[Amps] B&W PT2500

[Steve]

For clarification, adding an attenuator doesn't guarantee a 50ohm load 
to the rig regardless. An attenuator makes VSWR lower, the amount of 
improvement related to the value of the attenuator.

For example, using the 2dB value featured in the link Mike gave, in 
round numbers, a 3:1 VSWR upstream will look like 2:1 at the rig; 2:1 
upstream will look like 1.5:1 at the rig and so on.

A higher value attenuator gives greater reduction in VSWR at the rig side.

The trade off for improved VSWR is that attenuator will dissipate power 
and need heatsinking - at least 37% of what you feed in for 2dB value 
and higher for higher values.

It's a good way to reduce interactions between amplifier stages and many 
professional designs build them in to deal with awkward problems.

Steve G8GSQ

> For an input SWR when using a solid state amplifier against a PT2500 Amplifier, 
> why not use something like this?  It will provide a 50hom load to the 
> transceiver input  regardless of the band exercised.  They offer 1db, 2db on up 
> of attenuation, and are matched at 50ohms to the Transceiver input of the amp 
> all the way to 1Ghz or better. The point being here the transceiver will always 
> see a ~50ohm load.  Just a thought.
> 
> https://www.ebay.com/itm/370603866564?hash=item5649b639c4:g:s2sAAOSwLzdWRTy4 
> 
> Thank you,
> 
> Mike
> W5CUL