prototypes before it works well, then goes into production and makes many all the same.

You aren't an expert with VHF and with surface-mount parts so maybe you must make 10 or more prototypes before it works. When it doesn't work then you don't have the skills and the test equipment to find out why not.

bananasiong · 28th December 2006, 02:29 PM

Make a number of prototypes? What is their different? Placing of components?

audioguru · 28th December 2006, 03:23 PM

Stray capacitance might cause the first ones to oscillate.
Stray inductance might cause the next few to have low gain.
You might have some prototypes that oscillate and have low gain.
Many parts might need their values changed to compensate for stray capacitance and stray inductance.

It would be a frustrating challenge to make one that works.

bananasiong · 28th December 2006, 04:01 PM

Wow, challenging, need to spend much time for this. Anyway, how far is the transmission?

Thanks

audioguru · 28th December 2006, 04:19 PM

It is designed for keyless entry for cars (and the car talks back?). The keyless entry RF system for my car has a range of about 20m but the transmitter's antenna is too small for better range.

There must be a ham radio operator around here who can calculate the range for you when the conditions are perfect.

Hero999 · 28th December 2006, 06:20 PM

Build it as small as possible, use SMT parts for all of the componants, even the inductors.

bananasiong · 29th December 2006, 06:04 AM

I haven't involved in SMT before, maybe this is the time for me to try the first time.

bananasiong · 30th December 2006, 06:15 AM

Oh, I couldn't get surface mount component here. Only one shop has it, but only certain value of resistor only, they don't have capacitor....

Hero999 · 30th December 2006, 12:34 PM

RS Components sell SMT resistors, capacitors and inductors.

bananasiong · 6th January 2007, 03:07 PM

Hi,
Sorry for pulling up this thread, but I have some question. The 'crappy' RF module that I mentioned before, is that FM or AM? I compared it with the mod4, the signal goes in to the base which the transistor is oscillating at its collector. So is it FM?

Thanks

Hero999 · 6th January 2007, 03:26 PM

Like the mod4, it produces both AM and FM. The amplitude changes as the transistor's gain is altered be adjusting the base current as does its capictance which changes the resonant frequency.

audioguru · 6th January 2007, 03:35 PM

Quote:

Originally Posted by bananasiong

The 'crappy' RF module that I mentioned before, is that FM or AM? I compared it with the mod4, the signal goes in to the base which the transistor is oscillating at its collector. So is it FM?

The Cmos oscillator in the transmitter turns on and off the RF oscillator transistor at about 4kHz. So the carrier is amplitude modulated (AM). It is very over-modulated so it must create a lot of interference.

The receiver looks like a super-regenerative piece of junk that also is AM.

bananasiong · 6th January 2007, 04:06 PM

OIC, thanks.
How about this,CC1000 from Texas Instrument, is it very difficult to make one?
http://focus.ti.com/docs/prod/folders/print/cc1000.html

Or it is as difficult as MAX7030?

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28th December 2006, 12:42 PM	#46
audioguru	The MAX7030 looks like a nice modern tranceiver IC. It might be a nightmare to get a prototype to work. It would be best to buy a module that is manufactured to work well. __________________ Uncle $crooge

28th December 2006, 01:09 PM	#47
bananasiong	Hi, Do you mean, it is too difficult to make one using max7030? Or this is impossible for me? Or I have chance to make one? Or it is a very very scary nightmare? BTW, the external components determines the operating frequency right? But I see the inductors are not handmade, just wonder if it is working. Then why maxim manufacture this product? Thanks __________________ bananasiong

28th December 2006, 01:47 PM	#48
audioguru	An expert might make 5 prototypes before it works well, then goes into production and makes many all the same. You aren't an expert with VHF and with surface-mount parts so maybe you must make 10 or more prototypes before it works. When it doesn't work then you don't have the skills and the test equipment to find out why not. __________________ Uncle $crooge

28th December 2006, 02:29 PM	#49
bananasiong	Make a number of prototypes? What is their different? Placing of components? __________________ bananasiong

28th December 2006, 03:23 PM	#50
audioguru	Stray capacitance might cause the first ones to oscillate. Stray inductance might cause the next few to have low gain. You might have some prototypes that oscillate and have low gain. Many parts might need their values changed to compensate for stray capacitance and stray inductance. It would be a frustrating challenge to make one that works. __________________ Uncle $crooge

28th December 2006, 04:01 PM	#51
bananasiong	Wow, challenging, need to spend much time for this. Anyway, how far is the transmission? Thanks __________________ bananasiong

28th December 2006, 04:19 PM	#52
audioguru	It is designed for keyless entry for cars (and the car talks back?). The keyless entry RF system for my car has a range of about 20m but the transmitter's antenna is too small for better range. There must be a ham radio operator around here who can calculate the range for you when the conditions are perfect. __________________ Uncle $crooge

28th December 2006, 06:20 PM	#53
Hero999	Build it as small as possible, use SMT parts for all of the componants, even the inductors. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

29th December 2006, 06:04 AM	#54
bananasiong	I haven't involved in SMT before, maybe this is the time for me to try the first time. __________________ bananasiong

30th December 2006, 06:15 AM	#55
bananasiong	Oh, I couldn't get surface mount component here. Only one shop has it, but only certain value of resistor only, they don't have capacitor.... __________________ bananasiong

30th December 2006, 12:34 PM	#56
Hero999	RS Components sell SMT resistors, capacitors and inductors. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

6th January 2007, 03:07 PM	#57
bananasiong	Hi, Sorry for pulling up this thread, but I have some question. The 'crappy' RF module that I mentioned before, is that FM or AM? I compared it with the mod4, the signal goes in to the base which the transistor is oscillating at its collector. So is it FM? Thanks __________________ bananasiong

6th January 2007, 03:26 PM	#58
Hero999	Like the mod4, it produces both AM and FM. The amplitude changes as the transistor's gain is altered be adjusting the base current as does its capictance which changes the resonant frequency. __________________ I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong. Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

6th January 2007, 04:06 PM	#60
bananasiong	OIC, thanks. How about this,CC1000 from Texas Instrument, is it very difficult to make one? http://focus.ti.com/docs/prod/folders/print/cc1000.html Or it is as difficult as MAX7030? __________________ bananasiong