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G8MNY > TECH 03.07.21 09:36l 53 Lines 2218 Bytes #999 (0) @ WW
BID : 39681_GB7CIP
Read: GUEST
Subj: HF Rx Suckout Trap
Path: IW8PGT<IZ3LSV<IR1UAW<IW2OHX<UA6ADV<I0OJJ<GB7CIP
Sent: 210703/0835Z @:GB7CIP.#32.GBR.EURO #:39681 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (Updated Oct 17)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
When doing demo stations with more than 1 HF Tx on different bands (or with a
nearby ham), QRM between stations is quite normal, even with the high Q tuned
circuit of an ATU.
Here is one method to remove most of the problem from the aerial lead. (from a
system built up years ago for 2 FT101s by G0SYR & revisited for more modern
rigs.)
STATION A STATION B
\|/ \|/
³ ÚÄÄÄ¿ ÚÄÄÄÄÄÄÄ¿RF ÚÄÄÄÄÄÄÄÄÄÄ¿ ÚÄÄÄÄÄÄÄÄÄÄ¿ RFÚÄÄÄÄÄÄÄ¿ ÚÄÄÄ¿ ³
ÀÄ´ATUÃÄ´Rx TRAPÃÄÄÄ´TRANCEIVER³ ³TRANCEIVERÃÄÄÄ´Rx TRAPÃÄ´ATUÃÄÙ
ÀÄÄÄÙ ³ B FreqÃÄÄÄ´ ³ ³ ÃÄÄÄ´ A Freq³ ÀÄÄÄÙ
ÀÄÄÄÄÄÄÄÙPTTÀÄÄÄÄÄÄÄÄÄÄÙ ÀÄÄÄÄÄÄÄÄÄÄÙPTTÀÄÄÄÄÄÄÄÙ
It uses switchable "Teed in series tuned traps" (notch) that are only in
circuit on Rx. If the transceivers have a transverting loop through ports, then
the circuit is quite simple, otherwise a relay operated by the PTT is needed as
well.
This device also stops the Rx safety lamps (if fitted) or F/Es from blowing up.
THE TRAP
It is only connected in Rx mode, so there is no high voltages, but good quality
components & layout in a sold metal box are needed to give the good Q & deep
reject notch on the 50ê line.
50ê coax coax coax
TXR o)ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄ(o ANT Rx<ÄÄÄÄÄÂÄÄÄÄÄÄÄÄ>Relay
_³_ ³ _³_ Socket Port o In/Out Port
Relay\_ \_ SW
( (
LED L1 (___ O R L1 (___
+12V>Ä´>ÃÄÄÂÄÄÄÄÄ¿ ( ³ Hi/Low ( ³ Hi/Low
D1 _³_ ÚÄÄÁÄÄ¿ L2 ( ø/ Band W I T H L2 ( ø/ Band
/_\ ³relay³ (___³ Switch (___³ Switch
D3 D2³ ÀÄÄÂÄÄÙ ³_ Rx P O R T ³_
d
|Bgm
struggling with /p setup
|A|B|A|B|A
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|A|B|Al
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