|Joined:||Sat, Apr 4th 1998, 00:00||Roles:||N/A||Moderates:||N/A|
|HF Beam Antenna Polarization||Aug 19th, 02:05||6||160||on 21/8/14|
|Above 148 MHz,below 144 MHz||Nater27||2 days, 14 hours ago|
|Generally the 136 to 143.900 MHz has been assigned to the U.S. Military for their communications, 143.9000 to 144.000 MHz is used for the Civil Air Patrol and 148.000 to 148.100 MHz is used for the Civil Air Patrol for their Repeaters & Simplex operations, above 148.100 up to 175 MHz is set aside as Commercial Business Band that Public Safety, Taxi Cabs, Hospital Radio Paging, the U.S. National Park Service, NOAA Weather, VHF marine communications, Several U.S. Federal Government Agencies, small Businesses i.e. Gas Stations / Towing Services and most of these radio channels are going to the newer Digital modes for better RF coverage and narrow band operation.
|One Antenna or Two for HF/VHF/UHF||pmc181||4 weeks ago|
I see that you have chosen two different Multimode Multiband transceivers. It would be a pity not to be able to use all of the modes or 10 m, 6 m, 2 m & 70 cm bands, traditionally Weak Signals CW / SSB use horizontal polarization which minimizes the man made noise levels whereas Analog FM uses vertical polarization, pretty much immune to man made noise. You could erect a small 10 m beam on a tripod with a 5/8 Wave Vertical on the same mast pipe. The erect another tripod to hold a 4 element 6 m, 11 element 2 m & a 14 element 70 cm beams horizontally stacked 3' apart with a Tri-Band 6 m, 2m & 70 cm Vertical on the top of the mast pipe and have the better of all four frequency bands to use.
BTW, Good Luck on Passing your License Test.
|40 foot tilt tower winch system||brakemanbobsmith||on 23/9/14|
I believe I know what you have as the Tilt Over Section is in the middle of the 40' being 20' above the ground and there should be a triangular brace that mounts to the top 3 rd section and over laps the 2 nd section above the ground. Those tower were marketed in the mid 1970s and probably production ran 10 years. The bottom of the triangular tower section that over lapped to of the main 10' sections normally had Galvanized steel cable attached to the over lapped bottom of the triangular section (this section was a little smaller to the standard 25G or 45G sections so it would lay flat against it) and on the very bottom 10' section Rohn mounted the hand crank assembly at 4' so one individual could raise or lower the Tilt Over Tower, Rohn used an unusual way of guying the tower, where the hinge is they set up four (4) individual guy lines but at the top they used three (3) individual guy lines. These tower could be set up as 40', 60' & 70'. I believe the 60' & 70' were hinged at 30' and naturally the over lapping triangular arm assembly straddled the 30' & 40' sections. Of course the length of the Galvanized cable had to be longer for the taller towers to Tilt Over. If this doesn't sound like what you have, perhaps it isn't a Rohn tower. The Crank assembly was similar to what people use to pull the boats up om to trailers so you might want to stop by a boating store to see if they can sell you that type of a Cranking assembly.
There a tower company known as Heights that uses a different method to raise and lower fixed length towers. They used a case harden huge steel screw something like 3 or 4' long built on to a triangular steel assembly. I hope this isn't what you have but they are still available:
|40 foot tilt tower winch system||brakemanbobsmith||on 22/9/14|
I'm trying to visualize what you have for a Rohn Tilt Over Assembly. Is this what you're using? http://www.antennasystems.com/Merchant2/graphics/rohn/BPH25G.jpg
Or something like this?
You haven't provided which Rohn tower size you have: 25G, 45G, 55G, or 65G?
These things matter when anyone would recommend what you might do. I hope you have cleared this with your City, Town or County's Building Department for a Permit as they require drawings in triplicate. You better know a Structural Engineer to approve what you're planning on doing or you'll end up having to remove the structure at your cost. PRB-1 is only as Good as you doing the official paperwork, not I thought I could do this and ask for foregiveness. Building Departments do not have that type of a Sense of Humor, no matter who it is.
|Restricted space multi band HF antenna recommendations||Alfdude1||on 8/9/14|
I wonder if Alldude1's HOA would approve my favorite Flagpole? It's located in Sheboygan, Wisconsin.
http://mortenson.wistia.com/medias/tejnwpitig Just Copy & Paste into your browser.