Re: Group Introduction: If you're going to post on the group, reply here!
Ryan,?
Thanks for setting this up.
Jerry / K0ES
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
I'm intrigued. On the Old Group, I had posted about building a homebrew phasing rig, I was reminded about the R2/T2 from KK7B. Those PDF's are at too, and I've downloaded both of them so I can start examining them. I need some NP0 1% capacitors and probably a ton of other things too. A binaural rig is just the i/q going to different audio channels, which is definitely interesting. I'd love to hear how that sounds!
I have been thinking about a similar CW transceiver project using the phase shift design.? If you look at the schematic of the QCX at QRPLabs it uses a QSD with I and Q outputs which can run direct conversion at frequencies of 3 - 100 MHz+ followed by a phased audio scheme for the unwanted side band rejection using common available components.? The VFO would be a DDS to drive the QSD and the transmitter.??
For the transmitter the QCX uses a Class E amplifier which is difficult to multi-band because the first section of the output filter must resonant with the capacitance of the output transistor/s.? I would use an amplifier chain driven from the DDS probably using IRF510/s for the final amp with switched output filters for each band you want to run.??
Is this something that sounds like a good home brew project?
Dan KA7GPP
-- Ryan Flowers W7RLF
https://miscdotgeek.com
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
I have been thinking about a similar CW transceiver project using the phase shift design.? If you look at the schematic of the QCX at QRPLabs it uses a QSD with I and Q outputs which can run direct conversion at frequencies of 3 - 100 MHz+ followed by a phased audio scheme for the unwanted side band rejection using common available components.? The VFO would be a DDS to drive the QSD and the transmitter.??
For the transmitter the QCX uses a Class E amplifier which is difficult to multi-band because the first section of the output filter must resonant with the capacitance of the output transistor/s.? I would use an amplifier chain driven from the DDS probably using IRF510/s for the final amp with switched output filters for each band you want to run.??
Is this something that sounds like a good home brew project?
Dan KA7GPP
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Re: "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
That article as available on the web at
Available to anyone. Mike K5ESS
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From: [email protected] [mailto:[email protected]] On Behalf Of Curt via Groups.Io
Sent: Monday, November 11, 2019 7:10 PM
To: [email protected]
Subject: [qrptech] "A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B ? Being interested in building something a little different, happened on this article while looking for info on IQ detectors.?
This radio was sold by Kanga as a kit, assume the IP is owned by KK7B and/or Kanga.? Presume the article was published so people might build one from scratch but with implied hope that people would buy the kit.
Has anyone built this receiver?? What were the results?? Planning to use Eagle to prepare gerber files and have a few boards fabricated for my personal use.? It will be impossible to share any of this because have no idea of how to obtain necessary permissions.
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Re: Group Introduction: If you're going to post on the group, reply here!
New member. Listen quite a bit, talk very little.
Frank KB4VU
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"A Binaural IQ Receiver" QST Mar 1999 Campbell KK7B
Being interested in building something a little different, happened on this article while looking for info on IQ detectors.?
This radio was sold by Kanga as a kit, assume the IP is owned by KK7B and/or Kanga.? Presume the article was published so people might build one from scratch but with implied hope that people would buy the kit.
Has anyone built this receiver?? What were the results?? Planning to use Eagle to prepare gerber files and have a few boards fabricated for my personal use.? It will be impossible to share any of this because have no idea of how to obtain necessary permissions.
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Re: Stockton vs Resistive SWR Bridge
The Stockton bridge is useful for continuous monitoring. In other words, it will tell you if your antenna is taken out or something else is amiss. The resistive bridge cuts your power by 6 dB, so it can be helpful if you're after the lowest power contacts you can get. Else, you have to remove it from the RF path to operate.
Ed AE7TE
Hi all
I'm new to the group and new to the world of QRP. I'm just getting my QRP station set up with a QRP-Labs QCX 40 at the heart. For checking SWR on my antenna setup, I'm trying to decide between a resistive SWR bridge (to measure impedance mismatch) or a Stockton bridge (to measure forward and reflected power). I'm leaning towards the Stockton bridge, as I'm thinking it will be more versatile (actual measurements of forward and reflected power, not just an indication of a rough impedance match), but I'm curious what the preference among more experienced hams is. Thoughts?
