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Author Topic: Jupiter / Gap Titan DX setup  (Read 4983 times)
W4XKE
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Posts: 67




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« on: January 15, 2006, 08:24:44 AM »

I’m running a Jupiter and would like to solicit some comments on setting up a Gap Titan vertical.  The fellows who reviewed the Titan seem to really like it or they really don’t.  Apparently there is a lot of stray RF within 30 – 50 feet of the antenna and the feed line sustains a voltage on the braid for at least that distance.

I know from past experience with trying to use an Off-Center-Fed dipole that the associated stray RF can be a disaster with the Jupiter.  The control software went nuts.  It would lock into TRANSMIT, change frequency, jump from one band to another and just cause havoc.  Once I got the OCF dipole down and went to a balanced, center-fed fan dipole, all of my problems were ended and the radio is as happy as I am.

For the past 3 months the Titan has remained in it’s shipping box out in the shop while I consider the best way to install it.  Here is what I am presently thinking:

## Get it out at least 75’ in the backyard, away from the shack.

## Mount it on a pipe (8’ or more above the ground)

## Insert the pipe mount into a PVC sleeve in the ground so it can be rotated.

## Bury the feedline.

## Put a Radio Works grounded isolator in the feedline just before it comes into the house.

I would like to do this in such a way that I won’t need to do it more than once.  Based on the reviews, I believe the success of this antenna lies entirely in the installation (and accommodating the surrounding metal structures) methods.

Making a hole in the ground here is a major project since there's only about 10 - 20 inches of soil and then solid rock.  The 14x24 shop has an enameled steel roof & siding and a garden-tool shed on the other side of my city lot has an aluminum roof.

  One ham’s Titan is the best thing since sliced bread and another ham’s Titan is the worst piece of trash he ever bought.  Given my Jupiter’s susceptibility to stray RF, I’d appreciate any advice to help me make this a first-time success.
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WA7UNW
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Posts: 71




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« Reply #1 on: January 16, 2006, 06:46:05 AM »

Post this on Tower Talk. RF problems are RF problems, no matter what you use. There are some great people that can help you out.

Mike
WA7UNW/4
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W4XKE
Member

Posts: 67




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« Reply #2 on: January 16, 2006, 07:34:46 AM »

My reasoning in posting this here was determined by the fact that RF interference isn't even a problem to the typical ham unless the power levels are incredibly high.  Only an SDR operator would likely acknowledge that there indeed is a problem.

(Kind of like comparing the effects of voltage transients on vacuum cleaners as opposed to computers.   The vacuum cleaner operator would simply ask, “Why are you concerned about a non-issue?”)  Only another computer operator could appreciate the problem.
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WA7UNW
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Posts: 71




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« Reply #3 on: January 17, 2006, 04:18:30 PM »

Sure it is much more noticable, but the problem exists for many. Read some of the posts here about amplified microphones, etc picking up RF. Just trying to help. You will get many more responses and assistance on Tower Talk.

Mike
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W4XKE
Member

Posts: 67




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« Reply #4 on: January 18, 2006, 07:45:14 AM »

Mike, I think perhaps you are right.  Thanks for your suggestion and your patience.  Respectfully, Johnny
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W4XKE
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Posts: 67




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« Reply #5 on: January 20, 2006, 05:49:14 AM »

Well that went about the way I originally thought that it might.  Most of the advice over there centered around selling my SDR.  

  "Ditch the Jupiter and get a rig that doesn't have these problems!"

I might as well try discussing an IRLP command problem with a bunch that says, "That ain't ham radio!" or walking into the locker room wearing a "KICK ME" sign on my back.  Thanks, but I believe I'll keep my radio.
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K4IA
Member

Posts: 66




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« Reply #6 on: January 31, 2006, 05:59:41 AM »

I had a Titan mounted four feet above a tin roof.  Here is what I found.  If I ran the coax across the roof , I had a problem.  That was also true with the Cushcraft R7000 the Titan replaced.  You must run the coax straight down to the ground as soon as you can and as far as you can before you make the turn horizontally.  Then add an RF Isolator at the shack end.  I found no difference between the grounded and ungrounded versions from RadioWorks - your mileage may vary.

Getting the antenna away from the radio is also a good idea with any antenna and any radio.  Any feed line will pick up RF if it is too close or out of balance.  That is why you feed a dipole at a 90 degree angle also.  I don't know why you would want to rotate the Gap.

I would mount on top of or above your metal roof, then get the coax under the roof or inside where it can run run horizontal on the floor to give you some additional shielding.  

Make sure you guy it just above the Gap - nothing fancy just something to keep it from whipping around.  You can get a clamp at Radio Shack and use that black antenna cord that doesn't rot or get eaten by the sun.  I would not mount the antenna near the side of the building unless you get the base of the antenna above the building.

Set up a good ground system in the shack with everything going to one point on the back of your antenna tuner (if you use one)and then a very short strap to ground.  Also ground your computer case to the same point.  If you still have trouble go to straps for all the grounding and add ferrites to the control cables.

I found the Gap to be a good antenna on 40 and above with marginal performance on 80.
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WA4OBJ
Member

Posts: 57




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« Reply #7 on: February 07, 2006, 10:54:59 PM »

I've been using a Titan DX for about 10 years now with great success. I'm on a hill overlooking Monterey Bay in California and can easily work just about anyone I hear.  There have only been a few issues you might want to consider.

I am running a TS950SDX with a TL922 1 KW amp.  When I first started using the amp, I was having problems with RF in the shack.  The cure was to put 10 or so ferrite beads on the feed line just below the Titan.  Mine sits about 50 feet from the house and about 100 feet from the shack.  I'm using 9913 coax with the first 50 feet buried about 12 inches in the ground and run through plastic conduit. The ferrites cured the RF problems.  I also grounded the coax where it comes out of the ground next to the house as well as where it enters the shack.  

The only other problem I've had is with screws and nuts working loose.  When I put the antenna together, I used anti-corrosion compound on all of the joints and screw heads so corrosion has not been a problem.  It is mounted on 1 1/4" water pipe about 10 feet above ground because I had problems with the deer trampling the counterpoise.  Once I got it into the air, the deer couldn't get to it and I've had no problems.  I take it down about once a year or so and check the screws and connections to insure they are clean and tight.  I am using a tilt over arrangement which makes it easy to maintain.

If you have the equipment, it is interesting to watch the SWR/Return loss shift when the antenna is swaying in the wind.  Mine is not guyed, although recommended by GAP, and sways quite a bit when the wind starts gusting over 25 MPH or so.  

All in all, I’m satisfied with the antenna and would buy another one if something ever happens to this one- like real tall deer running over it or the gophers tunneling under it and toppling the beast.

Hope this helps,

Dave, WA4OBJ
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