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Post by bandolero on Sept 28, 2017 16:18:06 GMT -5
Hi, I would like to know if the ballast of a 11 m-cb bandwidth will change, by feeding the antenna with rg 58 / cu at the base with the ground loop ... what type of isolating transformer must be interposed between the node and RTX ?  |
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Sandbagger
Administrator/The Boss 
Posts: 6,247 
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Post by Sandbagger on Sept 28, 2017 21:27:43 GMT -5
Hi, I would like to know if the ballast of a 11 m-cb bandwidth will change, by feeding the antenna with rg 58 / cu at the base with the ground loop ... what type of isolating transformer must be interposed between the node and RTX ? Hmmm..... Not quite sure what you're asking.... What do you mean by "ballast" and "ground loop". And what do you mean by "node" and "RTX". Sounds more like networking than RF.......  Generally speaking, we don't use isolation transformers between feedline and antennas, unless it's a balun matching an unbalanced coaxial feedline to a balanced antenna like a dipole. |
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Post by bandolero on Sept 29, 2017 10:17:17 GMT -5
hello, sandbagger I confused with "ballast" ... I meant antenna impedance and "ground loop" = ground / ground ... i would like to feed the 1/4 wave wire not on the base but on the top (slooper-wire ) ... at the food base with 30w and i think i saw high node current = low impedance type 50/70 ohm ... but if food at the top and always 50 ohm or change impedance with slooper system ... i can use a two-wire line instead of the 50 ohm coaxial cable? |
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Sept 30, 2017 8:19:26 GMT -5
hello, sandbagger I confused with "ballast" ... I meant antenna impedance and "ground loop" = ground / ground ... i would like to feed the 1/4 wave wire not on the base but on the top (slooper-wire ) ... at the food base with 30w and i think i saw high node current = low impedance type 50/70 ohm ... but if food at the top and always 50 ohm or change impedance with slooper system ... i can use a two-wire line instead of the 50 ohm coaxial cable? I have not had much experience with sloper antennas. Most of the setups I've seen have been fed at the ground level. If you feed it at the top, you'd need to run a wire to the ground, and it essentially becomes a dipole at that point. |
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Post by bandolero on Sept 30, 2017 16:24:34 GMT -5
Ah,ok You are right ... it is better to power from below and connect the coaxial shield to ground, transformers (balun) on this type of antenna are not needed, because they already have a 50 ohm impedance ... its technical name and "markers" it has twice the gain db compared to the dipole and the strong return of "rf" on the radio and the microphone, I tried to make 10 coils in the coaxial but it does not block the radio frequency (RFi) ... maybe I could isolate the current with a tuner type "L" or type "T" ... do you have the wiring diagram of this tuner, specific for a "branded" antenna?
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Generally speaking, we don't use isolation transformers between feedline and antennas, unless it's a balun matching an unbalanced coaxial feedline to a balanced antenna like a dipole.