Thanks
Cory
KG7BBV
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Stockton vs Resistive SWR Bridge
Hi all
I'm new to the group and new to the world of QRP. I'm just getting my QRP station set up with a QRP-Labs QCX 40 at the heart. For checking SWR on my antenna setup, I'm trying to decide between a resistive SWR bridge (to measure impedance mismatch) or a Stockton bridge (to measure forward and reflected power). I'm leaning towards the Stockton bridge, as I'm thinking it will be more versatile (actual measurements of forward and reflected power, not just an indication of a rough impedance match), but I'm curious what the preference among more experienced hams is. Thoughts?
Thanks
Cory
KG7BBV
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Re: Norcal 40a (testing 4.9MHz xtals)
I've sometimes seen counters display harmonics. It could be a matter of overloading the counter. Try attenuating the signal to the counter a bit, possibly just be using a very small coupling capacitor.
73-
Nick, WA5BDU
Hi Ram,
Do you have an oscilloscope? If so look at the waveform from your
crystal test oscillator--I bet it's more of a square wave than a
sine wave and if so your counter is looking at the stronger 3rd
harmonic component and reading that instead of the fundamental.
73,
Steve AA7U
On 11/11/2019 9:52 AM, Ramakrishnan
Muthukrishnan wrote:
I am very early into the
project. As a first step, I thought of building a G3UUR
crystal tester to select crystals for the filter and the
oscillators. I have got about 100 4.9152 MHz crystals that I
got from aliexpress. Last weekend I built the G3UUR Colpitts
Oscillator (straight out of the EMRFD book and also described
in many other webpages). I also have a counter with a 1 Hz
resolution, again obtained from Aliexpress specifically to
hook up into the Oscillator.
Unfortunately, when I plug in the
4.9152 MHz crystal, I get a reading of 14.742475. Looks like it
is 3x the frequency of the crystal. I tested many from the lot
of 100 crystals, which came in lots of 50 from two different
vendors and they all read the same. I had a 28.04 MHz crystal
which seem to be oscillating at the correct frequency. I don't
know what to make out of these readings. Is the crystal, a 3rd
overtone crystal? Or is it that the colpitts oscillator is
designed to operate at a higher frequency and the 3rd harmonic
is where the tuned circuit that comprise the crystal (which is
inductive?) and the two capacitors are getting tuned?
73
--
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Re: Norcal 40a (Was Re: [qrptech] Group Introduction: If you're going to post on the group, reply here!)
During 2017-2018 worked 20 states, France, Bonaire, Cayman Islands using the NC40a set to 1W output.? It was a fun project and a very nice transceiver.
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Re: Norcal 40a (Was Re: [qrptech] Group Introduction: If you're going to post on the group, reply here!)
If anyone is interested in NC-40a, I made a folder in the Files section "WB6OGD_NC-40a".
Inside you can find the basics of my build, any questions, just ask..
You can get the NC-40a RevE manual that I built from on the web or on Chuck's old group (at least you could 2 years ago)...
Its a very good manual and very very good design.? There were even college classes that used it for the course, that course
notes used to be available including the textbook that goes through the design in college level math and theory.
You can learn a lot building an NC-40a, and when you are done, you can make a lot of contacts, I am normally a 100watt
guy but 3watts absolutely amazed me.
73,
Gary
WB6OGD
El Dorado Hills, CA
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Re: Norcal 40a (testing 4.9MHz xtals)
Hi Ram,
Do you have an oscilloscope? If so look at the waveform from your
crystal test oscillator--I bet it's more of a square wave than a
sine wave and if so your counter is looking at the stronger 3rd
harmonic component and reading that instead of the fundamental.
73,
Steve AA7U
On 11/11/2019 9:52 AM, Ramakrishnan
Muthukrishnan wrote:
toggle quoted message
Show quoted text
I am very early into the
project. As a first step, I thought of building a G3UUR
crystal tester to select crystals for the filter and the
oscillators. I have got about 100 4.9152 MHz crystals that I
got from aliexpress. Last weekend I built the G3UUR Colpitts
Oscillator (straight out of the EMRFD book and also described
in many other webpages). I also have a counter with a 1 Hz
resolution, again obtained from Aliexpress specifically to
hook up into the Oscillator.
