600 Ohm Ladder Line vs Coax

[Robb]

Does the roof of my house compromise the distance from the apex to ground? In other words; would putting up a 35 ft mast on a 10 ft roof be realized as a distance of 45 ft from the apex to the ground - or is it considered to be 35 ft height? There's no real metal in it except nails.

Mole: you run your dipole over your home - yes?

 

[Robb]

If I use 50 ohm coax; should I install a 1:1 current balun at the feedpoint? Or should I use a lot of ferrite instead?

 

[W5LZ]

Suit your self. I haven't found them to be of any particular benefit. The typical result of not using a balun is that the radiation pattern is slightly skewed, not a biggy. I do use chokes though, and they seem to work fine.
- 'Doc

 

[Robb]

Here is another dumb question...

I have a 32 ft push-up pole (all metal) that I would like to use to put up the dipole.
Can I use a 4 ft 1 1/2 in wood dowel at the top of it? Would it be OK to do it that way - or no. Would the dipole be coupling to it?

Told ya it wuz a dumb question!

 

[W5LZ]

Use that metal pole, it's not a dumb idea. You would want to insulate that antenna from the pole, don't let it touch it, but that's really about all you need do.
- 'Doc

 

[Captain Kilowatt]

Here is another dumb question...

I have a 32 ft push-up pole (all metal) that I would like to use to put up the dipole.
Can I use a 4 ft 1 1/2 in wood dowel at the top of it? Would it be OK to do it that way - or no. Would the dipole be coupling to it?

Told ya it wuz a dumb question!

You saw my setup with that fat tower section parked right smack dab in the middle of the antenna and you have to ask about a metal push-up pole? op:

 

[Robb]

You saw my setup with that fat tower section parked right smack dab in the middle of the antenna and you have to ask about a metal push-up pole? op:

Yes I did see it.
I am trying to find out if there are considerations if/when doing that. Obviously, there can be RF coupling and I wanted to know if using that mast that I already have -which would save me some money- could be used w/o any coupling issues - such as SWR or ?
I'm cheeeep!
Didya see the pictures of my lawn?!?

 

[Captain Kilowatt]

IMHO no matter what you do with a simple low wire antenna there will be good points and bad points. Also IMHO just put the antenna up and see if it works. If it does GREAT! If it does not then start asking why. Like Beetle always says, "Try it and see what happens. Experiment. That's what it's all about."

 

[Moleculo]

Does the roof of my house compromise the distance from the apex to ground? In other words; would putting up a 35 ft mast on a 10 ft roof be realized as a distance of 45 ft from the apex to the ground - or is it considered to be 35 ft height? There's no real metal in it except nails.

Mole: you run your dipole over your home - yes?

It's total height to ground for your installation. I use a 30 foot push up metal mast on my roof with a fiberglass stick hanging off of sideways to suspend the dipole. I have an antenna over the top of the dipole, too. I wouldn't use a wooden dowel...they don't last. I used to have a broomstick handle that I cut and painted black...after a couple of years it sagged from the sun damage. There's a ham a couple blocks away from my that has his G5RV up on wooden dowel above the metal mast. Every couple of years the winds break it down.

 

[GnG8d]

Suit your self. I haven't found them to be of any particular benefit. The typical result of not using a balun is that the radiation pattern is slightly skewed, not a biggy. I do use chokes though, and they seem to work fine.
- 'Doc

Isn't a 1:1 balun the same as a choke? This whole thing still has me confused. I understand a 2:1 or 4:1 balun a lot better than a 1:1 balun. It seems to me that a 1:1 balun is a choke.

 

[Beetle]

Isn't a 1:1 balun the same as a choke? This whole thing still has me confused. I understand a 2:1 or 4:1 balun a lot better than a 1:1 balun. It seems to me that a 1:1 balun is a choke.

A choke is not a balun.

A balun is a transformer, used to transform a BAL-anced antenna (e.g. a dipole) to an UN-balanced transmission line (e.g. coaxial cable). Many baluns do that without any particular "choking" action. A coil of coax in the feedline may choke off currents on the outside of the coax shield, but they do nothing to transform BAL to UNbal.

 

[Beetle]

...which is perfect for MARS use

Back about 30 years ago was the last time I was involved with Navy MARS. I was control for a couple CW nets, passing traffic through Japan and Hawaii mostly, but we had ZKEs (checkins) from Station Ships in Hong Kong, Singapore, Perth and Diego Garcia on a regular basis. No NVIS needed (or wanted) here! Fortunately, my quad has a nice bandwidth and things worked beautifully.

 

[Moleculo]

Back about 30 years ago was the last time I was involved with Navy MARS. I was control for a couple CW nets, passing traffic through Japan and Hawaii mostly, but we had ZKEs (checkins) from Station Ships in Hong Kong, Singapore, Perth and Diego Garcia on a regular basis. No NVIS needed (or wanted) here! Fortunately, my quad has a nice bandwidth and things worked beautifully.

Yep, those days are pretty much long gone. Any traffic that needs to get routed out of your local state is done so by dumping it into the Winlink system, where it's normally routed through the internet. It might get picked up at the other side and ultimately get delivered again over the air on another local traffic net. All of your daily traffic nets are going to be within your state and likely on 75 meters. For Robb, that's going to be Northern California (NCA). You can check into other state nets, too..but you're probably only going to regularly do that to AZ, SCA, NV, OR...the ones right around you. Any longer distance nets will still be within the U.S. and would probably be handled around 20 or 40 meters so your wire antenna will work fine.

The mission of MARS has definitely changed from handling "Health and Welfare" traffic to providing a national well trained HF ECOM capability.

 

[Robb]

So at this point I will mount the antenna (getting it within the week) on a tubular piece of steel with the last five/ten feet of it being thick 1 1/2 in OD PVC tubing to get all of the height I can muster out of it.

It will be guyed at two ends approx. 2/3 of the way up of the mast. I'm going to use the ends of the dipole as the other means to secure it - using wood or more PVC pipe - probably wood. Total of four points secured.

No balun is necessary - because the recommendations have said that coax should suffice for this installation. No one has commented on the need for ferrite; any comments?

The antenna ends will be 12-15 ft from the surface of the ground, and the apex should be at 45 ft from the ground. As seen from my dog-eaten property satellite picture, the antenna is relatively clear of any obstructions. This is optimal; yes? I am concerned of any possible coupling that may de-tune the antenna's properties.

Will the Alpha Delta DX-CC need to be re-tuned for 75 meters as received? If so; how much should it be shortened by?

Any other comments before I commit to buying?
Any/all inquiries/thoughts/suggestions appreciated!

 

[packrat]

Dont add anything at all to the mix until you know if it is needed. KISS.