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That sounds very promising. There are a few wide band amps on Ebay which are in aluminium cases. I would probably get an open one, shorten the board and fabricate a box. I would be worried by the strain on the sma connector.

Maybe a future Tinysa could have a built-in switchable amp, which would then give a 60db controlled input range, with the built-in attenuator (woops, I am suggesting future possibke developments and I promised I would not do that any more).

Steve L. G7PSZ

On Tue, Aug 25, 2020 at 05:58 AM, Stephen Laurence wrote:

is it possible to put the vcc direct to the ?tinysa ?input sma

Yes, there is a DC blocking capacitor at the input so you can put the Vdd to the SMA center pin using an appropriate inductor. Best to add a switch too

On Mon, Aug 24, 2020 at 12:30 PM, Roy Appleton wrote:

Could you link to your source of the amp?

This is a SPF5189Z amp. Many are available on eBay but make sure you buy from a reputed seller and check the current drawn as there are many fake SPF5189Z components on eBay.
Officially it should run from 5V/100mA but for low input levels 3.3V/70mA works as well.
They work well below 50MHz

Note added, see:?

I am impressed.

However to make it a bit easier, is it possible to put the vcc direct to the ?tinysa ?input sma (assuming there is a blocking capacitor) so that it is similar to a bias tee ( is that what they are called?). Then the lna (also with a blocking capacitor) only has to be connected to the sma, without the need for the power lead.

Steve L. G7PSZ

HI Erik,

? Great! ?Would be a good idea to list the maximum current draw of the VDD pin right there on the LNA page. ?Certain amps are hungrier than others and I'm not sure offhand how much you can draw before starving the rest of the board.

73
Phil W1PJE

For those that want to do QRM hunting, having a LNA with the tinySA would be nice.
This can be easily done in about 10 minutes.
More detail here:?
Result: noise floor with a 3kHz RBW at -135dBm