I remember that ole Ringo, i bought that antenna originally at Traders over by the Avalon mall before they moved and changed their name to Cash Converters and now reside on Freshwater road. Yes sir that SO239 connector did turn to dust from our salty air, most likely that connector was the cheapest they could find i'm sure. Thank you for fixing up the connector, i did use the antenna for awhile then replaced it with something else, can't remember what it was now, perhaps one of your CONE dipoles? Glad you made some use of that antenna afterwards and had some fun building your own version of it. BTW, i think i may have another version of the same antenna here now and some other antenna's. You are welcome to them, one is a TRAM 1487 VHF 5/8 wave ground plane, great antennas. 🙂
👍👍👍👍👍 you have done a good job. I don't like verticale Half wave length antenna. 5/8 are Better and have more gain. 3/4 Is even Better. The strange thing for me is the 75 ohm cable. But if It is so, It's so. Good job mate. I like building antenna. All the best.
I first tried with 50 Ohm and couldn’t get the SWR lower than 1.5 When I tried it with 75 Ohm it tuned just about FLAT ! Thanks for watching and share with your friends. Check out my other videos on this channel to see some of my other projects.
@@madeinfoxtrap5539 I believe you 100% that you got flat SWR with a 75 ohm cable. RF Is strange. I have been working for more then 40 years in communication, MF, HF, VHF, UHF and microwave, and I have seen too many strange thing with RF. 👍👍👍👍👍👍👍
You did not described the end part. From where the ring connects to the 1/8th piece, what is the lenght to the wooden part. Or is the square piece in total 9 5/8 inch?
Forgive me as I'm a new ham and new to antenna theory so I'm trying to understand what's going on here. How is it OK for the radiating element be shorted directly to ground? How would that not burn up the transmitter?
Don’t feel bad as I asked the same question when I was first licensed !! Connection is made on a two-turn coil to provide Inductive Matching This design was a LOT of trial and error but eventually became a resonant antenna
The thing that makes this "short circuit" okay is frequency. The lowest frequency you could have is "on" with no change. An antenna is used at a higher frequency than this - at 2m (145MHz) the voltage switches polarity one hundred and forty five MILLION times a second. Because of how fast the change in voltage (and thus current) is, you can actually measure different voltages along a single conductor like an antenna. This is because the electrons simply can't travel as fast as they are being asked to. If you get the length of the "short circuit" just right, the point where the short is will be a zero voltage point, and thus zero current will flow. RF is like the punk kid that sat at the back of the class - They don't follow our rules.
Question please.... I have a new, unused 100 dollar 5/8 wave vertical for ~ 27 MHz and not quite sure of how the "internals" are connected. An ohmmeter check is NOT the proper tool, but, I am measuring damn near a short ~ 1 ohm which is similar to what you show at about 4:30 which would measure as a short at DC level and is the meters residual reading between the outer threads to center conductor of the antenna's PL259 female. I can see that the resistance between the coax center conductor and the tuning stub will indeed measure a DC short, but, am asking the PRO for his opinion.... Thank you ahead of time.... Hank
Not sure what your question is but resistance and impedance are both expressed in Ohms However impedance is a vector of resistance and reactance. I haven’t seen the matching section of your antenna so I can’t really say but I’d guess that it is matched through a Tapped Coil and possibly some fixed capacitors to Tune out reactance and achieve resonance. Reactance may be inductive if the antenna is too long or Capacitive Reactance if the antenna is too short Not sure if this helps any or adds more confusion ! Thanks for watching and good luck.
@@madeinfoxtrap5539My further investigation found the tuned stub at the SO239 antenna connector was classified as a "direct ground type circuit".... What may **appear** as a short is, indeed, a DC short, but, this low resistance is an **RF** tuned circuit with a nominal 50 ohm impedance.... This direct ground type of circuit provides some protection against a lightning strike, but, I believe you would still need a new radio regardless of how well the lightning was discharged to ground.... A "practical" test is that if your are receiving signals you are good to go with transmitting....
I haven’t tried ground radials on this design. I would encourage you and others to experiment and see what works. This design evolved from a lot of experiments and eventually found resonance ! Thanks for watching and share with your friends who may be interested.
@@madeinfoxtrap5539, well, I thought it through and your addition of that 1/8 stub makes the antenna a full wave antenna in length but the radiating element remains 5/8th wave. It’s a clever idea adding the stub.
I remember that ole Ringo, i bought that antenna originally at Traders over by the Avalon mall before they moved and changed their name to Cash Converters and now reside on Freshwater road. Yes sir that SO239 connector did turn to dust from our salty air, most likely that connector was the cheapest they could find i'm sure. Thank you for fixing up the connector, i did use the antenna for awhile then replaced it with something else, can't remember what it was now, perhaps one of your CONE dipoles? Glad you made some use of that antenna afterwards and had some fun building your own version of it. BTW, i think i may have another version of the same antenna here now and some other antenna's. You are welcome to them, one is a TRAM 1487 VHF 5/8 wave ground plane, great antennas. 🙂
it's solid matching part! thx..
