Home |
Search |
Today's Posts |
#11
![]() |
|||
|
|||
![]()
On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote:
Two sections above guys next to the house is pushing prudence. With a clear area next to the proposed tower in the back, three sections with just a VHF antenna seems reasonable in view of your description. I'm curious why two sections above the guys, next to the house, is marginal but three sections self-supporting out in the open seems OK. Actually the three sections self-supporting would be as close to the house on one end as the guyed tower is on the other end. Perhaps the tribander on the guyed tower makes the difference, but in truth I think the chances are fairly slim that I'll end up doing that. I have two inverted vees and two NVIS dipoles, which together cover 160 through 40, which these days are the only HF bands that really hold my interest... I never was much of a DX hound and with the Internet and satellite phones, it doesn't seem like hardly anybody wants to pass any traffic or run phone patches anymore. Perhaps when the sunspots get more favorable I'll re-think the notion of the tribander but until then it's probably pretty low on the priority list. |
#13
![]() |
|||
|
|||
![]()
On Sun, 01 Jul 2007 16:52:04 -0400, "Rick (W-A-one-R-K-T)"
wrote: my From: line is an attempt to deter spammers, who no doubt harvest this and other rec.radio.amateur forums for call signs, Hi Rick, I've laid my return address out there bare for more than a dozen years, and the amount of spam hardly compares to my other email (professional and social) accounts (sometimes 40-60 in a day for them, compared to one or two a month here). 73's Richard Clark, KB7QHC |
#14
![]() |
|||
|
|||
![]()
I have fifty feet of 25G standing next to a pole barn... It is
bracketed to the eve at ~14 feet and free standing above that... It has a gaggle of vhf/uhf stuff on it... It has withstood 80mph wind gusts... It is a bit loosey goosey when you are at the top so I pull some light rope up there when I climb up, and cinch it off to stop the sway... denny / k8do |
#15
![]() |
|||
|
|||
![]()
On Sun, 01 Jul 2007 15:20:54 -0400, "Rick (W-A-one-R-K-T)"
wrote: On Sun, 01 Jul 2007 16:58:42 +0000, Dave wrote: sorry, think again... no hinge bases allowed on free standing towers. Hmmm ... OK, I guess I will have to be able to climb it... I suppose I could install temporary guys while I'm up on it doing antenna work, but in that location permanent guying wouldn't work too well... free standing towers must embed the base section in concrete. How about the BPC25G base plate (non-hinged)? I already have a concrete base in place, 6 feet deep, intended for the predecessor to the US Tower MA-series crank-up mast. The mast (and the base, and the tower on the other end of the house) belonged to my father when he lived with us, but he sold the mast many years ago, and the new ones are a bit too pricey for me right now. So, it's too late to embed the bottom section directly into the concrete, at least in that location. I have the early model Crank up mast (Wilson, CT-77) that I brought with me from Ohio in 1993. No one would give me $400 for it! The top section failed (overloaded with VHF-UHF stuff in 1980's while in a guyed configuration. It twisted and developed a diagonal crease. Some time in the late 1990's I restored the mast and built a home brew base for it. With the top section removed it is about 55 feet. I had an opportunity to examine a factory built erection base and I felt too many compromises were made to keep it shippable. I was able to acquire scrap steel from a local salvage yard. I mounted a 1/2" steel plate (actually 2 1/4" pieces) about 20" x 30" on wide spread 1/2" J-Bolts embedded in 5 Yards of concrete (5 yards is overkill, but that was the minimum charge so I elected to use it). I think they were about 36" long. I feel the J-Bolts are the weakest part of the design. I mounted an I-Beam vertically (about 12 feet tall) to the plate with 1/2" Grade 8 bolts and heavy angle iron to the base. I also mounted the hinge plate for the mast to the plate. Then I fashioned a pulley arrangement from the upright to raise & lower the tower. The tower at the 23 foot mark with a Cushcraft A3S beam and a G800 Yaesu rotor is load enough to raise and lower. In that configuration a ladder is still needed to reach the beam mounting bolts due to the length of the antenna elements and the boom length. The combination seems to handle the weather better at about the 45 foot mark