Kenwood TS-450S Auto-ATU?
Steve Netting
Quick question. It looks like I might soon be the proud owner of
a Kenwood TS-450S. I've been told this has an auto-ATU.
My question is:- Would this internal ATU tune a random length
of wire? I've heard that some integral ATU's are only
effective if the SWR is a reasonable match in the first place.
Due to less than ideal conditions, I'll need this sort of
flexability.
Does anyone have experience with this radio & ATU?
Thanks,
Steve
M3NSP
--
Amateur Radio UK ...http://www.electro-clash.com/amateur/index.php
Starr
"Steve Netting" <st...@catflap.electro-clash.com> wrote in message
news:newscache$r8xjxh$0e8$1...@catflap.electro-clash.com...
> Hi,
>
> Quick question. It looks like I might soon be the proud owner of
> a Kenwood TS-450S. I've been told this has an auto-ATU.
>
> My question is:- Would this internal ATU tune a random length
> of wire? I've heard that some integral ATU's are only
> effective if the SWR is a reasonable match in the first place.
>
> Due to less than ideal conditions, I'll need this sort of
> flexability.
>
> Does anyone have experience with this radio & ATU?
>
> Thanks,
I don't know much about the auto ATU of the ts TS-45OS but as far as I know
Auto ATU's are no better than manual ones. they can't achive the impossible.
What I do is tune as low as I can go and if still to high then i drop the
power and tune again. It's not ideal but it may stop you blowing up the
radio or the radio shutting down.
HTH
--
S
--
I live my life like I play games, I cheat.
-
Trolls are your enemies, wipe them out.
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-
Trevor Day
writes
>
>
>
>"Steve Netting" <st...@catflap.electro-clash.com> wrote in message
>news:newscache$r8xjxh$0e8$1...@catflap.electro-clash.com...
>> Hi,
>>
>> Quick question. It looks like I might soon be the proud owner of
>> a Kenwood TS-450S. I've been told this has an auto-ATU.
>>
>> My question is:- Would this internal ATU tune a random length
>> of wire? I've heard that some integral ATU's are only
>> effective if the SWR is a reasonable match in the first place.
>>
>> Due to less than ideal conditions, I'll need this sort of
>> flexability.
>>
>> Does anyone have experience with this radio & ATU?
>>
>> Thanks,
>
>I don't know much about the auto ATU of the ts TS-45OS but as far as I know
>Auto ATU's are no better than manual ones. they can't achive the impossible.
>What I do is tune as low as I can go and if still to high then i drop the
>power and tune again. It's not ideal but it may stop you blowing up the
>radio or the radio shutting down.
Auto ATUs are generally not good at matching very high or low
impedances. Most are designed to achieve a good match into a load not
too far removed from 50 ohms. The reason for this is to enable its
associated (solid state) PA to put out full power to the aerial system.
Most modern radios will reduce power markedly once the VSWR reaches
around 2 to 1; the auto ATU will allow you to develop full power on ,
say, a vertical when operating away from its resonant frequency.
Having said this, some Auto ATUs perform well even with large changes in
impedance as will be found when using a random length wire. The ATU
fitted into the Elecraft transceiver is particularly good in this
respect.
If you intend to use a random wire, then be prepared to use an external
matching system. They are very simple and cheap to put together and
there is plenty of help available on the net to build your own. Twenty
or so feet of wire, an insulated tube and a variable capacitor can be
made to match pretty much anything!
gl
Trev G3ZYY
--
Trevor Day
SIP: 8441...@voiptalk.org
Davo
in any antenna I used on any band...... really wicked...
D@vo
"Steve Netting" <st...@catflap.electro-clash.com> wrote in message
news:newscache$r8xjxh$0e8$1...@catflap.electro-clash.com...
Steve Netting
I posted this yesterday - but the mail server seems to have ate it ...
I'm about to buy a Kenwood TS-450S. I've been told this has an integral
ATU.
Does anyone have any experience with this? Due to a less than ideal operating
environment, I'll be looking at using this with a random length of wire.
I understand some auto-ATU's only tune if the initial SWR is within a certain
limit (eg, 10:1 or under).
Am I likely to still need an external ATU in this situation?
Thanks in advance,
Steve
M3NSP
Andy Cowley
Yes. Most internal ATUs can only manage to tune about a 3:1 SWR to
something the PAs power reduction circuitry won't detect. I don't
know the TS-450S but the manual gives the matching range as 20 -
150 ohms (~ 3:1 SWR), so it will cope with the band edges for an
aerial that is resonant in the band but not with a random length
wire unless you are very lucky. It doesn't work on top band.
The manual, and service manual are available as PDFs at
http://www.mods.dk under ->Kenwood->manuals.
hth
vy 73
Andy, M1EBV
Steve Netting
>> Am I likely to still need an external ATU in this situation?
>>
>>
> Yes. Most internal ATUs can only manage to tune about a 3:1 SWR to
> something the PAs power reduction circuitry won't detect. I don't
> know the TS-450S but the manual gives the matching range as 20 -
> 150 ohms (~ 3:1 SWR), so it will cope with the band edges for an
> aerial that is resonant in the band but not with a random length
> wire unless you are very lucky. It doesn't work on top band.
>
> The manual, and service manual are available as PDFs at
> http://www.mods.dk under ->Kenwood->manuals.
>
Thanks - that's what I suspected. I'll grab the pdf's too...
Thanks again,
Steve
M3NSP
Steve Netting
> In message <c7qlpr$fj1$0...@pita.alt.net>, Starr <thic...@plank.net>
> writes
> >
> >
> >
> >"Steve Netting" <st...@catflap.electro-clash.com> wrote in message
> >news:newscache$r8xjxh$0e8$1...@catflap.electro-clash.com...
<snip>
> >I don't know much about the auto ATU of the ts TS-45OS but as far as I know
> >Auto ATU's are no better than manual ones. they can't achive the impossible.
> >What I do is tune as low as I can go and if still to high then i drop the
> >power and tune again. It's not ideal but it may stop you blowing up the
> >radio or the radio shutting down.
>
> Auto ATUs are generally not good at matching very high or low
> impedances. Most are designed to achieve a good match into a load not
> too far removed from 50 ohms. The reason for this is to enable its
> associated (solid state) PA to put out full power to the aerial system.
> Most modern radios will reduce power markedly once the VSWR reaches
> around 2 to 1; the auto ATU will allow you to develop full power on ,
> say, a vertical when operating away from its resonant frequency.
>
> Having said this, some Auto ATUs perform well even with large changes in
> impedance as will be found when using a random length wire. The ATU
> fitted into the Elecraft transceiver is particularly good in this
> respect.
>
> If you intend to use a random wire, then be prepared to use an external
> matching system. They are very simple and cheap to put together and
> there is plenty of help available on the net to build your own. Twenty
> or so feet of wire, an insulated tube and a variable capacitor can be
> made to match pretty much anything!
>
Thanks for the advice ... once I get the radio I'll give it a go and see
see what happens. An external ATU isn't a problem - I was just hoping
I wouln't need one :)
Thanks again for your response ... I may have a go at making one :)
Regards,