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Benefits of Telescopic Masts

post #1 of 17
Thread Starter 
Telescopic Vs. Fixed-length antenna masts

Per the Channel Master Off Air Antenna Installation Guide:
Quote:


A telescoping mast is used in installations for which standard 5 or 10 foot lengths of mast stacked together would not be sufficiently strong or rigid. (1.) A length of telescoping mast is stronger and more rigid than the same lengths made up of standard mast pieces stacked together. Because of their additional strength, some telescoping masts used with ground mounts (2.) can be extended up to 15 feet above the roof line without requiring guy wires. Another advantage of telescoping masts is that they can be (3.) easily adjusted to odd heights without having to cut the tubing.

Quote:


(4.) For extra strength when installing large antennas, use a telescoping mast that is one size larger than actually needed. This will permit you to attach the antenna to the mast section immediately below the topmost one. This section is larger and stronger than the topmost section because it is reinforced by the 1-1/4 diameter section that remains inside.

- CM Telescoping Masts - Note: Current models are now made from 18-guage tubing. Older models used to be 16-guage.

- Rohn Telescoping Masts - Note: Top section is 18-guage, lower sections are 16-gauge.

Questions:
  1. Is CM's list of benefits for telescoping masts accurate?
  2. Are there any disadvantages other than their additonal cost & weight not mentioned by CM?
  3. Are there other brands worth considering?
Thanks
post #2 of 17
I have a couple of older Radio shack telescoping masts and find them very convienent. I have not fully extended them in years, so they are very ridgid with the thinner uppermot sections still in part of the lower sections. I have both about 15 feet above the roofline with no guy wires and get practly no sway, and this is windy West Texas. The other great advantage is the ease of getting them up. I find it much easier to push up the sections than to fit aditional masts into another while holding it off the ground.
Yes, I am sure shipping is expensive. I do not know if Radio Shack will ship to the store for free, I heard on this forun at one time that True Value Hardware will provide that service.
post #3 of 17
I think it was either True Value or Ace that did a ship-to-store for one of the ChannelMaster Telescopic mounts.
post #4 of 17
post #5 of 17
I'd go with Rohn. More $$, but it's Rohn.
Search any Amateur radio supply outfit for towers.
post #6 of 17
Thread Starter 
Quote:
Originally Posted by Mister B View Post

I have a couple of older Radio shack telescoping masts and find them very convienent. I have not fully extended them in years, so they are very ridgid with the thinner uppermot sections still in part of the lower sections. I have both about 15 feet above the roofline with no guy wires and get practly no sway, and this is windy West Texas. The other great advantage is the ease of getting them up. I find it much easier to push up the sections than to fit aditional masts into another while holding it off the ground.
Yes, I am sure shipping is expensive. I do not know if Radio Shack will ship to the store for free, I heard on this forun at one time that True Value Hardware will provide that service.

Hi Mister B,

Sounds good. Does the 15' above the roofline include a rotor + rotor mast?

I just searched the RS & TVH web sites and they appear to no longer carry telescoping masts, just fixed-length masts.
post #7 of 17
Thread Starter 
Quote:
Originally Posted by ProjectSHO89 View Post

I think it was either True Value or Ace that did a ship-to-store for one of the ChannelMaster Telescopic mounts.

Hi ProjectSHO89,

Yes, True Value does offer "ship-to-store" but appears to no longer offer telescopic / telescoping masts.

Ace offers the CM-1830 (18-guage, 30 ft) and free shipping to one's local Ace. I suspect the previous 16-guage models would be less likely to need guy wires.
post #8 of 17
Thread Starter 

Hi arxaw,

CM has very reasonable shipping charges. However, all their models are now 100% 18-guage.

Ace is a better deal for shipping - free shipping to one's local Ace.

Shipping a Rohn telescoping mast from 3starinc is very cost-prohibitive and unfortunately is located about 2.5 hrs. away from us one-way.
post #9 of 17
Thread Starter 
Quote:
Originally Posted by videobruce View Post

I'd go with Rohn. More $$, but it's Rohn.
Search any Amateur radio supply outfit for towers.

Hi videobruce,

Yes, now that all CM telescoping masts are 100% 18-guage, Rohn appears to be the better choice. With Rohn, the lower sections are 16-gauge. However, the top section is 18-guage.

1. How far above the roof can the 18-guage top section extend without needing guy wires?

2. Or, is it recommended that one:
Quote:


...use a telescoping mast that is one size larger than actually needed. This will permit you to attach the antenna to the mast section immediately below the topmost one. This section is larger and stronger than the topmost section because it is reinforced by the 1-1/4 diameter section that remains inside.
post #10 of 17
Thread Starter 
Per 3starinc., the CM telescoping masts manufacturing unit has been sold by PCT to another company. Hopefully, they'll return to 16-guage models.
post #11 of 17
Quote:
Originally Posted by ota.dt.man View Post

Hi Mister B,
Sounds good. Does the 15' above the roofline include a rotor + rotor mast?

No rotor, I have used several different antennas in this configuration though, even some of the old style with the elements for low VHF.
post #12 of 17
Thread Starter 
A search turned up the following Oct., 2006 post (click on the blue arrow to see orignial post with pictures):

Quote:
Originally Posted by cpcat View Post

This is called a ground mount and is one of the most sturdy installations. I don't see any advantage of sinking the bottom into the ground. Just use a footer of some sort i.e. large flat rock or cement sidewalk tread.

I would recommend using a telescoping mast. I used a 30 footer and installed it upside down so the stiffest part is at the top. This also allows you to raise/lower the antenna very easily for fine tuning the signal.

There's an antenna installation guide at CM's website. I think it says 10 feet above roofline without need for guying with this type of mount. This is a rough estimate and obviously depends on your particulars, primarily how big of an antenna you put up.

I've had my rig up for a couple of years now and it's about 8 feet above roofline without problems. I could go higher but it actually is in the "sweet spot" for signal as is.
post #13 of 17
I came across this blog the other day searching for some old rotor information and this guy has been using a telescoping mast for 34 years.


http://wd4eui.com/Channel_Master_3610_VHF_FM_Antenna.html
post #14 of 17
Thread Starter 
Definitely, a well documented antenna system clearly showing that one can use a telescopic mast even with two large antennas if one has a sufficient guy wire system.
post #15 of 17
Thread Starter 
Please see Steve Inglett's blog for another example:

- 08/04/2011

- 08/25/2011

- 09/02/2011

I emailed Steve to see how much of the telescopic mast was unsupported above the roof. However, I didn't receive a reply. With a Google search I unfortunately discovered Steve had recently passed away in an auto accident. He was only 48 yrs old. frown.gif

I had previously corresponded with Steve about his VHF-hi antenna experience. Steve was a member of AVS and most recently learned how to repair his CM-7000 from the ReplayTV & Showstopper PVRs forum - Dead CM 7000. I will miss Steve and his blogg.
Edited by ota.dt.man - 6/12/12 at 10:33am
post #16 of 17
I know one thing, I would hate to be without mine.

tongue.gif
post #17 of 17
Thread Starter 
Quote:
Originally Posted by McDonoughDawg View Post

I know one thing, I would hate to be without mine.
tongue.gif
What aspect(s) of it has/have been most helpful to you?
Please post a picture. Thanks smile.gif
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