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-   -   Wire antennas again - counterweight question (https://www.radiobanter.com/shortwave/159529-wire-antennas-again-counterweight-question.html)

bpnjensen February 14th 11 04:14 AM

California's 'Golden' Railroad History
 
On Feb 13, 7:36*pm, RHF wrote:
On Feb 13, 8:56*am, bpnjensen wrote:









On Feb 13, 4:03*am, RHF wrote:


On Feb 12, 10:03*pm, bpnjensen wrote:


On Feb 12, 6:38*am, Joe from Kokomo wrote:


On 2/11/2011 2:22 PM, bpnjensen wrote:


So, a mechanical question this time -


On a relatively short run of wire of fairly light weight (in this
case, 14 gauge stranded, insulated, and about 60-65 feet horizontal),
what's a good estimated counterweight for the far end? *The wire
itself is light, but the counterweight needs to account for tension as
well. *The support line is over a freewheeling pulley and is currently
tied off, but I think a modest eight would be better in this
circumstance as the near end of the line is a treetop with some sway
in the wind.


So, I ask if anybody has an idea about what a good weight night be to
maintain tension and avoid too much sagging. *For starters, I was
thinking a simple barbell weight of 5 lbs or so more or less, but I'm
wide open on this one.


Thanks so much!
Bruce


Let me point you in a different direction...


When you ask about a weight, that implies you will also be using a
pulley (block, for you sailors). This is another piece to purchase and
another piece to rust up and fail, at least the hardware store
galvanized ones. Don't ask what the ones for sailboats cost.


I have had a 130 foot dipole (stranded 14 ga.) up between two trees
since 1994, with no failures here in the great Midwest (lots o' wind,
lots o' snow).


I considered the weight/pulley arrangement but ultimately decided on
using a screen door spring at each end. These are typically *a foot (or
a little more) long and readily available at any hardware store. I would
recommend you pay a buck or two more and get the ones that are chrome
plated and then spray paint it too, for a little additional
weatherproofing (belt AND suspenders). Works fine, lasts a long time.


Hi, Joe- I have thought about a spring - those screen door springs
provide enough tension and travel? I expect up to about 3 feet travel
on that tree in the highest winds we get here.


To be honest, a counterweight is not a problem as to position and
safety. *A spring might be a little bit neater if it has enough
strength and give. *Neither one sounds very expensive.


Thanks, Bruce


OSH Hardware* has Good Quality Chromed Pulleys
with Brass Roller; Poly & Nylon Rope and a fair
selection of Zinc Plated Springs of all Diameters,
Lengths and Gauges. ~ RHF


Pulley : Chrome-Plated Zinc Die-Cast Housing
and Swivel Eyehttp://www.fdsons.com/popup_image.php?pID=19638http://www.acehardware...


* ACE, *Home Depot and Lowe's too.
*.


- OSH is my store, not the least of which because
- they have great free train calendars :-)

Free Train Calendars :-) :o) :-) :o) :-) :o) :-) :o) ~ RHF
*.
"Railtown" 1897 State Historic Parkhttp://www.parks.ca.gov/?page_id=491
-location- Jamestown, Californiahttp://www.railtown1897.org/railtown/default.asp
*.
California State Railroad Museumhttp://www.csrmf.org/
-location- Old-Town Sacramento, Californiahttp://www.parks.ca.gov/?page_id=668
*.
Western Railway Museumhttp://www.wrm.org/
-location- Suisun City, California
* Bay Area Electric Railroad Association

They are all Part of California's "Golden" Railroad History ~ RHF
*.
*.


We have a great place near my home - Niles Canyon Railway and Golden
Gate Railroad Museum:

http://www.ncry.org/

http://www.ggrm.org/

Steam train rides all the time :-)

RHF February 14th 11 04:26 AM

Wire SWL Antennas : ? The Question Is . . . Are Your SWL AntennasFit-To-Be-Tied !
 
On Feb 13, 8:57*am, bpnjensen wrote:
On Feb 13, 6:18*am, dave wrote:

On 02/13/2011 04:03 AM, RHF wrote:


OSH Hardware* has Good Quality Chromed Pulleys
with Brass Roller; Poly& *Nylon Rope and a fair
selection of Zinc Plated Springs of all Diameters,
Lengths and Gauges. ~ RHF


You need real antenna rope. UV treated Dacron polyester antenna rope.


- I've always used "regular" polyester rope, which
- I think is inherently UV resistant. *It lasts longer
- than the antennas do. *I think Dacron is just a
- brand name for polyester anyway.

BpnJ : You got that right :o)
http://en.wikipedia.org/wiki/Dacron
http://www.davisrf.com/dacron.php

Dacron is a TradeMark {Name} for a Polyester Fiber.
http://www.answers.com/topic/dacron
http://www.encyclopedia.com/topic/Po...phthalate.aspx

dave February 14th 11 02:51 PM

Wire SWL Antennas : ? The Question Is . . . Are Your SWL AntennasFit-To-Be-Tied !
 
