I like the new format. Just don't stop the old format. You have been a wealth of information on the technical end that we can count on for good information. I may deviate a bit from time to time, but your info is solid. Much appreciation and respect.

Dropping The Knowledge!

Very well done son. Keep the lessons rolling. 73

It’s nice to see the OCFD getting some love. I like using them but also need to learn more about them.

I once had acres and acres of land and at the suggestion of a friend I built a 160 meter full wave loop. It was a worthwhile project, the loop really delivered the DX. I'm back in the city now and employ a Rybakov (4:1 UNUN), a 135' EF (9:1 UNUN), and an OCFD (4:1 Balun). All three work well, and have their own plusses and minuses.

Excellent format! Love what you’re doing!

A very good explanation of the OCF dipole. Due to my lot size I have been using a 66' Wndom in an inverted vee for several years. It has served me well on 80-10m. Thanks for doing this type of videos. KC8WVG 73

Great info Ape, most just roll over the fine points

I used a 40 meter commercial off center fed dipole for one reason: there were two trees in my front yard 70’ apart and a right angle feed to my upstairs shack was right at the 1/3-2/3 portion of the antenna. So it fit between the trees and the coax feed came straight into my shack. I used a tuner on 30 meters but the other bands were matched quite well. It was not objectionable to my wife and worked well until we moved a few years later.

I like pictures so I will give you a 👍. Excellent job Ape!

Cool series you got going Ape!

You can feed a half wave dipole anywhere along its length. The feedpoint impedance is lowest in the center, and highest at the ends. If it fed with coax, there will generally be a mismatch and therefore reflected power. The main issue is that coax is lossy. At low HF frequencies losses are small. Something to remember (this can be found in the ARRL Antenna book) - an antenna does not have to be resonant to radiate well. When we say an antenna is "resonant", we are inferring that reactances cancel out on the antenna and the feedpoint impedance becomes totally resistive. This does not infer that the feedpoint will have a perfect match with coax, and with a half wave dipole there is a a 1.5:1 mismatch at resonance. Does this matter? No. Losses will be a fraction of a dB and undetecable to the receiving station. Design issues are mostly concerned with feed lines and feed points. An OCF dipole works extremely well when fed with balanced feedline, which is lossless at HF, despite seeing very high VSWR levels. It makes a great multi-band antenna (HF) with a minmum of cheaply sourced materials. Here's a tip to help understand what's going on. Visualise a halfwave sine wave superimposed on the wire. This helps determine the feedpoint impedance. An OCF dipole does not need to be resonant on any frequency, and works on any HF band, provided you use balanced feeders. These feeders are high impedance, therefore high voltage/low current which keeps I squared R losses to a minimum. Their velocity factor is also close to 100%. You must use a tuner at the transmitter end, preferably a high end tuner containing a roller inductor and proper balun and balanced outputs. The reflected power is not "lost", but travels up and down the feedline, and because of the low losses, pretty much most of the energy will be radiated by the antenna. I used a simple OCF doublet way back when, and had excellent results with it, especially on QRP (5 watts or less). There are various designs of the OCF dipole using different proportions, but generally the two thirds/one third point works well. You can determine the radiation pattern using popular free software. The general rules about installation height and ground conditions, porximity to metal structures and objects still apply. I construct HF antennas with cheap insulated speaker wire, using the wire for both feedline and radiator, and whatever I find for spreaders. This arrangement will allow a bit of power because of the high impedance, so it saves a few bucks on expensive high grade coax and connectors.

Thank you, sir! I appreciate it. Cheers. That inverted L configuration you mention gives me some more ideas to play around with too. That's always a good thing... (just don't ask my wife about it). 🍻

nice job. a lot of end fed with a counter poise can be a off set center fed. just depends how you look at it. most do not count the counter poise. but it is part of the antenna system. solar weather crazy. getting buffering on internet a lot lately during the day. even noticed the GPS lock in car nav system was off the outher day. ham bands been messed up. farmers having trouble planting crops with GPS needing a good lock for precise seed planting. getting high noise 80/160 meters making un usable in NY for me. this is common . their is a random wire center fed. that uses a 9:1 Balun . still needs tuner. same wire lengths just 2 of them. still prone to common mode current. have not tried that yet. Walt made one with speaker wire and worked great . the trouble I had with off set center fed di pole was tunning. and keeping feed line at right angle to antenna. 73's

Indeed, a random wire with counterpoise is essentially a random OCF dipole.

Dear Ape, As always time very well spend watching/listening to your videos. Thank You. FM KQ4IXD

Good stuff Apeman. I like this new series. I was just looking at a VK seller for an OCFD and may buy it for my QTH. I asked him for a pic of the toe-roid and he sent me a pic.... I need to show it to you. Dual core, both with different windings. May send you the pic on Discord but just don't share it just yet as I'd need to ask for his permission. I think you'll be interested to see it. It's new to me anyway. :)

Good video of a complex subject! I prefer single band antennas and have several. Actually I prefer single band dipoles broadside on the direction I want to work. A good Yagi may be a S-unit better but is much more costly and takes a lot more effort. I have had them and they work but the dipoles do almost as good. Regardless of the antenna, no one antenna does it all! I like fan dipoles as they give single band performance off one coax. My 20/10 meter dipoles are not much more effort to build than a single dipole. Trying to do a 40/20/10 fan dipole takes more patience but the results give me excellent results. I use spacers between the dipoles so all the dipoles are broadside to the same direction. Since I cut my antenna for the CW band, my 40 dipole covers 15, but the pattern is not broadside as with the halfwave dipoles. I frequently hang a temporary 15 meter dipole broadside on Europe for DX contests. All halfwave horizontal antennas will have essentially the same pattern. They are resonant and can be fed anywhere. Center fed presents less problems but OFC can give easy multiband coverage. The transformer ratio and location varies and are a compromise to accommodate the various bands. If coax is good and inherent loss is small, the built in tuner in most radios can fix a lot of mistakes. Height above ground determines the peak radiation angle for a horizontal antenna. Usually the lobe is rather broad between the 3 dB points, for moderate heights. Higher antennas have multiple lobes which results in deeper nulls and sharper lobes. Great for extreme DX, not so much for everyday use.

I’m currently running a 80m ocfd with a balun designs 4:1 balun and a atu-100 tuner. The antenna works well even though feed point is only 22’ high with ends tapered down slightly. I would love to be able to dial it in better but I don’t know how to adjust it.

A dipole antenna has a centre feed point impedance less than 50 Ohms and the legs of the dipole are fixed. How do you increase the impedance at the feed point to match the 50 Ohm transmission line? Why is the impedance of the HAM radio typically 50 Ohms.?

I'd appreciate advice regarding HT rechargeable batteries. I have TYT TH-350 (LB-75L) batteries that will not fully recharge and deplete very quickly. Any suggestions? Thanks and 73! Tim VE3TCS

Is there a radio good for listening to police calls?

So you said you don't really like fan dipole are you saying you don't really like the dx commander because it is basically a fan dipole put up vertical direction