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Mikefromms
Senior Member
Username: Mikefromms
Post Number: 1055
Registered: 6-2003
| | Posted on Thursday, August 26, 2010 - 10:25 am: | 
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After failure after failure to build a suitable antenna for stealth operation on 11 meters I bought an end fed half wave from Par Elecronics. now LnR Precision, Inc. I'm in a HOA community and no antennas.
All I can say is wow! With no exaggeration, when I hooked up this antenna I thought what did I just hook up, an Imax 2000? I couldn't believe the receive and I didn't have any problem with getting a "radio check".
I guess the inside of an Anron 99 or old big stick probably contains the same design only this is a well built match box and 16 gage insulated wire with an isulator on the end. I converted a 12 meter model to 11 meters. No, you can't run much over 100 watts into it and it's not a beam, but I think it is every bit as good as a big stick or A-99. Dale, the engineer who designed these antennas (they come in 40 thru 6 but no 11 advertised) certainly got these antennas right! I mean, the power from your radio gets radiated from the wire like gang busters. The match box is the trick. Just for fun, type par electronics end fed antenna reviews into your search box and enjoy the reviews. I concur with what they say.
Point: if you can't put up a ground plane or beam you can still get on the air in fine style and no one may ever know.
Hope this stirs some conversation. |
Mikefromms
Senior Member
Username: Mikefromms
Post Number: 1079
Registered: 6-2003
| | Posted on Wednesday, September 08, 2010 - 11:12 am: |
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No conversation....I arranged the end fed wire in a perfect vertical position. The feed point is only one foot off the ground. Last night, a guy was asking for radio check. We talked about 10 minutes. He was in a mobile and parked at his house. His 10-20 was over 20 miles away and he said I had good audio and signal. I think this end fed would work just as good as an old big stick or A-99. In fact, isn't that all they are is an end fed wire with a matching system inside of a fiberglass container? Anyway, this Par electronics 12 meter antenna cut for 11 meters is getting out good. I want to try to get it up higher. As a reminder, I'm in a HOA community so I can't put up the A-99 without taking a change on getting caught. |
Assaulter
Junior Member
Username: Assaulter
Post Number: 45
Registered: 1-2003
| | Posted on Monday, September 13, 2010 - 9:01 pm: |
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I actually have something very similar for the hf bands - it's an efab antenna by antenna solutions... similar design but all band - at 25 feet long!
So far I've had pretty good luck with it down to 40 meters, and the matchbox is mounted about 3 feet from the ground.
I had it running as a sloper into a tree and was using an antenna tuner on it, when I said 'what the hell' and decided to try hooking it to my 11 meter rig.
Whaddya know? 1.4 swr across the channels.
I hop on 38 lsb and some guy in new albany indiana (about 10-15 miles away) said I was giving him a 3 or so. Suprising considering I didnt think it would even radiate on 11!
Unfortunately, the service/maintenence people had to DRIVE THRU the freakin common area (where it sloped up to the tree) and took it down afraid they'd hit it i guess.
Gonna try hoisting it up around the roof soon.
I've been thinking about getting one of those par end fedz, myself, Mike. How much did you take off of it for 11 meters? |
Revpo
Advanced Member
Username: Revpo
Post Number: 649
Registered: 7-2006
| | Posted on Friday, August 30, 2013 - 2:25 pm: |
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I know this is old subject.. but what dimensions was the antenna cut for, for 11 meters and is it still in operations?
I have a end fed antenna on another radio up at 22 feet and in the form of a sloper and it is a talker/listener on 40 meters and a flat swr.
Anyhow if one of you are still around let us know if not maybe someone else.
REVPO/CEF 795
73
REVPO/DOCTOR/CEF 795
Wavin a hand from the cornfields of INDIANA
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Revpo
Advanced Member
Username: Revpo
Post Number: 693
Registered: 7-2006
| | Posted on Friday, July 04, 2014 - 5:06 pm: |
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I have a end fed at 68 feet for 6 thru 80 meters, and hooked it up on 11 meters with my GALAXY 979, swr with a tuner flat, needed a tuner because of the length, anyhow 1st contact on 11 meters was N.C. and a 10 min qso on AM, surprised me, next was Louisiana, so the end fed does work good.
CEF795
73
REVPO/DOCTOR/CEF 795
Wavin a hand from the cornfields of INDIANA
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Starface
Senior Member
Username: Starface
Post Number: 3308
Registered: 1-2005
| | Posted on Friday, July 04, 2014 - 11:05 pm: |
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Just one Question? Why live in a HOA and be or become a CBer or Ham?
