adding an sma connector to a laptop for an external antenna.  - Page 1
Forum section: electronics / general

author: m3vuv
author_rank: Super Contributor
timestamp: March 27, 2021, 10:25:36 am
content: hi all,ive ordered a sma pigtail to connect an external antenna to my laptop wifi card,my lappy wifi card has 2 rf connectors,what one do i hook up the sma too?

author: Twoflower
author_rank: Frequent Contributor
timestamp: March 27, 2021, 11:30:59 am
content: You provided a lot of information here. I just assume you have a .11b WIFI module in your laptop it doesn't matter as only one stream will be used the module will use the antenna with the best signal (diversity) but that is still limited to 11MBit/s (yes that's meant to be sarcasm ;-).In case your module is a more recent one all channels will be used (MiMo) to get the advertised bandwith/range. In that case it still doesn't matter. But you might get even less bandwith than expected as the WiFi module might depends on a maximum distance between the antennas. Also the latest incarnations of WiFi (not sure if since .11ad or only .11ax) use the different antennas for beam forming which will not work with such a setup. Only in case you have to use a very high gain antenna and that will be the only signal the WiFi-Module will see that might make sense. But also of course you'll see only the maximum bandwith os a single channel.Why didn't you just buy an USB WiFi dongle with a longer USB cable? Some come with external antenna/antenna arrays. This way you don't need to modify your laptop case and still can use the laptop' build in WiFi in case of need.

author: m3vuv
author_rank: Super Contributor
timestamp: March 27, 2021, 12:14:36 pm
content: well i have ordered these:https://www.aliexpress.com/item/1005002039069913.html?spm=a2g0s.9042311.0.0.34ac4c4du8YrsChttps://www.ebay.co.uk/itm/4W-Power-Amplifier-5dBi-Antenna-WiFi-Signal-Booster-Repeater-for-Wireless-Router/392992915935?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l49https://www.ebay.co.uk/itm/1-13-Cable-RP-SMA-Jack-Bulkhead-to-Ufl-IPX-Connector-Ext-Pigtail-Cable-30cm/124281611991?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649i want to hook it up to my dell inspiron 1720 laptop for a project and was unsure how to hook it up to my wifi card as that has 2 rf input connectors and the pigtail has one,i dont mind modifying the laptop case to fit the sma pigtail,its the wifi card connection that im not sure about,i assume the card has 2 connections for diversity reception,i wonder if connecting the external antenna+amp will work just connected to one,i have a friend owns a pub about 200 meters away and says i can use his wifi,so i hope with the setup i have in mind i can use his wifi and save some money,at the moment i use my phone as a portable hotspot but its crappy + costly!,cheers m3vuv.

author: Twoflower
author_rank: Frequent Contributor
timestamp: March 27, 2021, 02:04:30 pm
content: Skip the amp! As it is probably not legal in UK to send such high power and the amp will most likely will disturb other signals as well. The gain from that directed antenna might be sufficient for 200m. Unless there's something in between. And even that could be questionable (e.g. not allowed here in Germany without reducing the transmit power).OK, the Laptop is a bit aged. And actually my sarcastic assumption wasn't that far off. Your assumption is probably correct and the WLAN module has two RF channels. Most likely it doesn't matter as on diversity the card will select the best signal. If the module has a label "main" this will probably the best one as the '"AUX" is the fallback. But even then I don't assume a big difference.Be careful with these connectors as they are extremely fragile and not designed to mate/un-mate often.

author: m3vuv
author_rank: Super Contributor
timestamp: March 27, 2021, 02:36:02 pm
content: yes i know they are fragile,luckily i have a few spare cards,the reason for using the amp was it has gain on rx as well as tx,i will wait for them to arrive and try them,at the moment it costs £25 a month for the data on my phone,if i can get this working then i save that each month,so worth a try in my opinion,cheers m3vuv.