The 160 Inverted-L is about 160 feet of wire.\u00c2\u00a0 To get a good match there is a series capacitor in line with the wire.\u00c2\u00a0 The bandwidth for any useful value of capacitance is about 40kc.\u00c2\u00a0 The object is to use a set of relays to switch in or out additional capacitors.\u00c2\u00a0 That will allow the antenna to be tunable across most of the band – from 1800kc to 1930kc.\u00c2\u00a0 There is also a 1.5:1 unun at the feed point, followed by a coax cable choke.\u00c2\u00a0 This lowers the SWR to a very nice 1.1:1 over the useful range.\u00c2\u00a0 The rig is very happy at resonance, and a good match will be a dial click away.<\/p>\n
Currently the capacitance in the system gives a nice 1:1 SWR at 1825kc.\u00c2\u00a0 Using the autotuners, either radio [K2, FT-920] can work from 1800 to 1875.\u00c2\u00a0 The goal is to be able to turn off the tuners and feed the antenna directly.\u00c2\u00a0 Maybe I’ll pick up a few extra QSO’s with a good match on the antenna end of the feedline.<\/p>\n
After several other projects using relays and the 3kv Panasonic capacitors for the band pass filters, enough extra parts are in the parts bin to make it happen.\u00c2\u00a0 So, why wait?<\/p>\n
A handy nearby line previously shot into a nearby biological antenna support provides an opportunity for expansion.\u00c2\u00a0 The line seems well placed to add an INV-L element for 80m.\u00c2\u00a0 One additional relay for switching bands.\u00c2\u00a0 Judicious choices for the capacitance values may allow the sharing the capacitor banks for either antenna.\u00c2\u00a0 Being able to cover the CW segments is most important, so the minimum value used would ideally resonate each wire near the bottom of either band.\u00c2\u00a0 Hmmmmm.\u00c2\u00a0 Time to pull the 80m wire up and start tinkering.<\/p>\n","protected":false},"excerpt":{"rendered":"
The 160 Inverted-L is about 160 feet of wire.\u00c2 To get a good match there is a series capacitor in line with the wire.\u00c2 The bandwidth for any useful value of capacitance is about 40kc.\u00c2 The object is to use a set of relays to switch in or out additional capacitors.\u00c2 That will allow the antenna to be tunable across most of the band – from 1800kc to 1930kc.\u00c2 There is also a 1.5:1 unun at the feed point, followed by a coax cable choke.\u00c2 This lowers the SWR to a very nice 1.1:1 over the useful range.\u00c2 The rig is very happy at resonance, and a good match will be a dial click away.<\/p>\n
Currently the capacitance in the system gives a nice 1:1 SWR at 1825kc.\u00c2 Using the autotuners, either radio [K2, FT-920] can work from 1800 to 1875.\u00c2 The goal is to be able to turn off the tuners and feed the antenna directly.\u00c2 Maybe I’ll pick up a few extra QSO’s with a good match on the antenna end of the feedline.<\/p>\n
After several other projects using relays and the 3kv Panasonic capacitors for the band pass filters, enough extra parts are in the parts bin to make it happen.\u00c2 So, why wait?<\/p>\n
A handy nearby line previously shot into a nearby biological antenna support provides an opportunity for expansion.\u00c2 The line seems well placed to add an INV-L element for 80m.\u00c2 One additional relay for switching bands.\u00c2 Judicious choices for the capacitance values may allow […]<\/p>\n