I’ll do my best to get there. I had to cut today short at work because of a keyfob going crazy with the jetta this morning at 2:30am (ended up at the dealership this afternoon because it kept randomly opening the trunk and activating the panic mode).
My car is stuck in the shop till sometime this afternoon. Which means I am not getting up there as early as I wished.
This eats into antenna time. I will go up there, but it may be closer to 5pm or so. With the sun going down and temperatures falling, tomorrow seems like the better day to get on the roof.
Sorry about the whiplashing.
I am off today if it didn’t get put up yesterday.
I didn’t get up to the space till about 7:30pm last night - no antenna install yesterday.
I will be up at the space around 1pm, maybe before. If we can find some support (I think it is going to take more than the two of us), lets get the antenna up there.
I am pleased with how the concrete dried. I am thinking we might be able to lift the sub-masts up there by the pole. We see.
I am heading up there right now to see if I can get some work done on the Jetta, so I’ll probably be up there when you get up there.
Hello All,
I took the tour last night and joined up. I’m K5SLR, interested mostly in digital modes and VHF and up. I’d be interested in helping out when time permits. I work in Carrollton these days, so I’m pretty close to DMS.
I didn’t see if the radios have been set up yet last night. Too many things to take in at once.
I look forward to meeting you all.
73’s de Todd Caldwell, K5SLR
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I haven’t been up there in about a week (probably more) because of work and other things…
All I have planned this weekend is to sit on JT65/9 at home and work some contacts.
@BenjaminGroves It is suppose to be beautiful weather this weekend. Any hope that we can get the antennas up?
Sorry all, I am in work travel mode this week.
I will look into setting up a meeting next Saturday where we can look into lifting to the roof.
Better update on Monday.
And welcome Todd! I look forward to meeting.
I’m late to this Talk thing, so playing catch up.
@BenjaminGroves: Let me know when you are doing installs and I will do my best to be there.
@tmc4242: Welcome to DMS Todd!
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Hey gang, I am a new member and General Licensed HAM. I would like to help when you start doing the set up. I am waiting for a new work schedule but post when your going to be there and I will try and make it. I will be at the open house if possible. If anything I can be spare labor hand to help lift the weight.
Hi all. This is the continuing epic of the Amateur Radio Antenna install.
With the big Open House coming up on Saturday I don’t think we can afford setting up. I know personally that I will be running around all day keeping things together, giving tours, and cleaning toilets.
I want to mark down Saturday, January 31st as our “Raise it to the Roof” day. I feel we will need a minimum of 5 people, three of which will have to get up on the roof. The more the better.
This thread is appropriately named for the antenna install on the roof, so even though it is long in the tooth I would like to keep it open for discussion.
I will follow this reply with some information about our design and situation on the roof. Stay tuned!
My two favorite questions. Where we at? Where we going?
This antenna is our goal. There is another simpler antenna, it will integrate or co-exist with this one.
The concrete buckets in our office will serve as the supports in this diagram.
We can expect 33 feet from far left to far right of the antenna, and assume another couple of feet for each bucket.
I got up on the roof to scope out what we have to work with.
We are directly above the wire drop into the building. Note that we are in the corner. In the background, the roof drops 6 feet.
On the other side, there is air conditioning systems. I imagine we don’t want to get too close to those.
This is a satellite map of the roof. I highlighted the existing mount above.
That is a really nice non-penetrating roof mount. I claim such in the name of KD5MS and our committee. It feels nice and stable.
Last bit, the existing coax is not suitable for our purposes. The look I got from @DHarris when I asked if it was even serviceable said it all.
I figure we can pass our good cable through the hole in the wall from the inside, then toss the loose lead up to the roof for connection. Them holes are about 20 feet up on the wall.
There are three questions:
-
Where to place on the roof? Closer to the ledge? Closer to the AC?
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Can we / do we bend the two leads into a “V” shape to make a better fit?
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While dipoles are roughly omni-directional, I understand there is some aiming for best performance. Put the points from North-East to South-West?
Open to comments.
So I have been playing with a dipole over the last few weeks with varying success (setup/teardown all the time). If we parallel it with the back wall of the building (the wall with the ramp / shipping bay), we will get a north west / south east null in coverage. This should give us the north east and south west coasts the strongest. If we go for parallel against the 6’ drop, we will get canada and south america instead the coasts of the US.
The dipole’s ends are the nulls in the signals.
