Some field antennas


Here are some brief examples of field antennas I have made. (Not...) All are made to use with Albrecht 2990.
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Above is backpack antenna for 10 meter band. It is basically aggressively shortened vertical dipole. Whip section is made of handbrake cable from saab. Loading coil is wired around pvc pipe. Ground side of dipole is about 20 cm of coil. It took couple of days to find right amount of turns on this to-sided coil. This antenna gives acceptable swr only when kept near users body. It gives range about...well lets say about one day walk. I made it for kind of aprs-beaconing, to send location data with AndPskmail.

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This is whip antenna for bicycle. It is quite usual. Steel whip and loading coil on down. Grounded to bicycle frame. Only peculiarity is that loading coil is upside down: Whip goes throw coil and connects on bottom side. It is maybie not best possible way: reason for that is only mechanical. Dont know about usable range: I havent been so far from home with this vehicle...
Strange black brick on bar is mp3 player and fm-radio. It can also be used as an external speaker for Albrecht.

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Here is really effective telescopic whip for handheld use. Loading coil is wound around plastic pill bottle. There is groundwire which can be pushed inside coil for easy transport. Antenna is in fact vertical a bit shortened dipole. It works well also on 12 meter when whip is totally up.
There is also extra ground connector as you may notice. If I remember right, huge telescopic whip came from some really old cordless phone.


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Same whip can be used also with this battery/linear pack.
It consist 4 Ah nimh-batteries, tiny voltmeter and "main switch" with orange led, holdind screw for whip and little linear.
Nowadays I think linear is a bit stupid idea here. It makes more sense to carry better antenna, not linear amplifier which need also bigger battery. Antenna wire is light and consumes no extra power. Better antenna also makes you receive better.




Spiderbeam-mast at Land Rover. Here it carries verticl moxon for 50 Mhz:
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