There are many DC-DC boost converter using the same National Semiconductor IC. The PCB are not all the same. Best to find a converter that has the better L-C filter at the output. For example this Ebay seller. Look for the output inductor on the PCB
3S Lipo is fully charged at 12.6V. Discharged 9.9V. In practice the Lipo fully charged steady state settles to 12.4V. The IC boost chip needs a 1V drop to work. I have used 2 x diode at the input. 2 x diode drops the voltage 2 x 0.7V so is 1.4V. Then the DCV into the converter is 12.4-1.4= 11V. If the output is adjusted for 12V then the IC spec for 1V drop is within tolerance to work.
Any silicon general purpose diode rated 1 Amp or more will work ok for this mod.
The IN4004 is a very common diode.
I have used the converter to supply 12V continuous up to 800mA.
Attached photo show the DC-DC boost converter details. The DC-DC is lighter than a separate lipo for the FPV gear. The voltage is regulated +12V.