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  1. ATU100
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Bypass mode behaviour & high SWR on 6m

 

Hi all,

I was testing the SWR of my tuner in bypass mode and I found that the SWR is nearly 2:1 on 6m!

Looking at what happens in bypass mode I see that the relays disconnect the L & C but the actual bypass relay stays energised.

The bypass relay only goes off if I remove power. SWR on 6m with no power is a more reasonable 1.3:1

Does anyone else have this issue ?

Is it "normal" behaviour for the bypass relay to stay energised when the power is on regardless of settings ?

Has anyone else tested the SWR of their tuner on 6m ?

thanks

Tim


--
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA
 

Yes I have tested it and it is 1:1.3 in bypass for 50mhz.?

Op zo 14 nov. 2021 20:50 schreef Tim <VK2XAX@...>:

Hi all,

I was testing the SWR of my tuner in bypass mode and I found that the
SWR is nearly 2:1 on 6m!

Looking at what happens in bypass mode I see that the relays disconnect
the L & C but the actual bypass relay stays energised.

The bypass relay only goes off if I remove power. SWR on 6m with no
power is a more reasonable 1.3:1

Does anyone else have this issue ?

Is it "normal" behaviour for the bypass relay to stay energised when the
power is on regardless of settings ?

Has anyone else tested the SWR of their tuner on 6m ?

thanks

Tim


--
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA
 

Hi Ono,

thanks for the quick reply

Is your bypass relay on or off when in bypass mode ?

thanks

Tim


--
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA
 

Hi Tim,

When in bypass or no power the relay is on. It's a true bypass. I will double check tomorrow when at home again but I am 99% sure.?

It could be that the relais are different type from expected? There are normally open and normally closed relays.?

Best regards Onno

Op zo 14 nov. 2021 21:07 schreef Tim <VK2XAX@...>:

Hi Ono,

thanks for the quick reply

Is your bypass relay on or off when in bypass mode ?

thanks

Tim


--
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA
 

Hi, Tim.
That is normal behavior, because on my tuner this position of C switch relay gives better SWR.
Please keep in mind, ATU 100 tuner works well on 3.5 - 28 Mhz only .
 

¿ªÔÆÌåÓý

Hi David,

OK, thanks - the Russian 1kW unit purports to operate to 6m and it does tune there nicely but the through SWR is higher than it should be.

A question for you... Where in the hex is the string "ATU-100" stored ?

I'd like to change mine to "ATU-1000" to match the tuner if possible.

regards

Tim


On 16/11/21 4:29 am, David Fainitski wrote:
Hi, Tim.
That is normal behavior, because on my tuner this position of C switch relay gives better SWR.
Please keep in mind, ATU 100 tuner works well on 3.5 - 28 Mhz only .
_

-- 
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA
 

I don't have such high see on 50 MHz.

Bypass relay is normally closed and with power off swr is 1.1:3. When power is connected and unit switches to bypass the relay is closed too.?

Tuning on 50mhz also works well with a random wire about 10 meters long.?

Perhaps I have a different version.

Regards Onno

Op ma 15 nov. 2021 20:51 schreef Tim <VK2XAX@...>:

Hi David,

OK, thanks - the Russian 1kW unit purports to operate to 6m and it does tune there nicely but the through SWR is higher than it should be.

A question for you... Where in the hex is the string "ATU-100" stored ?

I'd like to change mine to "ATU-1000" to match the tuner if possible.

regards

Tim


On 16/11/21 4:29 am, David Fainitski wrote:
Hi, Tim.
That is normal behavior, because on my tuner this position of C switch relay gives better SWR.
Please keep in mind, ATU 100 tuner works well on 3.5 - 28 Mhz only .
_

-- 
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA
 

Hi, Tim.
You can change the prescription ATU-100 trough a hex changing but you can not add any symbol more in that string.
To All - 1000 W version is much larger physically , has different relays and has larger own L and C values so SWR will be larger too .
 

Hi David,

OK, understand the string length, can you reveal where it can be changed ?

RR re SWR on 6m , I fixed mine? - I found the one of the SO239s on the back panel was slightly loose.?

thanks

Tim

On 17/11/21 4:25 am, David Fainitski wrote:
Hi, Tim.
You can change the prescription ATU-100 trough a hex changing but you can not add any symbol more in that string.
To All - 1000 W version is much larger physically , has different relays and has larger own L and C values so SWR will be larger too .
--
VK2XAX : QF56if : ITU59 : CQ30 : BMARC : WIA

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