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What's the usable frequency range of the "filter/modulator" board?

Posted: Tue May 30, 2017 9:42 am
by i2NDT
I just received my "filter/modulator" board and noticed that the I/Q modulator chip is an AD8345 whose operating frequency range is 140=>1000 MHz (http://www.analog.com/media/en/technica ... AD8345.pdf).
It seems that it is usable up to 1255 MHz...but what about 2300 MHz?
In facts I would like to use the Portsdown TX to access the es'hail satellite...
In a previous post (http://www.batc.org.uk/forum/viewtopic.php?f=103&t=4877) M0HOJ says that he can get a tiny output at 2300 MHz but amplify it can be a problem (G8GKQ).

And now the question:
is it easier to build an up-converter to convert 437 to 2300 MHz
or
try to amplify that tiny signal
or
replace the AD8345 with an AD8346 (rated for 2500 MHz) as described here: https://wiki.batc.tv/images/7/7f/RBTVMOD_30_SCH_P3.pdf?

best 73
de
i2NDT Claudio

Re: What's the usable frequency range of the "filter/modulator" board?

Posted: Tue May 30, 2017 9:50 am
by g8gtz
Hi Claudio

The full specs are available here: https://wiki.batc.tv/Portsdown_Output_Levels

The output at 2400 is -7dBm which is useable by some PA modules or can be very easily amplified up using a PGA103 or similar so is the easiest way to go.

73
Noel - G8GTZ

Re: What's the usable frequency range of the "filter/modulator" board?

Posted: Tue May 30, 2017 10:33 am
by i2NDT
Thanks Noel!

Claudio