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VHF-index of pa0nhc technical HAM pages.
20150407 / 201701231

Since 20150113 this site is located at: http://www.pa0nhc.nl   
(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.

EN = read English version article   NL = Nederlands

EN


Last update : 20171217.

New version 144MHz ARDF direction finding receiver.
All info in easy printable PDF files.
The professional double sided PCB is available at : 
See also the 80m version
Optimal receiving properties :
144 - 145.4 MHz.
Very sensitive (0.22 uV AM)
Max input 12 mV.
Very good selectivity.
Power : 9V @ 20 mA max.
Most components wired, readily wound coils.
Cheap die cast ALU box.

EN
28 - 435 MHz directional couplers on a small piece of PCB, in a cheap metal enclosure.
With PDF MASK files for DIY PCBs.

For factory made PCBs ask info at 

Updated : 20180103


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


Coupler with DC ouput.
New design for factory made PCB.

EN
28 - 435 MHz wideband low-noise
hi-IP
preamp
.

New PCB design


DIY PCB version 2003


New smaller PCB 2018

EN
NL

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.

EN  
145MHz ARDF / radio fox hunt Yagi antenna.

VERY EFFECTIVE and light
Proven design.


Horizontal plot of 3 el. version

EN

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

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

NL

De oude techniek van de Rotterdamse repeaters
PI3RTD en PI2RTD (ca. 1995-2005)
20170302


First adjustment of the PCB duplex filter