Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Jun Sun 16, 2019 4:25 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 55 posts ]  Go to page Previous  1, 2, 3
Author Message
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 10, 2019 11:23 pm 
Member
User avatar

Joined: Jun Sat 18, 2011 3:36 am
Posts: 2226
Location: Milton, FL 32570
I believe it will do whatever it wants. If it wants to be a ball, a sprite or a regular bolt.

jason

_________________
Thanks,
Jason
KN4UCQ


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 10, 2019 11:44 pm 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 11250
Location: Powell River BC Canada
Lightning can send earth waves just fine.

Audio Telegraph needs no wires, sends through earth 200 feet. However finding
an eighty cent telegraph key may take some time.

Radio for the millions, pages 22,23,24.
Attachment:
Earth telegraph.jpg
Earth telegraph.jpg [ 228.21 KiB | Viewed 329 times ]

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Mon 11, 2019 12:14 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5285
Location: Montvale NJ, 07645
fifties wrote:
Waterski wrote:
So all in all the thought that lightening will strike a tall object first is busted.

I believe the idea is that lightning will hit the shortest path to ground.

i will go with the path of least resistance, which would normally be the shortest as you state.


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Mon 11, 2019 11:30 pm 
Member
User avatar

Joined: Jun Mon 20, 2011 6:09 pm
Posts: 949
Location: 56401
I read somewhere that lightning will not strike a horizontal wire. In my small sample of a few strikes over 60 years, that seems to be true.

_________________
Prediction is difficult, especially about the future. Niels Bohr


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Tue 12, 2019 4:08 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 12549
Location: Mpls, Minnesota
Lightning strikes wherever it wants to. I was standing in my side yard working on my camper when lightning struck the ground about 100 feet away in the lowest area of the property by about 30 ft. My hair stood up and the flash and boom was instantaneous.

Dave


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sat 16, 2019 7:43 pm 
Member

Joined: Apr Thu 11, 2013 11:03 pm
Posts: 511
Location: 649 Lacy Wilkerson Rd Roxboro, NC 27574
On page one of this thread post #6, Copiertech posted a reference to an article on a method of antenna installation. What opinions of this design do you guys have?

_________________
Joel Walker


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sat 16, 2019 10:56 pm 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 11250
Location: Powell River BC Canada
The method of reducing noise introduced through a noisy earth electrode could be
explored using information in the "Earth Telegraph" article posted that
was in Radio for the Millions.

Simply, use a battery amplifier (Audio) connected to two rods and listen to
what noise currents exist in the earth around your location. If you have a battery
oscilloscope, even better. Then you can see supersonic noise, and if sweep is slow enough
even infra sonic.

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 17, 2019 10:14 am 
Member

Joined: Jun Sat 09, 2007 8:14 am
Posts: 3645
Location: Florida
radiotechnician wrote:
Lightning can send earth waves just fine.

Audio Telegraph needs no wires, sends through earth 200 feet. However finding
an eighty cent telegraph key may take some time.

Radio for the millions, pages 22,23,24.
Attachment:
Earth telegraph.jpg


I had great fun with something like this when I was a kid. I connected the output of an audio amp to two ground rods (I may have used a reverse connected output transformer for matching) and then listened for the signal with a simple transistor headphone amp I built into a Band-Aid box. I don't remember much as to electrode spacing but I suspect the transmit side used 20 feet or so and the receive side maybe six feet. I tried it all over the yard and could easily hear the audio for 100 feet or so on our rural lot. I do remember there was noticeable hum, but hey! it worked!

I also built a setup to transmit audio over a light beam. I used the photo tube from an old movie projector and the reflector, bulb, and socket from a flashlight. I remember discovering that it worked much better when I arranged things so the light was on all the time and modulated by the audio instead of no "carrier". This was well before the days of lasers and fiber optic cables so I don't know why I thought of trying it but it was fun.

Those were the days.

RRM


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 17, 2019 12:50 pm 
Member
User avatar

Joined: Jun Sun 03, 2012 12:40 am
Posts: 1190
Location: Cromwell, Connecticut
Some recent expierience with lightning.

Top mounted (250’) 450MHz fiberglass antenna was struck by lightning. The N connector center pin on the antenna and 7/8” hardline was vaporized. This included the 3’ jumper. All equipment down stream was fine. Common practice is to have coax ground kits at the top, bottom, and entry point to master ground buss. The Polyphaser is inside tied to master ground buss. I have seen several sites where this has happened and all equipment inside was fine.

In a second site with two 220Mhz fiberglass antennas mounted with 40’ of vertical separation, the lower antenna was struck. Same scenario where the center pin was burnt. Proof that lightning does what it wants. Also at this site, a network switch and router was toasted. It was not grounded, just screwed in the rack.

Another site took a strike that found its way in via a telephone POTS line. Equipment that was connected to the phone line was burnt out which included an alarm panel and other equipment connected to it. The phone suppressor was tied to a different ground point than the alarm panel. The difference was enough to cause the burn up of equipment. Since that time, all equipment was tied back to the master ground buss at the site.

