gizmotchy 5 element

[bryan scott]

hello guys, new to the forum, i have a 5 element gizmotchy set up and a maco 5/8 ground plane,


I am not seeing any better signal from people on the beam, and the same on transmission.

I am seeing that there are a few guys setting up the spacing differant on the boom , i have mine set up by the direction from gizmotchy,109'' reflector 5'2'' to 105'' driven radial ,3'8'' to 100'' director ,3'8'' to next director and so on.

My 5/8''maco ground plane is right at 30' off the ground and so is the boom on the giz's.

So should the giz's give me more signal on some one in the distance than the ground plane.????????

 

[wavrider]

So you are saying the 5/8 wl ground plane works as good as the five element jo gunns/gizmotchy?

Is this on tx and rx?

Do some research, the gizmotchy is built like a tank, but there claims are basically huge exaggerations.

Gain on a yagi is achieved by the boom length and spacing of the elements.

If you increase the boom length and the spacing you will have a yagi that performs better than stock gizmotchy.

 

[W5LZ]

I would expect any directional antenna, especially a 5 element beam, to 'hear' better than any omnidirectional antenna. If yours isn't, then I think I'd start looking at everything connected with that beam. If you turn that beam away from particular stations, does the signal strength go down, at least some? If not, then the beam definitely has problems. No idea what to tell you other than to take another look at the assembly instructions. Maybe re-tune it?
Changing element spacings on that beam can make a difference, but don't expect a world of difference, some, sure.
- 'Doc

 

[radiohobby]

Are you using a coax switch or switching coax? If a switch make sure the switch is not messed up. You should see a very large difference between the two antennas, unless the station you are talking to is just down the block.
I have just a simple super scanner and can see big difference when I switch from omni to directional.
And try pointing it towards them, off to the side, and from the back. Try to get a station out about 5 miles so you can really tell the difference. If need be get some bud to go out in a mobile and use that as your test.

 

[bryan scott]

Thank for the help guys!

Thanks

 

[bryan scott]

Thank for the help guys!

The beam is working, it does have really nice rejection, you can move it 15% and see the signal change allot. front to back is huge and side rejection is great. The ears are great with the beam it cuts out all the noise and lets you hear who you are pointing at but the signal that i am receiving is always about the same as i see with the ground plane it just kills all noise from other directions.

Its about the same on transmit, most people say they cant see any difference in the signal between the two antennas as long as i have the beam pointing at them too. there are a few station that tell me that i put 1 to 2 db more on them from the beam but they are usually some one that puts little or no signal on me with a very low antennae.

I have ran it for a while and have my ground plane down to same height to compare the two. I will say that the beam would show the same signal as the ground plane at 25' lower height , when the beam was 50' to the boom and the ground plane radials were 73' off the ground . i had guy wires brake with the beam going into the trees and my ground plane mast has been broke in half from all the high winds where i am at.so i have rebuilt and starting to play with the antennas again.

The ground plane is right at 30' to radials and the beam is about 25' to the boom right now.i am going to play with the beam and see if i can get better performance out of it,

I have checked everything , hooked coaxes straight to radio to eliminate any problems, now i want to address the beams moderate performance, i have noticed that there have been a few differant spacing set ups for the gizmotchy . and i have heard and read that people see allot of gain . but as of yet this eludes me and i am after the performance that the antennae is supposed to be capable of.

If i can get this thing to show me 2 db difference over the ground plane or at least better at a lower height , i might be satisfied. maybe play with the spacing ??????????

 

[wavrider]

2db of difference?

Perhaps 2 S units, an S unit is 6db, on some 11 meter radios an S unit is 3db so can not really tell by the S unit reading but if the beam is performing properly it should give one to two S units over the ground plane.

Roughly around 10db to 12 db of gain. A five element should be around 17 feet minimum length on the boom. A better longer one at 24 feet would give more gain. Not much more but it will be more.

Here is a link to a Hygain five element manual. claims 10 db of gain.

http://www.cbtricks.com/ant_manuals/hygain/model_411/graphics/hy-gain_411_five_element_beam.pdf

Sorry to hear about the high winds and damage to the yagi. Mother nature does play havoc with antennas up in the air.

 

[bryan scott]

?

Well not real clear on the db to s unit, but he said i had a 7 with the ground plane and a 9 with the beam, most say that they are the same. this is with bare foot radio.

so what should the beam be doing over the ground plane, in the numbers on the meter,

 

[radiodawg259]

Yes it should be stronger on the beam than the ground plane.....

 

[wavrider]

It should give one to two more S units on transmit to the receive station.

You should also notice an increase in receive signal strength using the beam when it is pointed in the direction of the transmitting station you are receiving.

Reading the thread it does seem like your beam is working for you.

 

[Highlander_821]

You might have a jealous report or two going on there too. Sometimes people just want to buzzkill.

I think your beam is working just fine. Play with it more, seek out more distant stations.

The fact that I think you said the beam is mounted a little lower will be a factor, and just the difference in mounting location with respect to the stations you are working can affect things.

 

[Road Squawker]

The beam is working, it does have really nice rejection, you can move it 15% and see the signal change allot....
Its about the same on transmit, most people say they cant see any difference...

it sounds to me that you are getting reports from (local?) operators,....... ground wave type propagation. are they using the same polarization as you?

gets some reports from stations further away. it sounds like you don't have a problem.

 

[bryan scott]

signal and reports

I do take into account on inaccurate reports , i have been on the cb for 10 years now, but i have never ran a beam and only know what the directions from gizmotchy have told me to set them up.

I have only had like two people tell me the beam was better and on both occasions they put very little signal on me.


The people that tell me they see no difference in the signal between the two antennas on transmit have the same signal on my receive between the two antennas , so there is no reason for me not to believe them, and they are guys i talk to all the time and will generally tell me if there bull shitting later or not.

I have not gotten a report from anyone over say 30 or 40 miles this go around , but when the antennas where both up in the air more i had some 70 to 80 mile reports and some good dx reports when the guys signal was in there for a good while that said they couldn't see any difference between the two antennas also .

The beam workd great for dx when the signal kind of fades i can go from vertical to flat and pick them up and talk some more, but the ears have always been great i am just not getting any gain from this beam, i have only seen 1 to 2 S units and that is all. The beam is advertised to have 18 db gain , and that is 6 ,S units right.?????

 

[W5LZ]

No, it would be 3 'S' units. And I wouldn't count on that 18 dB of gain very much.
- 'Doc

 

[Highlander_821]

Real world gain for your vertical, using a half-wave dipole for reference is maybe 1.2 DB. Your Gizmotchy would be around 7 DB (I'm assuming it has gain similar to that of a 5 el Yagi) So that's around 6 DB over the vertical. So around 1 s-unit is reasonable. Then, factor in the different height and location, most of this sounds pretty much like what you are getting. I'm sure if you built it to spec and have double checked everything, all is probably fine with your beam.