Yep, that is for sure. And, if you think about it, swr on the antenna
wires themselves is what makes them work, but that is another story.
Actually with today's rigs, swr is much over rated, and is important.
Not so much that it won't transmit as well, all things being equal, but
these solid state radios want a good match both on receive and transmit.
Way back when, a lot of guys ran as much wire as they could get up.
They center fed this with open ladder line and through a tuner such as
the Johnson matchbox and then to the radio. The tuner kept the rig
happy, (tube rigs weren't all that particular to a point), and they put
out a very gbood signal, even though the swr was very high. This is
really a complicated and often misunderstood subject. But, to keep it
simple, as far as your radio is concerned, 1.5 or less is ideal. Of
corse, a good tuner can match anything, but it depends on feed line loss
radiation resistance and so forth. A flat free space dipole if I
remember right, has a feed impedence of around 70 ohms so your swr is
going to be 70/50 or which is 1.4 to one. If your dipole is an
inverted v, dropping the ends changes the impedence, I think it lowers
it, but I'm not sure about that. I run a solid state magnus amp that
pulls around 80 amps on 12 volts, and the lower the impedence, the more
it kicks out as far as power. If the antenna shows an impedence of 25
ohms, even though the swr is 2 to one, the amp loves it. If the
impedence was a hundred ohms, same swr, the amp doesn't work nearly as
well.
I've bored you all long enough.
Later.
73
Butch Bussen
wa0vjr
open Node 3148
Las Vegas
On Wed, 10 Mar 2010, Buddy Brannan wrote:
> Bear in mind that a 50-ohm dummy load will give you a 1:1 SWR, =
> too...there's really a lot more to this stuff than SWR.=20
> --
> Buddy Brannan, KB5ELV - Erie, PA
> Phone: (814) 860-3194 or 888-75-BUDDY
>
>
>
> On Mar 10, 2010, at 1:10 PM, Eric Patterson wrote:
>
>> Rick and others:
>> =20
>> It was my understanding that it is best to have an SWR of 1 to =
> 1.
>> However, 1.5 or 2 to 1 is also acceptable. It was also my =
> understanding
>> that if your SWR goes above 2 to 1, you could lose transmitter power =
> or have
>> trouble tuning your antenna. I do not use amplifiers, but I learned =
> about
>> SWR when I studied for my technician license back in 1993. Others on =
> this
>> list can let me know if my understanding is correct. Thanks.
>> =20
>> Eric
>> =20
>> -----Original Message-----
>> From: For blind ham radio operators =
> [mailto:[log in to unmask]]
>> On Behalf Of Rick
>> Sent: Wednesday, March 10, 2010 7:49 AM
>> To: [log in to unmask]
>> Subject: What is the highest safe swr?
>> =20
>> 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 =3D
>> 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.
>
>
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