The bottom line here is that if proper grounding techniques are followed and the correct equipment is used, minimal damage will result. A direct strike will cause problems, but not toast everything. I have seen time again that Polyphasers do work. I also make it a point to inspect grounding when I visit sites to make sure we are correct.

For a home antenna, it’s always best to disconnect equipment from the antenna. Most home setups don’t meet commercial standards, so why take a chance. Commercial users don’t have the luxury of disconnecting equipment every storm, and quite often they are using their systems no matter what the weather is.

_________________
Tony

People may not remember how fast you did a job, but they will remember how well you did it.


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 17, 2019 5:50 pm 
Member
User avatar

Joined: Jun Wed 14, 2006 11:49 pm
Posts: 7508
Location: Leo, IN or Zellwood, FL
As to Lightning hits and grounding setups: In my backyard I have three towers. 175', 130' & 88' to the top antenna on each of those towers. On these towers are 23 yagi style HF antennas + Wire antennas for 80m and 160m bands + a couple 2m VHF vertical antennas. The ground system consists of 100 ground rods connected by 1200 feet of 3/8" ID copper tubing. This system was put in in 1989. To Date the tall tower has had over 50 direct hits. Yes it has a "Hit Counter" on the tower. Do Date total damage to the entire antenna system and all equipment connected to the station consists of ONE Fiberglass vertical I put up above the top of the tallest of the towers. I was totally vaporized after about 4 direct hits. Now the top of that tower only has a 2" Steel Pipe that is the top most metal object. Other than that VHF antenna I have had ZERO damage to any of the rest of the antenna system. There are 5 rotators and a couple dozen relay control boxes on the towers to change direction and select which of the antennas or combination of antennas one wants to use at any given time. ALL Coax lines to the house go through Polyphaser protection devices some are at the base of the towers and ALL of them at what is called the Ground Window where all this stuff enters the house. That is an aluminum plate 2' x 5' attached to two of the ground rods as well as rods going through the house wall and other grounding straps from the inside equipment are attached to this same ground window plate. All wires cables coaxes and anything else that is metal that comes or goes from that house has Polyphaser Lightning Protector devices on those lines. This also includes two Polyphaser Whole House power line protectors. One on the main breaker box and another on the 200A sub panel that is in the room with the ham radio equipment.
One great big THANK YOU to the guys at Polyphaser who helped me design this ground system.
Polyphaser turns BLITZ into BLISS


I don't even turn the equipment off during storms let alone try to disconnect any of it. That is what can be done with a Commercial Proper Lightning protection system. Leave one little bitty wire going to some itty bitty box of something that isn't properly protected and for sure that gadget is going to be TOAST. I have seen in others homes equipment that was disconnected and setting 10 feet away from the incoming coax rotor antenna wires coming into the house damaged. The piece of equipment was totally disconnected from everything. It was setting on top of a metal 4 drawer filing cabinet and the filing cabinet was setting a tile floor over concrete. BOOM it caused enough damage to that radio it was instantly turned into a Part Box of Maybe they work Parts.


As to the average hobbyist who has a single wire up in a tree you should have an adequate Lightning Protection Device and at minimum an 8 foot ground rod at the point of entrance into your house. That Ground Rod also needs to be connected to the Power Company ground rod and any other ground rods around your house. Connected with something #4 bare stranded wire or in my case I used copper tubing... difficult to work with... That is as per Electrical CODE .. then the Grounding Books will also say 8 foot rods spaced 16 feet apart for the "Perimeter Ground" around a building. So maybe you need a couple more rods between antenna entrance point and power company ground.


Back the question posed above about is this a good method to install an antenna? As to NOISE in our homes you have two choices. Either FIND AND KILL the offending devices or CURE them. ala... lots of toroid cores, replacement of wall wart switching supplies by different real transformer linear supplies. OR ELSE keep the antenna a significant distance away from all the noise generators and get the signal into the house as the guy above stated .. Ground rod both ends of coax. And NO don't run additional ground wire to the far ground rod. Idea there is to keep the NOISE off the coax shield coming to the house. Sometimes requires toroid choke at the house but if coax is buried probably it won't need the choke. Inside the house at the radio end of the coax depends on the type of radio ... if radio is equipped with Coax Input will be 50 to 75 ohms all is well direct connect the coax. However if a 1930's consumer type radio.. our antiques that is for the most part they are looking for Hi-Impedance Antenna Inputs... not 50 to 75 ohms more like 500 ohms plus or minus a bit ... so add another of the Un-Un transformers thats Unbalanced load to Unbalanced Load ... many will call it a BALUN but that is a wrong name BALUN means Balanced to UnBalanced and that it ain't. Coax is Unbalanced as is our old radio A and G inputs. Anyway... something like a 6 to 1 ratio or 9 to 1 ratio will make the old radio happy.

In my case I have done BOTH of the above. Killed noises within my own home plus built antennas away from the house plus keep common mode noise from the feedlines.

