LMR-195 Coaxial Cable for bringing out rear-panel instrument connections

[matthuszagh]

I've accumulated a reasonably large number of instruments housed in 19" racks. A lot of this is microwave gear with useful rear-panel connectors. In my current setup, it's a pain to get to these rear connectors, so I'm planning to bring these connections out to the front of the rack with custom BNC cable assemblies. The reason to custom make these is partly for cost, but also I'd like to get in the habit of assembling my own coaxial cables.

I'm currently leaning toward primarily using LMR-195 for this application. What do people think?

Here's my thought process. I've seen a lot of endorsements of RG-400 cable and I'm very intrigued by it, but at least at Pasternack, the RG-400 is 10x the price of LMR-195. It seems like the main downsides of LMR-195 vs RG-400 are

(1) foam PE can't handle as high voltage
(2) foam PE can melt at soldering temperatures
(3) the foil shield can be damaged by repeated flexure (see https://www.eevblog.com/forum/rf-microwave/cable-brand-and-type-for-lab-bnc-cables-50-ohm/msg3597975/#msg3597975 and https://www.eevblog.com/forum/beginners/coaxial-cable-rg142-rg400-lmr400-confusion/msg2547201/#msg2547201)
(4) dielectric contamination (see https://www.eevblog.com/forum/beginners/coaxial-cable-rg142-rg400-lmr400-confusion/msg2547201/#msg2547201)

Am I missing any? Reason (1) doesn't matter since I won't be dealing with high enough voltages where this matters. For (2), I plan to assemble these using crimp for both the ferrule and center contact with a Daniels HX4 and Y205P die. For (3), these cables will be left in position and flexed very little, so I don't see this being a major issue. For (4), I'm not really sure what this means. Is this humidity ingress? Something else? What's the symptom? Reflections? Loss?

On the other hand '195 is lower loss and more flexible (though that shouldn't really matter here). I expect LMR-195 is somewhat overkill for a number of these connections (and indeed for some I may use RG-58 or whatever's cheapest), but at $1/ft from a reputable manufacturer it's cheap enough that it doesn't make a big difference for the total cost of these assemblies, and I'm happy to have the peace of mind of good performance.

I'm still interested by RG400 and will probably use it for high-quality patch cables that undergo frequent flexing. I do understand it's not very flexible, and for applications that don't need the shielding performance I may go with RG-316 instead.

I should also mention that one of the benefits of LMR-195 and RG-400 is a degree of mechanical compatibility with RG-58, which means it's easy to find crimping tools and connectors for them.