[Yaesu] Why are we so SWR-phobic

[John Geiger]

Is that what they did in the older solid state rigs?  As I pointed out in my
original post, many older rigs would handle higher SWRs.  The Yaesu FT100D
would do full power into a 2:1 SWR.  You could try that on a FT857 or FT897,
but the audio would be unreadable.

73s John W5TD

----- Original Message -----
From: "N4AOF" <n4aof at arrl.net>
To: "Yaesu Maillist at QTH.net" <Yaesu at mailman.qth.net>
Sent: Sunday, June 18, 2006 10:38 PM
Subject: Re: [Yaesu] Why are we so SWR-phobic


> The rig designers are giving us the rigs "we" have told them we want to
buy
> - Solid state
> -- High Power
> --- Low cost
>
> It would be possible to design a solid state rig that could withstand high
> SWR -- but doing so would increase the cost
>
> Perhaps more importantly it would be bad for the company's reputation
>
> If a company built a 200W solid state rig that could withstand the SWRs
> common in old tube rigs, it would be running the finals at much less than
> their full output power -- basically they would be building a 400W rig
> configured to operate at half-power into any SWR from 1:1 up to 2:1
>
> That might suit you -- but I guarantee some ham would take one look at the
> circuit and figure out that a "simple mod" would let the rig put out the
> full 400W
>
> Of course none of the circuitry would have been designed to do this, but
> that wouldn't stop hundreds of hams from making the "simple mod" -- and
> either burning out the finals into a 1.5:1 SWR or burning out some other
> component that wasn't meant to support the demands of the 400W finals.
> Either way, the manufacturer would be blamed for the rig not being
reliable.
> No one would care that the rigs that were burning up were modded.  "We're
> hams, we have a right to mess around inside the rig!"  It would be the
> manufacturer's fault for making a rig that burned up when modified.
>
> The only way to design a bullet-proof 200W rig, is to first design a
> complete 400W rig all the way through, then beef that up, then finally
> incorporate circuitry at every point to limit it back down to 200W to try
to
> make it idiot-proof.
>
> But who would buy a 200W rig that costs more than a 400W rig should cost?
>
> ----- Original Message -----
> From: "John Geiger" <w5td at lcisp.com>
> To: "ICOM Reflector" <icom at mailman.qth.net>; <kenwood at mailman.qth.net>;
> <yaesu at mailman.qth.net>; <dx-list at yahoogroups.com>;
> <cq-contest at contesting.com>
> Sent: Sunday, June 18, 2006 18:16
> Subject: [Yaesu] Why are we so SWR-phobic
>
>
> Am I the only one who things that the SWR protection circuits in currents
> are ridiculous?  I mean, most of them start cutting power back with a
1.5:1
> SWR?  Are today's rigs so poorly designed that you could damage the finals
> with a 2:1 SWR?  Older solid state rigs used to handle that just fine.
The
> ad for the Yaesu FT107M advertised that it would put out 75% power into a
> 3:1 SWR!!  Most Ten Tecs will put out almost full power into a 3:1 SWR.
But
> most other moderns rigs are putting out 50% power or so into a 2:1 SWR.
>
> The worst is the Yaesu FT857/897 series which cuts up the audio if the SWR
> gets above 1.5:1 or so, and people think that this is a good thing?
>
> So what is going on with the rig designers?  Do people really want this
> aggressive of an SWR circuit?  I find it kind of annoying to have to
return
> the tuner every 25 kcs or so on some radios.  Are the finals today really
> that fragile?
>
> Or is it just me?  Anyone else with ideas?
>
> 73s John W5TD
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