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Re: 7 MHz Oscillator Ideas

 

Nick,

I've made some measurements using the?SA612?oscillator in my WWV +?30m receiver.
The crystal is a single, 10 MHz nominal.? Keep in mind that this is a simple DC receiver and may not meet the specs for a $5k buck rig.

I'm using a fairly well regulated bench power supply.? Not a cheap 9V battery that sags quickly under?load.

So are we saying that the DC supply to the receiver is drifting plus and minus several mV?? And that would significantly change the oscillator tuning?

Or is the power supply stable within a few mV?? And that it stays at the set voltage unless deliberately changed.

I'm measuring the oscillator frequency via gimmick with set voltages at 10, 12 and 14. I've measured the output of the 5V regulator to the SA-612 with no significant change at each set voltage.

With both O'scope and DVM?on most sensitive levels, there is no significant DC voltage?ripple.

Yes, the highest?tuned?frequency changes at each of the set voltages.? BUT is doesn't change?once set!

So unless the set voltages are changed, I doubt that anyone, by ear, could detect any change while listening to a specific station, e.g., WWV-10MHz with test RX.

And I have done that with the RX I built, both WWV and CW station on 30 m.

--
Chuck, W5USJ (ex K2OFN)
Point, Rains Co, TX? EM22cv
Re: What level math is in the RF design books?

 

Rob --

If you have a copy of "Experimental Methods of RF Design", take a look at chapter 2 "Amplifier Design Basics", first few pages, which discusses simplified models of semiconductor devices. I think that level of intuition is great to have while building and debugging circuits. It does not have a lot of advanced math.

73
Ram VU3RDD

On Mon, Dec 9, 2019, at 5:47 PM, Rob via Groups.Io wrote:
What level of math course would I need to study to learn how to comprehend the equations presented in
design books like Introduction to Radio Frequency Design?? by? W7ZOI.

I have been tinkering with circuits from these books for 50 years but never really learned what is in the math.

There are all sorts of online math course now so.....

What level of math class would teach this gobbledygoop?

and

Do any of you? ACTUALLY use this level of math to build radios or is the math only used by
the guys designing the transistors????





73 Rob KB3BYT




Attachments:
  • math0.jpg

--
Ramakrishnan
Re: 2n2xx Transceiver R.I.P.

 

Doug,
From Jim's email on November 10th:

Finally, all of the documentation for the 2N2/XX is on my web site:??(??) so you can get the docs, build any of the 3 bands Manhattan-style, like I did originally, or make your own PCB using DipTrace or KiCAD with the changes you see fit (like DDS tuning and Digital Display) on a PCB sized to your liking.

It seems that he has no problem with copying the design or modifying it, along with creating a pcb. Obviously it would be immoral to profit from it.?

I remember when I first saw that design and how amazed I was at what he accomplished within the (arbitrary) confines of the contest. Amazing work!

Best regards and 73
Mike M?
Ku4qo

On Sat, Dec 14, 2019, 1:03 AM Doug Hendricks <ki6ds1@...> wrote:
Rob, the 2N22 is the intellectual property of Jim Kortge.? He has asked that it not be made available.? Please honor his wishes and stop promoting this project.? It would be wrong for anyone to layout their own board and distribute it to anyone.? I would hope that such an idea would NOT be allowed on this list.? Flame suit on.? Doug, KI6DS

Re: 2n2xx Transceiver R.I.P.

Rob
 

¿ªÔÆÌåÓý

OK..no problem.

My point of view was that it is a well documented hands on DIY project transceiver

worthy of hand crafting for yourself..... not any money making ventures....

and since I learned how to kitchen etch PCBs I have learned much much much more about radio building.

I was not real successful with with my manhatten radio building.

So when I learned how to take a schematic and turn it into a PCB in my kitchen I began a steady stream of

very rewarding hobby electronics projects and I always shared HOW to do this stuff because there is no HEATHKIT

or RADIO SHACK to make it easy to want to play with the hobby of radio electronics.....

which tends to push newbies into the appliance operator ...instead of tinkerer... category.....

which leads to addictions like FT8.





