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Re: DDS VFO!

Bob Macklin
 

开云体育

BTW:
?
The NRR group operates 40M CW in the old Novice segment. Or what's left of it. 7100:7125, 7125:7150 is Extra territory.
?
SKCC also has CW activity in the 7100:7125 segment.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
Sent: Wednesday, November 06, 2019 6:11 AM
Subject: Re: [qrptech] DDS VFO!

I built my NC-40A about a year ago.? One of the nice things about the rig is its VFO. I set mine up for 7015 to 7047 kHz. A bit limited in that it doesn't cover the activity around 7112 to 7123, but still a pretty good range. I think it's about right for use of a single-turn control with tuning not becoming too critical. A wider range with a multi-turn pot would necessitate a turns counter or AFA or similar complication.? I have a paper scale/bezel that I can read to near 1 kHz.

With that said, why add a synthesizer? "Because it's there." is one answer. It's ham radio, after all - do what seems fun. Any of those Si or AD based units ought to work fine.

I'm currently enhancing the software in my Si570 VFO. I'm adding it to a transceiver project so it needed the ability to detect key-down and do the CW shift (if in CW mode) and also incorporate stuff like RIT and USB/LSB (or Normal/Reverse) operation. It's close to ready.

Speaking of RTTY, I have an AD9851 signal source that I've programmed a lot of feature creep into, including the ability to send a 60 WPM 170 Hz shift RTTY message repetitively. I'd already added a CW message but wanted to stay in step with the Elecraft XG3, which can do both. So, that was a fun thing.

73-

Nick, WA5BDU
Re: DDS VFO!

 

The schematic is on page 9.

Lots of guys on here probably have extra NC-40 boards, you could use one of those,

and later add the IF and make a better receiver...

73,

Gary

WB6OGD

On 11/6/2019 6:25 AM, Bob Macklin wrote:
Does anyone make a PCB for a 40M DC receiver. Maybe clone the old Ramsey
receiver?

The PCB pattern is in the published manual. But not the schematic.

Maybe I should reverse engineer the Ramsey Rx and Tx.

A Ramsey 40M DC receiver with a DDS may be interesting to try.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message -----
From: "Jim Pruitt" <jpruitt67@...>
To: <[email protected]>
Sent: Tuesday, November 05, 2019 10:31 PM
Subject: Re: [qrptech] DDS VFO!



On 11/5/2019 3:40 PM, wb6ogd wrote:
My NC-40 (homebrew copy) tunes 7014-7066. Below that they go too fast for
me, above that is only

the digital modes and the novice band.
What is wrong with the old novice band? I frequently listen there.
NC-40 filter is too narrow for SSB (though I have listened to

some canadians and you can mostly understand them but with very bad
quality). Why would you

want more than that?
Because it is there...errr because I can.

There was some comment that a DDS vfo has a pretty low upper frequency but
the AD985x series are good to at least 30.0mhz.

The NC40 VFO runs in the 2 mhz range and the Si5351 and the AD985x would
loaf along at those frequencies. VK5TM had some pretty good circuits on
his web pages. As I recall, he even had the PIC code. That code could be
modified to set the band range to match your rig.

My pet project is a DDS (or PLL) vfo for the HW8. My HW8-Franken vfo would
run between 8.4 and 8.9mhz. Have you seen anyone else do that to an HW8?
My plan is to use one of the ebay 6 digit counters and measure the
frequency directly so no IF offset needed and would be undesirable anyway
since circuits do drift and it would be easier to measure the frequency
than to predict the drift!

Thank you.

Jim Pruitt
WA7DUY
Re: DDS VFO!

Bob Macklin
 

Just found one on eBay:


Ordered it. Will convert it to a DDS VFO.

I am sitting here with an operational set of Benton Harbor S-Line Twins!

Do I really need this kind of stuff.

The Heathkit HW-7 and HW-8 were DC receivers. But I have never owned one. I
am just curious about DC receivers.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: "Bob Macklin" <macklinbob@...>
To: <[email protected]>
Sent: Wednesday, November 06, 2019 6:25 AM
Subject: Re: [qrptech] DDS VFO!


Does anyone make a PCB for a 40M DC receiver. Maybe clone the old Ramsey
receiver?

The PCB pattern is in the published manual. But not the schematic.

Maybe I should reverse engineer the Ramsey Rx and Tx.

A Ramsey 40M DC receiver with a DDS may be interesting to try.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message -----
From: "Jim Pruitt" <jpruitt67@...>
To: <[email protected]>
Sent: Tuesday, November 05, 2019 10:31 PM
Subject: Re: [qrptech] DDS VFO!




On 11/5/2019 3:40 PM, wb6ogd wrote:

My NC-40 (homebrew copy) tunes 7014-7066. Below that they go too fast
for
me, above that is only

the digital modes and the novice band.
What is wrong with the old novice band? I frequently listen there.

