2025 SVHFS Conference Update
Below is an update on the schedule of speakers and presentations for the Southeastern VHF Society Conference. The conference will be held at the Quality Inn at Exit #4 in Clarksville, TN April 4-5, 2025. This is an opportunity to meet other VHF+ enthusiasts, learn, exchange ideas, and have FUN. The $69 registration fee for the?conference is required, and it includes a 1 year membership in the SVHFS. Details are here:?. Advance registration?is highly recommended as the hotel requires a head count in order to prepare the food for the event. There will be door prizes given away at the banquet on Saturday evening. Feel free to contact me??via?email if you have any questions:? RobinK4IDC@....
Preliminary 2025 SVHFS Conference Schedule Friday 8:00 AM Registration 9:00 Charles Osborne -K4CSO 每 RF Zero - 30 min 9:30 Robin Midgett 每 K4IDC 每 RF Zero 2 Meter Beacon- 30 min 10:00 Bob Lear 每 W4ZST Power Dividers and Cable Loops 每 30 min 10:30 15 Minute Break 10:45 Mike Stipick 每 KC4RI 每 5.7 GHz SDR Transceiver - 45 min 11:30 Bill Pence 每 Grid Square Locator 每 30 min 12:00 PM Lunch - Steve and Sandra Kostro 每 Designing a Multi Band Transverter 1:15 2:00 Paul Wielozenski - K4PEW - VHF Nets 每 30 min 2:30 Ben Lowe 每 Rover Radiators 每 30 min 3:00 George Presley 每 10 GHz Beacon 每 30 min 4:00 Charles Osborne / Kent O＊ Dell 每 10GHz Antenna test Range - 30 min 5:00 Dinner 每On your own 7:00 Swap Fest and Hospitality Suite Saturday 9:00 AM Brian McCarthy 每 Lunar Rover Truck, 2.3GHz Amp 每 1 hour 10:00 Peter Van Horne 每 KA6U - Moon Bounce Rover 每 45 min 10:45 15 Minute Break 11:00 Chris Arthur - NV4B 每 45 min 12:00 PM Lunch - On your own 1:30 Larry Cagle - K4WLO 每 Meteor Scatter with MSK144 - 45 min 2:15 SVHFS Business Meeting 3:00 每 5:00 Rover Round Up and 10GHz Antenna Range 6:00 Social Hour- Hotel Bar 7:00 Dinner Banquet followed by the Door Prize Extravaganza!?
Thanks,
Robin Midgett K4IDC
Thanks,
Robin Midgett K4IDC
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Hi Chuck, We have plenty of crystals, but they are all the frequencies for the different VXOs used in the 1W and 5W radio kits. The IF frequency crystals are all gone (apart from a handful?of each in my parts-bin).
I've always questioned the "match the frequency of oscillation as closely as possible" approach for picking crystals for IF filters. If you look at my data, the closest two crystals using the "passive" method that Jim describes are #7 and #8. They are within 2 Hz. But if you look at the results of those same two crystals using the oscillator method, they are 101 Hz apart. Which one is correct??
My anecdotal results are in using filters selected using Jim's method. They built excellent filters, confirmed by a SA with Tracking Generator plot. I haven't had the time, but would love to build one filter with the closest crystals and one with the widest spread and see how they differ in an actual filter. I'm sure someone must have already done this, but I wasn't able to find anything with some casual googling.
I think it is much more important to get rid of any crystals that have high Rs, and characterize the batch of crystals so that you can use the batch Lm and Cm values and model the best filters possible.?
Best regards and 73 Mike M.? KU4QO
On Fri, Mar 14, 2025 at 9:10?PM chuck adams via <chuck.adams.phd= [email protected]> wrote: Sorry, this was not intended for the group. I'll be more careful.
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Hi Dave,
Thanks for the intel on Dan's Small Parts source for MV1662
varactors!
I am submitting an order on Monday.
"I even used a 3 terminal regulator device in place of the zener in
mine *shock horror*"
LOL, I might do something similar Dave, I already have "The K8IQY
Islander Amp" designed by Jim K8IQY that I built manhattan style on
6/26/13. It is the best sounding discrete amp I have ever built! I
might use it instead of the stock 2N2/40+ amp to save me a little
bit of time. I really should compare the circuits. Jim can chime in
on the details :)
73,
Alan, N8WQ
On 3/15/25 12:58, davidgeorgerichards
via groups.io wrote:
toggle quoted message
Show quoted text
Thanks for the transformer recommendation Mike. I'm currently
assembling a 2N2/20 from a kit, but am hoping to do a 2N2
scratch build afterwards, if I haven't burned myself out by
then! With that in mind, I bought 3 x 42TU400-RC from Mouser but
was a little disappointed when they turned up, as they are
bigger and heavier than the transformer used in the kit version.
