[NLRS] [Mw] 10 GHz Preamp Protection

[Zack Widup]

I sent a private message to Scott but I have used power levels up to 10
watts (on 2304) and 2.5 watts on 10 GHz with various SMA relays and have
never had a receive LNA go bad. I forgot to mention to Scott that I do
always turn off the power to the LNA before switching the relay and powering
the amp.

73, Zack W9SZ

On Tue, Aug 18, 2009 at 10:26 AM, Randy Bynum <nr6ca at sbcglobal.net> wrote:

> Scott,
>
> It depends. All relays are different so some are better than others when it
> comes to isolation. You could have one with 30 dB isolation or it could be
> 60 dB. Most likely in between. At the very least you want to make certain
> that power is removed from the LNA prior to the relay switching. A
> sequencer
> such as the W1GHZ or the Demi is a must. Remove preamp power, then switch
> the relay then turn on transmit.
>
> Try locating the data for your relay or better yet measure it with a signal
> generator and spectrum analyzer, if they are available. If you want to send
> it to me I can measure it for you if you don't have the equipment or have
> no
> one nearby.
>
> Good luck
>
> Randy Bynum, NR6CA
> 160 meters - 80 GHz plus laser
> Reno, NV DM09cj & Soda Springs, CA CM97tj
> http://www.nr6ca.org
>
>
>
> -----Original Message-----
>
> Subject: [Mw] 10 GHz Preamp Protection
>
> Question:  If I "break" the RX coax and insert the preamp between the
> T/R relay and the RX input of the transverter, will there be enough
> isolation in the relay to keep from blasting the preamp during TX or
> should I use some other sort of protection?
>
> If you have a sketch of how you do it, you can attach it to an email
> sent directly to me at acepilot at bloomer.net
>
> Thanks!
> Scott N0EDV
>
>
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