Here is why I ask. I have 3 cables which are all 50ft long. If i connect the 3 cables together with 2 couplers will that make my connection bad or unstable? I couldnt find any 150ft straight through cable at my local stores .
shouldn't pose that much of a problem.. you should look into getting cable made for that distance though... most mom&pop computer stores will make cables for you for cheap.. usually about 25cents/foot plus ends, depending on the place.
technically, it will make the cable less stable, but not enough that it would effect your network adversely. you may see a slight dip in speeds, if anything
the main problem with them is that you are un-twisting the cable.. it untwists before it goes into the RJ45, while it's in the RJ45, then it may/maynot be twisted through the coupler, then through the RJ45 again.. it's untwisted for a long time, considering that you can get data loss from over 1cm untwisted..
any bad EMI in the area will cause problems.. but generally, it should be fine