Love it, I’ll have a go at this
GR8 Project ! TNX for your efforts , 73 W5heh
Thanks !
73 de VO1DV
Awesome job Dave
👍👍👍👍👍 you have done a good job. I don't like verticale Half wave length antenna. 5/8 are Better and have more gain. 3/4 Is even Better. The strange thing for me is the 75 ohm cable. But if It is so, It's so. Good job mate. I like building antenna. All the best.
I first tried with 50 Ohm and couldn’t get the SWR lower than 1.5 When I tried it with 75 Ohm it tuned just about FLAT !
Thanks for watching and share with your friends. Check out my other videos on this channel to see some of my other projects.
@@madeinfoxtrap5539 I believe you 100% that you got flat SWR with a 75 ohm cable. RF Is strange. I have been working for more then 40 years in communication, MF, HF, VHF, UHF and microwave, and I have seen too many strange thing with RF. 👍👍👍👍👍👍👍
Your build is really cool. 73 KM7Y
Thanks ! 73 de VO1DV
You did not described the end part. From where the ring connects to the 1/8th piece, what is the lenght to the wooden part. Or is the square piece in total 9 5/8 inch?
Yes
The 5/8wl should have a slightly smaller appature aka better gain.
Forgive me as I'm a new ham and new to antenna theory so I'm trying to understand what's going on here. How is it OK for the radiating element be shorted directly to ground? How would that not burn up the transmitter?
Don’t feel bad as I asked the same question when I was first licensed !!
Connection is made on a two-turn coil to provide
Inductive Matching
This design was a LOT of trial and error but eventually became a resonant antenna
@@madeinfoxtrap5539 Thank you for the reply, I eventually found a video that explained how J-poles work. Still scares me!
The thing that makes this "short circuit" okay is frequency.
The lowest frequency you could have is "on" with no change.
An antenna is used at a higher frequency than this - at 2m (145MHz) the voltage switches polarity one hundred and forty five MILLION times a second.
Because of how fast the change in voltage (and thus current) is, you can actually measure different voltages along a single conductor like an antenna. This is because the electrons simply can't travel as fast as they are being asked to. If you get the length of the "short circuit" just right, the point where the short is will be a zero voltage point, and thus zero current will flow.
RF is like the punk kid that sat at the back of the class - They don't follow our rules.
5/8 Antenna
Question please.... I have a new, unused 100 dollar 5/8 wave vertical for ~ 27 MHz and not quite sure of how the "internals" are connected. An ohmmeter check is NOT the proper tool, but, I am measuring damn near a short ~ 1 ohm which is similar to what you show at about 4:30 which would measure as a short at DC level and is the meters residual reading between the outer threads to center conductor of the antenna's PL259 female. I can see that the resistance between the coax center conductor and the tuning stub will indeed measure a DC short, but, am asking the PRO for his opinion.... Thank you ahead of time.... Hank
Not sure what your question is but resistance and impedance are both expressed in Ohms
However impedance is a vector of resistance and reactance.
I haven’t seen the matching section of your antenna so
I can’t really say but I’d guess that it is matched through a
Tapped Coil and possibly some fixed capacitors to
Tune out reactance and achieve resonance.
Reactance may be inductive if the antenna is too long or
Capacitive Reactance if the antenna is too short
Not sure if this helps any or adds more confusion !
Thanks for watching and good luck.
@@madeinfoxtrap5539My further investigation found the tuned stub at the SO239 antenna connector was classified as a "direct ground type circuit".... What may **appear** as a short is, indeed, a DC short, but, this low resistance is an **RF** tuned circuit with a nominal 50 ohm impedance.... This direct ground type of circuit provides some protection against a lightning strike, but, I believe you would still need a new radio regardless of how well the lightning was discharged to ground.... A "practical" test is that if your are receiving signals you are good to go with transmitting....
@@madeinfoxtrap5539 Reactance maybe inductive if antenna is too SHORT or Capacitive Reactance if too LONG.
@@zsradioham you have it backwards
Nice work! How much clearance do you need from the stub to attach ground plane elements?
I haven’t tried ground radials on this design. I would encourage you and others to experiment and see what works. This design evolved from a lot of experiments and eventually found resonance !
Thanks for watching and share with your friends who may be interested.
@@madeinfoxtrap5539, well, I thought it through and your addition of that 1/8 stub makes the antenna a full wave antenna in length but the radiating element remains 5/8th wave. It’s a clever idea adding the stub.