NC-40 filter is too narrow for SSB (though I have listened to

some canadians and you can mostly understand them but with very bad
quality). Why would you

want more than that?
Because it is there...errr because I can.

There was some comment that a DDS vfo has a pretty low upper frequency
but
the AD985x series are good to at least 30.0mhz.

The NC40 VFO runs in the 2 mhz range and the Si5351 and the AD985x would
loaf along at those frequencies. VK5TM had some pretty good circuits on
his web pages. As I recall, he even had the PIC code. That code could be
modified to set the band range to match your rig.

My pet project is a DDS (or PLL) vfo for the HW8. My HW8-Franken vfo
would
run between 8.4 and 8.9mhz. Have you seen anyone else do that to an HW8?
My plan is to use one of the ebay 6 digit counters and measure the
frequency directly so no IF offset needed and would be undesirable anyway
since circuits do drift and it would be easier to measure the frequency
than to predict the drift!

Thank you.

Jim Pruitt
WA7DUY
Re: DDS VFO!

Bob Macklin
 

Does anyone make a PCB for a 40M DC receiver. Maybe clone the old Ramsey
receiver?

The PCB pattern is in the published manual. But not the schematic.

Maybe I should reverse engineer the Ramsey Rx and Tx.

A Ramsey 40M DC receiver with a DDS may be interesting to try.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: "Jim Pruitt" <jpruitt67@...>
To: <[email protected]>
Sent: Tuesday, November 05, 2019 10:31 PM
Subject: Re: [qrptech] DDS VFO!




On 11/5/2019 3:40 PM, wb6ogd wrote:

My NC-40 (homebrew copy) tunes 7014-7066. Below that they go too fast for
me, above that is only

the digital modes and the novice band.
What is wrong with the old novice band? I frequently listen there.

NC-40 filter is too narrow for SSB (though I have listened to

some canadians and you can mostly understand them but with very bad
quality). Why would you

want more than that?
Because it is there...errr because I can.

There was some comment that a DDS vfo has a pretty low upper frequency but
the AD985x series are good to at least 30.0mhz.

The NC40 VFO runs in the 2 mhz range and the Si5351 and the AD985x would
loaf along at those frequencies. VK5TM had some pretty good circuits on
his web pages. As I recall, he even had the PIC code. That code could be
modified to set the band range to match your rig.

My pet project is a DDS (or PLL) vfo for the HW8. My HW8-Franken vfo would
run between 8.4 and 8.9mhz. Have you seen anyone else do that to an HW8?
My plan is to use one of the ebay 6 digit counters and measure the
frequency directly so no IF offset needed and would be undesirable anyway
since circuits do drift and it would be easier to measure the frequency
than to predict the drift!

Thank you.

Jim Pruitt
WA7DUY
Re: DDS VFO!

Bob Macklin
 

Adding a prescaler does not reduce the accuracy if you extend the sample
time.

You could have two sample times. FAST for quick look and SLOW for accuracy.

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: "Bo, OZ2M" <groups.io@...>
To: <[email protected]>
Sent: Tuesday, November 05, 2019 11:42 PM
Subject: Re: [qrptech] DDS VFO!


Hi

Some but not all Arduinos can count up to 6,4 MHz, i.e. 40% of clock
frequency. Empiric data shows a bit higher, ~43%. The Arduino Zero can count
up to 90 MHz e.g. as implemented in the RFzero:
I don't know about the
Arduino Due.

Here is a video of my presentation of "Arduino, GPS, RF and the Si5351A for
radio amateurs" at the RSGB 2019 Convention:


Adding a prescaler reduces accuracy.

A word of caution: a good spectral performance does not come from "trowing"
parts together. Many Si5351A spectral plots on the web show that clearly.

Prego
Bo
Re: DDS VFO!

 

I built my NC-40A about a year ago.? One of the nice things about the rig is its VFO. I set mine up for 7015 to 7047 kHz. A bit limited in that it doesn't cover the activity around 7112 to 7123, but still a pretty good range. I think it's about right for use of a single-turn control with tuning not becoming too critical. A wider range with a multi-turn pot would necessitate a turns counter or AFA or similar complication.? I have a paper scale/bezel that I can read to near 1 kHz.

With that said, why add a synthesizer? "Because it's there." is one answer. It's ham radio, after all - do what seems fun. Any of those Si or AD based units ought to work fine.

I'm currently enhancing the software in my Si570 VFO. I'm adding it to a transceiver project so it needed the ability to detect key-down and do the CW shift (if in CW mode) and also incorporate stuff like RIT and USB/LSB (or Normal/Reverse) operation. It's close to ready.

