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G8MNY > TECH 28.02.13 19:41l 150 Lines 7380 Bytes #999 (0) @ WW
BID : 13590_GB7CIP
Read: GUEST
Subj: Palstar AT1500CV ATU
Path: IZ3LSV<IR1UAW<IW2OHX<IW0QNL<JH4XSY<JE7YGF<7M3TJZ<UA6ADV<GB7CIP
Sent: 130228/1127Z @:GB7CIP.#32.GBR.EU #:13590 [Caterham Surrey GBR] $:13590_GB
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
By G8MNY (Updated Jan 13)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ FEATURES
³ ³/~~~\³ ø ø Þ ³ 4:1 Balun transformer for balanced output.
³ ³__ __³ /~~\ /~~\ ....... ³ Direct coax 1 & 2 & bypass outputs.
³ ÀÄÄÄÄÄÙ | () | | () | : ø\ : ³ Tuned coax 1 & 2 & wire outputs.
³ ::Ü:: \__/ \__/ : ø: ³ 300W & 3kW cross needle lit power meter
³ '' '' :.....: ³ 60W & 600W reflected.
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ The T arrangement C L C has with vernier
drives & counter on the inductor.
This unit is not fitted with the same sized capacitors or smaller rotary
ceramic & wire roller coaster as shown in the 2 Radcom articles below (*), but
it uses slightly smaller capacitors (still 4.5kV rated) & a large surface area
static silver plated flat spiral coil (very high Q) with a rotating internal
2 surface griping roller simular, but bigger than the one used in the MFJ 989D.
_ _ INTERNAL LAYOUT SIMPLIFIED CIRCUIT
ÚÁÄÁÂÄÁÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿ Direct Outputs
³ S ³ (\\\\\) v Fire ³ Wire o)ÄÄ¿
³ W ³ T ÜÜÜÜÜÜÜÜܳ TxÄ[SWR]Ä>oÄÄÄ(ú)Coax1ÄÄÄÄ¿ ³ o<¿WAFER
³ R ³ ÞðððÛðððݳ oÄÄÄ(ú)Coax2ÄÄ¿ ³ ³ o ³SWITCH
³~~SW ======= ======= ÞðððÛðððݳ oÄÄÄ(ú)Thu ³ ³ ³ o ³
³ ÜÜÜ ======= ======= ÞðððÛðððݳ Via o¿ ³ ³ ÀÄo ³
³ º ==C1=== ==C2=== ÞðLðÛðððݳ o´ ³ ÀÄÄÄo ³
³ º ======= ======= ÞðððÛðððݳ ATU o´ RF HOT ÀÄÄÄÄÄo ³
³ º ======= ======= ÞðððÛðððݳ ÀÄÄÄ´ÃÄÄÄÂÄÄÄÄ´ÃÄÄÄÄÄÙ
³ º ======= ======= ÞðððÛðððݳ WAFER C1 ) C2 ÚÄÄ(o
³ º ======= ======= ÞðððÛðððݳ SWITCH L)<¿ _(|T
³ º ======= ======= ßßßßßßßßß³ ) ³ ³ (|
³ º ºÚÄÄÄÄÄ¿º [º] ³ ) ³ ³ ÀÄÄ(o
ÀÄÄ×ÄÄÄÄÄÄ×ÁÄÄÄÄÄÁ×ÄÄÄÄÄÄÄÄ×ÄÄÄÄÙ ÄÄÄÄÄÄÄÄÄÄÄÁÄÁÄÄÄÄÁÄÂÄÄ(o
ßßß ßßßßß ßßßßß ßßßÝ T ATU Á
SWR CIRCUIT
(ú)ÄÄÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄ>Switch Ref 60W +1k2
Rig === Cal (((() Cal === ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄo<ÄÄÄÄÄÂÄÄÄÄ(M)Ä¿
6p8³ / ³16T³ \ ³6p8 ³ ÚÄÄÄÄÄÄÄÄÄÄÄo600W ===10n ³
ÃÄ´ÃÄÂÄ´<ô ô>ÃÄÂÄ´ÃÄ´ ³ ³ 300W Á ³
10p³ ) ³ ³ ) ³10p ³ ³ ÚÄÄÄÄÄo<ÄÄÄÄÄÂÄÄÄÄ(M)Ä´
=== )680 22 22 680) === ³ ³ ³ ÚÄo3KW === +1k2 Á
³ )uH ³ ³ uH) ³ CAL CAL CAL CAL For Á10n
ÃÄ´ÃÄ´ Á Á ÃÄ´ÃÄ´ 100K 100K 100K 100K
Á 10n³ ³10n Á ³ ³ ³ ³
³For Ref³ 6K8 47K 47K 100K
³ ÀÄBlackÄÄÄÄÄÄÄÁÄÄÄÁ´Ã´ÃÁÄÄÄ´
³ 10n Á 10n ³
ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄRedÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ____ o
12V>ÂÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄWhiteÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÂÄ´7810ÃÄo<ÄÄÂÄÄ>
=== 10n ===ÀÄÂÄÄÙ 10n=== Lamp
Á 47uÀÄÄÄÁÄÄÄÄÂÄÄÄÙ
Á
HI Q ROLLER COASTER
Unfortunately this large 1500W QRO ATU flashed over & caught fire (smells of
burning), due to poor design of the QRO roller coaster coil mounting brackets,
flammable construction fibre board, & inexperienced user (me) when tuning up
with only 400 Watts.
