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Author Topic: Yaesu FT920/ FL2000B  (Read 2320 times)

Posts: 40

« on: January 29, 2006, 11:21:05 PM »

I recently reported a transmit audio distortion problem when using my transceiver with the FL2000B Linear. A UK Ham recommended I purchase a relay cable that is being sold on ebay that plugs into the Band 8 pin DIN socket on the FT920. He had purchased this cable and it cleared up all his problems. The cables are being made up by a US Ham (cwman).Has anyone purchased this cable for use with a FT920/FL2000 combination? I now have this cable but find that as soon as I switch to OPER from STBY on the linear the linear relay goes over even though I am still on receive with the 920.In other words there is a short to ground when the switch is moved to OPER. I am also concerned whether using a connection to the BAND DIN socket could damage the FT920 as I am not sure of the current loading for the  relay in the FL2000B?
Would be interested to hear any comments especially from anyone using this lead.
73 Mike G3XLB

Posts: 656


« Reply #1 on: February 01, 2006, 10:34:24 AM »

I'm going to start by saying I'm not familiar with either the FT-920 or the FL2000 (especially the keying voltages & currents of the amp).  

However, I did find the following information on the Yaesu website in the FT-920 manual....

According to Pg15 of the manual, under the heading "Interconnection with non-QSK Amplifiers (FL-2100 series or others)":

As the FT-920 is supplied from the factory, the internal relay is disabled, and a high-dissipation NPN
transistor�s (open) collector is connected to the TX
GND jack. To enable the relay for use with amplifiers
requiring it, move the rear panel TR-RY switch, located
in the hole near the center of the rear panel, to
the RY position. Use a thin, insulated object like a
toothpick to move the switch. Then connect the center
contact of the TX GND RCA jack to the amplifier�s
relay control line, using the outer contact of the TX
GND jack for the shield. Connect the RF coaxial cable
and, if compatible, the ALC cable as described in the
QSK amplifier interconnection section above. Refer
to the drawing below for details.

With the relay enabled, the FT-920 can support non-
QSK linear Tx/Rx switching voltages of up to 220 VDC
(maximum permissible DC voltage) at 270 mA, 30
VDC at 2 A, or 125 VAC (maximum permissible AC
voltage) at 500 mA.

Do not exceed the maximum ratings of the
switching circuitry (transistor or relay) of the
FT-920 made available via the BAND or TX GND
jacks. Your warranty does not cover damage
caused by improper interconnections to linear
amplifiers. When in doubt, it is always safest
to utilize the TX GND jack with the TR-RY switch
set to TR, as this configuration should handle
the switching requirements of most all commonly-
available amplifiers.

If you do not have the manual go to and search FT-920.
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