First antennas

Started by linkclan, August 16, 2014, 01:02:00 AM

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linkclan

Hello all, first post with a question.

I'm setting up my new 897D as a kinda/sorta base station in my office and am preparing to get the antenna thing going on.

I will be going up inside a wall into the attic space and making a roof penetration for the coax and control wires and.... I would really like to do this only once as, I am sure there will be more antenna in the future.

My first antenna will be a Diamond X3200A and I am sure this will be an ongoing process as I live in a deep valley with only two relay stations in my line of sight.

My question is; Can I run the control wires for the rotational motor in the same conduit for the directional or would it be a better idea to run separate conduits.


Thanks



KK0G

First. welcome to the forum, glad to have you aboard.

Yes, it's perfectly fine to run rotator cable and coaxial feed lines through the same opening. I run all mine through the wall via 4" PVC fittings with an elbow pointed downwards on the exterior to keep rain out, then I stuff it with insulation. Although the "rules" say you shouldn't, I even run my balanced feed twin lead through the same opening, been that way for years and works just fine.
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

cockpitbob

Ditto.  Run them all in the same conduit.

linkclan

I thought for sure the dreaded answer would be to "keep them separated" a foot or more apart!

As an electrician, I am always concerned about transient voltages and inductive loops especially with data cabling. I have had zero experience with coax and its parameters even after 30 years of practicing in commercial applications.

Thanks again!

cockpitbob

The worst that could happen is if your antenna doesn't like the unballanced drive of coax and puts RF on the coax's shield.  Even if you get RF on the shield you'll probably never notice.  And the fix is easy:  a balun of some sort - coil the coax or put beads on the coax.

KK0G

Quote from: linkclan on August 16, 2014, 11:31:36 AM
I thought for sure the dreaded answer would be to "keep them separated" a foot or more apart!

Definitely no need for that, but there is a small grain of truth in what you may have heard regarding separating feedlines although it's taken out of context.

The fact that all the RF stays "inside" the coax (for the most part, under most circumstances) is precisely why coaxial feedlines became so popular right after WWII - that and the fact the market was flooded with cheap surplus coax. After that, balanced feedlines (ladder line, window line, twin lead, open wire feeders, etc.) got a reputation as being difficult to work with and spewing stray RF all over the shack when nothing could be further from the truth.

The small grain of truth comes from the fact that balanced feedlines shouldn't be run parallel to and right next to another conductor for any appreciable length as it can unbalance the feedline and could cause RFI.
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

linkclan

Thanks guys,

I think I am going to run 3ea RG-8 to the roof(only utilizing one at this point) and I believe I have some 4 conductor shielded #14 cu around here somewhere and I will run that also in the event a rotator ever materializes.

I would imagine it would be okay to bring a ground conductor along with it as there is no available ground point on the roof.

Lamewolf

Quote from: linkclan on August 16, 2014, 01:02:00 AM
Hello all, first post with a question.

I'm setting up my new 897D as a kinda/sorta base station in my office and am preparing to get the antenna thing going on.

I will be going up inside a wall into the attic space and making a roof penetration for the coax and control wires and.... I would really like to do this only once as, I am sure there will be more antenna in the future.

My first antenna will be a Diamond X3200A and I am sure this will be an ongoing process as I live in a deep valley with only two relay stations in my line of sight.

My question is; Can I run the control wires for the rotational motor in the same conduit for the directional or would it be a better idea to run separate conduits.


Thanks

The Diamond X3200A requires no control wires, its an omnidirectional ground plane antenna.

linkclan

Well, this is just like a time capsule!

Since my first post, I feel just a bit more in tune (so to speak)!
Just reminiscing here, hope you don't mind.

Still have the 897D
Never went through the roof, went through the wall instead with a bulkhead entrance and overkill grounding and lightning suppression.
Don't think I ever intended to rotate the tri-band VHF/UHF antenna but I thought I was thinking ahead for a directional of some sort.
Since then, I have activated a few more brain cells and will not be putting a directional on the roof.
It took me a while to realize that I live on a large property with lots of trees!
Waited till November to go take the exam and passed element 2 and 3 in the same sitting.
Got a 135ft dipole up and got on the air. Thinking back, even checking into the local 2m net was nerve racking at first.
Really got exciting around Christmas time when I got some silly idea to maybe learn CW. What ever was I thinking!
Passed element 4 a couple months later.
Wife and kids are still asking if I am going to fill the yard with antennas.
Now, the addiction continues; Ordered a KX3 yesterday and I get to wait impatiently for it to arrive.
Big thanks to you guys here as I was chomping at the bit for an Icom7600 or Yaesu DX3000.
I will still work on my full wave loop and I don't think I mentioned it but I have a lot of steel and am building a modest tilt-up/crank-up tower.
Still have the hots for a log periodic and it will probably end up being a Tennadyne T-11. I might even try to get this up in a tree prior to the tower.
In the mean-time, I think I will get a BuddiPole system and make a bunch of wire antennas to help me through the learning process of propagation.
Wondering how to juggle all my other hobbies and I decided to go punch some paper holes this weekend.

Thanks for listening.

73-K6PLE




madball13

get it and shoot some .45 while you are still allowed to.