3 ms·
Looks like it works, but I think that it is far from being optimal. CATV coax usually has an impedance of 75 Ohms, while the antennas of routers (and most RF st
by ale42 4y ago
Looks like it works, but I think that it is far from being optimal. CATV coax usually has an impedance of 75 Ohms, while the antennas of routers (and most RF stuff, except TV) are usually 50 Ohm. If impedance was right, the signal would probably be able to go much further.
- Gordonjcp 4y agoAt the very low frequencies involved, the impedance mismatch is pretty much negligible.
- MisterTea 4y ago> At the very low frequencies involved, 2.4GHz is low frequency?
- NovemberWhiskey 4y agoIf you're a ham-radio operator, no; if you're a mmWave engineer, yes.
- MisterTea 4y agoYou know I was originally going to be snarky and answer "low frequency? You must be a microwave engineer."
- nomel 4y agoCorrect me if I'm wrong, but this where you build circuits with parasitics, correct? ;)
- Gordonjcp 4y ago73 de MM0YEQ, I love working on stuff where a snipped-off bit of component lead is a "random long wire" antenna.
- Gordonjcp 4y agoIt's practically audio rate. It's not radio until you need to use jeweller's rouge to tune the aerial.
- upofadown 4y agoThe 50Ω to 75Ω mismatch loss doesn't make a big difference in practice. The cable loss on the other hand... If you have 60 foot of RG6 you would have 6 dB of loss at 2500 MHz[1]. That is a factor of 4. So you would only have a quarter of the normal signal and output power. If you use a splitter you have to take that loss into account as well. [1] https://www.net-comber.com/cable-loss.html https://www.net-comber.com/cable-loss.html
- hulitu 4y agoDamn, someone forgot to insert the bloody terminator. /s
- NovemberWhiskey 4y agoOK sure, but putting my access point six feet from my laptop (as it is right now) gives about -40dBm from what I think is 100mW of power and that's regarded as a pretty excellent signal strength. So if we're starting from a place where -60dB is "excellent" then we probably don't care about 6dB of losses so much.
- ale42 4y agoActually, the loss can be useful, I wouldn't want to inject the full output power of the transmitter into a receiver... ok it's maybe just 100 mW but still... that's not the power level a receiver expects to get from an antenna.