Any ideas on this? The Ultimate DIY Microphone (super low self-noise!)

I realize that this is quite an old thread, but in case you are still interested in the project, I figured I'd add a few thoughts:

The Rode NT1a is a reasonably low-noise microphone, but the marketing outstrips its real-world performance. They use noise shaping to get a very low A-weighted number, but the amount of noise you perceive is probably comparable to most microphones commonly used for this sort of purpose. Still, the NT1a is cheaper than most of those, for what it's worth.

His assessment of what contributes to the noise levels of recorders is also innaccurate. Most handheld field recorders like the Zooms he uses in the test have pretty poor preamplification stages. While larger condenser diaphragms will have lower noise than small diaphragm condensers, you can still get much better noise performance than the zoom offers by plugging a good-quality SDC into a low-noise preamp.

The main problem I see with this is that the NT1a is not really meant to be used outside of climate-controlled studios. Most microphones used for location recording are RF-condensers, which handle high moisture and other bad weather better than traditional condensers. I'd be worried about consistently using the Rode LDCs outdoors, especially if there is moisture in the air. Condenser microphones that get too much moisture in them can develop very distinctive artifacts that can ruin the audio captured with them.