George
KI4NBE
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Possum_lodge
Junior Member
Username: Possum_lodge
Post Number: 47
Registered: 5-2014
| | Posted on Wednesday, July 09, 2014 - 1:58 pm: |
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A antenna is a antenna is a antenna.
It does not matter if it was designed for 10 meters or 12 meters, it will still work on 11 meters.
A rough guestimate is that a full wave @ channel 19 is around 36' long. Take into consideration the velocity factor of the wire used, and you can cut a dipole antenna about 16.5 - 17.5' long - depending upon the type of wire used and the diameter and it will tune up somewhere in the 11 meter band.
Physic's dictates that most of the signal is at the base of the antenna and that there is a null at the end. The higher you get the feed point, the more power you will radiate.
If you use the antenna horizontally and try to talk to mobiles locally, the mismatch in the polarization will be so severe - they probably won't even hear you unless you are right on top of them.. Once the signal goes over the horizon the polarization changes and after that it does not matter if it is horizontal or vertical - except that horizontal is usually quieter.
The key is to start out with a antenna that is longer then the desired band and cut it down until you get the match you desire on the frequency you desire. If you cut it for channel 40, it is not going to perform well on channel 1 - too short, and if you cut it for channel 1 - it will be too long for channel 40.
If your radio has a built in antenna tuner, the small mismatch probably won't matter anyhow.
All vertical antenna's needs some sort of ground plane, just sticking up a solorcon without a groundplane does not do it any justice. |
Tech237
Moderator
Username: Tech237
Post Number: 1801
Registered: 4-2004
| | Posted on Thursday, July 10, 2014 - 10:26 am: |
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Possum-Lodge, once again a little off accuracy.
1) An antenna cut for 12 or 10M will not work properly on 11m IT IS NOT RESONANT. An antenna needs to be constructed for the band it will be used on to work efficiently.
2) Not all antenna's need to have a high feed point to work properly. A shunt fed tower does not for example.
3) Cross polarization loss is less than 6dB (1 S-point). Most mobile to base contacts with cross polarization won't even notice the loss. I have worked many USB stations on 2m using a vertical (mobile) while they had horizontal antennas, and still got reports of 57 to 59 from them. This is with both local and "DX" contacts.
4) There are vertical antennas out there that are designed not to require a groundplane to work effectively - such as any half-wave antenna. In fact using a ground plane with some of the antennas actually REDUCES efficiency and bandwidth. I used to install capacitive fed, half-wave antennas on fibreglass bodied vehicles for frequencies ranging from 27Mhz up to 500Mhz all without any ground plane. All had great communication ranges. All had antennas that matched well to the radios.
You were right with starting with an antenna longer than required for the band and trimming it to match. By the way a thicker conductor gives you a better chance of getting a good match across the band, compared to a thin one.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Possum_lodge
Junior Member
Username: Possum_lodge
Post Number: 49
Registered: 5-2014
| | Posted on Saturday, July 12, 2014 - 11:26 am: |
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Tech 237 - I don't like to argue with people over the internet, it usually turns out bad.,
As far as what you say about what you did, I'm sure you believed every word of what you just said.
However -If I had to pick and choose links to show you where you were wrong, I would be wasting my time.
If you want to talk efficiency, you need to understand the Q of a electrical circuit.
A antenna is looked at as being a load, and the radio is looked at as being the generator.
Yes you do get the most out of it when the antenna is resonant on the frequency desired. This is why you see so many Ringo Ranger antenna's above the roof of most police stations, firehouses and ambulance services.
The purpose of the Ringo was to get you close to the frequency desired with one antenna design and be able to shorten or lengthen the antenna without having to cut it. It allowed one antenna to work anywhere from 40 - 50 MHz, just not very good everywhere. It would have a near 1:1 match at the desired frequency and a poor match everywhere else.
Just because the match is poor, does not mean that you are not radiating power.
Except for amateur radio, most all radio communications with the exception of television is vertically polarized. The reason why television was horizontally polarized was due to the fact that there was less noise when horizontally polarized - because everything else was vertical.
An antenna is a transducer that converts radio frequency electric current to electromagnetic waves that are then radiated into space. The electric field or "E" plane determines the polarization or orientation of the radio wave. In general, most antennas radiate either linear or circular polarization.
A linear polarized antenna radiates wholly in one plane containing the direction of propagation. In a circular polarized antenna, the plane of polarization rotates in a circle making one complete revolution during one period of the wave. If the rotation is clockwise looking in the direction of propagation, the sense is called right-hand-circular (RHC). If the rotation is counterclockwise, the sense is called left-hand-circular (LHC).
An antenna is said to be vertically polarized (linear) when its electric field is perpendicular to the Earth's surface. An example of a vertical antenna is a broadcast tower for AM radio or the "whip" antenna on an automobile.
