jollydet
Post a photo of your antenna it sounds like the source of your issues.
+1 - would like to see your antenna as well
I had to do some tweaking on my home network earlier this week and came across some info in regards to HT20 / HT40 / HT80 and what affects they have.
I had already understood the channel width as far as how the HT20 is more segregated but did not know that there were affects on allowable bandwidth / data rates tied in.
HT40 is probably the most rounded, has higher data load then HT20 but has higher signal noise and starts to be affected by walls ect. HT80 has even grater data transfers but really becomes hampered by walls and to truly get the most out of it you need line of sight. HT80 is great in wide open spaces.
If you are not in the same room and even on a different floor then your AP HT20 should probably be used. This is probably the reason why you saw the difference when you set your 9260 to HT20. In reality you should log into the verizon router (with a computer or laptop via an Ethernet port) and tell it to do a scan of the local RF environment then pick a clear channel and set the 5ghz to HT20. Set your 9260 to auto so that it automatically matches what the verizon AP is working at.
I also highly suggest (If you have an android device) get the wifi analyzer app (linked too in an earlier post) to double check the channels for congestion. When you are looking at the 5ghz stuff you will see other AP's in the area with a wide curve, those guys are using HT80 and you will notice your AP at 20 will have a much higher peak.
Just looking at my clients connected, with the AP's all set for HT20 on the 5ghz they are at around 173Mbs. Depending on how well that verizon AP works though I wouldn't expect anything over 200Mbs though. You could play around with the verizon router placement and different channels with HT40 if you feel you need faster rates to find a sweet spot.
Cheers and good luck
post edited by GGTV-Jon - 2018/12/19 20:48:30