FA-VA6 FAQ / Ideas / Additions
FAQ (Frequently Asked Questions)
Accessories including USB cable missing
Q: My kit is missing screws, rubber feet, and the USB cable?
A: These items are located underneath the upper foam insert in the case.
Alignment of the front and back panel of the case bottom to the top cover
Q: On my case, the front or back panel protrudes or sits too far inward. Can this be aligned?
A: Despite CNC manufacturing, tolerances can occur. Without the circuit board installed, you can manually bend the front and back panels to align them perfectly.
Inserting and removing the circuit board from the case
Q: How can I insert or remove the circuit board without risking damage to the USB-C socket?
A: Face the case with the BNC socket toward you and use your thumbs and index fingers to gently lever the board in and out. Gloves may help.
Insertion: Index fingers on the bottom edge of the board, thumbs on the inside bottom of the back panel.
Removal: Index fingers against the battery holder, thumbs on the inside top of the back panel.
Alternative: Use 2–4 old credit cards or similar between the board and the back panel on both sides to help lever it out.
Display shows vertical red line
Q: My display shows a vertical red line?
A: That is the protective film on the display. Remove it by peeling from the green corner.
Loose screws on the keypad
Q: The M2 screws on my keypad are loose — should I tighten them?
A: No, the screws need some play to allow proper alignment of the keypad. The nuts are glued in place.
Keypad alignment to upper case shell
Q: The keypad buttons aren’t perfectly aligned with the holes. Can it be adjusted?
A: Yes, slightly shift the keypad sideways using as many buttons as possible until the alignment fits.
Usable 18650 Battery / Part 1
Q: Can a different 18650 battery be used?
A: The FA-VA6 uses the MCP73871T-2CCI/ML charging controller, which is designed for a 4.2V charge cutoff. Batteries with a different cutoff voltage may be overcharged or not fully charged. The internal protection circuit is also set for this voltage. We strongly recommend using the specified battery type NCR18650BD.
Usable 18650 Battery / Part 2
Q: Can a 18650 battery with internal protection be used?
A: Protected 18650 batteries are generally mechanically longer and may not fit in the holder. The FA-VA6 has its own internal protection circuit. We strongly recommend using the specified battery type NCR18650BD.
Frequency used for measuring the velocity factor (VF) in cable application
Q: What frequency is used when measuring a cable's velocity factor?
A: The frequency is variable and depends on the cable length. The electrical length (and thus the VF) is determined using a quarter-wave (λ/4) transformation approach.
Feature requests for firmware updates or application ideas
Q: How do I submit a feature request for a firmware update?
A: Ideally by email to
support@dg5mk.de. Please check here first to see if your request has already been listed.
Discussions about the FA-VA 6 are covered in the following groups.io forum:
https://groups.io/g/fa-va5-users
Feature Ideas and Additions
Firmware Version 2.0
- Cover 23 cm band (1.3 GHz) using 7th harmonic
Status: Open - Merge cable applications into one application
Status: Open - Implement a rudimentary spectrum analyzer operation mode
Status: Open - Implement impedance matching application
Status: Open - Implement balun / unun matching application
Status: Open
Firmware Version 1.0
- Display more than 5 frequencies (>10) in the style of the 5-Band measurement
✅ Status: Largely implemented in firmware 2.0 with the new 6-band application. - Add additional frequency bands, e.g., 8-meter band
✅ Status: Implemented according to IARU guidelines and the bands defined therein. - Selection by frequency band also for single frequency and 5Band modes (center frequency)
✅ Status: Implemented in firmware 2.0. - Simplify frequency entry in kHz and MHz, e.g. by long-pressing zero during input, or entry in Hz by ENTER and kHz by Arrow-Down
✅ Status: Implemented in firmware 2.0. - Increased measurement rate for single frequency mode, e. g. using an additional parameter
✅ Status: Implemented in firmware 2.0. - Add additional cable types into the catalog
✅ Status: Implemented in firmware 2.0. - Extend callsign to two lines to add name
❌ Status: Not implemented for aesthetic reasons. - Extend frequency span using ham-band selection to factor 1.5 or 2
✅ Status: Frequencies follow IARU band limits. Spreading can easily be achieved after selection using the arrow keys. - Implement reference trace from current trace capability
✅ Status: Implemented in firmware 2.0. - Implement zoom function for Smith chart
❌ Status: Not implemented for technical reasons. - Add return loss view with bar in single frequency mode
✅ Status: Implemented in firmware 2.0. - Implement often used Ham radio calculation tools
✅ Status: Implemented in firmware 2.0. - Adapt cable applications to measure symmetrical feedlines
✅ Status: Workaround described in publication FUNKAMATEUR and groups.io forum. - Establish screenshot over USB (PC) functionality
✅ Status: Implemented in firmware 2.0. - Local saving of TDR data
✅ Status: Implemented in firmware 2.0.
Known Errors and Workarounds
Firmware Version 2.0
- none
Firmware Version 1.0
- Vertical lines may show up for SWR measurements in multi frequency mode with open or shorted port, because a calculated negative SWR is set to zero instead of positive infinity.
Workaround: None, as this does not affect any practical measurement.
✅ Status: Resolved in firmware 2.0. - Wrong measurement values may show up in multi frequency mode (mostly using continuous measurement) with a center frequency of 150 MHz / 450 MHz and a small span.
Workaround: Use a larger span and/or single measurement.
✅ Status: Resolved in firmware 2.0.