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Author Topic: L band antennas  (Read 654 times)

Offline NJQA

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L band antennas
« on: April 08, 2020, 1329 UTC »
Some good construction info here for L band antennas:

http://www.merseyradar.co.uk/airband-radio/l-band-diy-antennas-for-jaero/


Offline ThaDood

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Re: L band antennas
« Reply #1 on: April 08, 2020, 1832 UTC »
Hmmmmmmmmmm, with some modification, that looks like it could be a decent 1.2GHz design for 1296 SSB in Amateur Radio.   
I can't decide upon what's worst, young and stupid, or old and chemically dumbed down.

Offline chanito

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Re: L band antennas
« Reply #2 on: April 08, 2020, 2124 UTC »

Nice antenna the 3d printed part one. Pretty sturdy.


I've found JAERO, Fleetnet, Safetynet all come in fine on an indoor antenna here in S. Texas.


I built these out of nothing more than cardboard, paper, aluminum foil, foam and some copper tape. They just sit there on top of an equipment rack pointing at the ceiling.



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PCR-1000, PCR-1500, RSP1A, RSP1, VR-120D, HDT-1, Accurian HD, Royal 3000
Caras HF-315, Belar LP-1A, SuperAntenna MP-1, RatShack 20-043 discone, MLA-30, 100' wire

Offline ThElectriCat

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Re: L band antennas
« Reply #3 on: April 09, 2020, 0405 UTC »
If you are feeling ambitious
http://lea.hamradio.si/~s53mv/wumca/cavity.html
these are some nicely built antennas
In another life, I could have been a telephone engineer.

Offline Brian

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Re: L band antennas
« Reply #4 on: April 10, 2020, 1909 UTC »
If you are feeling ambitious
http://lea.hamradio.si/~s53mv/wumca/cavity.html
these are some nicely built antennas

I get a security warning from Chrome when I visit that site!

Offline ThElectriCat

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Re: L band antennas
« Reply #5 on: April 11, 2020, 0408 UTC »
Sorry guys, I didn't get that message originally, but if I use chrome it shows up.
I have been looking at this guys website for years, and I doubt that the posting is legitamate, but its probably best to play it safe.
https://imgur.com/EtzwGm5
Here's the drawing of the antenna, The designer (and owner of the problematic website) is Matjaz Vidmar, S53MV. credit for the drawing goes to him, not me.
In another life, I could have been a telephone engineer.

Offline Pigmeat

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Re: L band antennas
« Reply #6 on: April 11, 2020, 1527 UTC »
I remember that guy because we were always discussing LPAM as it wasn't legal where he lived.

Offline jasmine

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Re: L band antennas
« Reply #7 on: April 15, 2020, 2005 UTC »

Nice antenna the 3d printed part one. Pretty sturdy.


I've found JAERO, Fleetnet, Safetynet all come in fine on an indoor antenna here in S. Texas.


I built these out of nothing more than cardboard, paper, aluminum foil, foam and some copper tape. They just sit there on top of an equipment rack pointing at the ceiling.



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[/size][/color]

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i would love to try to build this antenna. do you have a step by step guide for a person totally new at this?
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Offline Josh

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Re: L band antennas
« Reply #8 on: April 16, 2020, 2016 UTC »
We do not encourage any radio operations contrary to regulations.

Offline chanito

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Re: L band antennas
« Reply #9 on: April 17, 2020, 1944 UTC »


i would love to try to build this antenna. do you have a step by step guide for a person totally new at this?





For the square 'patch' type I just used some modified dimensions from the that Youtube project at the bottom of the  http://www.merseyradar.co.uk/airband-radio/l-band-diy-antennas-for-jaero/. He gives the dimensions. I just did it with cardboard and foil instead of aluminum. The spacer is a thin foam I had lying around.


The helical antenna is just math and craft, using the helical antenna calculator here: https://www.daycounter.com/Calculators/Helical-Antenna-Design-Calculator.phtml


The feedpoint is 1mm off the aluminum foil backplane. The copper tape can be found on Amazon or at Hobby Lobby. Double sided Scotch tape is useful as well for some of the construction.


I have the actual print file for the sheets of paper somewhere. I'll see if I can dig it up and post.


It does work surprisingly well. Screen grab from today. Using SDR# with the Scytale-C plugin you can see the 1537.700MHz NCS44 channel (Fleetnet&Safetynet) and some adjacent FSK streams:




PCR-1000, PCR-1500, RSP1A, RSP1, VR-120D, HDT-1, Accurian HD, Royal 3000
Caras HF-315, Belar LP-1A, SuperAntenna MP-1, RatShack 20-043 discone, MLA-30, 100' wire

Offline chanito

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Re: L band antennas
« Reply #10 on: April 18, 2020, 1306 UTC »
Here's the paper template https://www.dropbox.com/sh/ydce3kx00w3sz5x/AAB9E3PEsEa8BVBx5jPNFb8Fa?dl=0


This print uses 4 sheets instead of 3. you have to print full page no borders, 'fit to page'.

PCR-1000, PCR-1500, RSP1A, RSP1, VR-120D, HDT-1, Accurian HD, Royal 3000
Caras HF-315, Belar LP-1A, SuperAntenna MP-1, RatShack 20-043 discone, MLA-30, 100' wire