interesting video! I just made a vertically polarized fan dipole for listening to VHF and UHF air band. what I found when tuning it is that the bandwidth increases as you increase the separation of the elements. I ended up settling on a 45 degree angle (about 6 1/2 inches max separation at the tip of the UHF element) with a bandwidth below 3:1 SWR of 20MHz on both VHF and UHF. I am really amazed that you can make a single antenna to cover multiple bands which is of interest to me as a scanner listener.
I tried a ferrite ring on my outdoor 60m inverted vee at the aerial and found it wasn't very good at stopping r.f. I now have it in the shack. I've seen both positions recommended by aerial manufacturers. I think r.f. got in below the ferrite ring. Perhaps one positioned some distance from the aerial would be better? I'm going to slide the rings up the coax to the ceiling to try on my attic dipoles, 14 mHz and 18 on one coax, 21 and 24 on the other with 28 on the other. Three coax cables for less interaction. I might try 14 and 21 together for that reason and 18 with 24 leaving 28 on it's own.. G4GHB.
I run a home built 75-40-20 fan dipole in an inverted V configuration. At first, I wasn't using a balun. But I then inserted a 1:1 balun. The effect was to reduce noise by 2 S units. I have used this antenna on the 15 meter and 10 meter bands as well. I find it a very good antenna. Tune the longest runs first, the the middle run and finally the shortest run. The center is at 35 feet on an MSJ 1917 fiberglass pole. I try to keep,the ends at 7 feet above the ground in order to avoid deer problems. I have the 75 meter run on a North-South azimuth. The 40 meter run is about 15 degree azimuth from that and finally the 20 meter run is at about 30 degrees from the 75 meter antenna. '73s AI7MY
can I run fan with a 72 ohm linear loaded 80m dipole and a 600 ohm folded 40m dipole on the same 450 ohm window line feed point into old style conventional LC tuner (Murch) with twin lead inputs?
The answer to the viewer question is to tune the lowest band first (longest wire) and then the next higher band and so on. The reason is that the longer wire has influence on the shorter ones and that has to be tuned out. Its not as complicated as this video wich also didnt answer the question. Made one years ago and it was easy and worked perfectly.
Interesting. Makes sense too. I'm considering playing around with some multi-band dipoles once the weather warms up, so this topic is somewhat timely for me.
that‘s not fair, man. dave is putting a big effort into this videos (try making one, yourself). and he only asks once for some support on patreon, which is completely fine. that there might be better ways to do the job, doesn’t change that.
everything effects everything. the shorter elements are capacitively coupled to the larger ones making them act like a gamma match and will change the resonant frequency of the longer one(s). the coupling decreases as the elements are spaced further away. so I tuned by first deciding on separation and then adjusting the band that need to be electrically shorter first. if you are comfortable with smith charts, a nanovna is a big help here and you can see where you are just by watching the chart.
Sorry, Dave...but I didn't hear anything related to the question and, certainly, the title is completely misleading. Wasting my time waiting for "Tuning a Fan Dipole" is not what I had in mind. Let's try and avoid "clickbait" in the future. You have some great videos and I enjoy your method of presentation but this one just didn't come up to par.
NO there is no minimum separation between elements. the bandwidth increases as they are spaced further apart but they can be tuned even when right next to each other.
interesting video! I just made a vertically polarized fan dipole for listening to VHF and UHF air band. what I found when tuning it is that the bandwidth increases as you increase the separation of the elements. I ended up settling on a 45 degree angle (about 6 1/2 inches max separation at the tip of the UHF element) with a bandwidth below 3:1 SWR of 20MHz on both VHF and UHF. I am really amazed that you can make a single antenna to cover multiple bands which is of interest to me as a scanner listener.
I tried a ferrite ring on my outdoor 60m inverted vee at the aerial and found it wasn't very good at stopping r.f. I now have it in the shack. I've seen both positions recommended by aerial manufacturers. I think r.f. got in below the ferrite ring.
Perhaps one positioned some distance from the aerial would be better?
I'm going to slide the rings up the coax to the ceiling to try on my attic dipoles, 14 mHz and 18 on one coax, 21 and 24 on the other with 28 on the other. Three coax cables for less interaction. I might try 14 and 21 together for that reason and 18 with 24 leaving 28 on it's own..
G4GHB.
I run a home built 75-40-20 fan dipole in an inverted V configuration. At first, I wasn't using a balun. But I then inserted a 1:1 balun. The effect was to reduce noise by 2 S units. I have used this antenna on the 15 meter and 10 meter bands as well. I find it a very good antenna. Tune the longest runs first, the the middle run and finally the shortest run. The center is at 35 feet on an MSJ 1917 fiberglass pole. I try to keep,the ends at 7 feet above the ground in order to avoid deer problems. I have the 75 meter run on a North-South azimuth. The 40 meter run is about 15 degree azimuth from that and finally the 20 meter run is at about 30 degrees from the 75 meter antenna. '73s AI7MY
Excellent tip! I put up a fan dipole in my attic, and it works, but it’s noisy so I’ll try using a Balun….
can I run fan with a 72 ohm linear loaded 80m dipole and a 600 ohm folded 40m dipole on the same 450 ohm window line feed point into old style conventional LC tuner (Murch) with twin lead inputs?
Thanks for another great video!
The answer to the viewer question is to tune the lowest band first (longest wire) and then the next higher band and so on. The reason is that the longer wire has influence on the shorter ones and that has to be tuned out. Its not as complicated as this video wich also didnt answer the question. Made one years ago and it was easy and worked perfectly.
Interesting. Makes sense too. I'm considering playing around with some multi-band dipoles once the weather warms up, so this topic is somewhat timely for me.
I appreciate you trying to answer the question. I guess Dave was preoccupied with trying to get more patrons….
that‘s not fair, man. dave is putting a big effort into this videos (try making one, yourself). and he only asks once for some support on patreon, which is completely fine. that there might be better ways to do the job, doesn’t change that.
everything effects everything. the shorter elements are capacitively coupled to the larger ones making them act like a gamma match and will change the resonant frequency of the longer one(s). the coupling decreases as the elements are spaced further away. so I tuned by first deciding on separation and then adjusting the band that need to be electrically shorter first. if you are comfortable with smith charts, a nanovna is a big help here and you can see where you are just by watching the chart.
Good job @migsvensurfing6310 let’s just hope the person that wrote in to David read your comments.
Tuning????
Sorry, Dave...but I didn't hear anything related to the question and, certainly, the title is completely misleading. Wasting my time waiting for "Tuning a Fan Dipole" is not what I had in mind. Let's try and avoid "clickbait" in the future. You have some great videos and I enjoy your method of presentation but this one just didn't come up to par.
NO there is no minimum separation between elements. the bandwidth increases as they are spaced further apart but they can be tuned even when right next to each other.