On 12/13/2019 08:59 PM, Doug Hendricks wrote:

Rob, the 2N22 is the intellectual property of Jim Kortge.? He has asked that it not be made available.? Please honor his wishes and stop promoting this project.? It would be wrong for anyone to layout their own board and distribute it to anyone.? I would hope that such an idea would NOT be allowed on this list.? Flame suit on.? Doug, KI6DS

Re: 2n2xx Transceiver R.I.P.

 

Rob, the 2N22 is the intellectual property of Jim Kortge.? He has asked that it not be made available.? Please honor his wishes and stop promoting this project.? It would be wrong for anyone to layout their own board and distribute it to anyone.? I would hope that such an idea would NOT be allowed on this list.? Flame suit on.? Doug, KI6DS
Re: 2n2xx Transceiver R.I.P.

Rob
 

¿ªÔÆÌåÓý

NO WAY

The project is only dead if you want to leave it resting.

All of the wealth of documentation is there to make the 2n2xx tranceiver on ANY base you want... island pads... manhatten ...

or

PRINT YOUR OWN CIRCUIT BOARDS

which I highly recommend you do because you can spread out the parts and resize for your own tastes.

There really is no secret here. Use GIMP to draw black and white line art.

Simply trace all schematic lines with a fat paint brush and draw all components like you see from a birds eye view.

here is an example of a PIXIE coming to life:


Etched on kitchen table.


the wet works in more detail here:

and if you MUST have China fabricate a few hundred PCBs for a massive club build project you can

easily convert YOUR black and white line art to GERBER files.



Have fun.



On 12/13/2019 06:20 PM, Leland L. Bahr wrote:

The designer has voiced he does not want to offer a board.? The project is dead.

Lee, w0vt

On 12/13/2019 3:50 PM, ohwenzelph via Groups.Io wrote:
i would like (at least) one
jerry aa1of
franconia nh

Re: 2n2xx Transceiver

 

¿ªÔÆÌåÓý

The designer has voiced he does not want to offer a board.? The project is dead.

Lee, w0vt

On 12/13/2019 3:50 PM, ohwenzelph via Groups.Io wrote:

i would like (at least) one
jerry aa1of
franconia nh

Re: 2n2xx Transceiver

 

i would like (at least) one
jerry aa1of
franconia nh
Re: 2n2xx Transceiver

 

Steve, if the Chinese wanted to copy it, they would do it gerbers or no.? If I were the designer, I would be more concerned about having to support the builders if I produced new boards.? One way around this is to put the board on OshPark as a shared pcb.? That way, the gerbers are not downloadable, but are useable by someone who wants to build the project.? This will be more expensive per board than getting a 100 boards built in China, but much more protective.? Dale

On Fri, Dec 13, 2019 at 9:06 AM sigcom1 <sigcom@...> wrote:
You can look back through the message subject for the details.
The designer of the 2N2-XX chose not to release the Gerber file for the PCB.
Frankly, I wholeheartedly stand behind his decision.

73.......Steve Smith WB6TNL

"What's the status of this? I would be interested in this as well."



--
Dale Hardin
Elberta, AL?
Re: 2n2xx Transceiver

 

I cut my gums on 741's and 2222's.? Put down for a couple.? Thanks, Howard, n3fel
Re: 2n2xx Transceiver

 

You can look back through the message subject for the details.
The designer of the 2N2-XX chose not to release the Gerber file for the PCB.
Frankly, I wholeheartedly stand behind his decision.

73.......Steve Smith WB6TNL

"What's the status of this? I would be interested in this as well."
Re: 2n2xx Transceiver

 

What's the status of this? I would be interested in this as well.
Re: Anyone Built the Rose 80?

 

Just keep in mind that the designer put those tuned circuits in for a reason.
He did it so a bunch of spurs would not show up on the air and exceed FCC specs.
Hard to know exactly where they all are and how strong without a spectrum analyzer.