Horizontally polarized (linear) antennas have their electric field parallel to the Earth's surface. Television transmissions in the USA use horizontal polarization.
A circular polarized wave radiates energy in both the horizontal and vertical planes and all planes in between. The difference, if any, between the maximum and the minimum peaks as the antenna is rotated through all angles, is called the axial ratio or ellipticity and is usually specified in decibels (dB). If the axial ratio is near 0 dB, the antenna is said to be circular polarized. If the axial ratio is greater than 1-2 dB, the polarization is often referred to as elliptical.
Maximum signal strength between stations occurs when both stations are using identical polarization.
On line-of-sight (LOS) paths, it is most important that the polarization of the antennas at both ends of the path use the same polarization. In a linearly polarized system, a misalignment of polarization of 45 degrees will degrade the signal up to 3 dB and if misaligned 90 degrees the attenuation can be 20 dB or more. Likewise, in a circular polarized system, both antennas must have the same sense. If not, an additional loss of 20 dB or more will be incurred.
Vertical polarization is most often used when it is desired to radiate a radio signal in all directions such as widely distributed mobile units. Vertical polarization also works well in the suburbs or out in the country, especially where hills are present. As a result, nowadays most two-way Earth to Earth communications in the frequency range above 30 MHz use vertical polarization.
Horizontal polarization is used to broadcast television in the USA. Some say that horizontal polarization was originally chosen because there was an advantage to not have TV reception interfered with by vertically polarized stations such as mobile radio. Also, man made radio noise is predominantly vertically polarized and the use of horizontal polarization would provide some discrimination against interference from noise.
Even if the polarizations are matched, other factors may affect the strength of the signal. The most common are long and short term fading. Long term fading results from changes in the weather (such as barometric pressure or precipitation) or when a mobile station moves behind hills or buildings. Short term fading is often referred to as "multipath" fading since it results from reflected signals interfering with the LOS signal.
The question then becomes - how much signal do you have at the receive antenna, if you are close by, you can practically talk to someone on a light bulb filament, a 65 watt light bulb can be used as a non linear resistor - dummy load, since its cold impedance is near 50 ohms.
But is it a efficient radiator - NO!
Once a radio wave is sent out into the atmosphere, there is no way to predict what will happen to that wave.. My guess is that your radio wave bounced off something and reflected back towards the other gentlemen's antenna and he had decent reception of your radio signal. That is not to say that everyone is going to have the same exact results.
A friend of mine - K3CC designed a Two Meter Mobile antenna for his 2001 Chevrolet Corvette.
If you visit his web site, he will be more then willing to explain Electromagnetism for you.
It isn't as simple as just sticking something up in the air and calling it a antenna and hoping that it will radiate the power produced.
If that was true, then the local AM radio station here on 1540 wasted a hundred thousand dollars by burying over 3 miles of copper wire beneath it's transmitter antenna tower.
Your problem is - you want to get every last watt of power out of your transmitter, while I probably spill more power on the floor then what you use.
A legal 3 watt AM / 12 watt SSB PEP CB radio needs all the help it can get, while a 100 watt transceiver doesn't really care if you apply 100 watts to the antenna or 80, the S meter won't show one iota of difference in the other persons receive.
Once the signals travels over the horizon, radio horizon being a lot further then visual - because they are of a different wavelength, the signals no longer stays horizontal or vertical..
This is one reason why I would never correct someone that understands this principal.
But most people believes that if you are going to work DX - out of the country, or long distance that you automatically have to be horizontally polarized.
One fine example is a guy that has a Technician Class License, lives about 30 air miles away.
I hear him on most VHF contests working the pileup, and all he has is a Ringo Ranger.
His signal is weak, almost non existent, because of the mismatch in polarization,but we have managed to work each other. A Ringo Ranger is basically a dummy load. But, it is all that he has. How can I condemn someone that is at least trying? |
Tech833
Moderator
Username: Tech833
Post Number: 2293
Registered: 8-2002
| | Posted on Saturday, July 26, 2014 - 4:11 pm: |
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Possum,
Some problems with your post:
"Except for amateur radio, most all radio communications with the exception of television is vertically polarized. "
You are forgetting almost all the commercial HF comms are horizontal, and a lot of point-to-point comms are horizontal on all bands. Horizontal works fabulous when you need to refract VHF over a hilltop, for example.
"The reason why television was horizontally polarized was due to the fact that there was less noise when horizontally polarized"
Incorrect. Television is on VHF and/or UHF. WHAT noise? Horizontal polarization was chosen for television because it made the antennas much simpler for amateur installers to erect them upon their homes, especially when rotators are added to the mix. It also makes it easier to have a side mounted transmit antenna be omnidirectional despite being side mounted to a tower.
