[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Arabic (?) music on FO-20 !!!


An inverting transponder is intended for SSB, however it will pass FM. 
When used in it's intended mode (SSB) the downlink mode is opposite to 
that of the input, IE: USB in = LSB out..

Also, as you tune your transmitter upwards in frequency through the 
passband, the downlink frequency will appear to tune down in frequency. 
So, the higher up the input  passband you transmit on the uplink, the 
lower down the output passband your downlink signal will appear..

AO-10's uplink is, say 435.100MHz LSB,  the resulting downlink frequency 
is about 145.900MHZ USB.  This is known as "Mode B"

 FO-29's uplink is 145.900 - 146.000 LSB and the downlink is 435.800 - 
435.900 USB, this is known as  "Mode JA"..

I hope this explains it?

73 de Alan, ZL2VAL..

William Leijenaar wrote:

> Hi Scott,
> Reply to 1.
> -----------
> The FO-20 transponder frequencies are as follows:
> Uplink: 145.900 - 146.000 MHz
> Downlink: 435.795 - 435.900 MHz (inverted)
> It is inverted what means that 145.900MHz is equal to 435.900MHz.
> When going up 50kHz in uplink frequency to 145.950MHz you get 50kHz 
> down in downlink frequency what is 435.850MHz etc...
> This is also the centre freq. where is most activity...
> Reply to 2.
> -----------
> FM on a inverting transponder sounds like normal FM.
> The transponder inverts the FM spectrum but when you know how a FM 
> spectrum looks like, you find out that the inverted FM signal is equal 
> to the none-inverting FM signal.
> I need a picture to explain it more in detail, but unfortunatly 
> email/amsat-bb has no graphic possibility :-(
> Maybe someone else can explain it better in words...
> 73 de PE1RAH, William
> ---

Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org