I have two of the SSB preamps — one at home and one strapped to the portable tripod and they’re really solid. Using an IC 9700, they can be turned on and off from the radio. When on, they tx/rx switch just fine and they can handle anything the 9700 might throw at them on tx.

Ray KN2K


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On Tuesday, December 27, 2022, 8:51 AM, Don Solberg via AMSAT-BB <amsat-bb@amsat.org> wrote:

Another really good preamp is made by SSB Electronics and sold by HRO https://www.hamradio.com/detail.cfm?pid=H0-016832

I have used this one for well over a year.

73,

Don K9AQ

On Tue, Dec 27, 2022 at 4:28 AM J. Hunt via AMSAT-BB <amsat-bb@amsat.org> wrote:

Hi Tom,

Beko Elektronik, represented by Island Amplifiers has your answer(s) with a complete remote 440mhz preamp with internal T/R by-pass relay. 



Another source is Down East Microwave

Best of knowledge, neither had a 1296 (23cm) complete remote pre-amp with internal T/R by-pass relay.
With my engineering background, I made a 600 watt model.  Works great on the weak signal / tropo scatter. 

Thanks n 73,
James
KI5DQ
On Monday, December 26, 2022 at 11:04:54 PM CST, Zach Metzinger via AMSAT-BB <amsat-bb@amsat.org> wrote:


On 12/26/22 22:31, tjschuessler--- via AMSAT-BB wrote:

> I do have a question for Yaesu FT847 users.  With that radio, you can
>  power a Preamp via the built in Bia- T power inserter, And assume
> that when this mode is turned on, it cuts the inserted DC to the
> preamp as the tranciever goes into transmit.  Does this work fast
> enough to protect, even RF switched preamps?  That might be a good
> safety measure as I have traditionally used external DC to power my
> preamps.

I have a homebrew UHF LNA that initially suffered the same fate as yours
before it was modified with protective PIN diodes on the output.

I am powering the relays which switch from "inline" (during RX) to
"bypass" (during TX) with the FT-847's bias-tee function. I found that
the relays might not be quite fast enough to avoid getting a significant
RF pulse back into the LNA output. This was most pronounced with CW,
while SSB was tolerated better -- probably because I waited a moment to
speak after pressing the PTT.

In a previous posting, I wrote:

>
> (The BAR64 PIN diodes were added to protect the MAR3-SM+ output gain
> block when transmitting. Without those, the MAR3 was dead within a
> few minutes of use at >10W TX.)

You might try putting some of those PIN diodes into your unit. It might
just keep it from going up in smoke.

--- Zach
N0ZGO

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