[Skimmertalk] T14 Transformers

Bob Wilson, N6TV n6tv at arrl.net
Sun Dec 10 01:11:49 EST 2017

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?

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
>> On Wed, Dec 6, 2017 at 3:52 AM, Bob Wilson, N6TV <n6tv at arrl.net> wrote:
>>> K5TR discovered that DigiKey currently has a better price than Mouser on
>>> the Red Pitaya STEMlab 125-14 starter kit ($306.79) and acrylic case
>>> ($22.73):
>>> https://www.digikey.com/product-detail/en/trenz-electronic-g
>>> mbh/27761/1686-1034-ND/6579245
>>> https://www.digikey.com/product-detail/en/trenz-electronic-g
>>> mbh/27773/1686-1044-ND/6579255
>>> More links:
>>> https://www.digikey.com/products/en?keywords=red%20pitaya
>>> I'm currently sold-out of the 14:1 transformers (
>>> http://www.kkn.net/~n6tv/XFMR).
>>> But I can order another batch from the company if there is sufficient
>>> demand.  Please send me a direct email if you want to be on the waiting
>>> list for one or more 14:1 transformers.
>>> 73,
>>> Bob, N6TV

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