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| VNA and Bridge Kit Bags |
Greg Ordy
The information on this page is intended to support the parts kits which came from the March 2004 group build. In some cases, the sections will refer to the corresponding assembled boards sections, since the information is identical.
Please see the corresponding section on the Assembled Boards page.
The kit box has the following contents:
Cover letter and shipping documents, if international.
VNA PCB zip bag, containing all of the VNA parts, including the PCB.
T1-6T Bridge zip bag, containg all of the bridge parts, including the PCB.
All parts are enclosed within a smaller zip bag with a three digit number. That number tags the contents of the bag, and is called the Inv (inventory) number. Please consult the parts spreadsheet for a table with the Inv. numbers and corresponding parts descriptions.
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| VNA and Bridge Kit Bags |
Please see the corresponding section on the Assembled Boards page.
Please see the corresponding section on the Assembled Boards page.
Please see the corresponding section on the Assembled Boards page.
Please see the corresponding section on the Assembled Boards page.
Please see the corresponding section on the Assembled Boards page.
NOTE: You need to consult the corresponding section since it describes the location of the new pull-up resistor, a 100 K Ohm 0603 package part, Inv. 059.
Please see the corresponding section on the Assembled Boards page.
The T1-6T bridge board for this group is not identical to the one in the first group (that I worked on). Specific information on this bridge board can be found by following this link. The schematic of and parts on the board have not changed since the original published design, so my first bridge page is still generally relevant, although the size, composition, and connector placement of the board has changed.
The Mini-Circuit transformer (Inv. 041) must have its leads bent to fit onto the board. I cut off the last segment of the leg, then fold the next segment under, and then bend the short stub down. The goal is to get the transformer seated on or very close to the board, with the legs coming down at an angle to meet the traces. Be sure all 6 legs are evenly seated on the copper before soldering the part.
When you are done building the bridge, you will be left with exactly two resistors in the 039 bag. These are 100 Ohm, 0.1% tolerance parts intended to be used to construct a 50 Ohm load standard. The two must be combined in parallel to achieve 50 Ohms.
The testing procedures I used for the assmbled bridge board are on another page.
The best advice I can give concerning the building of the main board is to follow the G3SEK VNA Build Notes document which is part of a build info zip file available on the N2PK web site. The instructions are not detailed part by part steps like building a Heathkit, but they follow a very logical order, and enable you to start testing as soon as possible. If there is a problem, tracking down the error should be relatively easier. The hardest parts to solder are saved for the end, so you get to build up your surface mount skills as you assemble.
As in the case of the Mini-Circuit transformer on the bridge board, the three transformers on the main VNA board require custom lead bending in order to fit where they belong.
All references to the LTC2410 ADC chip now apply to the substitute LTC2440 part. You will find the LTC2440 in bag 051.
This board includes a single extra resistor which is not described in the N2PK articles. This is a pull-up resistor for the control pin of the LTC2440 ADC. The resistor is Inv. number 059, and is 100 K Ohms in a 0603 package. This resistor is mounted on the bottom of the board. More information on the resistor and controlling the LTC2440 is on the assembled board page.
Inv. bag 044 will contain either the Valpey-Fisher oscillator, or, the For JITO-2.
All of the parts in the bags should be consumed completely. There should be exactly one part left over, a single Inv. 001 capacitor. If you are missing any parts, please let me know, and I will provide them. If you need to purchase any parts, perhaps due to sneezing them off the table, please see this page.
The testing procedures I used for the main VNA board are on another page. The N2PK documentation contains more information, in particular, the schematic diagram in the second article is annotated with voltage test points.
Back to my March 2004 Group Build Page
Back to my Experimentation Page