Roofing TS-850 / AO-Journal p178

ex -----> now

Insertion loss
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last Update 29/01/2009

29/01/2009

Link from Russia

Форум QRZ.RU > Основные форумы > КВ техника > КВ - KENWOOD > TS-850
Перезагрузить страницу Inrad фильтр в TS-850

28.09.2008, 18:08 #23
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Интересная ссылка по теме http://pagesperso-orange.fr/F6AOJ/ca.../crbst_49.html

Link from Japan

Y amada Radio Clinic

English version

FAQ

" I dont have VNA ! "

The network analayzer has been use full to design the project seriously,
now everything is working well, so now this study phase is over.
Now with a simple SWR meter or a Impedance meter instead of vector network analyzer,
it is easy to reproduce the hardware.
MFJ 269 in exemple or any equivalent going up to 75 Mhz are enough.

Run Tunning procedure step 1 to 3
Tune ajustable capacitor for minimum swr at nominal frequency
in same conditions as describe on the web page.

You just have to know,
tolerance on ferrites are usualy +20% -50% ,
so it is possible you will have to add or remove 1 turn on the toroid
if SWR dont go below 2 / 1 .

Tunning procedure steps 4 & 5
was necessary to confirm the design concept,
but they are not necessary in case of duplication.

-- links --
-
TS-850 Paradise par TK5EP
-
Inrad TS-850 Xtal Filters
DK9IP TS-850 manual
-
Quadrature Hybrid Roofing Filter PA3AKE
Swept Receiver Dynamic Range Testing in ARRL Lab
-

QEX jun 96

F5PED  &  F6AOJ

Roofing Filter
for TS-850 ?

  Yes it's possible !

You will never find it in the INRAD catalogue,
because a "plug & Play" solution
is not compatible with this transceiver.

However if you accept, without cuting any track on pcb,
to remove 2 soldered composants, then it is possible. ##

- Composants to remove are 2 cases HC49/U holding  3 pins
constituting 70 Mhz filter marked XF1 on "RFunit" board.
Before removing take a picture or note position and orientation
of 2 matched cases HC49/U ( blue dot and red dot ) .
Down grade to return to  factory configuration is fully realist.

- To replace them, first you must supply :
   ( a virtual kit from INRAD or one of its dealers, items  1and 2 )

          1 - the preamp board designed by INRAD for the FT1000-D
                and the male / male coax cable associated.

          2 - a filter with the same case and impedance as 1000-D require
               but on 73.050 Mhz ( instead of 73.620 used for 1000-D )

         3 - parts to build 2x Pi circuits with purpose to convert 2 Kohm to 50 ohm
              part list :
                        - 2x toroids T37-10 (  make 12 turns enamelled copper wire gauge #26 )
                        - 2x  12 pF capacitors
                        - 4x  5-25 pF ajustable capacitors

Pi circuits must be assembled back to back on opposite sides
of a small pbc who is  also used as sheild between input and ouput.

It will be necessary to isolate 2 areas from the ground on each side,
face to connect  coils wires. Dont locate isolated areas of one side
front to thoses of opposite side.

Ground areas must be connected as short as possible to main board ground
to holses previously used by HC49/U cases ( center pin ).
Male-male cable once cut in 2 parts make  connections between Pi circuits to INRAD
board.

## Beginers keep out

Used for first time in CQWW ssb 2007
this system was fully appreciated
by TM2S team

Above module under test.
Left insertion loss measurement,
2 Pi circuits are in series : 1.3 dB.

Wires capturing ground and +12v for the
INRAD board must be connected on the "RF
unit" board as close as possible of of the
original XF1 location. ( and nowhere else )

INRAD board is fixed on the side of the
chassis by self adhesive stand-offs.

Below sytem completed.

Tuning procedure :

for each Pi
1- Load high impedance output with a non inductive 2 Kohm resistor.
2 - Connect 50 ohm output to SWR bridge meter. ( Pwr in 100 mW max )
3 - Tune ajustable capacitors to reach 1/1 SWR

4 - Connect the 2x Pi in série by 2 Kohm output side.

5 - Check global insertion loss, it must be below 2 dB,
      with a 2 ports analyzer,

as in exemple here, HP 8505A Vector Network Analyzer ( VNA )

or HP 141T + HP 8443A  +HP 8421A
a Spectrum analyzer + Tracking generator + SWR bridge

or  MiniVna ,  PC and dedicated software.