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Carrier between dits and dots

Daniel Moeller
 

Dear OMs and YLs,

I hope i can explain my problem in English - I'll try my very best...

I use the kit for my beacon on 10m because I had some problems with my old x-tal transmitter.

After I soldered the U2 I first had only a very very small signal althought I had all three FET in the bench setup at 12 Volt and about 450 mA. I turned the blue poti on the DDS until I had the most powerful signal strength. Output is a bit less than 1 Watt. That's fine.

But there is still a problem left. I set up plain CW with 12 wpm. In the pause between the dits and dots i can clearly hear a carrier on the same frequency. The power of this carrier is about 100 mW and you can still hear it in big distance to the trnasmitter and not only in the shack. That means this carrier is on the antenna.

Has anyone an idea?

73s, Daniel DL3RTL
Hans Summers
 


Hi Daniel

The keying transistor Q1 does not provide perfect on/off switching. There is a leakage even when it is switched off. The carrier suppression on key-up is around 25-30dB.?

I am planning to stop this, in firmware v2.04, by setting the DDS frequency to ZERO key-up. I should hopefully have v2.04 ready in 1-2 weeks.

73 Hans G0UPL


On Tue, Aug 6, 2013 at 9:43 PM, Daniel Moeller <dmoeller.berlin@...> wrote:
?

Dear OMs and YLs,

I hope i can explain my problem in English - I'll try my very best...

I use the kit for my beacon on 10m because I had some problems with my old x-tal transmitter.

After I soldered the U2 I first had only a very very small signal althought I had all three FET in the bench setup at 12 Volt and about 450 mA. I turned the blue poti on the DDS until I had the most powerful signal strength. Output is a bit less than 1 Watt. That's fine.

But there is still a problem left. I set up plain CW with 12 wpm. In the pause between the dits and dots i can clearly hear a carrier on the same frequency. The power of this carrier is about 100 mW and you can still hear it in big distance to the trnasmitter and not only in the shack. That means this carrier is on the antenna.

Has anyone an idea?

73s, Daniel DL3RTL
Keith Maton
 

¿ªÔÆÌåÓý

I wonder if there's an alternative transistor to Q1 with similar performance but less leakage?

73 Keith, G6NHU


On 7 Aug 2013, at 03:48, Hans Summers <hans.summers@...> wrote:

?


Hi Daniel

The keying transistor Q1 does not provide perfect on/off switching. There is a leakage even when it is switched off. The carrier suppression on key-up is around 25-30dB.?

I am planning to stop this, in firmware v2.04, by setting the DDS frequency to ZERO key-up. I should hopefully have v2.04 ready in 1-2 weeks.

73 Hans G0UPL


On Tue, Aug 6, 2013 at 9:43 PM, Daniel Moeller <dmoeller.berlin@...> wrote:
?

Dear OMs and YLs,

I hope i can explain my problem in English - I'll try my very best...

I use the kit for my beacon on 10m because I had some problems with my old x-tal transmitter.

After I soldered the U2 I first had only a very very small signal althought I had all three FET in the bench setup at 12 Volt and about 450 mA. I turned the blue poti on the DDS until I had the most powerful signal strength. Output is a bit less than 1 Watt. That's fine.

But there is still a problem left. I set up plain CW with 12 wpm. In the pause between the dits and dots i can clearly hear a carrier on the same frequency. The power of this carrier is about 100 mW and you can still hear it in big distance to the trnasmitter and not only in the shack. That means this carrier is on the antenna.

Has anyone an idea?

73s, Daniel DL3RTL
"Carlo Strozzi"
 

Hans,

I'm in need of this function too. When you are done with the mod, will upgraded chips be available for purchase ? Or will one need to buy the updated version of the whole kit? In other words, how can I upgrade from v2.03 to v2.04 ?

thank-you,
Carlo

--- In QRPLabs@..., Hans Summers <hans.summers@...> wrote:

Hi Daniel

The keying transistor Q1 does not provide perfect on/off switching. There
is a leakage even when it is switched off. The carrier suppression on
key-up is around 25-30dB.

I am planning to stop this, in firmware v2.04, by setting the DDS frequency
to ZERO key-up. I should hopefully have v2.04 ready in 1-2 weeks.

73 Hans G0UPL


On Tue, Aug 6, 2013 at 9:43 PM, Daniel Moeller <
dmoeller.berlin@...> wrote:

**


Dear OMs and YLs,

I hope i can explain my problem in English - I'll try my very best...

I use the kit for my beacon on 10m because I had some problems with my old
x-tal transmitter.

After I soldered the U2 I first had only a very very small signal
althought I had all three FET in the bench setup at 12 Volt and about 450
mA. I turned the blue poti on the DDS until I had the most powerful signal
strength. Output is a bit less than 1 Watt. That's fine.

But there is still a problem left. I set up plain CW with 12 wpm. In the
pause between the dits and dots i can clearly hear a carrier on the same
frequency. The power of this carrier is about 100 mW and you can still hear
it in big distance to the trnasmitter and not only in the shack. That means
this carrier is on the antenna.

Has anyone an idea?

73s, Daniel DL3RTL
www.dl3rtl.de/beacon.php
Hans Summers
 


Carlo

Yes! Firmware upgrade chips are available separately, price GBP ?3.00. The current version is v2.03. As soon as v2.04 becomes available, you will be able to get it in the shop .

73 Hans G0UPL


On Mon, Aug 12, 2013 at 2:25 PM, Carlo Strozzi <carlos@...> wrote:
?


Hans,

I'm in need of this function too. When you are done with the mod, will upgraded chips be available for purchase ? Or will one need to buy the updated version of the whole kit? In other words, how can I upgrade from v2.03 to v2.04 ?

thank-you,
Carlo



--- In QRPLabs@..., Hans Summers wrote:
>
> Hi Daniel
>
> The keying transistor Q1 does not provide perfect on/off switching. There
> is a leakage even when it is switched off. The carrier suppression on
> key-up is around 25-30dB.
>
> I am planning to stop this, in firmware v2.04, by setting the DDS frequency
> to ZERO key-up. I should hopefully have v2.04 ready in 1-2 weeks.
>
> 73 Hans G0UPL
>
>
> On Tue, Aug 6, 2013 at 9:43 PM, Daniel Moeller <
> dmoeller.berlin@...> wrote:
>
> > **

> >
> >
> > Dear OMs and YLs,
> >
> > I hope i can explain my problem in English - I'll try my very best...
> >
> > I use the kit for my beacon on 10m because I had some problems with my old
> > x-tal transmitter.
> >
> > After I soldered the U2 I first had only a very very small signal
> > althought I had all three FET in the bench setup at 12 Volt and about 450
> > mA. I turned the blue poti on the DDS until I had the most powerful signal
> > strength. Output is a bit less than 1 Watt. That's fine.
> >
> > But there is still a problem left. I set up plain CW with 12 wpm. In the
> > pause between the dits and dots i can clearly hear a carrier on the same
> > frequency. The power of this carrier is about 100 mW and you can still hear
> > it in big distance to the trnasmitter and not only in the shack. That means
> > this carrier is on the antenna.
> >
> > Has anyone an idea?
> >
> > 73s, Daniel DL3RTL
> >
> >
> >
>

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