Electrical engineer here, I deal with these connectors all the time. And if you're having trouble figuring out the actual correct connector for mini pcie wifi cards... it's understandable.
Originally, and most commonly, the connector was called a
U.FL connector. Now however, the same connector goes by many names. All of these connectors are, in fact, the exact same connector, just called by a different name:
U.FL,
IPEX,
IPAX,
IPX,
AMC,
MHF and
UMCC. All of those refer to the connector used on mini pcie wlan cards, amongst other things. There are so many different names for the same connector because originally, Hirose had a patent on the U.FL connector, and U.FL was/is also a trademark. Some years ago, that patent expired, so several other connector manufacturers began making clones of that same connector, just under different names. They became so numerous that they started being called by both the original name (
U.FL), clone names l(like
MHF & UMCC), as well as simply by the name of the company that makes the clone (
IPEX). Sort of like how Kleenex is used to refer to tissues. But on crack.
So why didn't that
MHF cable you bought fit? Well, this is where it gets even more confusing. There are three smaller variants of the
U.FL/MHF connector, and they have different names as well. Basically, if you see any name that would normally refer to a U.FL connector, but with a number after it, it's not a U.FL connector.
MHF4 is, specifically, the smallest variant, with a larger
MHF3 variant and even larger
MHF2 variant also on the market.
MHF (which is technically "MHF1") is the only MHF connector that is the same connector as
U.FL and all those others I listed.
Anyway, I am not sure what you are expecting on the other end of this cable, but I'm going to assume you want the standard connector that you'd find on the back of a full-size desktop PCIE card for external antennas to screw onto.
If that sounds right, what you want is a
U.FL to RP-SMA pigtail. But anything called "XXX to RP-SMA pigtail" where XXX is one of the various names for the U.FL connector is also the right cable (they're all the same thing). Note,
RP-SMA is not the same as SMA. The "RP" in front of the SMA is important, it stands for Reverse Polarity. RP-SMA connectors have the genders reversed, so look like SMA connectors without actually being compatible. Wi-Fi antennas all use RP-SMA,
not SMA, so there's another trap heh. They definitely make U.FL to SMA pigtails as well, so just be careful.
One last bit of advice: unlike low speed analog (audio) or digital signals, the microwave RF analog signals that transmit WiFi are very sensitive to things like connector and cable quality. A cheap pigtail will work, but you'll definitely have a meaningful amount of signal loss (in terms of dB) compared to a quality pigtail that has had its insertion loss and transmission loss measured.
Now, if you just want something cheap, then really whatever you can find on ebay or similar is fine, but if you want to make sure you have the best possible signal and by extension, the fastest WLAN connection, it's worth paying a bit more for something by a quality vendor.
Unfortunately, I don't really know any distributors in France, but for anyone who stumbles on this thread and happens to live in the USA, this is a very solid but relatively cheap pigtail that will work:
Silicon Labs pigtail. $4.75 a pop.
If you want the absolute best (but we're pretty far into 'diminishing returns' territory at this point), then my goto is
L-com's pigtail. But, at $20 each, I also wouldn't actually buy them for my own personal use
.
Finally, be sure you secure the antenna end of the cable securely to a grounded bulkhead for the best SNR. Not required, but still worth your time to do.
