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  #12   Report Post  
Old September 14th 03, 02:37 AM
Rob Judd
 
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Richard,

I believe the K2 is what you should be aiming to compete with. It
evidently is fairly good for the money.

I'm in Melbourne and would be happy to help in any way I can, time
allowing.

All the best,

Rob


Richard Hosking wrote:

Rob
My long term goal is to design a backback portable HF SSB/data rig to
compete with the current offerings (SG2020) and Elecraft. I will probably
never get there! I think with some new ideas and SM technology I could get
the current drain 100mA on receive and keep the size V small, while
having digital programmability etc
BTW I would be interested in formiong a cooperative group on this if anyone
is interested.

Richard

Rob Judd wrote in message
...
Richard,

How extremely strange. I just announced a week or so ago on a private
forum that I was designing exactly the same thing. And I've also
searched the net to see whether this was an original idea, and it seemed
to be unique at the time. You wouldn't be another SDR-1000 owner by any
chance?

BTW, I'm still trying to locate relays also. My reply at the quoted
$10.00 price from CIT was "Freow! Skip it!" or something similar. As you
say, 20-30 of those makes it VERY expensive indeed.

Rob


Richard Hosking wrote:

Anyone know a good source of surface mount latching relays DPST or DPDT,

5V
to be driven by logic?
I want to build an automatic antenna tuner for HF QRP
Digikey has them but they areUS$12 ea and it is a bit too expensive if I
want about 20 of them
I would prefer a permanent source if possible - not only a temporary
surplus - although this would be better than nothing

Thanks in advance

Richard

  #13   Report Post  
Old September 14th 03, 02:37 AM
Rob Judd
 
Posts: n/a
Default

Richard,

I believe the K2 is what you should be aiming to compete with. It
evidently is fairly good for the money.

I'm in Melbourne and would be happy to help in any way I can, time
allowing.

All the best,

Rob


Richard Hosking wrote:

Rob
My long term goal is to design a backback portable HF SSB/data rig to
compete with the current offerings (SG2020) and Elecraft. I will probably
never get there! I think with some new ideas and SM technology I could get
the current drain 100mA on receive and keep the size V small, while
having digital programmability etc
BTW I would be interested in formiong a cooperative group on this if anyone
is interested.

Richard

Rob Judd wrote in message
...
Richard,

How extremely strange. I just announced a week or so ago on a private
forum that I was designing exactly the same thing. And I've also
searched the net to see whether this was an original idea, and it seemed
to be unique at the time. You wouldn't be another SDR-1000 owner by any
chance?

BTW, I'm still trying to locate relays also. My reply at the quoted
$10.00 price from CIT was "Freow! Skip it!" or something similar. As you
say, 20-30 of those makes it VERY expensive indeed.

Rob


Richard Hosking wrote:

Anyone know a good source of surface mount latching relays DPST or DPDT,

5V
to be driven by logic?
I want to build an automatic antenna tuner for HF QRP
Digikey has them but they areUS$12 ea and it is a bit too expensive if I
want about 20 of them
I would prefer a permanent source if possible - not only a temporary
surplus - although this would be better than nothing

Thanks in advance

Richard

  #14   Report Post  
Old September 15th 03, 12:52 PM
Richard Hosking
 
Posts: n/a
Default

Rob

A quick search of the revealed not much apart from the two mentioned. I have
not used either but on paper at least, the 2020 appeared the most
attractive. Elecraft kindly published their tuner design, which is simply a
series of capacitors and inductors in a L network configuration switched by
relays. They use a conventional SWR bridge to measure the match, with the
whole thing controlled by a micro. Is that how you are planning to do yours?
I have done a few successful projects using AVRs to control RF devices (see
http://members.iinet.net.au/~richardh/VK6BRO.htm ) so I reckon I could do
the board design.
The code would take a bit of work - I am not sure what algorithm would be
used
Do you have any ideas on this?

Richard

Rob Judd wrote in message
...
Richard,

I believe the K2 is what you should be aiming to compete with. It
evidently is fairly good for the money.

I'm in Melbourne and would be happy to help in any way I can, time
allowing.

All the best,

Rob


Richard Hosking wrote:

Rob
My long term goal is to design a backback portable HF SSB/data rig to
compete with the current offerings (SG2020) and Elecraft. I will

probably
never get there! I think with some new ideas and SM technology I could

get
the current drain 100mA on receive and keep the size V small, while
having digital programmability etc
BTW I would be interested in formiong a cooperative group on this if

anyone
is interested.

Richard

Rob Judd wrote in message
...
Richard,

How extremely strange. I just announced a week or so ago on a private
forum that I was designing exactly the same thing. And I've also
searched the net to see whether this was an original idea, and it

seemed
to be unique at the time. You wouldn't be another SDR-1000 owner by

any
chance?

BTW, I'm still trying to locate relays also. My reply at the quoted
$10.00 price from CIT was "Freow! Skip it!" or something similar. As

you
say, 20-30 of those makes it VERY expensive indeed.

