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Author Topic: t-r switching  (Read 665 times)
WB0DKY
Member

Posts: 44




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« on: March 26, 2005, 03:32:12 AM »

Hi Guys and Gals,
                How many of you are using your tranceivers receiver with your Qrp rig. I am building
the Tuna Tin xmtr and want to use my old Ft-101E as
the receiver. I was just wondering if the manual t-r
switch on the Tuna Tin would be enough isolation to
keep from doing any serious damage to the front end
of the receiver. I thought i would ask instead of doing
something stupid. 73 de WB0DKY Harold
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HA5RXZ
Member

Posts: 380




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« Reply #1 on: April 19, 2005, 07:26:46 AM »

As the FT101E has lots of tubes in it I doubt that you will do much damage HOWEVER:

1) Place a couple of back to back 1W 5 volt zener diodes across the input.

2) Find a couple of reed relays. Wire the first relay across the two diodes and power the coil with the transmit power so that it is closed when you transmit. Wire the second reed relay in series with the receiver coax and arrange for it to be closed on receive, switch using either your PTT line or some logic.

Email me if you can't figure this out and I'll send you a pdf diagram. Address is pmgant@freestart.hu.

HA5RXZ
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