Will look into your recommendation.
?
Alan - Dan's Small Parts and Kits has the MV1662. The
ordering process is a bit of a pain, as you have to write out
your order and mail it to him with a check or money order. It's
worth calling him first, to ensure he actually has it, as
sometimes he will substitute other parts without saying
anything. Hopefully someone else knows of an alternative
supplier for the MV1662, or has a suggestion for another
varactor with similar properties.
?
I'm planning on following the schematic of the Norcal version
of the 2N2 for my scratch-build, as I figure it's the most
optimized version. Mine doesn't have to be all 2N2222's. I even
used a 3 terminal regulator device in place of the zener in mine
*shock horror* :D I do plan on making the crystal filter in mine
variable bandwidth, as in the 2N2/40+ though. I wish the kit
version had that.
?
I'll be following this, and other 2N2 threads, with interest.
?
Dave
AA7EE
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Multi-function test jig idea for homebrew radios.
I had an idea to combine many different test jigs into a 80mm x100mm 2 layer PCB.
So far I have the following test jigs on the board:
1. Inductor Q/Self resonant frequency test jig. This connects to your spectrum analyzer with tracking generator. It allows you to measure the center frequency and 3dB B/W in order to calculate inductor Q. It can alao give you an idea of the inductors self-resonant frequency.
2. Mixer diode forward voltage tester. Used your 13.8V power supply and a 2.7K ohm resistor to force 5mA across a diode to grade them for forward voltages.
3. Crystal oscillator for measuring the frequency of crystals so that they can be selected for crystal filters. The switch switches? in and out a 39pF capacitor to measure frequency shift and allow calculation of Cm and Lm.
A picture of the current lay out is attached.
My question is, are there any other test jigs which might be useful in homebrew radio projects which could fit in the empty area at the bottom of the board?
Steve
WA6ZFT
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If anyone is curious, I have all the data files on github for my take on the 2N2-40+ The VFO, BFO and Xmit signals are synthesized, the output amp is the now "traditional" trio of BS170, but the core of the receiver stays true to the original design.? All the Kicad files are there. If I were to build another one, I'd fix the few issues that I have with the original boards (which is outlined in the readme). Or maybe redesign the digital side for a more modern processor and abandon the Arduino Nano. Feel free to ask if you have any questions. Like I said before, it is my favorite home-brew rig.? Mike M.? KU4QO
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Chuck - the value of 43V is the one that sticks in my mind for PA sections. I bought a small bag of them for that very purpose.
?
My SST, despite not having an IF amp, is sensitive enough on 20. For a relatively minimal component count, it works quite well.
?
Dave
AA7EE
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Thanks for the transformer recommendation Mike. I'm currently assembling a 2N2/20 from a kit, but am hoping to do a 2N2 scratch build afterwards, if I haven't burned myself out by then! With that in mind, I bought 3 x 42TU400-RC from Mouser but was a little disappointed when they turned up, as they are bigger and heavier than the transformer used in the kit version. Will look into your recommendation.
?
Alan - Dan's Small Parts and Kits has the MV1662. The ordering process is a bit of a pain, as you have to write out your order and mail it to him with a check or money order. It's worth calling him first, to ensure he actually has it, as sometimes he will substitute other parts without saying anything. Hopefully someone else knows of an alternative supplier for the MV1662, or has a suggestion for another varactor with similar properties.
?
I'm planning on following the schematic of the Norcal version of the 2N2 for my scratch-build, as I figure it's the most optimized version. Mine doesn't have to be all 2N2222's. I even used a 3 terminal regulator device in place of the zener in mine *shock horror* :D I do plan on making the crystal filter in mine variable bandwidth, as in the 2N2/40+ though. I wish the kit version had that.
?
I'll be following this, and other 2N2 threads, with interest.
?
Dave
AA7EE
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Re: Sasquatch Stomp March 28
Wayne
?
Thanks for the Stomp Reminder.? I have fond memories of that event.? Hope to see you then.
?
72 de Gary W0ITT
?
