dual band antenna
Can you inform the correct cable lenght to connect a dual band 144/440MHz base antenna to my YAESU FT-7800R tranceiver?
I have a KENWOOD SW100 SWR/POWER/VOLTAGE meter but cutting the cable couldn't get less then 2:1 SWR reading. I'm using RFS KMP RGC58 cable with two UHF connectors (the one that has white plastic as isolator) on each end.
73,
Fernando call sign PU2PLL
When you go on VHF band, it is the first choice to use RG213 which will have least loss compared to the RG58. Too let me know which antenna you are using. If it a a homebrewed, it need to be alligned to 1:1 swr or if it is a commercial one, please install the same at some friends place with his cable and read the SWR. Coz the SWR will be affected only when the cables are broken, water logged or the antenna is not tunned. Good luck.
I don’t know what kind of antenna you are using, but if is a vertical antenna, the ground provided could affect dramatically the VSWR.
For example vertical antennas needs ground radials, if are connected in the top of a pole.
RGC-58 RFS-KMP, is a semi-rigid coaxial cable and should be fine for UHF applications up to 50W.
Anyway, 2:1 VSWR is not very bad for a dual band VHF/UHF antenna.
As an additional comment: If we can assume, that the transceiver has a fair 50 ohm matching, the cable length almost doesn't affect VSWR.