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EN
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Pa0nhc
"Double Delta" 145MHz loop antenna.
A portable, very
small, less visible, light, narrow band
(selective),
low power 145MHz antenna.
Horizontally polarized and really omni directional.
(No 1/2 lambda coax phasing cable needed).
Updated
20211028.
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Only 16.5 cm wide.
(that is 6 times smaller than a dipole)
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EN
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First prototype with old PCB.
Top quality 145MHz ARDF direction finding receiver.
Last
update : 20211028.
Most wired components, readily wound
coils or self wound coils on available Neosid forms.
Optimal receiving properties :
Tuning range (adjustable) abt. 1.4 MHz.
Very sensitive (0.22 uV AM).
Max input 12 mV (S9+68dB). Continues sensitivity reduction range abt.
90dB.
Very good selectivity (better than 80dB) with cheap Xtal IF filter +
highQ IF coils.
Power : 9V @ 9-24 mA. Mean abt. 15 mA. Many hours operation on one 9V alkaline
battery. Low battery voltage warning.
Easy soldering.
Cheap die cast ALU box. Best screening and RF-filtering.
See
also my 80m
version
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Short and light, three
element ARDF / radio sport
Yagi antenna.
VERY EFFECTIVE, proven design. |
Horizontal plot of pa0nhc 3 el. version
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Six versions of
directional couplers with RF or DC output for 28 - 435 MHz.
Installed in a cheap steel enclosure.
Updated : 20180124/
20210310
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Coupler with RF output
(Old mask for DIY PCB).
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Coupler with DC ouput for in TEKO 371 box.
Factory made PCBs available.
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EN
NL
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DIY
VHF helix filters.
Very selective, low insertion loss.
One to four resonators.
Combinations with coax filters.
145MHz band pass and 160MHz reject.
Cheaply made from paint cans
and copper wire.
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28 - 435 MHz wideband low-noise
hi-IP
preamp.
Reorganised 20220508
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vhf_preAmp_PCBtop.jpg)
New smaller PCB design 2018
for TEKO 371 box.
With screen and DC filtering.
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DIY PCB prototype 2003.
Without DC filtering.
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Home build 145MHz repeater duplex filter,
made from cheap PCB material and
cheap 22mm copper water pipe.
(GW4AKZ and Dirk Rijnenberg constructed one). Republished 20130529
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EN
NL |
Full theory on (145MHz) cavity filters.
(After a pencil paper from G8AMG) |
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NL
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De oude (ca. 1995-2005)
techniek van de Rotterdamse repeaters
PI3RTD en PI2RTD.
20170302 |
First adjustment of the DIY PCB duplex filter
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