so I seldom raise it above that. I use an electric boat winch to raise & lower the mast extent ion. I have been using a crank winch to raise & lower the tubular assembly. Hopefully, I will get that converted to an electric winch sometime this year. Age is catching up with me. We have Hurricanes & Ice in North Carolina. However, the wind rarely exceeds 80 mph in my area. I expect to lose the antenna some day but I doubt the tower will fail. Although I had an electric welder available I used nuts & bolts because I felt my welding skills were suspect. I had a small back hoe (Terra Mite) available for the digging & Heavy lifting. I would do it again. But I would not consider it with a non retractable mast. John Ferrell W8CCW "Life is easier if you learn to plow around the stumps" |
#16
![]() |
|||
|
|||
![]()
Dear Rick: Sorry to have received the call-sign incorrectly. Your
Father's call does not ring any bells. The main reason for two sections above a house bracket is because of the significantly greater probability of greater wind pressure on the two sections compared to three sections that start at ground level. You also expect to have more effective area for the greater wind pressure to work on. I have become convinced that the reason few urban TV/FM antennas and Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in wind pressure up to about 35 feet above ground in a typical urban environment. The real limitation (for you) may turn out to be due to the building code used in your area. When the time comes to have a serious antenna tower for HF, do find a professional engineer licensed in your State who's advice about how to satisfy the building code and 222G will be worth every penny you pay to him or her. Warm regards, Mac N8TT P.S. My neighbor K8DO still does things that give me the willies. Even when I was young, I sure would not climb 50 feet of un-guyed Rohn 25. Medical school instills rather more "confidence" than engineering schools do. -- J. Mc Laughlin; Michigan U.S.A. Home: "Rick (W-A-one-R-K-T)" wrote in message news ![]() On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote: Two sections above guys next to the house is pushing prudence. With a clear area next to the proposed tower in the back, three sections with just a VHF antenna seems reasonable in view of your description. I'm curious why two sections above the guys, next to the house, is marginal but three sections self-supporting out in the open seems OK. Actually the three sections self-supporting would be as close to the house on one end as the guyed tower is on the other end. Perhaps the tribander on the guyed tower makes the difference, but in truth I think the chances are fairly slim that I'll end up doing that. I have two inverted vees and two NVIS dipoles, which together cover 160 through 40, which these days are the only HF bands that really hold my interest... I never was much of a DX hound and with the Internet and satellite phones, it doesn't seem like hardly anybody wants to pass any traffic or run phone patches anymore. Perhaps when the sunspots get more favorable I'll re-think the notion of the tribander but until then it's probably pretty low on the priority list. |
#17
![]() |
|||
|
|||
![]()
On Mon, 2 Jul 2007 19:52:24 -0500, "J. Mc Laughlin"
wrote: Dear Rick: Sorry to have received the call-sign incorrectly. Your Father's call does not ring any bells. The main reason for two sections above a house bracket is because of the significantly greater probability of greater wind pressure on the two sections compared to three sections that start at ground level. You also expect to have more effective area for the greater wind pressure to work on. I have become convinced that the reason few urban TV/FM antennas and Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in wind pressure up to about 35 feet above ground in a typical urban environment. The real limitation (for you) may turn out to be due to the building code used in your area. When the time comes to have a serious antenna tower for HF, do find a professional engineer licensed in your State who's advice about how to satisfy the building code and 222G will be worth every penny you pay to him or her. Warm regards, Mac N8TT P.S. My neighbor K8DO still does things that give me the willies. Even when I was young, I sure would not climb 50 feet of un-guyed Rohn 25. Medical school instills rather more "confidence" than engineering schools do. Shucks, I met him way before he became so conservative. |
#18