Experimenting to measure power out into a dummy load is perfectly fine.
Going on the air with a 5W transmitter that has some spurs 30dB down
is not encouraged, but they probably wouldn't throw you in jail for very long.

Jerry


On Thu, Dec 12, 2019 at 09:40 PM, John Roland wrote:
Jerry, This is very helpful, especially your explanation of the right side of T3. ?? I think I'll play with your idea of bypassing T3 and see what it does to the stability of the power out.???
And thanks for the hint about the Private button, never noticed it before.
/John
Re: Anyone Built the Rose 80?

John Roland
 

Jerry, This is very helpful, especially your explanation of the right side of T3. ?? I think I'll play with your idea of bypassing T3 and see what it does to the stability of the power out.???
And thanks for the hint about the Private button, never noticed it before.
/John
Re: Group Introduction: If you're going to post on the group, reply here!

Jim Klas
 

Thanks for the group and all the effort it takes to moderate a group.

Thank you!

Jim
KF9VV
Re: Anyone Built the Rose 80?

 

In my previous post I was wrong about why the secondary of T3 is non-resonant.?
Double tuned RF transformers are quite common in radio gear.

I think on T3 for the Rose-80 with a secondary of only two turns of wire,
it simply has too little inductance to inhibit much of anything at 3.5mhz.

Let's take it to an extreme, bring that frequency down from 3.5mhz to just 60hz.
Those two turns now look like a very short piece of wire,
and the only impedance presented to our 60hz signal is that of the 470pf cap at C44.
The impedance of the cap is far larger than any contribution from the inductor,
to where the inductor has virtually no effect

Jerry


On Thu, Dec 12, 2019 at 07:15 PM, Jerry Gaffke wrote:
Getting to your primary puzzle, I doubt the right side is trying to be resonant.
The datasheet says the right side only has 2 turns, whereas the left side has 14 turns,
So the inductance is far less, your inductance meter speaks the truth.
I'm guessing the cap at C44 would work about as well if it were 0.1uF instead of 470pf.
Would be an interesting experiment to tack a cap in parallel, see if performance changes.
It does sort of look like a series resonant circuit, so we might think it would not conduct
unless at the resonant frequency.? However, the output of that transformer is a voltage source
with our 3.5mhz sine wave, the 470pf cap at C44 does not see an inductance to interact with.
Re: Anyone Built the Rose 80?

Rob
 

¿ªÔÆÌåÓý

Thank you for the details about the caps and transformer.




On 12/12/2019 10:15 PM, Jerry Gaffke via Groups.Io wrote:

John,

I prefer to have these conversations within the forum
Often there's somebody else with the extra info needed to resolve an issue.
As Ryan says, people come to this forum because they want to see a technical discussion.??
I spent a career in digital design, much of this RF stuff I am only now figuring out
by hanging out in these forums.? It's how we learn, both by hearing what others have
to say, and by trying to put into coherent words that what we think we know.

Private email can be sent by going to a forum post on the website such as
? ??/g/qrptech/message/397
Then click "Reply", fill in your message, then click "Private" on the bottom right, and "Send".
Me, I may not respond, I prefer to have these discussions within the forum.

Anyways, here's a datasheet plus a brief description of the transformer used at T3 and T5
? ??
? ??
The left side has 14 turns, nominally 4.5uH, Diz says it's adjustable between 3.2 and 5.7 uH
Internally, there's a 47pF cap.
With just the 47pF cap (plus a few pf of stray capacitance due to board traces and such)
in parallel with the mid-range setting of 4.5uH on the coil, it resonates at 10.7mhz.

As you surmise, with a 470pf cap at C43 in parallel with the internal 47pf cap,
it can be parallel resonant at our target frequency of around 3.5mhz.
A parallel resonant circuit is a short circuit to all but the resonant frequency,
so only our 3.5mhz energy goes on through the transformer to show up at the secondary.