On 02/13/2011 08:26 PM, RHF wrote:

-but- I still use Antenna Insulators between the 'Poly'

Why?

dave February 14th 11 03:34 PM

Kiss It Stupid Simple
 
On 02/14/2011 06:51 AM, dave wrote:
On 02/13/2011 08:26 PM, RHF wrote:

-but- I still use Antenna Insulators between the 'Poly'

Why?


If you use insulating rope there is no need to buy insulators.

bpnjensen February 14th 11 03:49 PM

Kiss It Stupid Simple
 
On Feb 14, 7:34*am, dave wrote:
On 02/14/2011 06:51 AM, dave wrote:

On 02/13/2011 08:26 PM, RHF wrote:


-but- I still use Antenna Insulators between the 'Poly'


Why?


If you use insulating rope there is no need to buy insulators.


I use them for strain relief. Wrapping a wire or a rope around an
insulator with a 3/4 inch radius puts less wear and tear on either
material per square mm of contact surface than tying the rope directly
to the wire. I cannot prove (off the top o' my head) this
quantitatively, but intuitively it seems right.

Having said that. I am sure there is nothing to gain electrically from
omitting the insulator.

dave February 14th 11 04:27 PM

Kiss It Stupid Simple
 
On 02/14/2011 07:49 AM, bpnjensen wrote:
On Feb 14, 7:34 am, wrote:
On 02/14/2011 06:51 AM, dave wrote:

On 02/13/2011 08:26 PM, RHF wrote:


-but- I still use Antenna Insulators between the 'Poly'


Why?


If you use insulating rope there is no need to buy insulators.


I use them for strain relief. Wrapping a wire or a rope around an
insulator with a 3/4 inch radius puts less wear and tear on either
material per square mm of contact surface than tying the rope directly
to the wire. I cannot prove (off the top o' my head) this
quantitatively, but intuitively it seems right.

Having said that. I am sure there is nothing to gain electrically from
omitting the insulator.


http://www.westmarine.com/1/1/81866-...mbles-1-4.html

bpnjensen February 14th 11 04:46 PM

Kiss It Stupid Simple
 
On Feb 14, 8:27*am, dave wrote:
On 02/14/2011 07:49 AM, bpnjensen wrote:





On Feb 14, 7:34 am, *wrote:
On 02/14/2011 06:51 AM, dave wrote:


On 02/13/2011 08:26 PM, RHF wrote:


-but- I still use Antenna Insulators between the 'Poly'


Why?


If you use insulating rope there is no need to buy insulators.


I use them for strain relief. *Wrapping a wire or a rope around an
insulator with a 3/4 inch radius puts less wear and tear on either
material per square mm of contact surface than tying the rope directly
to the wire. *I cannot prove (off the top o' my head) this
quantitatively, but intuitively it seems right.


Having said that. I am sure there is nothing to gain electrically from
omitting the insulator.


http://www.westmarine.com/1/1/81866-...bles-1-4.html- Hide quoted text -

- Show quoted text -


Yepp, those should work too :-)

Joe from Kokomo[_2_] February 14th 11 05:19 PM

Kiss It Stupid Simple
 

On 02/14/2011 06:51 AM, dave wrote:
On 02/13/2011 08:26 PM, RHF wrote:

-but- I still use Antenna Insulators between the 'Poly'

Why?


On 2/14/2011 10:34 AM, dave wrote:

If you use insulating rope there is no need to buy insulators.


Well, that could be debatable. Do you have any way to quantify the RF
leakage of wet rope vs. a wet insulator to support your contention?

bpnjensen February 14th 11 05:21 PM

Kiss It Stupid Simple
 
On Feb 14, 9:19*am, Joe from Kokomo wrote:
On 02/14/2011 06:51 AM, dave wrote:
On 02/13/2011 08:26 PM, RHF wrote:


-but- I still use Antenna Insulators between the 'Poly'


Why?


On 2/14/2011 10:34 AM, dave wrote:

If you use insulating rope there is no need to buy insulators.


Well, that could be debatable. Do you have any way to quantify the RF
leakage of wet rope vs. a wet insulator to support your contention?


How important would that be for receive?

m II February 14th 11 06:15 PM

Kiss It Stupid Simple
 
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On 11-02-14 10:19 AM, Joe from Kokomo wrote:

On 02/14/2011 06:51 AM, dave wrote:
On 02/13/2011 08:26 PM, RHF wrote:

-but- I still use Antenna Insulators between the 'Poly'

Why?


On 2/14/2011 10:34 AM, dave wrote:

If you use insulating rope there is no need to buy insulators.


Well, that could be debatable. Do you have any way to quantify the RF
leakage of wet rope vs. a wet insulator to support your contention?



Rainwater doesn't conduct very well. Also, the voltages are very low.
Power lines will arc over insulators, but that's usually caused by filth
accumulating over the insulator knob and the fact that it's a few
thousand volts.



mike
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