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Author Topic: Repair of a 5BTV  (Read 1316 times)
W8JX
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Posts: 6421




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« on: February 28, 2013, 02:30:53 PM »

I thought I would pass along a recent experience I had with my 20+ year old 5 BTV. We had a very windy storm come through nearly 2 weeks ago and I went out side a few days later and much to my surprise I found it laying in field. (I had not been active on air during this time) It had snapped clean off just above the heavy inside base pipe the mast slide over and where weep hole was too. I decided to try to salvage it and make it operational until I can replace it. I lost about 11 inches of mast so I smoothed off broken end and split it for clamp and I guessed and eyeballed adding some length between various traps to make up for it and mounted main mast back on base but not fully down the last 3 inches or so. I was shocked when I checked SWR and found it well below 2 to 1 on 10, 15, 20 and 40. (I have not tried 80 yet) It is basically flat on 40 and nearly flat on 20 from 14.200 down. I gets close to 2 to 1 20 above 14.300 but rarely go up there but may tweak it later.   
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N0NZG
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Posts: 127




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« Reply #1 on: February 28, 2013, 06:34:46 PM »

Good job.  I hate listing to Nay Sayers say it can’t be done.  When I bought my 5BTV about 4 years ago the same tube was kinked from shipping damage. I did the same thing like you did to fix it. I cut the bad length off put it together and retuned the traps. I DO have very low SWRs on all bands.

73,

Jeremy
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KF6ABU
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Posts: 351




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« Reply #2 on: March 04, 2013, 02:15:07 PM »

If its flat across 10m it must have a whole bunch of loss.
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W8JX
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Posts: 6421




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« Reply #3 on: March 04, 2013, 03:01:44 PM »

If its flat across 10m it must have a whole bunch of loss.

Funny thing is, it flatter on 10 now than before breakage. I very rarely get on 10m anyway. Mostly 40 and some 20.
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N4UM
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« Reply #4 on: March 04, 2013, 06:53:46 PM »

I think the Hustler BTV series is the best bang per buck in antennas.  If you're not too serious about 80 meters I would suggest installling about 50 radials - each 20 feet long.  As mentioned earlier, use ground staples.  Fertilize and water liberally after installation. Maybe even sprinkle some grass seed over the radial field.  There will be some mismatch with the 70 ohm hardline but the losses on good quality hardline shouldn't be a big problem.  The thing will play on 80 but it's pretty short for that band and the bandwidth will only be 20 or 30 khz. 
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W8JX
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« Reply #5 on: March 04, 2013, 07:00:11 PM »

The thing will play on 80 but it's pretty short for that band and the bandwidth will only be 20 or 30 khz. 

Mine is good for about 75 kc under 2 to 1 swr
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N4UM
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« Reply #6 on: March 05, 2013, 05:46:41 AM »


"W8JX-Mine is good for about 75 kc under 2 to 1 swr"

BTW my post was in response to the previous post about Hustler verticals - Had a "senior moment!" 

Anyway, from some of the things I've read about ground mounted BTV verticals, one should become somewhat suspicious when they tend to exhibit a a broad bandwidth.  I've installed a number of 4/5/6-BTV's using decent radial systems over the years and none of them exhibited more than about 20-30 kHz of 2:1 SWR bandwidth.  I'd start by checking the coax if you're seeing a 75 kHz bandwidth.  You also might want to check the bandwidth by measuring the SWR right at the base of the vertical. 
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W8JX
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« Reply #7 on: March 05, 2013, 09:16:56 AM »

My  SWR rises very sharply out side the range. It is below 1.5 for about 35 kc.
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