[Skimmertalk] DC2PD Pre-Amplifier for Red Pitaya

Bob Wilson, N6TV n6tv at arrl.net
Sun Dec 10 01:24:17 EST 2017

I found the construction manual:


Bob, N6TV

On Sat, Dec 9, 2017 at 10:11 PM, Bob Wilson, N6TV <n6tv at arrl.net> wrote:

> Never mind, I found the "Technical specifications" tab.
> Looks like it needs 5V, 80 ma, and has "<= 43.5 dB (55.5 dB), depending on
> the gain range" and a Noise figure of "3.7 dB (according to the data sheet
> of the AD8331)"
> I don't understand how to control the gain.  You have to use Pavel's SD
> Card image (Alpine Linux), instead of the Ubutnu Linux distributed with the
> Red Pitaya, and add some additional connection between the boxes besides
> the coax?
> 73,
> Bob, N6TV
> On Sat, Dec 9, 2017 at 10:06 PM, Bob Wilson, N6TV <n6tv at arrl.net> wrote:
>> Thanks Martin.  The pre-amplifier looks interesting.  What is the gain?
>> What is the voltage requirement?  Does it include a power supply?  I assume
>> it doesn't have the 14:1 transformer built-in, though it would be nice if
>> it did.
>> N4ZR managed to homebrew a transformer board using that transformer
>> component, but couldn't find a male right angle PC mount SMA connector like
>> the one that the Red Pitaya folks use.
>> I'm planning to order a third batch of 14:1 transformers from the Red
>> Pitaya company, which you will be able to order from me using
>> http://www.kkn.net/~n6tv/XFMR once they're back in stock.  In the mean
>> time, as mentioned, please email me directly (off list) if you want to be
>> on the waiting list for one or more.
>> 73,
>> Bob, N6TV
>> On Sat, Dec 9, 2017 at 3:43 PM, Martin Rath <martin.rath at gmail.com>
>> wrote:
>>> Hi,
>>> I found that the T14 transformers are available in Germany from Box73 :
>>> http://www.box73.de/product_info.php?products_id=1552
>>> At 6.20 EUR there are not cheap especially considering the cost of
>>> shipping (flat rate of 4,90 EUR in Germany / 6,90 EUR WW) but even
>>> considering this I guess one could easily build there own input 14:1
>>> transformer PCB for less than 15 USD a piece.
>>> They also have a broadband 0-60 MHz LNA designed by DC2PD for the Red
>>> Pitaya ( http://www.box73.de/product_info.php?products_id=3737 ). The
>>> LNA was described in the Funakamteur 12/2016 : I'm a subscriber so I could
>>> most probably scan it for you if there is any interest. It will however be
>>> in German :-)
>>> 73's Martin 9V1RM

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