Here’s a coax loss calculator. For the SWR loss contribution you must specify the approximate SWR at the antenna end of the coax. For short lengths of good quality coax at HF frequencies RG-174 is probably fine.
https://www.qsl.net/co8tw/Coax_Calculator.htm
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@OE5JFE and @MM0FMF what would be the impact of a poor screening quality (e.g. 85 % instead of 95 %) when using RG-174 for SOTA?
Probably not that much for such a cable.
Less screening often implies a cheaper cable. A cheaper cable may be made to less strict quality control and tolerances. So not only is there less screening but the centre core may have less wire (copper) and be higher resistance. The VF may not be what you expect and physically, the plastics may fail sooner with flexing etc.
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I was making a J-Antenna for 2m some years ago with bad coax cable. It was just not working (resonant). Changed to good quality cable and it worked.
On HF probably not the biggest problem but I expect loss of power in the cable. Maybe some fake capacitance when analysed.
73 Joe
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My RG 316 arrived…
I am a bit amused, it says wonderful… What does that mean, I know its a wonderful cable but…
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Doesn’t look like any RG-316 I have ever seen. Outer jacket is normally transparent FEP.
It seems the manufacturers name is “Wonderful”. A company apparently from Malaysia… Well, how did I end up with their cable, I dont know. Obviously some surplus at Wimos warehouse. However, physically the cable makes a pretty sturdy and solid impression.
However going through their datasheet it seems it has higher attenuation than a RG174 
http://images.100y.com.tw/pdf_file/03-WONDERFUL-RG316U.pdf
I’ll send it back.
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I use a 3Ft piece of RG58 for my endfeds, usually rigged as a sloper. Coils up small and is easy to handle with gloves and in the cold, very durable under field conditions.
This was taken yesterday. Long time since I made a QSO on 10 meters!
Another shot doing an activation a week ago:
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Well, after a very disappointing experience with WIMOs customer service I had to discard the cable that I got (it was broken right around the middle). So I found another shop that has a enormous offer of coax cables.
I am not quite sure if I should take a /C or /U cable. What is better? Pure copper or a steel/copper core? Does this even matter at all?
Does this even matter at all? - NO!
Use whatever you can get quick and locally and get out in the mountains.
73, Heinz
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Hi Aleksander,
I’m a bit late to the party but wanted to share my experience with the RG174A/U from Sotabeams.
I bought this MIL-spec coax nearly 4 years ago, did nearly 400 activations with it and it still works like on the first day, even I stepped on it on several occasions.
I know the shop is not local to you, but maybe you need other stuff?
73 Stephan
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