[YARDStick] TX / RX amplifiers on Yardstick

[Dominic Spill]

On 24 April 2017 at 13:32, Dave Wakelee <dwakelee at rochester.rr.com> wrote:
>
> Does anyone know the details of the TX and RX amplifiers used in the YARD
> Stick One?

RX: Infineon BGA 420 H6327
TX: RFMD SPF5043Z

> The schematic just has general placeholders (TX_AMP / RX_AMP)
> without part numbers, and there is no BOM / parts list on github (unlike
the
> other greatscottgadgets projects).

If you right click on the parts in the schematic and select "edit", you can
find the part details.  I'm not sure why we don't have a BOM in the
repository for this project.

> I'm asking as I'm having some trouble receiving certain low power 915MHz
OOK
> messages with the Yard Stick, whereas the RTL-SDR dongle gets these
messages
> without trouble.  OOK settings are per the TI app note, and I can receive
> other OOK messages (433MHz, long preamble) without issue.

Are you able to receive some of the 915MHz packets?  But not all?  Does
enabling the RX amp make any difference, or none at all?  How about for the
433MHz packets?

> Although I have no problems transmitting, I'd like to also understand what
> constraints and capabilities exist when the transmit amp is enabled (what
is
> the dB gain, what is the max output that the TI chip can be set to when
> using the amp, etc).  I've not seen either the TX/RX dBm levels documented
> anywhere for the YARD Stick One, either with or without the amplifiers
> engaged.
>
> I'm fairly certain that my receive problem has to do with analog and
digital
> gain (and AGC), so any info regarding the TX and RX amplifier details
would
> be appreciated.
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