Hi,impedance match,input circuit and etc!

[gameaya]

1. How to calculate the input circuit?(the C3,C4,C6 and L2) The frequency is 40.455MHz.
2. How to use the impedance match? (the R2)
3. How to use the coil instead the CD? (CD : ceramics discriminator)
Thanks a lot!

[leu1]

C3=10nF
C4=5pF
C6=Cancel
L2=3uH

R2=1K

C1=10uF
R1=15K
C2=330pF
L1=sumida coil 5114-JPS-010
C5=27pF
(According to the TA31136 datasheet)

BTW you should add a front-end low noise amplifier, or the mixer of TA31136 will not work efficienly.

good luck!

[gameaya]

Thank you ! but how did you Calculate it,can you teach me?

[leu1]

The anttena filter should be:

It a band pass filter, center: 41MHz

[gameaya]

Thank you ! How to add a pre-end LNA?

[leu1]

you can try this. good luck!

[gameaya]

Thanks ,but there is no pre-LNA!
How can i do it ?

[Zlatko]

Yes, there is.

Look for RX.BMP in BMPSCH.ZIP inside rx.zip

Cheers

EDIT...
I know this is the DIY Forum, but a lot of us have given up on the idea of making our own RXes because of the parts availability and the expense of filters and resonators. I've modified a few BlueArrow RXes for indoor use but the new Corona RXes have a much better RX front end. Why don't you buy one ( say RS410 v2) and play with that. You should be able to find them for under $20.
http://rchobbyboy.com/store/comersus_viewItem.asp?idProduct=478 for 36MHz

Cheers

[leu1]

Yes, FET J310 is a LNA.
I did not try this design, it seems very complex (PLL included). If you really want to build a receiver yourself, there is many things to do, you must manage to buy some unique ICs, inductor coils and transformers. Further more, you must have a spectrum analyzer and a oscilliscope at lest, in order to tune LC filter and calibrate LNA bias circuits. If you do not know RF circuits much, these will be very difficult.
If you only interested in Rx circuit and want to do some test, it highly recommend to modify it rather than build it.

[gameaya]

OK?
Can I do it?

[leu1]

Woo, what a mass! You have strong will to do this! You even want to build a Tx circuit, is that right? Long time ago I wanted to do the same thing like you, but I abandoned at last. Mail to me if you need help,

leu1@eyou.com

<<< Write In Chinese >>>

[gameaya]

Good eyesight!
Did you know chinese words?
are you chinese?
I want to make friends with you!

Yes,I have finished the TX part, and the RX part have finished 90%,May be
a week later ,I will finish it!

[leu1]

Yes, I am a RF engineer, come from Tianjin China.
Mail to me, I am very interesting in your project.

[gameaya]

我刚刚发了一封邮件给你，忘了告诉你我的联系方式了！
Qq:373362831

[leu1]

Sorry, I did not receive your mail. Would you please resend it? BTW I am in Japan now and I can not use QQ, How about MSN? leu1_1@hotmail.com You can send mail to this address too.