Speaking of RTTY, I have an AD9851 signal source that I've programmed a lot of feature creep into, including the ability to send a 60 WPM 170 Hz shift RTTY message repetitively. I'd already added a CW message but wanted to stay in step with the Elecraft XG3, which can do both. So, that was a fun thing.

73-

Nick, WA5BDU
Re: DDS VFO!

 

On 11/5/2019 3:40 PM, wb6ogd wrote:

My NC-40 (homebrew copy) tunes 7014-7066.? Below that they go too fast for me, above that is only

the digital modes and the novice band.
What is wrong with the old novice band?? I frequently listen there.

NC-40 filter is too narrow for SSB (though I have listened to

some canadians and you can mostly understand them but with very bad quality).? Why would you

want more than that?
Because it is there...errr because I can.

There was some comment that a DDS vfo has a pretty low upper frequency but the AD985x series are good to at least 30.0mhz.

The NC40 VFO runs in the 2 mhz range and the Si5351 and the AD985x would loaf along at those frequencies.? VK5TM had some pretty good circuits on his web pages.? As I recall, he even had the PIC code. That code could be modified to set the band range to match your rig.

My pet project is a DDS (or PLL) vfo for the HW8.? My HW8-Franken vfo would run between 8.4 and 8.9mhz.? Have you seen anyone else do that to an HW8?? My plan is to use one of the ebay 6 digit counters and measure the frequency directly so no IF offset needed and would be undesirable anyway since circuits do drift and it would be easier to measure the frequency than to predict the drift!

Thank you.

Jim Pruitt
WA7DUY
Re: Group Introduction: If you're going to post on the group, reply here!

 

Hi,
I don’t post much (or ever!) but I do lurk daily and usually learn something in the process. Thanks for carrying the flag!

Newt
N4EWT
Re: DDS VFO!

 

Hi

Some but not all Arduinos can count up to 6,4 MHz, i.e. 40% of clock frequency. Empiric data shows a bit higher, ~43%. The Arduino Zero can count up to 90 MHz e.g. as implemented in the RFzero: I don't know about the Arduino Due.

Here is a video of my presentation of "Arduino, GPS, RF and the Si5351A for radio amateurs" at the RSGB 2019 Convention:

Adding a prescaler reduces accuracy.

A word of caution: a good spectral performance does not come from "trowing" parts together. Many Si5351A spectral plots on the web show that clearly.

Prego
Bo
Re: DDS VFO!

Bob Macklin
 

开云体育

You can put a divide by 10 in front of the 328 counter input and go higher in frequency if you want.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: wb6ogd
Sent: Tuesday, November 05, 2019 10:04 PM
Subject: Re: [qrptech] DDS VFO!

Arduinos can count to 6.4MHz so Digital
dial for a NC-40 is a piece of cake.
Resolution to the Hz, accuracy depends on
calibration and temp/voltage variation.
You COULD GPS discipline it for real
accuracy.
73,
Gary
WB6OGD?



On Nov 5, 2019, at 9:53 PM, Bob Macklin <macklinbob@...> wrote:

?
How about digital tuning accuracy?
?
I have several GOOD HF receivers with analog tuning and they do not have precision readouts. Only good to about 25KHz.
?
There was a digital display for the NorCal Sierra. But I have only seen pictures of it. You could make one of those with ATmega328 and a LCD.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message -----
From: wb6ogd
Sent: Tuesday, November 05, 2019 9:34 PM
Subject: Re: [qrptech] DDS VFO!

And...
Though I don't see the need to add a DDS VFO to a NC-40, my own NC-40 does have an Arduino add-on.

It functions as:
? AFA? audio frequency annunciator (in CW)
? Iambic keyer
? Keyboard CW sender
? CW decoder (displays on computer through USB)

73,
Gary
WB6OGD

Re: DDS VFO!

 

开云体育

Arduinos can count to 6.4MHz so Digital
dial for a NC-40 is a piece of cake.
Resolution to the Hz, accuracy depends on
calibration and temp/voltage variation.
You COULD GPS discipline it for real
accuracy.
73,
Gary
WB6OGD?



On Nov 5, 2019, at 9:53 PM, Bob Macklin <macklinbob@...> wrote:

?
How about digital tuning accuracy?
?
I have several GOOD HF receivers with analog tuning and they do not have precision readouts. Only good to about 25KHz.
?
There was a digital display for the NorCal Sierra. But I have only seen pictures of it. You could make one of those with ATmega328 and a LCD.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message -----
From: wb6ogd
Sent: Tuesday, November 05, 2019 9:34 PM
Subject: Re: [qrptech] DDS VFO!

And...
Though I don't see the need to add a DDS VFO to a NC-40, my own NC-40 does have an Arduino add-on.

It functions as:
? AFA? audio frequency annunciator (in CW)
? Iambic keyer
? Keyboard CW sender
? CW decoder (displays on computer through USB)

73,
Gary
WB6OGD

Re: DDS VFO!

