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Author Topic: Planned New Station  (Read 1675 times)
KF5RKV
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Posts: 7




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« on: August 06, 2012, 07:01:21 PM »

Hello to all.  First, these various forums helped me arrive at a basic plan for my new station; a plan which I invite you to criticize (gently, please).  I've got a General ticket with the ink still drying.  My "goal" in ham radio is vaguely phone DX, just making long distance contacts, not contesting.  Beyond that, I'll see what piques my interest.

So, what I've got in mind is a ZeroFive 29' vertical, an IC718 feeding through an AH4 tuner, maybe an optional ICOM mike, and an Astron PS.  I've got an all metal shop about 60 feet out back of the house with a very gently sloped roof (about 10-15 degrees) with the peak of the roof aligned basically north-south; that is, the sloping surfaces are aligned east-west.  I can mount the antenna dead center in the roof very easily and that would require about 100' of coax between tuner and antenna.

Location, if that matters, central Oklahoma.  So, is this a viable starter HF setup?

Larry
KF5RKV
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W9GB
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« Reply #1 on: August 06, 2012, 07:13:29 PM »

Larry --

I assume you have already performed the Icom AH-4 calculations for antenna lengths (resonant wavelengths) to avoid?
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KF5RKV
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« Reply #2 on: August 06, 2012, 07:28:02 PM »

Well, full disclosure:  I selected the AH-4 on the recommendation of a local ham.  I have the manual on my desktop, see the note there regarding those "to avoid" lengths, but haven't done the calculations.  Do you think I'll find a problem? (And, yes, I'll get on the math before I jump.)
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KF5RKV
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« Reply #3 on: August 06, 2012, 07:47:31 PM »

OK, my math says the lengths to avoid are, by band: 10m - 17', 12m - 20', 15m - 23', 17m - 27', with 40m and 80m greater than the length of the antenna (29' vertical, the lengths I find for the latter bands are 34' plus.)  Is the assumption that the 17m "problem" is nearly the length of the antenna?
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N4CR
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Posts: 1650




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« Reply #4 on: August 06, 2012, 09:26:42 PM »

For less money you can put up a Cushcraft R-8. It's a half wave antenna with a self contained counterpoise and it is resonant on 8 bands. It can handle 1500 watts PEP and 500 watts continuous.

If you're going to go after the more difficult DX, you'll need to get through pileups. A lot of time, 500 watts will do a job that 100 will not. Which eventually means you'll want to add a small amplifier like an AL-811 or any of a number of other small amplifiers.

The AH-4 max power is 120 watts. So if you find you can't do what you want with the AH-4 and the ZeroFive with 100 watts, you have to start over.

Since last July, I've worked 170 and LoTW confirmed 125 countries on an R-8. It's almost like cheating. Mine is sitting on a 10' tripod and fed with 300 feet of LMR-400. It's about 200' behind my house with my shack situated on the front side of the house. I have it lightly guyed with nylon parachute cord that's about 1/8" diameter. No tuner is needed on any band it is designed for. I feed it direct with either my radio or my Collins 30L-1 amp. Typically around 600 watts peak for pileup busting, but if conditions are good, just the radio.

Hy-Gain sells a knock off of the R-8 called the AV-640. My good friend Jeff has one and it works similarly to my R-8. The R-8 is a little heaver duty in construction. The specs compare between the two and the design is virtually identical.

My advice, get a tuned antenna that can handle a LOT more power, skip the remote tuner and keep some cash in your pocket.
« Last Edit: August 06, 2012, 09:43:25 PM by N4CR » Logged

73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
KF5RKV
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Posts: 7




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« Reply #5 on: August 06, 2012, 09:42:26 PM »

Strange you'd mention the Hy Gain, Phil; that was on my short list.  I'll give it another look-see.  Thanks.

Also, I gotta go back and look at my math.  Something ain't right there.  Too old and it's too late.

Larry
KF5RKV
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K5LXP
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« Reply #6 on: August 07, 2012, 05:57:04 AM »

Is an antenna on the metal shop the only installation option, or do you have other areas where more/different antennas can be placed?

Mark K5LXP
Albuquerque, NM
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KG6YV
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« Reply #7 on: August 07, 2012, 11:36:24 AM »

IF you choose to install any vertical with its own counterpoise you should make sure that the counterpoise is at least 5 ft. above the metal.  Otherwise you will find that the manufacturer's suggests lengths for the antenna and tuning stubs (if present) will be "way off" do the proximity of the counterpoise to the metal roof. 

