Band-I Link Receiver Circuit

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reverend
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Band-I Link Receiver Circuit

Post by reverend » Fri Jun 18, 2021 10:59 am

Here's a circuit for a really simple Band-I receiver without too many parts. It's not crystalled or synthesised, however it uses the AFC from the CA3089 to keep the receiver locked on frequency. This works pretty well as long as the oscillator doesn't drift too far and works even better if the band is relatively quiet so that it doesn't drift onto someone else's dial.

It has a carrier sense relay built in but this can be omitted if you don't need it. The coil that is connected to the oscillator could be replaced by a crystal with very few other changes (and the AFC wouldn't then be needed!)
Rev-Band-I-Link-RX.jpg
Rev
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if it ain't broke, keep tweaking

radium98
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Re: Band-I Link Receiver Circuit

Post by radium98 » Sat Jun 19, 2021 7:54 am

our freind in forum Sinus also provide a good schematic too :)
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reverend
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Re: Band-I Link Receiver Circuit

Post by reverend » Mon Jun 21, 2021 9:54 am

Here's a 2-sided PCB layout (excluding the top layer ground plane which isn't shown otherwise it would hide the traces on the bottom of the board. If anyone's interested, I could post the Gerber file?
pcb-layout-rev-band-i-link.jpg
Rev
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Rfdiva
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Re: Band-I Link Receiver Circuit

Post by Rfdiva » Mon Jun 21, 2021 3:08 pm

Go ahead thank you .if you have it in .lay ? If not the gerber will do thanks.

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reverend
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Re: Band-I Link Receiver Circuit

Post by reverend » Mon Jun 21, 2021 4:55 pm

Here you go. Here are the Gerber files for the PCB.
Rev2.02b Band-I RX.zip
Incidentally, the reason that the majority of components are surface mount but some are not, is that the ones which are not SMD need to be changed if:
  • there is a significant change required in the operating frequency (i.e. those around the input and the VCO), or
  • there is a significant change in the wanted deviation of the received signal. The RX is set for 75 kHz deviation with ~250 kHz channel bandwidth but this can be reduced to 50 kHz channel bandwidth and lower deviation (say +/- 15 kHz) with some changes in the resistor/capacitor values around the CA3089.
Rev
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Rfdiva
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Re: Band-I Link Receiver Circuit

Post by Rfdiva » Mon Jun 21, 2021 10:43 pm

Thank you.what about a tx and or aerial .

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