Compact, No-Radial, HF Vertical Antenna based on Flagpole Technique | Ham Radio

  • 🎬 Video
  • ℹ️ Published 3 months ago

Here is an interesting project that enables you to produce an efficient, yet short, vertical antenna that requires no radials. The concept and design is discussed by Peter G3OJV. Maybe you can adapt this idea to suit your own particular needs.

Flagpole DX Antennas

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💬 Comments

This is one of the BEST I've seen on this channel. Bravo Peter. I can confirm that feeding the vertical at 1/3 up from ground does work well because the lower end is coupling to ground, making it electrically longer. The balanced line up inside a conduit will have a slight imbalance, but no big deal. The outer sheath acts as a sort of "folded balun". Placing the real 1:1 choke/balun at the input of the tuner is by far the best location for it. The only thing I would add is that any control cables for the ATU also need to be choked, otherwise return currents will pass through them and render the ATU not actually "floating". I have done this with my AH-4 to feed a doublet at the center, and yes it does work well. 73 Peter, and thanks for sharing an excellent discussion. I hope others make and experiment with this design.

Author — WECB640


Very informative video and fascinating antenna design! It's potentially a stealth antenna as well, though I believe my XYL would have noticed if a 7 meters tall pole popped up in the garden.

How would this antenna work if you substituted the tubing with wires? I assume it would work, but most likely at the cost of the bandwidth.
It would definitely be interesting to build and experiment with.

Author — LB5SH


Good video, thanks Peter. This idea is very interesting as it might be adapted to make a useful multiband portable/field antenna. One thing that occured to me is, if the "flagpole" was next to a wooden fence, the balanced line may be hidden by running it along the fence.... UK hams maybe need to unite - make flagpoles in our gardens a common feature, just like our US friends.😂

Author — Steve GM0HUU


Hi Peter - A GREAT video - I really enjoyed your explanation and how easy it is to build - I am sure you will encourage your subscribers to have a go especially as it covers so many bands - excellent -Dave

Author — David Cole


Hi Peter, as always a great informative video, i have been using an Aluminium scaffold pole 10m in length as a vertical and am pleased with the results, mounted on my garage isolated from earth with ceramic, fed from an Icom AH 4 mounted inside the garage, i do have copper radials and an earth all terminations hidden under my decking. Can resonate on all bands between 80 and 6m . Ultimate stealth as one of my wife’s friends came round and commented why her washing line was so tall. Regards. Paul G7JVB

Author — Bruton Street Tailor


hello Peter Love your videos, i have just started my foundation course and don, t have much money the video about a year ago that you did LOW COST HIGH PERFORMANCE HF ANTENNA is a real gem. My question is would a slightly smaller ferrite ring still work and insulated copper wire as I have both.

Author — Peter Rowland


Hi Peter, another excellent video. May I ask you were you bought the bamboo stand that is sitting over your two radios? Look fantastic!

Author — Glenn Stevenson


GREAT video Peter. What would your thought be on elevating the flagpole antenna approximately 25 feet or so. Since it does not require a ground there shouldnt be a problem? Please let me know what you think. Thanks again for the awesome video Very well presented.


Author — Jerry Boyer


I love your channel Peter... and this is another really interesting video... got me thinking for sure on how I could use this idea...many thanks, much appreciated.

Author — David Portch


I have been using vertical dipoles for single bands, and as doublets for a couple years now. This is an antenna that is overlooked far too often. I feed mine with twin RG-6 cable, using only the center wire, one per antenna element. RG-6 is very insulated and can be ran parallel to the lower antenna element, down a metal mast, alongside gutters, etc. It eliminates the issue of metal interacting with the RF field of traditional twin line feed. So you can skip the running of the feed line at right angles to the antenna. I still run it to the 4:1 posts on my ATU.

Author — Liberty Cave WS7PB


Hi Peter, your video is very usefull and informative. One question for the 1:1 balun, is this used only to stop common mode currents flowing to the shack or is it for impeadance matching?

Author — 32bits


This looks like an off center fed but vertical. The balance line could act like part of the matching network depending on length. The tuner is making the match.
I'm guessing the return currents get to ride on the bottom short piece of wire. Same idea as adding a ground side to the End Fed half wave for improved performance.

Author — Ken


A very interesting topic and an extremely well delivered presentation.
Thank you Peter.

Author — Richard Powell


This is very interesting however knowing that the ATU's require DC to operate and this is supplied down the coax. Having reviewed the video you referenced, I use an SDG tuner that requires the use of an iso-T to strip off DC from the signal in the coax. The type of balun needed is a 1:1 CURRENT BALUN. So one needs to install the system as such, current balun, iso-T, tuner and antenna. What does one do for lightning protection at the antenna point? Can we use a spark gap lighting protector at the point where the ladder line meets the tuner? When not in use I keep all antennas isolated (disconnected) from my equipment. Dropping a flag pole is out of the question as to the fact it would arise suspicion why it’s lowered for t-storms. We live in a "hot zone" for lightning strikes being up hill and near the ocean.

Author — Subgunman


Could you then run the wire out horizontally from the top of the fibreglass pole across your garden, forming a sort of inverted L? How would it affect the impedance at the feed point, would it be higher as you're now further from the centre towards the end of the wire? Would it still work as a doublet?

Author — Paul Sengupta


I bought the 20' version of the Flagpole antenna and used it with the RT-100 and 1:1 choke but never got good performance out of it. I'm in mid-US and could only get to western Europe. I corresponded with John many times and although he was very helpful the best we could do was mid Europe after putting down 32 radials which were not connected to the antenna but merely acted to increase soil conductivity. One of the problems with this antenna is hiding the remote tuners esp. if you don't want to bury it in the ground. I used a planter box but still you could tell something was fishy and it didn't fool my more curious neighbors. Interesting concept though

Author — Charles Loewe


Cheers Peter, very interesting, will turn my doublet 90ds at the weekend.. loving my new Zero QRM /!QTH from IO66 Inner Hebrides!! Regularly RX ..YB, VK and RA0 on 15ms, 10 still to come alive like last October 73, Mm0hlt

Author — Andrew


Balanced line inside a conductive tube, is called TWIN-AX. IBM was using this type of cable for digital networking back in the 70's

73 de K1TDG

Author — Terry Gilsenan


Excellent video but would it not be just as easy when attaching the atu to the doublet just to use a short piece of coax the centre to top doublet and braid to bottom as your using short piece coax to go to balan oviously using pl259s to plug into atu or is there specific reason for connecting doublet directly to atu just wondering

Author — sniperchaz111


Brilliant I have a home made ZL6BKW, I will have a go with my 300 Ohms Ladder-line and the 10m pole and use my LDG 4:1 I use my 10m pole for my EFHW 33ft up, Brilliant video how much wire do I need both side 20m in total Thanks Tom 2E1FUE 73's.

Author — Tom - 2E1FUE