Feel free to add information to the wiki or make edits as needed. Please respect the work of others by adding your own content rather than editing or removing someone else's content unless doing things like updating URL's etc.?
Feel free to add information to the wiki or make edits as needed. Please respect the work of others by adding your own content rather than editing or removing someone else's content unless doing things like updating URL's etc.?
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Re: Group Introduction: If you're going to post on the group, reply here!
I mostly lurk unless something of personal interest comes up (like adding a DDS VFO to a NC40A!) because my technical knowledge is pretty low. But I do learn a lot from the folks to regularly post so I am glad that Chuck's group will live on in a way. Sad to see him shut it down but nothing lasts forever in the cold November rain.
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Re: DDS VFO!
Bob Macklin
I do have 3 NC-40 boards. and one NorCal Sierra board with 4 band modules.
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There was a time the Heathkit HW-7 and HW-8 were popular. They are direct conversion. I'm thinking about building a clone of the Elecraft K2. (with a DDS) Bob Macklin K5MYJ Seattle, Wa. "Real Radios Glow In The Dark" ----- Original Message -----
From: "wb6ogd" <garywinblad@...> To: <[email protected]> Sent: Wednesday, November 06, 2019 6:41 AM Subject: Re: [qrptech] DDS VFO! The schematic is on page 9. |
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Re: DDS VFO!
Bob Macklin
开云体育BTW:
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The NRR group operates 40M CW in the old Novice segment. Or what's left of it. 7100:7125, 7125:7150 is Extra territory.
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SKCC also has CW activity in the 7100:7125 segment.
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Bob Macklin
K5MYJ Seattle, Wa. "Real Radios Glow In The Dark"
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Re: DDS VFO!
The schematic is on page 9.
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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 |
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Re: DDS VFO!
Bob Macklin
Just found one on eBay:
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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 |
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Re: DDS VFO!
Bob Macklin
Does anyone make a PCB for a 40M DC receiver. Maybe clone the old Ramsey
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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!
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Re: DDS VFO!
Bob Macklin
Adding a prescaler does not reduce the accuracy if you extend the sample
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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 |
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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 |
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Re: DDS VFO!
On 11/5/2019 3:40 PM, wb6ogd wrote:
What is wrong with the old novice band?? I frequently listen there. 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 |
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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 |
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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.
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Bob Macklin
K5MYJ Seattle, Wa. "Real Radios Glow In The Dark"
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Re: DDS VFO!
开云体育Arduinos can count to 6.4MHz so Digitaldial 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:
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Re: DDS VFO!
Bob Macklin
开云体育How about digital tuning accuracy?
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I have several GOOD HF receivers with analog tuning and they do not have precision readouts. Only good to about 25KHz.
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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.
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Bob Macklin
K5MYJ Seattle, Wa. "Real Radios Glow In The Dark"
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Re: DDS VFO!
Bob Macklin
开云体育BTW:
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Above 7125 is PHONE space. No one looks for CW between 7125 and 7300.
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The only time I hear phone activity on 40M is during contests.
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Bob Macklin
K5MYJ Seattle, Wa. "Real Radios Glow In The Dark"
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Re: DDS VFO!
Bob Macklin
开云体育I want the DDS so I can have CAT control.
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Currently I use CW Get and CW Type for CW operation.
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I'm 85 years old and my hands don't work very well anymore.
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They are not the only things that don't work very well anymore!
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Bob Macklin
K5MYJ Seattle, Wa. "Real Radios Glow In The Dark"
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Nick Kennedy
Newt N4EWT
Bo, OZ2M