On the back coil insulator combs, there are 3 right angle brackets, that are
mounted on inflammable thick fibre glass board, that have sharp corners only a
few mm away from the "RF HOT" top of the tuned circuit. This is a very high
voltage point!
_______________________1 of 3 Fiber Glass
³ ºo o Combe Support Bars
(³ º]____________________
Flammable(³ º] RF³³³³³³³³³³³ Contact
Fibre ³ ³ HOT³³Silver Plated ======H===Û= Wheel Rod
Board ³ ³ END³³Flat Coil Spiral Wheel Û
³ ³ OF³³³³³³³³³³³ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÛÜÜÜAxil
³ ³COIL³³³³³³³³³³³
³ ÃÄÄÄÄÁÁÁÁÁÁÁÁÁÁÁÄÄÄÄÄ Flammable
"L" ³ ºo_o_________________ Support
Bracket ³ ÇÄÄÄÄÂÂÂÂÂÂÂÂÂÂÂÄÄÄÄÄ Combs Bars
Screws (³ º] /^Sparks
(³ º]v Jump Earth
ÄÄÄÄÄÄÄÄÄÄÁÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄChassis
The Caps C1 & C2 are designed for very high voltage & should be the first thing
that arcs over, not these sharp cornered brackets!
REPAIR
The burnt fibre board & shaped mounting comb strip must be cleaned of any
charred material with a sharp knife. This may mean removal & part disassemble
of the roller coaster support combe bars.
MODIFICATION
To stop reoccurrence at the RF hot ends of the 3 "L" shaped brackets, they were
cut down in length & the redundant nuts & bolts left out of each.
__ ___ __ __ __
Screw³ ³
holes ORIGINAL MODIFIED
³ 4 HOLE ³ 2 HOLE
BRACKET BRACKET
³
Doing this to all 3 brackets (even the top one not near to ground), adds about
1cm to the flashover arc distance! And has no effect on the sturdiness of the
roller coaster assembly as long as the bolts are kept tight.
OTHER BURN MARKS
The 3 combe supports bars can suffer. They are all different with the coil
slots all moved 1/3 of the pitch. But I have managed to reverse the top one so
the burnt RF hot end, is now the cold end.
LOOSE SCREWS
As this unit has been used for /P work, some other screws had soon rattled lose
despite locking washer nuts! These have been tightened up & threads painted.
IN USE
I use it for /P demonstration stations with a DRAKE L-4B PA or T500M PA & IC735
exciter, on mains or of generator.
___________ptt+ALC
_____ ³ ³ _________ ______
³IC735ÃÄÙ ÚÄÄÄ¿ ÀÄ´DRAKE PA ÃÄ´ HF ³_ oÄ>1kW Dummy Load
MicÄ´ 12V ÃÄÄÄÄÄÄÄ´ATUÃÄÄÄ´_________³ ³Filter³ \oÄ¿ _____
³_____ÃÄÄÄ¿ ³ ³ ³DRAKE PSU³ ~~~~~~ ³ ³ QRO ÃÄ>80m Dipole
BatteryÄ´PSU55³ _³_ ³___ÃÄ¿ ~~~~~~~~~ ³_³1.5kWÃÄ>40m Dipole
~~~~~ ³BHI³ _³_ Topband 160m ³ ATU ÃÄ>3el Beam
HeadphonesÄÄ´LS ³ /// long wire aerial ³_____ÆÍ>G5RV
~~~
The small ATU after the Rig (VECTRONICS VC300LP) can select an internal dummy
load or the long wire. On the newer WARC bands the extra ATU is used to tune
out the DRAKE L-4B linear's bad SWR of its "out of tune" input matching
circuits, the PA output tank ciruit matches quite OK.
The HF filter is sometimes used to make sure there are no VHF harmonics, if
station is in a sensitive RF area & "direct" is in use not ATU to aerials. With
the G5RV then the ATU's transformer balanced output is used.
For public demos, a RF proof AF PA is used with mic audio from the AUX socket
of the IC735 & BHI noise reducing LS system, so that both sides of the QSO can
be clearly heard.
* RSGB Radcom Review Article May 2005 P26, & Comparative one to the MFJ 989D
Jan 2007 P30.
See also my Tech buls "HF ATU & SWR Bridge VC300LP/QT-1", "Drake WH7 QRO HF
SWR Bridge" & "QRO 1kW HF Metered Dummy Load".
Why don't U send an interesting bul?
73 De John, G8MNY @ GB7CIP
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