(Yeti from some years ago.)
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Re: Looking for 2N2/xx Unbuilt Kit
Well, if there is an unassembled kit with Parts, PCB, and Enclosure looking for a home, I'd be interested in knowing cost plus shipping to 19047.? ?Please email me directly.? ?Thanks!? Howard, N3FEL@...
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Thank you!? ?I downloaded and created a new directory, 2n2xx.? ?That's a start.? ?Next step: Dive into my junque box of resistors, capacitors, diodes, transistors, crystals, pots, etc.? ?Not sure whether the xfmr will emerge, but who knows.??In the meanwhile, are their fixes and enhancement suggested by prior builders that I should add to my directory???Anyone else in for the challenge?
?
I have a very fond memory of the Tooty-Too-Tooty-Too and its '2907 sibling.? ?Those, and '741 Op-amps, hex-inverters, and '555 timers.? ?Building analog filters and relay logic boards were among my first professional assignments as a newly-minted PSU EE at the then GE-HVDC Projects Operation in Philadelphia, 1969.? We didn't use copper-clad boards, rather rivets and a fiberglass matrix board on 0.1" centers.? All point-point wired.??
?
Howard, n3fel
?
?
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Just checked. It's in the files section -- along with the AZ Scqrpions' layout board and other tidbits. Here's the QRPp issue.?
?
?
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."
?
?
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Do you have the Winter 1998 issue of QRPp? It is a construction manual for the original 2N2/40 that Jim Kortge developed: broken down by subcircuits with tests, drawings by Paul Harden, parts list, and other tidbits.
?
Must have.
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."
?
?
?
?
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Are there any other hard-to-find parts in the 2N2/40+ Transceiver that has a replacement that can be found?
?
It seems hams are gravitating (is this a real word) towards this radio to build Manhattan construction.? It is on my bucket list, but way down my bucket list because I figured I needed more build experience to build this.? But if I have built a NorCal 40B CW Transceiver kit and done some Manhattan construction like some blocks in Curt's transceiver, would I have the experience to build a 2N2/40+ ??? I do like the concept of building one block at a time.?
?
Thanks,
Daniel KK4MRN
?
?
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Sorry, this was not intended for the group. I'll be more careful.
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Yes, it's very readable when I save the image and view it with gthumb in debian Linux.
Thanks a lot.
Question, if I may.? In the kitsandparts inventory, at one time, there were a large number
of crystal frequencies for the 1Ws and 5Ws.? Are there any left?
Again, thanks for the time and trouble to provide the data.? I'll put it with the values
that I create and what others have done.
BTW.? The delta-f I would attribute to heating.? I'll do the same experiment here with
a test setup that I'll build.? I think I'll come up with a PCB and put them on pcbway
and online in the files section.
Nice test equipment setup.
ciao dude,
chuck, aa7fo
toggle quoted message
Show quoted text
On 3/14/25 14:35, Michael Maiorana via groups.io wrote: Chuck,
I'm still looking for the HC-49S data that I have, but I did find some data from a batch of 8MHz HC-49U crystals that I have. I used the method outlined in Jim?K8IQY's excellent paper on crystal characterization. I built the impedance-reducing circuit to measure, and used an HP8640B as the signal source, Philips PM6665 counter and an HP400EL RMS voltmeter for measurements. I created a spreadsheet to do the math that followed Jim's procedure. The first 4 columns are measured, with the following 4 calculated. Out of curiosity, I added an entry for the crystal's frequency in the G3UUR oscillator test fixture (labeled Fosc). The last column is the difference between the resonant?frequency measured with the signal generator and the G3UUR oscillator. I expected to see a fairly?consistent difference between the two methods, but I did not. You can see that in the last number in the?spreadsheet.
I think an advantage over the oscillator method is the crystal under test is only seeing very low power (-20dbm to -30dbm) which prevents heating. The crystal frequency in the G3UUR oscillator drifts quite a bit, although it does seem to stabilize over 5-10 minutes. I can't remember exactly, but I believe I waited the same amount of time with each crystal in that fixture before taking the reading. Maybe I have a problem with my G3UUR fixture?
Hopefully this is readable.
image.png
73
Mike M.? KU4QO
On Thu, Mar 13, 2025 at 1:03?PM chuck adams via groups.io <> <chuck.adams.phd@...> wrote:
What is SSB?? :-)
Yes, you're right.? Yes. Please post.? We need more data.
