quad reflector versus yagi reflector

[Needle Bender]

Hey NB, I have continued to work with my model of the 5 element Quad using your information as best I understand it. I have not matched the antenna as yet. Do you recall or know even close to the length of your matching line you used...or did you use a gamma match? It sure might save me a lot of trial an error if you would give up that little secret.

My model to this point has been tuned for a good match and not maximum gain. I think that limits the optimizing possibilities somewhat using the spacing and loop size to get more gain.

I have been working with this 5 element and I have seen some really good gain figures but the match was really bad and I was thinking it might be possible to get some more gain and then tune it with a 75 ohm line to show a good match at resonance without destroying the match.

I already have a whopping good rejection model with over -40db front to back. I know you could tell that using only your radio...but I'm not to sure one could really tell the difference in gain I've been seeing...and it isn't much difference using a balance spacing scheme thus far.

Below is the Free Space pattern with the max front/back noted in the antenna details printed out here.

OK, for a matching line just use a 1/4 wave of 75Ω direct-drive, but tune for maximum front - back.

...and if I didn't design & tune the quad used in comparison to a Yagi, I don't trust it.

 

[cdx304]

You have heard on dBd, gain over dipole, and dBi, gain over isotropic. He is using dBdl, gain over dummy load.
Rich

The radio was a yaesu FT 101 and a FT 301 both meters were calibrated the antenna was 52 feet of the ground and the the guy at the time had a .64 vertical antenna his signal was 60 plus over s-9 and with antenna turned back side i would hear him at a few s units and the side i would not hear him at all .
So with that said !
I got a moonraker 4 antenna light weight compared to the 3 element with 2 inch boom and 1 inch elements .
Put up the moonraker and what a joke had the worst front to back and did the 5 wire mod (don't start with pattern is screwed up) to the reflector and it did help a little .
The antenna is still up (put up 1987 in july ) .
I still want to replace the quad reflector with a yagi reflector with element spacing changes and length changes .
I just do not trust the wire for front to back i did do lots of modelling and sure you can get good front to back and tighter pattern with the quad reflector .
The question still is do you really or is the yagi reflector better ?
Yes you could go full quad design but i want vertical and horizontal and doing that with a quad is not easy and matching is a not easy either .
so many questions !!!

 

[Captain Kilowatt]

The radio was a yaesu FT 101 and a FT 301 both meters were calibrated the antenna was 52 feet of the ground and the the guy at the time had a .64 vertical antenna his signal was 60 plus over s-9 and with antenna turned back side i would hear him at a few s units and the side i would not hear him at all .

I don't believe it. If the meters really were calibrated at 6dB/S-unit that would mean the antenna had almost 96dB front/rear rejection assuming "a few S-units" was about S-3 and even more front/side rejection. That's not going to happen unless you have a parabolic dish. Something is not as it appears and I suspect the meter calibration. If someone was giving you 60dB over S-9 you would hear them with no antenna attached to the end of your coax.

 

[JAF0]

I don't believe it. If the meters really were calibrated at 6dB/S-unit that would mean the antenna had almost 96dB front/rear rejection assuming "a few S-units" was about S-3 and even more front/side rejection. That's not going to happen unless you have a parabolic dish. Something is not as it appears and I suspect the meter calibration. If someone was giving you 60dB over S-9 you would hear them with no antenna attached to the end of your coax.

Maybe if it was a Collins you'd see close to 6dB/S-unit. Most rigs I've used, CBs & Amateur, panned out to be between 3-4dB/S-unit.

 

[Ack Meedo]

Oh how I can't wait to see the results of both these tests.

How about a quagi reflector / driven vs. moonraker style reflector / driven comparison? I'm very interested in this, since I've done a gongola of reading on it, and everyone so far says quagi config..... I'd be interested to see if you've played at all with this? YOUR the antenna expert (wasn't it easier being a newbie on rrcb and NOT having your inbox innundated with emails from EVERYONE )

I might have to put something together around here for 2 meters and see if I can figure out what works better. Lots easier to build for 2 than 11 meters!!!

--Toll_Free

ok we are working on a quagi ref and driver is set up like signal engineering lighting. then forward horizonal elements. reason for this is ... our humble but correct opinion... after adding more than 5-6 quad elements there is no substantial gain. but adding yagi elements will. has anyone else done this?

 

[Marconi]

Ack, I have not done anything but examples of real Quads, except to model them with Eznec if I could get some dimensions.

I could try and change one of my old SE Quads and just add several Horizontal Yagi elements like you described above. That would all be...just a wild guess on my part...without your help and the details.

Maybe I can help you some with this idea.

To avoid my guessing at the dimensions and many details for your basic idea...do you feel comfortable giving me your details and dimensions?

A drawing with dimensions Length" x wire and/or tubing diameters." A few words to describe the details where you think necessary.

Take into account, I am 83 years old and not in good health, since I had Covid, and recent surgery for a heart valve replacement.

Eddie - Marconi

 

[Marconi]

Ack, take a look at some of Henry's antenna work at:

Check out some of Herny's antennas.

 

[Ack Meedo]

Ack, I have not done anything but examples of real Quads, except to model them with Eznec if I could get some dimensions.

I could try and change one of my old SE Quads and just add several Horizontal Yagi elements like you described above. That would all be...just a wild guess on my part...without your help and the details.

Maybe I can help you some with this idea.

To avoid my guessing at the dimensions and many details for your basic idea...do you feel comfortable giving me your details and dimensions?

A drawing with dimensions Length" x wire and/or tubing diameters." A few words to describe the details where you think necessary.

Take into account, I am 83 years old and not in good health, since I had Covid, and recent surgery for a heart valve replacement.

Eddie - Marconi

ed
ok the reflector wire is 453in divided by 4 is 113.25 per side. the driver element is 438 divided by 4 is 109.5 per side. distance between them are 84.5in. the L6 calls for them to be 102in apart. i can do either. boom is 3in diameter. i think the max i will try is 65ft or so on 3 in. does anyone have any idea the max 3in will carry? i really havent looked at larger antenna designs.
ack