I’d say as far away as possible from the AC units. But either parallel against the back wall, or the drop off wall (personally I’d say drop off wall… But then again I do stuff weird sometimes).
The V shape idea would change the impedance of the antenna. It probably wouldn’t work out well.
From what I saw in the room also, we have no legit coax. There’s a black CAT5 type cable that is wound up to look like coax, but we have none…
I’d suggest we get some good line like from dx engineering. RG-213/U for the HF antenna, and some LMR400 type for the VHF/UHF antenna. The LMR400 would keep the losses to a minimum on the higher frequencies, but costs almost a dollar a foot. I personally have a 100ft run of their LMR400 I use on my portable setup when I need that length.
I would suggest crimp type connectors instead of solder, and I do have a coax crimp set.
I can be around almost anytime, with notice. I’ll mark off the 31st as a day up at the space.
Epic Radio Antenna Setup Amateur Radio Meeting Fun Time Turbo! (01/31 edition)
@DHarris, @Kluper, Pay Hykkonen, and @BenjaminGroves met Saturday January 31st. We did not lift the sub-masts to the roof (manpower and rain), but we make further progress on the indoors side.
We got up in the ceiling and found the wall penetration that we will use. The wires go right into the seam.
Estimations are that 50-60 feet of coax will cover our needs. We will run 2 or 3 coaxial antenna lines, and a simpler wire run for a scanner we also want to get going.
We looked at our current dipole antenna and the way it is wired is lacking for our grande DMS install. We will save that as a portable option and for future amateur radio field day events.
We have a few parts to purchase. I will start collecting these this week and have them on hand for our next meeting where we start putting things together.
Behold the antenna shopping list:
- 120 or 200 feet of LMR Coax
- A PVC Balun with 4:1 current
- Wire for the dipole ends (need total length)
This is a running list. I can update it to keep the information in one place. Please contact @BenjaminGroves with feedback and comments.
Current design of the antenna is updated to a 80 offset dipole running near the back of the building. We want to stay away from the AC units. We will install the masts back a few feet to as not to be an eyesore to the street, and thus incur grousing from the building management.
This is a little after the fact, but I like the suggestion @zmetzing made last night about a satellite antenna. I am totally willing to fold it into our plans and installation (send me info).
We also practice-made a knot to lift the 80 pound sub-masts buckets and lifted with the shop gantry. The results are solid, I even kicked it a few times. I wish I grabbed a photo. Looks something like this:
We have better rope.
All in all I am very happy with the progress we made yesterday. I think we are largely through planning and logistics, and getting properly into implementation phase. I have some purchases to make and we will push on.
Thanks all!
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Suggested coax is LMR400 or equivalent. This is one of the lowest cost places I’ve seen…
http://www.shireeninc.com/low-loss-rf-coax-cables-uv-rated/
Specifically we will want the RFC400UF which has a tighter bend radius. Going for about $1.00/ft.
I still suggest an off-center-fed dipole cut for 80m. An article on a build: http://www.w0hc.com/ocf-dipole/
We can certainly build our own antenna. Would need to purchase the following:
4:1 Balun
End inuslators
Appropriate wire, coated clothes line wire is good for this. Durable and weather resistant.
I went to that Ham Radio Supply yesterday at lunch and checked about the LMR400 cable - they want $1.49 / foot.
Think I am going to go with Pat’s link.
I won’t be able to schedule installation effort for the next couple of weeks, but I will work to prepare for a day coming up after that (around the 21st). Goal is to have collected our bill of materials by then.
Thanks all!
You can also check TT’s web site to see if they have any acceptable short lengths of wire on markdown.
Ben, I just saw your concrete buckets.
You might want to drill 4-6 1/4" holes around the bucket right at the top of the concrete to allow any water to drain out.
Since the concrete does not come to the top of either bucket’s rim, without the holes the bucket may hold water and accelerate rust on the pipe.
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And we want to be good citizens and not create mosquito breeding grounds.
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One thing I haven’t seen mentioned: It would be nice if we ran a piece of outdoor rated Cat5e or Cat6 up along with the antenna leads. That would make it easy to install a Broadband Hamnet node.
Also, how many RF cables are we running ? LMR-400 is great for UHF/VHF and upwards. It’s somewhat overkill for HF though. Not a bad thing, but just wondering. As in it might make sense to use LMR-400 for the higher freq stuff and a lesser but cheaper coax for HF, unless we have an enormous HF amp I haven’t seen yet. 
Just curious, and somewhat late to the party.
Todd - K5SLR
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