[hpsdr] New TAPR Product: the "PulsePuppy"

[John Ackermann N8UR]

Below is a message I sent to the time-nuts mailing list about a cute 
little project I just finished, that TAPR will be offering as a 
semi-kit.  I'm forwarding it to the HPSDR list because it might be 
interesting for use as an external frequency reference for SDR radios.

The time-nuts are mainly interested in the performance an oven 
oscillator ("OCXO") can provide.  But an OCXO is overkill for most SDR 
uses -- they draw a lot of power (as much as 800ma when warming up and 
200ma steady-state) and they have a long warm-up period.

Well, it turns out that TAPR has a supply of the Crystek 
temperature-controlled oscillator ("TCXO") we used in the HPSDR 
Excalibur board, and we've designed the PulsePuppy to work with that 
oscillator as well.  The Crystek TCXO provides ±1 PPM (e.g., 10 Hz at 10 
MHz) stability over -10 to +60 degrees C, and 1 PPM aging rate per year. 
  It draws very little power and has almost no warm-up time.  In short, 
it's a great match for an SDR system.

While supplies last, TAPR is offering a bundle that includes the 
PulsePuppy kit for $69 and the Crystek TCXO for $30.  For comparison, 
the current Digikey price for the TCXO is $53.85.  If you're interested, 
go to http://tapr.org/kits_pp.html for more details and a link to place 
an order.  (We're expecting to ship kits in mid-February.)

73 and happy holidays!
John

PS -- The pictures referred to below aren't in this message; they're too 
large for the list.  The TAPR web page has a nice picture.


----

I've developed a little board called the PulsePuppy that supports 
surplus OCXOs in the common "Eurocase" form factor to provide outputs at 
10 MHz, or at 1 PPS/10 PPS/100PPS using an on-board 12F675 PIC with one 
of TVB's picDIV firmware images.

The attached pictures show one prototype unit in closeup, and a panel of 
three that are used for TICC counter production testing (providing one 
10 MHz and two independent PPS outputs).  Also attached is an ADEV plot 
of the inexpensive Isotemp OCXO131-100 oscillator I'm using to give an 
idea of the performance you can expect from these small oscillators 
(they and others like them are available from several eBay sources for 
<$30).

The PulsePuppy is available from TAPR as a semi-kit and can be ordered 
at http://tapr.org/kits_pp.html for $69.  We expect to ship the kits in 
mid-February (delivery of the boards from our contract manufacturer is 
the gating factor).

The assembly manual with schematics can be downloaded at 
http://www.tapr.org/~n8ur/PulsePuppy_Manual.pdf but here are the specs 
in brief:

* Footprint for either Eurocase OCXO or Crystek CXOH20-BP-10.000
   TCXO (TAPR has a bunch of these TCXOs remaining from another project
   and, while they last, is offering them bundled with the PulsePuppy
   for an attractive price).

* PPS divider uses TVB PD-13 firmware that includes capability to
   synchronize to an external clock.

* TTL-level output at jumper-selectable 10 MHz, 100 PPS, 10 PPS,
   or 1 PPS rates.

* A BNC output connector is included, but the board contains a footprint
   to install a user-provided SMA.

* 25-turn EFC trimmer with 0-5V range.

* Option to support sine-wave as well as square wave oscillators.

* Board dimensions are 1.5 x 3.5 inches.

TAPR is offering the PulsePuppy as a "semi-kit" that includes the 
printed circuit board with all surface-mount components installed, and a 
handful of through-hole parts (like voltage regulators, jumpers, and 
connectors) for the user to install.  By leaving these parts for the 
user, the board can be customized -- for example to use different 
voltages or to support a sine-wave oscillator.

Note that the kit DOES NOT include the oscillator, unless you buy the 
Crystek TCXO bundle.

Happy Holidays to all!

John