Getting to your primary puzzle, I doubt the right side is trying to be resonant.
The datasheet says the right side only has 2 turns, whereas the left side has 14 turns,
So the inductance is far less, your inductance meter speaks the truth.
I'm guessing the cap at C44 would work about as well if it were 0.1uF instead of 470pf.
Would be an interesting experiment to tack a cap in parallel, see if performance changes.
It does sort of look like a series resonant circuit, so we might think it would not conduct
unless at the resonant frequency.? However, the output of that transformer is a voltage source
with our 3.5mhz sine wave, the 470pf cap at C44 does not see an inductance to interact with.
If you didn't want this filter in place, could remove C43, T3, and C44, drive the base
of Q6 through a series DC blocking cap from a clean source of 3.5mhz (sine or square wave).

At T5, we have our roughly 4.5uH inductor in parallel with the internal 47pf plus the
external 470pf of C64.? As with T3, the parallel resonance does not allow our desired
3.5mhz energy to pass through, so the 3.5mhz must find its way out toward the base of Q7 instead.
What T5 does allow through is DC into Q6 from the power supply.
To make T5 broadband it could be replaced with an RF choke just like L4, be sure to remove C64

Anyways, if I am correct, you pretty much had it figured out on your own.


Yup, the ride from Lewiston to Enterprise gives you a couple hundred sharp curves
on the Rattlesnake and Buford Grades where you cross the Grande Ronde.
Good road to practice your cornering on a bike, assuming you don't find a log truck.
We're off grid in a straw bale house about 3 miles west of the top of that Buford Grade,
but would take us a 30 minute drive to get there.? It's rough country.

Jerry, KE7ER


On Thu, Dec 12, 2019 at 05:05 PM, John Roland wrote:
Jerry,
Thanks for all your response and interesting ideas.?? My frustration beyond the fluctuation in the output over about 100 kcs, is that I don't really understand how the filter works.?? I think see a parallel resonant circuit comprised of the left side of T3 and C43 plus the internal capacitor which I assume shunts out of band frequencies to ground but passes desired frequencies (3.5 mHz).?? I'm having trouble with the right side of T3.?? My inexpensive Chinese inductance meter gives me a very low value of inductance between the 2 pins on the right side of T3 (pins 4 and 6 from the datasheet)? (.16 uH)? which would resonate with C44 at around 18 mHz if I'm using my online calculator correctly.?? At which point I decide that must not be how it works..... ?
Sorry to drag the group through this, but I couldn't find your email address.? I'm in QRZ and visible in the directory for this group.
And yes you're just over the hill from me.? I grew up in Lewiston and Enterprise was a frequent day trip on the motorcycle 50 years ago.??
/John
Re: Anyone Built the Rose 80?

 

John,

I prefer to have these conversations within the forum
Often there's somebody else with the extra info needed to resolve an issue.
As Ryan says, people come to this forum because they want to see a technical discussion.??
I spent a career in digital design, much of this RF stuff I am only now figuring out
by hanging out in these forums.? It's how we learn, both by hearing what others have
to say, and by trying to put into coherent words that what we think we know.

Private email can be sent by going to a forum post on the website such as
? ??/g/qrptech/message/397
Then click "Reply", fill in your message, then click "Private" on the bottom right, and "Send".
Me, I may not respond, I prefer to have these discussions within the forum.

Anyways, here's a datasheet plus a brief description of the transformer used at T3 and T5
? ??
? ??
The left side has 14 turns, nominally 4.5uH, Diz says it's adjustable between 3.2 and 5.7 uH
Internally, there's a 47pF cap.
With just the 47pF cap (plus a few pf of stray capacitance due to board traces and such)
in parallel with the mid-range setting of 4.5uH on the coil, it resonates at 10.7mhz.

As you surmise, with a 470pf cap at C43 in parallel with the internal 47pf cap,
it can be parallel resonant at our target frequency of around 3.5mhz.
A parallel resonant circuit is a short circuit to all but the resonant frequency,
so only our 3.5mhz energy goes on through the transformer to show up at the secondary.

