Maco v quad installation help

[bestro]

I have a maco v quad an need a little help with installation.I will be mounting it on my roof 2 the chimmeny with a chimmeny mount.The chimmeny is 2.5' tall.My question is how long should my mast be from the chimmeny 2 the rotor an rotor 2 v quad..I was thinking in the range of 4' mast 2 rotor an 1' mast between rotor an v quad.Am I in the right range.Using 1 1/4 diam mast pole...U follow me...Did i explain it right..please help....148 GTL Texas star DX-500-RG 8X coax....

 

[Robb]

How high off of the ground to the base of the antenna?

 

[bestro]

Im not sure but if i had 2 guess i would say 40'..My house has 3 floors.Thats 40' to the bottom of the chimmeny.

 

[Robb]

Im not sure but if i had 2 guess i would say 40'..My house has 3 floors.Thats 40' to the bottom of the chimmeny.

Should work just fine . . .

 

[bestro]

Thanks Robb.1 more thing should i make a rf choke an if so how big should the loop be.Thxs again.

 

[Robb]

Thanks Robb.1 more thing should i make a rf choke an if so how big should the loop be.Thxs again.

Wouldn't hurt to put one on.
5 turns of RG-58 coax on a 4 inch PVC coil form below the feed point and not touching any metal of the mast should work OK.

 

[wavrider]

The V quad if I am not mistaken uses a gamma match to adjust the impedance.

An RF choke is not needed to prevent CMC, but as ROBB said it sure would not hurt anything.

If you live in a windy location the chimney mount may vibrate in the wind eventually cracking the mortar between the bricks on the chimney.

 

[n0zna]

dont

put it on chimmney mnt,it wont hold durring winds,it has a good wind load and ice load,73 de JW

 

[bestro]

I really have no other option.The v quad is 7 or 8 lbs the rotor another 4 lbs.A 4' mast 2 hold the rotor and a 1' mast between rotor an v quad.Thats about 12 or 13 lbs.That would bring down the chimmeny.I figure if i keep the mast short it would'nt move a lot.short an stout.Less vibration...How do i ground my station an antenna...Please help an thanks 4 the get back.

 

[wavrider]

roof antenna mount tripod - Google Search

You could look at something like this mount if you do not want to use the chimney.

 

[gamegetter]

greetings;

i would not be drilling any holes into the chimney, if i'm seeing it right this sounds to be a small chimney to vent gases maybe from a gas furnace or other gas appliance but let us know if it is other wise.

i would check the integrity of the mortar and bricks well. I lived in an older house built in the 40's at one time and the mortar was falling apart after 45 odd years just from the elements alone.

My preference(if the integrity of the chimney is good) would be to use mounting hardware with stainless steel straps that wrap around the entire chimney.

Some folks say that standard antenna mounts are ok, but i like to be sure because there are considerable wind forces on the mast and antenna.

What would be worst case scenario, the chimney crumbles you may or may not be able to use said appliance, you hire a mason to rebuild you a chimney, then you buy a separate mast or tower. Just thinking outloud here, i like to think things through.

Hope this helps out and not hinders any. Best of luck

 

[Lefty]

I use a Mosley TA33JR mounted on my garage. I used a 3' tripod from Radio Shack. 5' mast to the rotor, then another 5' to the beam. I also guyed the bottom of the rotor to the roof to cut down twisting and spread out the wind load. Braced in the rafters, used stainless bolts and lots of silicon to seal. Been up for about 10 years and still running strong. No leaks in to roof either.

 

[GnG8d]

The V quad if I am not mistaken uses a gamma match to adjust the impedance.

An RF choke is not needed to prevent CMC, but as ROBB said it sure would not hurt anything.

A gamma fed antenna won't create CMC?


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[wavrider]

A gamma fed antenna won't create CMC?


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The transmission line (coax) shield is not part of the antenna or counter poise per say.

Common mode current

Some reading on CMC.

The Gamma match provides a transition from unbalanced coax to balanced antenna. Adjusting the Gamma for lowest Z or VSWR if only a VSWR meter is available will usually eliminate CMC as equal but opposite currents are flowing on the transmission line.

I have never seen a yagi excited with proper drive cause CMC, now I have seen amplifiers being over driven into saturation and beyond cause splatter but the yagi can not be blamed for the splatter, the operator sure can.

 

[Needle Bender]

I used the bottom 3 sections of a heavy-duty 5 section telescoping TV mast for my 13' long (.2 /.15) 3 element quad.
The bottom telescoping section was 10' and I had the next two extended 9' and 8' respectively, plus a 30" mast coming from the top of the HD-73 rotator. This was all on a 20' roof peak and guyed 4 directions so the boom was right at 50'.
Having no tower it was all I could do, and it lasted for over 10 years without issue before I took it down to try something different.
I didn't use a tripod at the bottom, I simply walked it up and set the bottom of the mast into the roof-mounting base (after setting the 12 well-insulated guy wires during a dry-run without an antenna on it) with the beam and rotator installed but collapsed down to about 15' total, then I leaned a ladder against the mast and pushed up the 2 top sections until the I saw the marks, then tightened the turnbuckles until taught & true.
It was a little hair-raising but it only took an hour or so afterword for my nuts to drop back down. :redface: