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Author Topic: 22m Beacon  (Read 748 times)

Offline IZS4

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22m Beacon
« on: January 10, 2020, 0029 UTC »
Is it considered against the rules or against FCC guidelines to use something like a G5RV or EDZ dipole antenna (more gain) to use on a low wattage beacon? I know a standard dipole or vertical is the norm. Just curious.
Listening on an Icom-718 with a 135' OCF dipole or a RSP2.  Grundig G3 and MLA-30 when portable. When QRP I use a Hendricks PFR-3 I built. Coverage is 20,30 and 40 meters.

Offline ChrisSmolinski

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Re: 22m Beacon
« Reply #1 on: January 10, 2020, 1106 UTC »
Is it considered against the rules or against FCC guidelines to use something like a G5RV or EDZ dipole antenna (more gain) to use on a low wattage beacon? I know a standard dipole or vertical is the norm. Just curious.

FCC regulations for a 22 meter Part 15 beacon are FIELD STRENGTH BASED. Not transmitter power based. See this for more information: http://www.w1tag.com/Hifer2.pdf

Do NOT just put one on the air without FULLY understanding the requirements and limitations, or you will almost certainly be in violation of Part 15 regulations.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 900 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 120 ft T2FD/ 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop / Discone in a tree

Offline IZS4

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Re: 22m Beacon
« Reply #2 on: January 10, 2020, 1159 UTC »
Just read. Thanks
Listening on an Icom-718 with a 135' OCF dipole or a RSP2.  Grundig G3 and MLA-30 when portable. When QRP I use a Hendricks PFR-3 I built. Coverage is 20,30 and 40 meters.

Offline Ed H

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Re: 22m Beacon
« Reply #3 on: January 10, 2020, 2032 UTC »
As Chris stated, the regulation is based on field strength. That equates, IIRC to about 2 mW into a vertical, or 4 mW into a dipole. Of course, what you are able to put up for an antenna will have some bearing, as will the local environment, on losses. But there's no point, obviously, in an antenna with gain. For a beacon, you want relatively uniform radiation in all directions anyway, to maximise the chance of reception.

The restrictions are pretty tight, but that is what seems to make HiFERs fun to many of us who operate and listen at 22 m.

Cheers

Ed

Offline IZS4

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Re: 22m Beacon
« Reply #4 on: January 10, 2020, 2355 UTC »
Thanks Ed. Yes I was ignorant about the topic, but after reading the attached article by Chris I understand that the concept is not just a matter of Mwatts into an antenna. I will make sure everything is up to par when I decide to proceed. I have starting working on modifying a power supply at work and have done some calculations to install components to get the proper voltage drop I would need.
Listening on an Icom-718 with a 135' OCF dipole or a RSP2.  Grundig G3 and MLA-30 when portable. When QRP I use a Hendricks PFR-3 I built. Coverage is 20,30 and 40 meters.

Offline Ed H

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Re: 22m Beacon
« Reply #5 on: January 21, 2020, 1826 UTC »
Sounds like you are on the right track IZS4

I have experimented with a couple of antennas, starting out with a 1/4 wave vertical plus radials, then (and most successfully in terms of reports) an inverted V type dipole. Both setups were mounted on the house roof.

Cheers

Ed

Offline kc3gfz

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Re: 22m Beacon
« Reply #6 on: January 22, 2020, 0300 UTC »
Good conversation. I was wondering if the field strength of a 20m half wave end fed antenna with a 50ohm match transformer in a vertical position would be comparable to a 20m half wave dipole center fed and 50ohm match?

Chris

Offline kc3gfz

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Re: 22m Beacon
« Reply #7 on: January 22, 2020, 0301 UTC »
The center fed one being horizontal or vertical.

Offline kc3gfz

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Re: 22m Beacon
« Reply #8 on: January 22, 2020, 0325 UTC »
I suppose what i would be asking is if you take a half wave dipole feed it at any point and match 50ohms. and lets say position it in a vertical, sloping, or horizontal config would you end up with about the same field strength? This is assuming no radials or grounds.

Offline Josh

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Re: 22m Beacon
« Reply #9 on: January 22, 2020, 0700 UTC »
They're known for sending teams out to each hifer on a monthly basis to ensure compliance.
We do not encourage any radio operations contrary to regulations.

Offline Prairiedog

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Re: 22m Beacon
« Reply #10 on: January 22, 2020, 0758 UTC »
In principle, Chris, under free-space conditions, an end-fed halfwave and a dipole should radiate very similarly...but in practice, they don't.  Interaction with the earth has a big effect, particularly on the end-fed antenna. The angle at which it is sloped also has a major impact, and not usually a positive one either.

A friend of mine out West had high hopes for an EFHW antenna for the ham bands that had been touted as something of a miracle, but in the end it never matched up well on any of the bands he wanted to work and the radiation angle was too high for appreciable distance. He's gone back to a basic multiband vertical with radials and gets much better results. (Fortunately, he has ample open space at his site.)

A ground mounted 1/4-wave vertical with radials or a good ground screen has the most predictable and repeatable characteristics and the best omnidirectional pattern--or a 5/8-wave for even better low-angle radiation, although it's physically more challenging in many locations.  But unless the ground is sufficiently unobstructed for a wavelength or two in all directions, you'll lose some of that signal locally.

A ground plane antenna or a dipole mounted a little above the earth may avoid some obstructions, but won't necessarily have good low-angle radiation or predictable performance, unless you can get its feedpoint half a wavelength above ground or more. A quarter wavelength above ground is the worst case for take-off angle, in fact. Higher or (if necessary) lower than 1/4 wave elevation is better.

The two most consistent performers here on the prairie are K6FRC from out west in California and RY down east in Maine.  At FRC, the antenna is a relatively tiny 20 meter Hamstick mobile antenna on a metal roof of a small building (a shipping container). It has the advantage, though, of a nicely elevated site with no lossy trees in the immediate vicinity.  RY uses a vertically mounted dipole, suspended from a tall enough tree that its lower end is well above ground and can maintain a low radiation angle. I would refer you to the "What antenna are using on your HiFer" thread on the LWCA message board back in October for more ideas.

Moral: a relatively simple antenna, well placed, can be effective and avoids a lot of the guesswork that goes along with some larger antennas.


Offline kc3gfz

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Re: 22m Beacon
« Reply #11 on: January 22, 2020, 1058 UTC »
Thanks for imputvand ideas. I was concerned if I needed to go lower then 4.6 mw power using end fed halfwave cut for 20 meter band losses to typical dipole or vertical being 2mw or 4 for dipole . Power sitting at about 4mw. I threw the antenna up hanging high from tree branch in vertical position.The feed point is about 15 feet off ground. The center of the wire is about 30-40 feet high.  I got swr to 1.19 and 42 ohms per the vna.  Would have gone more simple but this was easier way in my situation to get antenna up as high as I could. It would be near impossible for me to get a horizontal dipole Desired 30 or so above ground. Quarter wave I could try out. Lots of dips hills and valleys where I’m at. Trying to aim high for antenna. John over at LWCA heard my beacon in SE Kansas about a week ago. I was impressed.

Offline NJQA

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Re: 22m Beacon
« Reply #12 on: January 22, 2020, 1135 UTC »

The two most consistent performers here on the prairie are K6FRC from out west in California and RY down east in Maine.  At FRC, the antenna is a relatively tiny 20 meter Hamstick mobile antenna on a metal roof of a small building (a shipping container). It has the advantage, though, of a nicely elevated site with no lossy trees in the immediate vicinity.

I frequently hear K6FRC from here on the East Coast.  I had always assumed he ran a little more than Part 15 compliant power into a more than average antenna since he is the only West coast 22M beacon I hear.  I am quite impressed with the coverage he gets with a hamstick at 1.8 mW.  But I think “nicely elevated” is not quite fully descriptive of the location...

http://www.k6frc.com/

What is it that Real Estate agents say....Location, Location, Location...?




Offline kc3gfz

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Re: 22m Beacon
« Reply #13 on: January 22, 2020, 1153 UTC »
I hear you the location,location location! I set mine up in October using a inverted v at like 15feet. It was  not until a month ago I set beacon up on A halfwave endfed with matching transformer in a vertical position. On January 9th beacon was finally heard about 800 or so miles away. Interesting how location and propagation works at such low power levels. I wonder about beacons I hear all the time and power being used. I’m certain now that they have really good locations that allow them to be heard often. Thankful I got two nice really tall trees or else my beacon would no way get out mounted low to ground.

Offline Prairiedog

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Re: 22m Beacon
« Reply #14 on: January 22, 2020, 2103 UTC »
But I think “nicely elevated” is not quite fully descriptive of the location...

OK... "VERY nicely elevated," then?  ;D

Yes, location is definitely the main secret to Paul's success. He is also one of the few HiFER operators who had access to the necessary field measurement gear to ensure actual formal compliance with the Rules when installing his rig, in addition to his engineering skill in applying antenna and transmission line specs to the problem.

« Last Edit: January 22, 2020, 2108 UTC by Prairiedog »