Unfortunately, when I plug in the
4.9152 MHz crystal, I get a reading of 14.742475. Looks like it
is 3x the frequency of the crystal. I tested many from the lot
of 100 crystals, which came in lots of 50 from two different
vendors and they all read the same. I had a 28.04 MHz crystal
which seem to be oscillating at the correct frequency. I don't
know what to make out of these readings. Is the crystal, a 3rd
overtone crystal? Or is it that the colpitts oscillator is
designed to operate at a higher frequency and the 3rd harmonic
is where the tuned circuit that comprise the crystal (which is
inductive?) and the two capacitors are getting tuned?
73
--
|
Re: Group Introduction: If you're going to post on the group, reply here!
mostly lurking, but comment on rare occasion
dave /nt1u
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Norcal 40a (Was Re: [qrptech] Group Introduction: If you're going to post on the group, reply here!)
On Mon, Nov 11, 2019, at 8:18 PM, wb6ogd wrote:
On Sun, Nov 10, 2019 at 08:57 PM, Ramakrishnan Muthukrishnan wrote:
Currently gathering parts to build a Norcal 40a. I will make a separate post on this later. It would be nice if a bunch of us get started building projects as a group again.
?
You guys who now can not get a PCB for that project should take a look at the NC-40a.? It uses ICs, that's a good
thing!? It might not have the receiver specs of the 2Nxx but it is fine for a qrp 2-3watt rig.? Chuck or the group found
a great deal on chinese PCBs back then, something like 10 boards or $5 shipped, MANY of the boards must still
be out there, many nice guys will probably share some of their extras.? Or the gerbers do exist, hopefully you could
get them and order more boards.? I designed my own board over a weekend with free ExpressPCB software and
home etched my own board, it was a very rewarding and successful project.? My board used mostly SMD which I
find much easier than through hole, I can give the design if anyone wants it.
The NC-40a has two good features I don't see in the 2Nxx (I might have missed them):
AVC and Sidetone.?? These are really needed I think, and the sidetone is actually your transmitted signal so
you know if it sounds correct and has the right offset, etc.? Mine puts out 3watts with a 20cent Chinese final that
doesn't even need a heatsink.
Thanks Gary for the nice experience report on Norcal 40a.
I have got the PCB from Rahul VU3WJM (met him at a hamfest early this year) who, along with Chuck, designed the PCBs for the qrp-tech project with consent from Wayne, the original designer of Norcal 40a. I also have "The electronics of Radio", the book that teaches electronics by building the Norcal 40a. So, it was very hard to pass the opportunity to do a bit of learning and experimentation in the weekend.
I am very early into the project. As a first step, I thought of building a G3UUR crystal tester to select crystals for the filter and the oscillators. I have got about 100 4.9152 MHz crystals that I got from aliexpress. Last weekend I built the G3UUR Colpitts Oscillator (straight out of the EMRFD book and also described in many other webpages). I also have a counter with a 1 Hz resolution, again obtained from Aliexpress specifically to hook up into the Oscillator.
Unfortunately, when I plug in the 4.9152 MHz crystal, I get a reading of 14.742475. Looks like it is 3x the frequency of the crystal. I tested many from the lot of 100 crystals, which came in lots of 50 from two different vendors and they all read the same. I had a 28.04 MHz crystal which seem to be oscillating at the correct frequency. I don't know what to make out of these readings. Is the crystal, a 3rd overtone crystal? Or is it that the colpitts oscillator is designed to operate at a higher frequency and the 3rd harmonic is where the tuned circuit that comprise the crystal (which is inductive?) and the two capacitors are getting tuned?
The Colpitts Oscillator base-emitter capacitor (C1) and Emitter-Ground capacitor (C2) are both 470pF. That value seem to be a little high for lower valued crystals.
So, that is where I am at with the Norcal 40a.
As for building the project, Chuck has some excellent videos on YouTube. I plan to build the receiver first (backward, from audio section onward) and then the transmitter.
73
--
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Re: Group Introduction: If you're going to post on the group, reply here!
