[Elecraft] K3EXREF

[Matt Zilmer]

The K3 connector is an SMA.  Almost all of the Trimble units came with
a splitter, because E911 required two 10 MHz references to function.
Unless you need two sources yourself, I'd go direct from the Tbolt to
the K3 without the splitter, but it really doesn't matter.  You'll
have plenty of 10 MHz signal to work with anyway.

 You're lucky you got the short cable.  For the run to the antenna, I
would recommend RG142B if the length is over a few feet.  This is
rated for use at 12 GHZ, so it's probably overkill for a run less than
20 feet.  I just happened to have a spool sitting around.

I'm using an old Thales land surveying antenna mounted on the roof
here.  Sigs are showing green for all eight, and most SNR's are above
42 dB.  

Recommend you set the Tbolt up with an AMR of 4.0 and a minimum EL of
20 degrees to reduce horizon ambiguities.  Also, note that the Tbolt
doesn't use SBAS, so every sat you receive is in motion.  If there
were a firmware rev for the Tbolt that recognized WAAS birds, I would
also use that in place of the stock firmware.  All SBAS sats are
geostationary so doppler isn't the major correction needed.

73,
matt W6NIA
Upland, CA.

On Sat, 16 Apr 2011 10:56:19 -0500, you wrote:

>Now I'm just waiting for Elecraft to get the K3EXREF board in production to the point they are available.   I have obtained a Trimble Thunderbolt, a Larsen marine GPS (read white mushroom) antenna and have ordered a 3 voltage power supply for the Trimble.  Right now I have it running on a pair of Lambda analog supplies (5 V and a +/- 12) tied together.  I still need to make up the cable to run from the Trimble to the K3.
>
>My main question at this time is - What type connector is going to be on the rear of the K3 for the external ref?  The only thing I can find in the K3 manual (Rev D9) is on page 17 and it indicated that it's an SMA so if that's the case, I'll need to make up an SMA male-to-male cable to come from the Trimble to the K3.  (My Thunderbolt came with a  Mini-Circuits ZFSC-2-1, 5-500MHz splitter.  It was already connected to the 10MHz output by a short BNC to SMA connector, leaving 2 output ports from the splitter open.
>
>I can make or obtain an SMA-SMA cable or if the K3EXREF input is a BNC, cables are already on hand for that.  
>
>Would appreciate any info on this prior to my being able to buy the board.
>
>Jim - W0EB
>
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