Flounder

#hamradio / #amsat / #antennabuilding question: I built a v-dipole for NOAA images, when I measure the SWR in my living room I get 1.8 to 2.0, *but* if I take it to the loft and get it positioned just right I can get that down to 1.3.

My question is: is this better reading a lie? Has something in the nearfield tricked my meter?
Or is it correct but getting that close to the ceiling will mess up the ceiling in other ways?

Oct 11, 2024 at 3:40amWeb
Show threadnotforsale ground stationOct 11, 2024

@fl0und3r noaa frequency is 137 mhz = 2 meter wave length. for better measurement you must put the antenna from ground at least 1/4 wave length = 50 cm height.

tips: rg6 coax cable is better than rg58.

Show threadFlounderOct 11, 2024
@notforsalegs at least according to my meter the loss in the coax isn't significant (although I don't remember the exact figure). It's a short run of cheap Amazon coax (still 50ohm though). I *do* need to get more coax but I find the options overwhelming.
Show threadnotforsale ground stationOct 11, 2024
@fl0und3r i also use v-dipole to capture noaa sat. from my experienced, v-dipole is best antenna for noaa and meteor especially when the sat maximum elevation > 30 degree from horizon. for cable i recommend using rg6 that usually used by dish tv. or belden 9116. 15-20 metre of coax rg6 db loss is far better than rg58.
Show threadComrade WeezOct 11, 2024
@fl0und3r If your antenna is close to RF reflective objects, reflected power will be read as reflected power. If you want a true reading, take it outdoors where there's nothing within a few wavelengths near it. Since you won't be transmitting on it, VSWR isn't a concern anyway.