Getting to your primary puzzle, I doubt the right side is trying to be resonant.
The datasheet says the right side only has 2 turns, whereas the left side has 14 turns,
So the inductance is far less, your inductance meter speaks the truth.
I'm guessing the cap at C44 would work about as well if it were 0.1uF instead of 470pf.
Would be an interesting experiment to tack a cap in parallel, see if performance changes.
It does sort of look like a series resonant circuit, so we might think it would not conduct
unless at the resonant frequency.? However, the output of that transformer is a voltage source
with our 3.5mhz sine wave, the 470pf cap at C44 does not see an inductance to interact with.
If you didn't want this filter in place, could remove C43, T3, and C44, drive the base
of Q6 through a series DC blocking cap from a clean source of 3.5mhz (sine or square wave).

At T5, we have our roughly 4.5uH inductor in parallel with the internal 47pf plus the
external 470pf of C64.? As with T3, the parallel resonance does not allow our desired
3.5mhz energy to pass through, so the 3.5mhz must find its way out toward the base of Q7 instead.
What T5 does allow through is DC into Q6 from the power supply.
To make T5 broadband it could be replaced with an RF choke just like L4, be sure to remove C64

Anyways, if I am correct, you pretty much had it figured out on your own.


Yup, the ride from Lewiston to Enterprise gives you a couple hundred sharp curves
on the Rattlesnake and Buford Grades where you cross the Grande Ronde.
Good road to practice your cornering on a bike, assuming you don't find a log truck.
We're off grid in a straw bale house about 3 miles west of the top of that Buford Grade,
but would take us a 30 minute drive to get there.? It's rough country.

Jerry, KE7ER


On Thu, Dec 12, 2019 at 05:05 PM, John Roland wrote:
Jerry,
Thanks for all your response and interesting ideas.?? My frustration beyond the fluctuation in the output over about 100 kcs, is that I don't really understand how the filter works.?? I think see a parallel resonant circuit comprised of the left side of T3 and C43 plus the internal capacitor which I assume shunts out of band frequencies to ground but passes desired frequencies (3.5 mHz).?? I'm having trouble with the right side of T3.?? My inexpensive Chinese inductance meter gives me a very low value of inductance between the 2 pins on the right side of T3 (pins 4 and 6 from the datasheet)? (.16 uH)? which would resonate with C44 at around 18 mHz if I'm using my online calculator correctly.?? At which point I decide that must not be how it works..... ?
Sorry to drag the group through this, but I couldn't find your email address.? I'm in QRZ and visible in the directory for this group.
And yes you're just over the hill from me.? I grew up in Lewiston and Enterprise was a frequent day trip on the motorcycle 50 years ago.??
/John
Re: Anyone Built the Rose 80?

 

Hey John,

You wrote "Sorry to drag the group through this, but ..."??

Please, please.... drag the group through it! There are a lot of people here whose joy is to read through such issues and learn along the way. I looked up the radio and glanced at the circuit just to get an idea what's going on. Such discussions are the primary reason this group exists. People sometimes worry that they are being a burden, but the exact opposite is true. You're giving a group of people something fun to talk about :?

73!
--
Ryan Flowers W7RLF
https://miscdotgeek.com
Re: Anyone Built the Rose 80?

John Roland
 

Jerry,
Thanks for all your response and interesting ideas.?? My frustration beyond the fluctuation in the output over about 100 kcs, is that I don't really understand how the filter works.?? I think see a parallel resonant circuit comprised of the left side of T3 and C43 plus the internal capacitor which I assume shunts out of band frequencies to ground but passes desired frequencies (3.5 mHz).?? I'm having trouble with the right side of T3.?? My inexpensive Chinese inductance meter gives me a very low value of inductance between the 2 pins on the right side of T3 (pins 4 and 6 from the datasheet)? (.16 uH)? which would resonate with C44 at around 18 mHz if I'm using my online calculator correctly.?? At which point I decide that must not be how it works..... ?
Sorry to drag the group through this, but I couldn't find your email address.? I'm in QRZ and visible in the directory for this group.
And yes you're just over the hill from me.? I grew up in Lewiston and Enterprise was a frequent day trip on the motorcycle 50 years ago.??
/John
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