How to Shorten Wire Antennas with Loading Coils

I show you how to calculate the right sized loading coil - and how to make your wire dipole or vertical antenna shorter by placing the correct loading coil in the right place on the wire. Links as follows:

[RicksHamShack]

Moving a fixed inductor up or down to change the antenna frequency of resonance-that's some great information. Thanks Callum.

[rickvia]

Loading coils have always been my worst fear when designing a shortened antenna, so I stopped even attempting it many years ago. Thanks, Friend.

[Mister-Six_]

I love this dude- Your channel is OUTSTANDING. 😂 Love it!

[robertmeyer]

That was real good. Placement of the coil is key as well. I did notice with base loading on vertable ground mount antenna . the diameter of the coil makes the Q of antenna band with of tune point change. shows up on VNA doing SWR sweep of band. large diameter coil increases the band with of the tune a tad and small diameter makes the band with of the tune smaller . higher Q . also the more inductance needed the tighter the Q is. more loading the tighter the tune and smaller band with. also the spacing of turns on coil changes tune as well. lot to keep track of when making a coil. Cheers !

[karlwalker]

Great video Cal, I used my dx expedition pole to create a 60m vertical using that web site. A loading coil made out of some 40mm plastic waste pipe and put half way up the 30ft element is working great, 50ohm at the feedpoint and an incredibly low swr!

[jackKFIT]

My 2nd antenna build was a 40m inverted V. Later I needed to add 80m but didn't have the room. I found a video by Dave Tadlock on youtube (2011 video) showing how to build loading coils for he ends of the 40m elements with an additional 4 or 5 ft of wire to get 80m. I built 2 and used them successfully for a year or so. It's 78 turns of 18ga magnet wire around a 50mm (1&1/2in pvc) core. 80 m was very narrow banded but all I wanted was one frequency anyway so it worked like a charm. I still have that antenna in storage.

[B_MAD_]

I spent a long time on that website designing my loading coil for the 630 meter band.

[patrickhooper]

The coil works great for the 40 meter element on the rapids mast. Colin actually told me the number of turns, worked great.

[IrishHamRadio]

This loaded 20/40 antenna is exactly what I want for SOTA…. Very interesting on the detail and online calculators as loading coils still somewhat of a mystery to me.
Between watching this and what Tim has been doing with coils also, building one has definitely moved up my priority list!

[BrokenSignal]

Those links are handy, bookmarking them now. Thanks Callum!

[MBVV-Phil]

Great to see you back on my screen Callum, as always some dam good information! P.S. I haven't seen your specs, I generally find mine down the side of my chair, hihi.

[EmJayArr]

Well that's a coincidence. Just this week I started thinking about how to do exactly that: making a 20m & 40m vertical with maybe a loading coil or hat. I hadn't gotten very far yet, but it's good to know it works and to get some hints!

[mewrongwayKOCXF]

Awesome Callum! Antenna's are so much fun!!

[johnrees..GEIJ]

Thanks Callum..Excellent, informative video...as always..73..John

[thomasperina]

Welcome Back Lord Callum: I definitely missed your humor as well as your antenna wisdom. The nice loading you made is terrific but how much power can you run into it or calculate, please advise sir. Maybe you could make a video on this as I'm certain it could become complicated. God Bless you sir & my best to Wendy and the dogs. TMP, Unit 22 from N.J

[matthewduhon]

Great video, I plan on trying to build a dipole 2 element yagi like your new videos. Using a loading coil and the Rapide poles for each leg for 40m

[FromthehamshackwithNJZ]

Brilliant Stuff!!!! great explanation!

[Jiminico]

Would like to calculate how much inductance is needed for a coil for an EFHW and how far from the unun so all the harmonics are tuned better. Not really trying to shorten the wire length as much as just trying to keep the higher harmonics better in tune as the fundamental frequency was tuned for.

[MoFoSoB]

Perhaps I am mistaken, but at minutes 1:19 and 3:01, you enter the value '2' in the calculator under the line 'diameter of the conductor in inches, ' which means 50 mm, the diameter of the coil's core. This seems too large for the diameter of the wire being used. Is this correct?

[philwhoareyou]

Hey Cal, great video. I have been playing with shortened verticals using loading coils. Reading up on them the position of the coil relative to the feed point, the lower you go also drops the coil impedance but also the efficiency of the antenna. So me being a smarty pants thought why not go higher and get as much omph as you can get. Well... so you end up with quite the coil at about 75% point. I was wondering if we swap out the wire wound coil for a ferrite wound inductor what happens, as this would take up less space and leave you with more wire for the given height that radiates but how does this effect the bandwidth with a higher Q inductor in place?. Any one tried this? We are in Winter down here in ZL so I haven't pursued this much further. I am using 4x40mm conduit as its relatively cheap and stays vertical. Anyway thought I just chuck that question out to see if any one has. End goal was a trapped vertical with loading coils.