Shack Board
The Shack Board provides power for PreampA, PreampB and SAPreamp as
well as interface from each of their outputs. Power is the input
10-16 VDC regulated with an adjustable LDO to produce 8V at the
preamp, after any voltage drop in the intervening CAT5 cable
First versions of this design contained LPF and HPF to create a
diplexer to allow combining two antennas to create a Hybrid antenna
system. Later versions use external filtering connected to
the Shack Board outputs.
This PCB may also be used for initial testing of Preamps,
Junction Box and cables.
Testing
There are also switches on the PCB to allow verifying proper
preamp performance.
Since assembled PCBs must be ordered with minimum quantity = 2 ,
this makes a good arrangement for testing. Using each of two
PCBs as a simple 50 Ohm <==> 100 balanced line adapter lets
transmission through a length cable be measured. Applying power
to either of the interconnected boards also allows checking power
function of each board.
DC tests can be performed with a multimeter for power supplies. For
RF testing a broadband measurement using a scalar or network analyzer
is a very good method. This may be done with a TinySA
or nanoVNA. Loss through the
system during a two-Shack board test should be near 0 dB. Typically
CAT5 cable loss should be about 3 dB/30m at 30 MHz.
Initial version of the Shack Board with diplexer included.
Use
In addition to its main function of supplying power to Preamps and receiving differential RF over CAT5 cable and delivering the filtered/combined results to a receiver, this board also has a switch to disconnect the 12V supply from the input circuits of a probe preamplifier while leaving output stages operative. This allows identifying common mode and other unwanted noise ingress apart from the intended balanced antenna. A better method is to simply short the dipole elements but this is not always possible or convenient so simply disabling the input high impedance OpAmps is useful to verify a system.
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Item Description |
Provider |
Source Code |
Notes |
Approximate Material Cost(excludes setup fees and shipping) |
Assembled ShackPCB PCB |
Download ShackPCB Kit Files==> JLCPCB |
Download ShackPCB Source Files==> KiCad |
Added Preamp12V/LED and shorting
relay switches |
US$ |
38x88x100mm Clam Shell Enclosure |
eBay |
Other sources possible. Enclosure needs to accept 84mm wide PCB. | US$12 |
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38x88mm ShackPCB Front Panel |
Download ShackPCB Front Panel Kit Files |
Download ShackPCB Front Panel Source Files |
Select 'Aluminum" when ordering.
These are panels only no components. |
US$1 |
38x88mm ShackPCB Rear Panel |
Download ShackPCB Rear Panel Kit Files |
Download ShackPCB Rear Panel Source Files |
Select 'Aluminum" when ordering. These are panels only no components. | US$1 |
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