dBm to Watt Conversion

dBm = log10 (mW)*10
mW =10^(dBm/10)

40 dBm	10.00 watts
36 dBm	4.00 watts	{ Maximum ERP allowed by FCC in U.S.
30 dBm	1.00 watts
27 dBm	500 milliwatts
26 dBm	400 milliwatts
25 dBm	320 milliwatts
24 dBm	250 milliwatts
23 dBm	200 milliwatts	{ Typical output from WLAN devices at 915MHz
22 dBm	160 milliwatts
21 dBm	130 milliwatts
20 dBm	100 milliwatts	{ Maximum ERP allowed by E.T.S.I. In Europe
15 dBm	32 milliwatts
10 dBm	10 milliwatts
5 dBm	3.2 milliwatts
4 dBm	2.5 milliwatts
3 dBm	2.0 milliwatts
2 dBm	1.6 milliwatts
1 dBm	1.3 milliwatts
0 dBm	1.0 milliwatts
1- dBm	0.79 milliwatts
5- dBm	0.32 milliwatts
10- dBm	0.1 milliwatts
20- dBm	0.01 milliwatts
30- dBm	0.001 milliwatts
40- dBm	0.0001 milliwatts
50- dBm	0.00001 milliwatts
60- dBm	0.000001 milliwatts
70- dBm	0.0000001 milliwatts
80- dBm	0.00000001 milliwatts	{Receive threshold for WLAN devices

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Common Wireless Antenna Connectors

We've photographed and labelled the most common types of connectors you get on wifi kit, so you can work out what cable you need to buy to join up your wireless card/access point and external antenna. Click on the pictures, to get a bigger picture.

Male N-Connector	Female N-Connector
N Connectors are usually found on external antenna and antenna cabling. It's usually cheaper to make your own cabling from RG-213 or LMR-400 cable and a couple of N-Connectors, than to buy fixed length cables from your Access Point manufacturer.
Male RP-TNC	Female RP-TNC
TNC connectors are usually found on access points such as the linksys WAP11.
Male RP-SMA	Female RP-SMA
SMA connectors are usually found on PCI wireless cards, such as the Belkin F5D6001 or the Netgear MA311.
Male MC (Lucent) Connector	Female MC (Lucent) Connector
These connectors are usually found on pcmcia cards like the Buffalo WLI-PCM-L11G.

The 'RP' in RP-TNC and RP-SMA stands for Reverse Polarity. Hardware manufacturers seem to love using connectors that are hard to find. Most commercial converter cables and pigtails, convert the antenna connector to an N-Type connector, as almost all external antenna (yagi,omni or patch) come with N connectors.

If you need to make an extension cable between the antenna and the pigtail/converter cable, we recommend using either LMR-400 or RG-213 cable as these are durable low loss cables suitable for 2.4 Ghz.

Thanks go to Mark for his correction on the RP images.a