New member here, I wasn't on the old list, just saw a blog post that it had closed and this was replacing it! So thanks for creating this, there's still a lot of interest.
New to homebrew and QRP (and recently back to radio), but its always interested me, ever since finding out about ham radio and visiting a QRP CW operator in Wales as a 12 year old.
Hoping to learn a lot. Should be slowly accumulating the equipment to actually build and test over the next few years.
Tristan
KJ7FWK / M3MQG
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Re: Group Introduction: If you're going to post on the group, reply here!
I rarely comment, but definitely enjoy reading...
jon, N0WL
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Re: Group Introduction: If you're going to post on the group, reply here!
YO,.. I'll b around,....? G'BYEE ? yoose Guys...
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Re: Group Introduction: If you're going to post on the group, reply here!
On Sun, Nov 10, 2019 at 08:57 PM, Ramakrishnan Muthukrishnan wrote:
Currently gathering parts to build a Norcal 40a. I will make a separate post on this later. It would be nice if a bunch of us get started building projects as a group again.
?
Hello Ram and the new group, Two years ago on Chuck's old group he started the NC-40a project.? Many of us built the rig and I really like mine. Yes, this group should do some group builds again.? I was getting excited by the 2Nxx everyone was talking about. I googled it and that killed my enthusiasm.? That rig looks like an amazing piece of engineering, wish I could design something like that (but no way!).? 300 parts on a really tight PCB is pretty crazy, would not be a beginners project for sure. You guys who now can not get a PCB for that project should take a look at the NC-40a.? It uses ICs, that's a good thing!? It might not have the receiver specs of the 2Nxx but it is fine for a qrp 2-3watt rig.? Chuck or the group found a great deal on chinese PCBs back then, something like 10 boards or $5 shipped, MANY of the boards must still be out there, many nice guys will probably share some of their extras.? Or the gerbers do exist, hopefully you could get them and order more boards.? I designed my own board over a weekend with free ExpressPCB software and home etched my own board, it was a very rewarding and successful project.? My board used mostly SMD which I find much easier than through hole, I can give the design if anyone wants it. The NC-40a has two good features I don't see in the 2Nxx (I might have missed them): AVC and Sidetone.?? These are really needed I think, and the sidetone is actually your transmitted signal so you know if it sounds correct and has the right offset, etc.? Mine puts out 3watts with a 20cent Chinese final that doesn't even need a heatsink. Think about it, 73, Gary WB6OGD
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PCBs for NorCal 2N2/XX Rig
For anyone who didn¡¯t see this on the 2N2 Group or original qrp-tech group ¡. ? Cheers ? Michael VE3WMB ?
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From: NorCal_2n2@... <NorCal_2n2@...> Sent: Sunday, November 10, 2019 5:54 AM To: [email protected]; norcal_2n2@... Subject: [NorCal_2n2] PCBs for NorCal 2N2/XX Rig ? ? All,
After a lot of discussion with close associates and thinking through all of the issues with making the PCB available for the NorCal 2N2/XX rig, I've decided not to do it.? Here are the main reasons why.
That PCB is really dense, so much so that many of the support issues I had to deal with came down to builders putting the parts in the wrong place.? In addition, there are 300 parts needed for that PCB, many of which are no longer available, and some of them were quite expensive like the 10-turn tuning pot at nominally $10.00 per unit.
It is obvious to me that a substantial amount of time would be required to find suitable replacements for the extinct parts; I have neither the time nor the inclination to do that for a design that is now 11 years old.? Additionally and realistically, since I was the designer of the rig, most of the support questions would come to me; I've moved on and can't get back into that mode.? When the kit launched, support issues took over my life for most of a year.? I'm going to be selfish and not let that happen again.
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.
So, I hate to disappoint all of those clamoring for 2N2/XX PCBs, but for the reasons above, (and a lot of other unspoken reasons) it won't be happening.
72/73 to all and enjoy the upcoming holidays,
Jim, K8IQY
PS....thanks to all who offered to help out with making boards available, I truly appreciate your support.
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Re: Group Introduction: If you're going to post on the group, reply here!
Hello.? I¡¯m here.?
Ted W7PO
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Nick Kennedy
dave
Ramakrishnan Muthukrishnan