I know this because I put an R-6000 above a metal capped large chimney.  Once I got it over 5 ft. from the top of the chimney the antenna tuned as sprecified for each band.  Below 5 ft. it was a crap shoot...

Greg
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KG4NEL
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« Reply #8 on: August 07, 2012, 11:45:11 AM »

Is an antenna on the metal shop the only installation option, or do you have other areas where more/different antennas can be placed?

Mark K5LXP
Albuquerque, NM

I was thinking if there were any trees nearby, I'd rather have a longer radiator than 29'. I've used my AH-4 like that before, and it works fairly well (albeit with a pretty good radial system).
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KF5RKV
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« Reply #9 on: August 07, 2012, 03:13:01 PM »

Thanks for all the inputs and questions.  Here's the poop.  W9GB, I went back to my calculator and found all the multiples of the "to avoid" lengths, so I think I can cover that.

The shop roof is not the only place I could put an antenna, but I would prefer to start off with just one and the metal roof seemed like it could act as a pretty good counterpoise in itself.  Tom at zerofive seems to think so.

N4CR, remembering that I don't have much experience with antennas (other than receive), how would you rate the setup effort difference for an R-8 type vertical versus the zerofive with a tuner?  Do the preset/starting positions of the movable elements of an R-8 "work" as in the installation instructions, or will I be putting it up and taking it down a few times to optimize it?

Larry
KF5RKV
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K0RGR
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Posts: 105




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« Reply #10 on: August 07, 2012, 07:49:31 PM »

I think I would look at 4 or 5BTV vertical on that shed roof, but to be honest, for what you want to do, a vertical beats a dipole at a low height, but some sort of yagi would make a big difference. One option you might consider would be rotary dipole on a TV push-up mast. Mosely makes one that you can start as a triband dipole, then add elements to upgrade it to 2 or 3 elements.

For the lower bands, particularly 40, the 4BTV or 5BTV would be good choices. I'm not as fond of the 6BTV due to the need to guy it, which I think looks wrong.
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KQ6Q
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Posts: 964




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« Reply #11 on: August 07, 2012, 07:53:38 PM »

The AH4 tuner is designed to be mounted AT the antenna feedpoint - not to feed an antenna through a long run of coax. it might work with the 43' vertical at the feedpoint, but that's not what it's designed for....
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KF5RKV
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Posts: 7




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« Reply #12 on: August 07, 2012, 08:14:11 PM »

RE: Mounting the AH-4 at the antenna - Does anyone sell a verrrry long control cable or do I fab one up?
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VA7CPC
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Posts: 2355




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« Reply #13 on: August 07, 2012, 11:02:57 PM »

As an alternative to the AH-4, consider one of the SGC "long-wire" tuners, mounted at the antenna feedpoint.   A 30' vertical pole is well within their ratings.

The SG-230 is common in marine installations -- I have one.  The SG-237 is less expensive (I think), and gets pretty good ratings in the Reviews here.

They need 12 volts DC -- no "control cable" is necessary, although you can use one if you  want to.

            Charles

PS -- forgive me if you've thought about this alternative, and rejected it.
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N4CR
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Posts: 1650




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« Reply #14 on: August 08, 2012, 06:14:34 AM »

N4CR, remembering that I don't have much experience with antennas (other than receive), how would you rate the setup effort difference for an R-8 type vertical versus the zerofive with a tuner?  Do the preset/starting positions of the movable elements of an R-8 "work" as in the installation instructions, or will I be putting it up and taking it down a few times to optimize it?

Follow the manufacturers suggested tuning and mounting positions and it will be just fine. They recommend that it be at least 10 feet above the ground and in the clear. I have a 10' tripod and a 4 foot mast which sticks out of the tripod about 2 feet. The antenna base to ground is a little over 11 feet. I did all the measurements and then prepared to tune up the antenna. First check showed it was all workable as installed. I then tuned the antenna to the PSK-31 frequencies since that is what I was doing back then. For the last year, I've worked mostly SSB and it's really working ok even though I don't have it centered on each band. The retuning process took about an hour.

I have the tripod that has two hinged legs. To get to the antenna I remove 1 bolt on the third foot of the tower and walk it over and down. An up or down operation takes about 30 seconds not counting removing and replacing the guy ropes. Which means I can lay it over in a storm in a few minutes. For tuning, you'll only need to take off the guy ropes once and put them back on at the end.

I have an egg insulator in the guy ropes about a foot from their anchor point on the antenna so that it doesn't detune in the rain.

This is a very good antenna. Better than I expected. If it breaks for some reason, I'll go buy another one just like it.
« Last Edit: August 08, 2012, 06:20:54 AM by N4CR » Logged

73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
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