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[K4RVN]

 I don't know why some make some simple things so difficult to find for we do it yourself antenna builders. Here are some items that may help cut  the search for info. for those like I am with limited math skills.

Electrical wave length in feet.
983.6 x velocity factor of wire divided by the frequency in MHz  is one wave length. If you need 1/4 wave multiply result by .25, 1/2 wave by .5 and so on . Good to know for matching impedance and determining feed line lengths of coax to transceiver.

Dipole Formula:
468 divided by frequency in MHz . If you want to make a 2 element fixed wire beam add a reflector behind the dipole driven element that is 5% longer. If you want a three element beam add an additional director 5% shorter out in front of the dipole. Works great. Other directors of the same length may be added for additional gain in the director direction. Spacing between elements around 15 to 25 feet will work. 25 will be better if you have the room.

Full wave loop for delta loop, quad loop, etc. 1005 divided by the frequency in MHz. For additional gain, add a reflector and /or director 5% longer and 5% shorter respectively. Makes an array with good performance. Spacing of 15 to 25 ft will work.

DXE catalog gives the VF of their coax types so a good source of information. I use .95 for insulated THHN stranded copper # 14,  but you can ignore it with little effect. I always add a little length to the calculated driven element so I can trim it as required.
Frank

[KC0W]

Spacing between elements around 15 to 25 feet will work. 25 will be better if you have the room.

 So a 3 element 160 meter wire Yagi has spacing between the elements of 25'? How about a 6 meter 3 element Yagi?...............I didn't think so.

                                                                            Tom KH0/KC0W

[K4RVN]

Tom I was thinking of 40 meters on spacing  but did not say so. Than being said, I have never seen a 160 meter Yagi so very little need to answer for that one as few probably exist.  My spacings are for 40 meter antennas so perhaps the readers will pick up on this as a result of your post. I wish I could correct my original post but can't. My bad!
Frank

[G4AON]

Unfortunately, many amateurs seem to lack the ability to make even a simple antenna. Note the numbers buying ready made wire antennas. It used to be G5RV antennas, more recently it’s end fed wire antennas.

Few bother to learn how to model antennas, yet it only involves basic school kid mathematics (at worst). I posted a thread on here with a link to a spreadsheet for calculating the coordinates of an inverted V dipole, which didn’t get much response and some criticism. I am only trying to help!

The calc is here:
https://www.qsl.net/g4aon/resources/inv_v.zip

73 Dave

[AI5BC]

I don't know why some make some simple things so difficult to find for we do it yourself antenna builders. Here are some items that may help cut  the search for info. for those like I am with limited math skills.

Well, that is because the vast majority of CB and Ham operators do not know squat about RF or electrical. Like yourself, they cannot do the simple 6th grade math. What is really funny, is they then try to teach others on a foru, and then wonder why they got roasted for it.

[K4RVN]

Dave, G4AON,
I can see what you mean about trying to help and then drawing the mean spirited replies. As for you Brad I just shared information, not trying to teach anyone anything about electronics as this is just a hobby for me. I was a PE,  registered Mechanical Engineer in 2 states as a work person qualified by written exam.
I passed my exam for general, and Advanced at the FCC office. Also 13 WPM code. I can do 6th grade math and get it right about 50% of the time. Just trying to help cut the search for info not teach anyone. Lighten up OM as this is a hobby to enjoy. If the information I posted is not needed, then don't use it. To those who are having difficulty finding info to build an antenna, I hope it may help.
Frank

[KB2WVO]

my lil soap box for this is .....

newbies are told its this way or it wont work for you... i never followed that.. why .. becuse 2 dipoles made purfect alike. will act diff in 2 diff spots in not only your own yard but in someone elses..

i say to all newbies... build it work it find out how it works for you try another .... thats the fun of the hobby..
dont take one word from one person sayin that wont work for you .. becuse...........

i use the crapest antenna in the world. nvis 75 slooper 3ft off ground to 30ft at end. the ground plane is 2 60ft 12g rolled up in a 5ft diam circle hangin on the tree next to it.. works fine .. i worked spain with it ..

[KF6QEX]

" buying ready made wire antennas. It used to be G5RV antennas, more recently it’s end fed wire antennas."

Next, we'll be able to buy pre-boiled  water (so we know "it works")

[W6SWO]

Good info Frank, and thanks for posting.  Not really new info, but it's in a quick "digest" format that I can easily carry on my phone as a note.  Like you, I am a Mechanical Engineer, but quite frankly, my brain is not working in my 60's like it did in my 20's.  Thanks for posting, and I agree on "Lighten up OM. This is a hobby". 

[K4RVN]

Thanks for  positive reply Tom, it made my day and I will quit on it. BTW, I will be 90 in two months if I make it so can relate to making a few incompletions now and then and sometimes a mistake.
Go Navy.
73
Frank

[KC3TEC]

Thanks for  positive reply Tom, it made my day and I will quit on it. BTW, I will be 90 in two months if I make it so can relate to making a few incompletions now and then and sometimes a mistake.
Go Navy.
73
Frank

Thank you as well, math skills are important  in any field but rarely taught properly.
With most hams starting out, unless they are starting young there is the issue of financial limitations.
Retiring healthy is one hell of a bonus, but if you have any health issues at all it puts a serious restriction on your funds.
So homebrew whether it's antennas or radios is a must.

There are many elitists in this hobby, same as with many hobbies.
(" if you can't buy the best, then stay out of the nest ")
Some hams refuse to talk to other when they find out they are using a pixie or baofeng, 
and the disdain exhibited puts a lot of new hams off.
You have many disgruntled hams griping about the dropping of the code requirement on the tests.
Are they the ones a new ham wants for an elmer?

[KG4LAC]

I was absolutely dumbfounded when a younger relative informed my they didn't get a factory job because they could NOT read a ruler. I know I stared at them in disbelief. My brain and mouth were, temporarily, disconnected. I finally managed to say, "You mean 3/8 inch or 1/2 inch"? They replied, "Yea".

Oh, boy...

[K7MEM]

I was absolutely dumbfounded when a younger relative informed my they didn't get a factory job because they could NOT read a ruler. I know I stared at them in disbelief. My brain and mouth were, temporarily, disconnected. I finally managed to say, "You mean 3/8 inch or 1/2 inch"? They replied, "Yea".

Oh, boy...

Many years ago, my company hired a technician, straight out of tech school, to help me out in the lab. We had a bunch of small 9" CRT monitors that were not working. There were only a couple of small circuit boards in each monitor, so I gave him the task of checking the transistor on the boards. At the time, we mostly use Simpson 260 in the labs. Well he came back to me and said that "all" the transistors were bad. I couldn't believe that because, each monitor was partially working. It turned out that, during his training at tech school, they only used digital meters. He didn't realize that the resistance scale of a analog meter read backwards.

But I guess, it all just a sign of the times. I know that when I was in 9th grade (1964 or 1965?) my father gave me a slide ruler and I quickly learned how to use it. I still keep my slide rules in a drawer, in case there is a power failure and I need to compute something. These days, the younger generation just pulls up a calculator on their phone. But they know much more than I do, or ever want to, about those phones.