![]() |
|||
|
|||
![]()
On 2 Jul, 17:52, "J. Mc Laughlin" wrote:
Dear Rick: Sorry to have received the call-sign incorrectly. Your Father's call does not ring any bells. The main reason for two sections above a house bracket is because of the significantly greater probability of greater wind pressure on the two sections compared to three sections that start at ground level. You also expect to have more effective area for the greater wind pressure to work on. I have become convinced that the reason few urban TV/FM antennas and Rohn 20 (no cross braces) towers fail is because of a dramatic reduction in wind pressure up to about 35 feet above ground in a typical urban environment. The real limitation (for you) may turn out to be due to the building code used in your area. When the time comes to have a serious antenna tower for HF, do find a professional engineer licensed in your State who's advice about how to satisfy the building code and 222G will be worth every penny you pay to him or her. Warm regards, Mac N8TT P.S. My neighbor K8DO still does things that give me the willies. Even when I was young, I sure would not climb 50 feet of un-guyed Rohn 25. Medical school instills rather more "confidence" than engineering schools do. -- J. Mc Laughlin; Michigan U.S.A. Home: "Rick (W-A-one-R-K-T)" wrote in message news ![]() On Sun, 01 Jul 2007 16:39:37 -0500, J. Mc Laughlin wrote: Two sections above guys next to the house is pushing prudence. With a clear area next to the proposed tower in the back, three sections with just a VHF antenna seems reasonable in view of your description. I'm curious why two sections above the guys, next to the house, is marginal but three sections self-supporting out in the open seems OK. Actually the three sections self-supporting would be as close to the house on one end as the guyed tower is on the other end. Perhaps the tribander on the guyed tower makes the difference, but in truth I think the chances are fairly slim that I'll end up doing that. I have two inverted vees and two NVIS dipoles, which together cover 160 through 40, which these days are the only HF bands that really hold my interest... I never was much of a DX hound and with the Internet and satellite phones, it doesn't seem like hardly anybody wants to pass any traffic or run phone patches anymore. Perhaps when the sunspots get more favorable I'll re-think the notion of the tribander but until then it's probably pretty low on the priority list.- Hide quoted text - - Show quoted text - Hey Mac, ask that medical neigbour of yours why a lot of disease of the body are not encapsulated in their own little prison instead of medics resorting to the knife? I, like many, was born in the industrial era where many caught T.B. and other disease and suffered from hunger. In my case when I got T.B. the pollutants I breathed created a calcinated shell around it thus rendering it harmless via prison. Now a days we move to the knife or drugs too often where accepting possesion of the disease is better by placing it in quarantean.. Seems like surgeons also have information but also reject under the "all is known" mantra. Art Unwin KB9MZ....XG |
#19
![]() |
|||
|
|||
![]()
Dear Neighbor Roger:
Oh my, and I clean forgot that the two of us fly little airplanes into and out-of strange places. Perhaps it is just antenna people in this part of Michigan. No. I am convinced that for DO it is the residue of surviving in a factory and medical school. Warm regards, Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Roger (K8RI)" wrote in message ... On Mon, 2 Jul 2007 19:52:24 -0500, snip P.S. My neighbor K8DO still does things that give me the willies. Even when I was young, I sure would not climb 50 feet of un-guyed Rohn 25. Medical school instills rather more "confidence" than engineering schools do. Shucks, I met him way before he became so conservative. |
#20
![]() |
|||
|
|||
![]() On Tue, 03 Jul 2007 15:28:08 -0500, J. Mc Laughlin wrote: Oh my, and I clean forgot that the two of us fly little airplanes into and out-of strange places. Oh, man, and to think I've been LISTENING to you daredevils... :-) Rick Bonanza N122X (KASH) |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
150' Rohn 45 tower complete with guys | Swap | |||
What are you guys saying..... | CB | |||
WTB Rohn 20 or Rohn 25 Tower sections (2) | Swap | |||
Okay,Guys..here's what I did!!! | Shortwave | |||
Wanted- Used Motorola UHF JT1000 High Split (470-520mhz), & a used Syntor X-9000 UHF High-Split | Swap |