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G8MNY > TECH 31.12.02 14:32l 90 Lines 3866 Bytes #999 (0) @ WW
BID : 2128_FG1JD
Read: GUEST OE7FMI
Subj: 144/432MHz Homebrew Duplexers
Path: DB0MRW<DB0RGB<OK0PPL<RZ6HXA<SP7MGD<7M3TJZ<F6CDD<FG1JD<FG1JD<VE2WXK<
F1FBB<ON4HU<ON0BEL<ON0AR<VK3TE<GB7YFS<GB7KHW<GB7CIP
Sent: 021229/0942Z @:GB7CIP.#32.GBR.EU #:34685 [Caterham] $:34685_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
-----------------------------
! 1T / 1T / !
! \ \ !
432 coax O-----!!-----!!-----!!-- !
! 15p 5.5p 15p \ !-- SO
!---------------------- \ --- 259
! 3T 4T 3T / !--
144 coax O--\/\/---\/\/\---\/\/-/ !
! ! ! !
! 18p === === 18p !
! ! ! !
-----------------------------
DESCRIPTION
Designed by G8MNY.
It consists of 2 paths of low & high pass filters, each path built on a wall of
a double sided PCB BOX on opposite sides.
The UHF pass filter consists of 15pF 1 Turn to ground 5.5pF (2.2//3.3) and
another 1 turn to ground, & finally a 15pF to the aerial socket at the end of
the Box. The coils are about 5mm diameter in 0.5mm dia Wire (22SWG).
The VHF pass filter consists of 3 Turns with 18pF to ground, then 4 Turns and
another 18 pF to ground, & finally a 3 Turns to the aerial socket.
The box is 1" square soldered to the socket, & about 3-4" long. The component
connections are soldered to knifed up 6mm square pads. The exact coil sizes
needed are dependent on the real Cap values & box layout. So adjust the coil
shapes (& size if needed) in the RF path for best SWR on each band.
The centre separator is soldered in after all SWR coil adjustments are made.
Then re-tested, then a lid is soldered.
-------------------------------------------------------
Here is a design for a VHF/UHF Diplexer, this came originally from VKNET I
don't know the bands, it is assumed from the inductors that the VHF is 2m and
the UHF 70cms.
VHF UHF DIPLEXER
ANTENNA
o
L1 L2 L3 ³ C4 C5 C6
VHF oÄÄÄÄÂÄÄ0000ÄÄÂÄÄ0000ÄÄÂÄÄ0000ÄÄÄÄÄÁÄÄÄÄ´ ÃÄÄÂÄÄ´ ÃÄÄÂÄÄ´ ÃÄÄÄÄÄo UHF
³ ³ ³ ³ ³
ÄÁÄ ÄÁÄ ÄÁÄ ³ ³
ÄÂÄ C1 ÄÂÄ C2 ÄÂÄ C3 0 L4 0 L5
³ ³ ³ ³ ³
³ ³ ³ ³ ³
oÄÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄo
GROUND
C1 10pF L1 4 Turns 5MM inside Dia 1 wire space 18 Gauge
C2 18pF L2 As above
C3 18pF L3 As above
- - - - - - - - - - - - - - - -
C4 10pF L4 1 1/2 Turn 3MM inside Dia 1 wire space 18 Gauge
C5 6.8pF L5 As above
C6 10pF
Capacitors disc ceramic or better if you can find them, leadless disc ceramics,
or surface mount (SMD) ceramics. (Don't expect the solder ends to support the
coils, they are not strong enough, use PCB to mount the caps and coils on).
Use good RF practice keep all leads as short as possible.
One option is to make up a box out of PCB material about 2" square by 1" high.
Solder all together to make up an RF tight box. This makes it easy to solder
components to ground. Once constructed solder a lid on.
Connectors can be "N" or "UHF" or BNC.
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
³ ³
³ ÃÄÄ¿
³ ³ ³ VHF Port
ÚÄÄ´ ÃÄÄÙ
Aerial ³ ³ Combined Port ³
ÀÄÄ´ ÃÄÄ¿
³ ³ ³ UHF Port
³ ÃÄÄÙ
³ ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ
73 De John, G8MNY @ GB7CIP
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