Bob Macklin
 

开云体育

How about digital tuning accuracy?
?
I have several GOOD HF receivers with analog tuning and they do not have precision readouts. Only good to about 25KHz.
?
There was a digital display for the NorCal Sierra. But I have only seen pictures of it. You could make one of those with ATmega328 and a LCD.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: wb6ogd
Sent: Tuesday, November 05, 2019 9:34 PM
Subject: Re: [qrptech] DDS VFO!

And...
Though I don't see the need to add a DDS VFO to a NC-40, my own NC-40 does have an Arduino add-on.

It functions as:
? AFA? audio frequency annunciator (in CW)
? Iambic keyer
? Keyboard CW sender
? CW decoder (displays on computer through USB)

73,
Gary
WB6OGD

Re: DDS VFO!

 

And...
Though I don't see the need to add a DDS VFO to a NC-40, my own NC-40 does have an Arduino add-on.

It functions as:
? AFA? audio frequency annunciator (in CW)
? Iambic keyer
? Keyboard CW sender
? CW decoder (displays on computer through USB)

73,
Gary
WB6OGD
Re: DDS VFO!

 

Ok guys.? Sometimes a project is worth doing just because its there!
An Si5351 VFO is a really good project just to have around so GO DO IT!

If you need any help with Arduino coding let me know.
73,
Gary
WB6OGD
Re: Group Introduction: If you're going to post on the group, reply here!

 

That is my hope as well!

--
Ryan Flowers W7RLF
https://miscdotgeek.com
Re: Group Introduction: If you're going to post on the group, reply here!

 

Thanks for creating this new space. I learned a lot from the old QRP-tech group and I am hoping this learning will continue here.?

Karl Heinz - K5KHK?
Re: DDS VFO!

Bob Macklin
 

开云体育

BTW:
?
Above 7125 is PHONE space. No one looks for CW between 7125 and 7300.
?
The only time I hear phone activity on 40M is during contests.
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: Mike M6MST
Sent: Tuesday, November 05, 2019 4:06 PM
Subject: Re: [qrptech] DDS VFO!

On Tue, Nov 5, 2019 at 03:49 PM, Bob Macklin wrote:
That wouldn't be a problem using a DDS VFO.
Bob, I was responding to Gary WB6OGD when he said "On the other hand if you are adding a VFO to a NC-40 I don't know why...? the NC-40 is amazingly stable and usable." He says he doesn't know why one would want to add a? DDS VFO to the NC40A, I replies with "Full band coverage would be nice."?

Re: DDS VFO!

Bob Macklin
 

开云体育

I want the DDS so I can have CAT control.
?
Currently I use CW Get and CW Type for CW operation.
?
I'm 85 years old and my hands don't work very well anymore.
?
They are not the only things that don't work very well anymore!
?
Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"

----- Original Message -----
From: Mike M6MST
Sent: Tuesday, November 05, 2019 4:04 PM
Subject: Re: [qrptech] DDS VFO!

On Tue, Nov 5, 2019 at 03:40 PM, wb6ogd wrote:

Below that they go too fast for me

DXpeditions and DX in general sometimes hang out down there.

above that is only the digital modes and the novice band.?

I like the Novice band

Why would you want more than that?

Frequency agility is a nice thing to have

If I did want more, a simple tap on the toroid with a switch would do the job just fine I would think...

But a DDS VFO that covers everything very inexpensively and very conveniently would do the job a lot better.

Re: DDS VFO!

 

Hi Allison,
That is an acceptable price to pay, for me at least!
Re: Group Introduction: If you're going to post on the group, reply here!

 

Hi all,

I like tube technology and building my own things, despite all the people who ask why I don't just go buy something instead. A lot of people on the internet want their hands stapled to their butts.

Ed AE7TE

On Tue, Nov 5, 2019 at 5:28 PM Ryan Flowers <geocrasher@...> wrote:
Hello everyone,

Thank you for joining this group! I am new to being an admin of a group, but not to groups in general. If you see something that needs to be changed, feel free to comment about it. I'm flexible! This isn't my group, it's?your group.?

My goal is to keep the old qpr-tech group alive under this new name, and I hope that all 2500+ on the old group will join this one, but I know that's not realistic. If you all could put the word out that the group has moved, it'll help keep this going. Despite those saying that "homebrew is dying" and the like, groups like this prove that it's alive and well. let's keep it that way!

Because of the way Groups.io is set up, I can either moderate peoples first post, or I can set it so that so that people have to be approved to join the group. qrp-tech was set to the former, and so I've set this group the same. Your first post will have to be moderated, but I'll approve it as soon as possible. I'm never far from a browser and it's easy to do.

Thank you and 73!

--
Ryan Flowers W7RLF
9361 - 9380 of 9415