"Vertical polarization also works well in the suburbs or out in the country, especially where hills are present."
No. Horizontal is superior to vertical when the path has hills between on just about everything above the MF band.
"Once a radio wave is sent out into the atmosphere, there is no way to predict what will happen to that wave.. "
Also incorrect. Using your logic, my goodness... That means that all the computer modeling and Longley-Rice computer software is just junk now! How on earth will the radio engineers ever be able to build another AM BCB directional array?
"...then the local AM radio station here on 1540 wasted a hundred thousand dollars by burying over 3 miles of copper wire beneath it's transmitter antenna tower. "
Speaking of AM BCB directional arrays.. They buried RADIALS for their antenna system. The FCC calls for a minimum of 200 equally spaced radials at least 1/4 wavelength long for an AM BCB antenna system for EACH tower (antenna). In some cases, radials can be shortened, like up against a property line or similar. Why do they spell this out? It's because an AM antenna system has to meet a minimum efficiency number in order to be certified. That is mainly to reduce skywave interference more than anything else.
"A Ringo Ranger is basically a dummy load."
While I am no fan of the Ringo Ranger antennas, (and this pains me to admit) you are mistaken. The trick to getting a Ringo to work well on HF (like CB) is to get it way above average terrain. A poorly performing Ringo is almost always simply too low.
Your radio 'Mythbuster' since 1998
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Mikefromms
Senior Member
Username: Mikefromms
Post Number: 1148
Registered: 6-2003
| | Posted on Tuesday, July 28, 2015 - 6:50 pm: |
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I remarried and moved where my wife already lived in HOA. We have moved and can now have better antennas. I can have loops, dipoles and Imax 2000! Life is really good again! |
Revpo
Advanced Member
Username: Revpo
Post Number: 767
Registered: 7-2006
| | Posted on Wednesday, July 29, 2015 - 8:47 am: |
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WELCOME BACK MY FRIEND,look for you on channel 36/usb , and I hang around 7240 on 40...
CEF 795
73
REVPO/DOCTOR/CEF 795
Wavin a hand from the cornfields of INDIANA
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Thespacemann
New member
Username: Thespacemann
Post Number: 5
Registered: 6-2016
| | Posted on Wednesday, May 31, 2017 - 9:29 pm: |
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Can one MAKE n end fed for 11 meters?? |
N3umw
New member
Username: N3umw
Post Number: 8
Registered: 1-2003
| | Posted on Friday, February 09, 2018 - 7:51 pm: |
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DIY PAR END FED XFRMR
Buy the parts on Ebay to make an 1:50 impedance transformer using a $5 FT140-43 ferrite toroid with 14 turns on the secondary and 2 turns on the primary using 20 to 24AWG enameled wire.
Twist the enameled wire together and wrap the twisted pair for two turns (turns are counted on the inside of the toroid). Wrap a single wire of the twisted pair for another 14 turns (16 total). Single turns can be grouped all together or crossed over the toroid after turn 7.
Install hardware in PLASTIC project case and solder the transformer inside of the case. Use a project case like the $10 Mouser waterproof case 1594BWBK. Solder turn one to the ground of the coax connector, turn two to the hot side (center conductor) of the coax connector, and turn 16 to the connector for the antenna wire.
Solder a 150 pF capacitor rated for 1000 volts or better between the ground and hot sides of the coax connector. RTV or hot glue toroid to case.
For 11 meters (CB), cut a wire 17.5 feet long for the antenna.
Hidden antenna - use Poly-Stealth 26AWG wire and run far end of wire through a clear plastic button for an insulator. Secure the insulator with fishing line to tree or other support as high as possible.
Stronger permanent antenna - use Poly-Stealth 18AWG wire and run far end of wire through a plastic "dog bone" insulator. Secure the insulator with UV 1/8" nylon cord to tree or other support as high as possible.
Trim antenna wire length for lowest SWR with the antenna mounted in it's final location. You can "trim" the wire without cutting it by simply folding the wire tightly back along the main section of wire. You'll probably need to trim the wire to 17.1 feet.
REFERENCE
https://pa3hho.wordpress.com/end-fed-antennes/multiany-band-end-fed-english/ |
Thespacemann
Junior Member
Username: Thespacemann
Post Number: 10
Registered: 6-2016
| | Posted on Saturday, March 09, 2019 - 12:15 am: |
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I made one using a 49:1 transformer and 17 1/2 feet of speaker wire! Works like a charm, and 1.1 SWR across the band! This is a great antenna for people in HOAs and apartments!! ;) |
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