VHF-index of pa0nhc technical HAM pages.
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(C) The use, copy and modification of all info on this site is only permitted for non-commercial purposes,
and thereby explicitly mentioning my radio amateur call sign "PA0NHC" as the original writer / designer / photographer /publisher.

PCB service : Available PCBs

EN = English   NL = Nederlands


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.

New improved  PCB is available.

Only 16.5 cm wide.
(that is 6 times smaller than a dipole)


First prototype with old PCB.

New improved  PCB is available.

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

Short and light, three element ARDF / radio sport
Yagi antenna.

VERY EFFECTIVE, proven design.

Horizontal plot of pa0nhc 3 el. version


Six versions of directional couplers with RF or DC output for 28 - 435 MHz.
Installed in a cheap steel enclosure.

Updated : 20180124/ 20210310

6 versions DC or HF output  PCBs available.

Coupler with RF output 
(Old mask for DIY PCB).

Coupler with DC ouput for in TEKO 371 box.
Factory made PCBs available.


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.


28 - 435 MHz wideband low-noise

Reorganised 20220508

New smaller PCB design 2018
for TEKO 371 box.
With screen and DC filtering.

DIY PCB prototype 2003.
Without DC filtering.


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

Full theory on (145MHz) cavity filters.
(After a pencil paper from G8AMG)


De oude (ca. 1995-2005) techniek van de Rotterdamse repeaters PI3RTD en PI2RTD.

First adjustment of the DIY  PCB duplex filter