Rob


Richard Hosking wrote:

Anyone know a good source of surface mount latching relays DPST or

DPDT,
5V
to be driven by logic?
I want to build an automatic antenna tuner for HF QRP
Digikey has them but they areUS$12 ea and it is a bit too expensive

if I
want about 20 of them
I would prefer a permanent source if possible - not only a temporary
surplus - although this would be better than nothing

Thanks in advance

Richard



  #15   Report Post  
Old September 15th 03, 12:52 PM
Richard Hosking
 
Posts: n/a
Default

Rob

A quick search of the revealed not much apart from the two mentioned. I have
not used either but on paper at least, the 2020 appeared the most
attractive. Elecraft kindly published their tuner design, which is simply a
series of capacitors and inductors in a L network configuration switched by
relays. They use a conventional SWR bridge to measure the match, with the
whole thing controlled by a micro. Is that how you are planning to do yours?
I have done a few successful projects using AVRs to control RF devices (see
http://members.iinet.net.au/~richardh/VK6BRO.htm ) so I reckon I could do
the board design.
The code would take a bit of work - I am not sure what algorithm would be
used
Do you have any ideas on this?

Richard

Rob Judd wrote in message
...
Richard,

I believe the K2 is what you should be aiming to compete with. It
evidently is fairly good for the money.

I'm in Melbourne and would be happy to help in any way I can, time
allowing.

All the best,

Rob


Richard Hosking wrote:

Rob
My long term goal is to design a backback portable HF SSB/data rig to
compete with the current offerings (SG2020) and Elecraft. I will

probably
never get there! I think with some new ideas and SM technology I could

get
the current drain 100mA on receive and keep the size V small, while
having digital programmability etc
BTW I would be interested in formiong a cooperative group on this if

anyone
is interested.

Richard

Rob Judd wrote in message
...
Richard,

How extremely strange. I just announced a week or so ago on a private
forum that I was designing exactly the same thing. And I've also
searched the net to see whether this was an original idea, and it

seemed
to be unique at the time. You wouldn't be another SDR-1000 owner by

any
chance?

BTW, I'm still trying to locate relays also. My reply at the quoted
$10.00 price from CIT was "Freow! Skip it!" or something similar. As

you
say, 20-30 of those makes it VERY expensive indeed.

Rob


Richard Hosking wrote:

Anyone know a good source of surface mount latching relays DPST or

DPDT,
5V
to be driven by logic?
I want to build an automatic antenna tuner for HF QRP
Digikey has them but they areUS$12 ea and it is a bit too expensive

if I
want about 20 of them
I would prefer a permanent source if possible - not only a temporary
surplus - although this would be better than nothing

Thanks in advance

Richard





  #16   Report Post  
Old September 15th 03, 02:07 PM
Mike W
 
Posts: n/a
Default

On Sun, 7 Sep 2003 17:31:00 +0800, "Richard Hosking"
wrote:

Anyone know a good source of surface mount latching relays DPST or DPDT, 5V
to be driven by logic?


Anyone have a URL on to how to use latching relays ?. I've found
single coil and double coil examples but no info on how they function
or how to switch them.
  #17   Report Post  
Old September 15th 03, 02:07 PM
Mike W
 
Posts: n/a
Default

On Sun, 7 Sep 2003 17:31:00 +0800, "Richard Hosking"
wrote:

Anyone know a good source of surface mount latching relays DPST or DPDT, 5V
to be driven by logic?


Anyone have a URL on to how to use latching relays ?. I've found
single coil and double coil examples but no info on how they function
or how to switch them.
  #18   Report Post  
Old September 15th 03, 08:20 PM
xpyttl
 
Posts: n/a
Default

The latching relays are fairly obvious, actually.

For the dual coil ones, you apply current to one coil to open, to the other
coil to close. The single coil ones generally have you reverse polarity on
the coil to change state. If they are latching relays, in both cases they
won't change state with no current applied.

...

"Mike W" wrote in message
...
On Sun, 7 Sep 2003 17:31:00 +0800, "Richard Hosking"
wrote:

Anyone know a good source of surface mount latching relays DPST or DPDT,

5V
to be driven by logic?


Anyone have a URL on to how to use latching relays ?. I've found
single coil and double coil examples but no info on how they function
or how to switch them.



  #19   Report Post  
Old September 15th 03, 08:20 PM
xpyttl
 
Posts: n/a
Default

The latching relays are fairly obvious, actually.

For the dual coil ones, you apply current to one coil to open, to the other
coil to close. The single coil ones generally have you reverse polarity on
the coil to change state. If they are latching relays, in both cases they
won't change state with no current applied.

...

"Mike W" wrote in message
...
On Sun, 7 Sep 2003 17:31:00 +0800, "Richard Hosking"
wrote:

Anyone know a good source of surface mount latching relays DPST or DPDT,

5V
to be driven by logic?


Anyone have a URL on to how to use latching relays ?. I've found
single coil and double coil examples but no info on how they function
or how to switch them.



  #20   Report Post  
Old September 16th 03, 01:55 AM
Richard Hosking
 
Posts: n/a
Default

Thanks
I wanted to know this as well!

Richard

xpyttl wrote in message
...
The latching relays are fairly obvious, actually.

For the dual coil ones, you apply current to one coil to open, to the

other
coil to close. The single coil ones generally have you reverse polarity

on
the coil to change state. If they are latching relays, in both cases they
won't change state with no current applied.

..

"Mike W" wrote in message
...
On Sun, 7 Sep 2003 17:31:00 +0800, "Richard Hosking"
wrote:

Anyone know a good source of surface mount latching relays DPST or

DPDT,
5V
to be driven by logic?


Anyone have a URL on to how to use latching relays ?. I've found
single coil and double coil examples but no info on how they function
or how to switch them.





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