My 160M DXCC record was advanced by ONE this last week. So it was a weekend of celebration for me. Successful 2 way contact on 1.8 mhz known as 160m Ham Band with a station in Brunei. V84SAA callsign. Now I only need 28 more to have 2 ways with all the countries of the World on 1.8mhz.

good luck
John k9uwa

_________________
http://www.JohnJeanAntiqueRadio.com


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 17, 2019 5:53 pm 
Member

Joined: Sep Thu 23, 2010 6:37 am
Posts: 11250
Location: Powell River BC Canada
Telco drop line protection works well, however I have seen station wire fused and
burnt open, but no fire.

We had a cormorant short out a 6600 volt tower circuit in the parking lot adjacent
the data center. Even though this was a 50 Hz. system, and the data center was 60 Hz.
if fairly wiped out most of the Gandalf modems in the rack which fed the terminals in the plant.

Attachment:
Short circuit bird.JPG
Short circuit bird.JPG [ 13.65 KiB | Viewed 233 times ]

_________________
de
VE7ASO VE7ZSO
Amateur Radio Literacy Club. May we help you read better.
Steve Dow
ve7aso@rac.ca


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Sun 17, 2019 7:36 pm 
Member

Joined: Apr Thu 11, 2013 11:03 pm
Posts: 511
Location: 649 Lacy Wilkerson Rd Roxboro, NC 27574
Thanks. I have things to think about now. All my serious radio listening is done in my shop. When I do serious listening I turn off or unplug anything I find that causes interference. As far as the Un-Un's are concerned, does it matter what size toroid I use? I have several large ones some big enough to put a finger through.

_________________
Joel Walker


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Mon 18, 2019 2:04 am 
Member
User avatar

Joined: Jun Wed 14, 2006 11:49 pm
Posts: 7508
Location: Leo, IN or Zellwood, FL
joelandjoyce wrote:
Thanks. I have things to think about now. All my serious radio listening is done in my shop. When I do serious listening I turn off or unplug anything I find that causes interference. As far as the Un-Un's are concerned, does it matter what size toroid I use? I have several large ones some big enough to put a finger through.


For receive Un-Un's size isn't the important part. The Correct Ferrite Mix is what is important. If you want to roll your own perhaps look at Beverage transformers and Beverage antennas on the W8JI.com website. Plus a google look at them. The Antenna end is difficult to know what ratio you need. This due to not knowing what the actual impedance of the antenna is at some specific frequency. If your looking at frequencies of 10mhz and lower perhaps a normal Beverage type antenna might be better if you have the real estate to run one. Your looking at a few hundred feet in length for a plain beverage antenna. Those will have a height above ground from 2 feet up to maybe 10 feet in height. Yes signal levels would be down from the same length wire that was much higher but the atmospheric and local noise will be greater than the reduction in signal level. Maybe consider something like a Flag or EWE. Those wouldn't take up more than 60 to 70 feet in real estate. It would be an inverted U shape fed from ground level and one end and also a ground rod and resistor at the other end. It then produces a Cardiod shaped pattern of reception. Or the Flag which is somewhat the same thing except it actually has a wire that goes from bottom of vertical wire to bottom of the other vertical. The EWE and FLAG antenas are much more broadbanded so frequency won't effect the design of the Un-Un near as much as a single wire thrown over a tree limb. Random length the actual input impedance could vary from 15 to 100 ohms or more.

John

_________________
http://www.JohnJeanAntiqueRadio.com


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Mon 18, 2019 4:13 am 
Member

Joined: Apr Thu 11, 2013 11:03 pm
Posts: 511
Location: 649 Lacy Wilkerson Rd Roxboro, NC 27574
I have ten acres to play with. I had thought about running a wire along the top of my pasture fence or even using the fence itself since it is electric and isolated from ground. Obviously I would disconnect it from the fence charger.

_________________
Joel Walker


Top
 Profile  
 
 Post subject: Re: Another Long Wire Antenna Question - UPDATE
PostPosted: Feb Mon 18, 2019 12:01 pm 
Member
User avatar

Joined: Jun Wed 14, 2006 11:49 pm
Posts: 7508
Location: Leo, IN or Zellwood, FL
joelandjoyce wrote:
I have ten acres to play with. I had thought about running a wire along the top of my pasture fence or even using the fence itself since it is electric and isolated from ground. Obviously I would disconnect it from the fence charger.


If I had 10 acres to put antennas on there is no question I would have SEVERAL beverage style antennas each of them in the 800 to 1000 foot length range aimed in different directions. They work extremely well for the bottom of the broadcast band up through about 10 mhz. They are low noise and directional if built correctly. And yes hopefully you never have to run the fence charger as they will make lots of noise issues. Read up on Beverage Antennas from W8JI's website and others will explain how they work. You may need a 10 to 20 dB pre-amp at the radio end to raise the signal level. But the antennas will be low noise with good radio signals.
John k9uwa

_________________
http://www.JohnJeanAntiqueRadio.com


Top
 Profile  
 
Post New Topic Post Reply  [ 55 posts ]  Moderator: sofaslug Go to page Previous  1, 2, 3

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 10 guests



Search for:
Jump to:  




























Privacy Policy :: Powered by phpBB