For a tube amp where you have plate tuning and loading controls, you have
some leeway.  I would say that you could go to at least 3:1, probably a
little more.  The actual power output will be (very approximately) the
difference between the forward and reflected power.  A high forward power
reading means that the current or the voltage along the line is not the
normal expected for a 50-ohm load.  Proceed with some caution, especially on
the low bands.  Also, if it's a solid-state amp without a tuner behind it,
you need to stay pretty close to 1:1.
73,
Lloyd Rasmussen, W3IUU, Kensington, Maryland
Home:  http://lras.home.sprynet.com
Work:  http://www.loc.gov/nls
 

> -----Original Message-----
> From: For blind ham radio operators [mailto:[log in to unmask]]
> On Behalf Of Rick
> Sent: Wednesday, March 10, 2010 10:49 AM
> To: [log in to unmask]
> Subject: What is the highest safe swr?
> 
> Hi list.
> What is the highest safe SWR?
> The reason I ask is, when on 20 meters for example, I tune my SWR to 1.0 =
> to 1, I get 700 watts out of my amp.
> When I have an SWR of 2.0 to 1 I get 1000 watts.
> I don't want to hurt anything, so I thought I'd ask here.
> Thanks in advance, 7 3.