There are always tradeoffs between the two crystals.
One operates in the shear mode and the other in the
flex mode.? One of the reasons I want a internal photo.
Some machinist is going to have to do that as I no longer
have my mill and lathe.
I didn't think (do I ever?) to do a search of youtube and
now I find several videos on measuring different ways.
I did not compare with G3UUR fixture, but we can add that
to the list of 'to do' things or better known and 'bucket
list'.
chow,
chuck, look at the leader of 'send in the clowns'
On 3/13/25 09:48, Michael Maiorana via groups.io
<> wrote:
> Hi Chuck,
> Yes, the HC-49S crystals can have excellent Q, but their Lm to Lc
> ratio is very high which makes them impractical for use in wider
> filters (SSB, etc).
> I have some measurements somewhere. If you'd like, I can dig
them up
> and post them.
> 73
> Mike M.? KU4QO
>
> On Thu, Mar 13, 2025 at 11:44?AM chuck adams via groups.io
<>
> <> <chuck.adams.phd@...> wrote:
>
>? ? ?One more thingy.
>
>? ? ?I forgot to mention.? If you will note, the K7QO paper had
one HC-49S
>? ? ?(the short
>? ? ?crystal).? In a current shopping spree I find that the
HC-49U has
>? ? ?practically
>? ? ?disappeared from the face of the earth.
>
>? ? ?But that may be a good thing.? Note:? the HC-49S crystal in
the paper
>? ? ?had the
>? ? ?highest Q rating!!
>
>? ? ?Figure 1 in Chucks paper shows a HC-49U carefully taken
apart. Try
>? ? ?to find
>? ? ?a photograph of a HC-49S.? I dare you.? Some take one apart
and do
>? ? ?a high
>? ? ?resolution photo.? Please.
>
>? ? ?chuck
>
>
>
>
>
>
|
Chuck, I'm still looking for the HC-49S data that I have, but I did find some data from a batch of 8MHz HC-49U crystals that I have. I used the method outlined in Jim?K8IQY's excellent paper on crystal characterization. I built the impedance-reducing circuit to measure, and used an HP8640B as the signal source, Philips PM6665 counter and an HP400EL RMS voltmeter for measurements. I created a spreadsheet to do the math that followed Jim's procedure. The first 4 columns are measured, with the following 4 calculated. Out of curiosity, I added an entry for the crystal's frequency in the G3UUR oscillator test fixture (labeled Fosc). The last column is the difference between the resonant?frequency measured with the signal generator and the G3UUR oscillator. I expected to see a fairly?consistent difference between the two methods, but I did not. You can see that in the last number in the?spreadsheet.
I think an advantage over the oscillator method is the crystal under test is only seeing very low power (-20dbm to -30dbm) which prevents heating. The crystal frequency in the G3UUR oscillator drifts quite a bit, although it does seem to stabilize over 5-10 minutes. I can't remember exactly, but I believe I waited the same amount of time with each crystal in that fixture before taking the reading. Maybe I have a problem with my G3UUR fixture?
Hopefully this is readable.
73 Mike M.? KU4QO
On Thu, Mar 13, 2025 at 1:03?PM chuck adams via <chuck.adams.phd= [email protected]> wrote: What is SSB?? :-)
Yes, you're right.? Yes. Please post.? We need more data.
There are always tradeoffs between the two crystals.
One operates in the shear mode and the other in the
flex mode.? One of the reasons I want a internal photo.
Some machinist is going to have to do that as I no longer
have my mill and lathe.
I didn't think (do I ever?) to do a search of youtube and
now I find several videos on measuring different ways.
I did not compare with G3UUR fixture, but we can add that
to the list of 'to do' things or better known and 'bucket
list'.
chow,
chuck, look at the leader of 'send in the clowns'
On 3/13/25 09:48, Michael Maiorana via wrote:
> Hi Chuck,
> Yes, the HC-49S crystals can have excellent Q, but their Lm to Lc
> ratio is very high which makes them impractical for use in wider
> filters (SSB, etc).
> I have some measurements somewhere. If you'd like, I can dig them up
> and post them.
> 73
> Mike M.? KU4QO
>
> On Thu, Mar 13, 2025 at 11:44?AM chuck adams via
> <> <chuck.adams.phd=[email protected]> wrote:
>
>? ? ?One more thingy.
>
>? ? ?I forgot to mention.? If you will note, the K7QO paper had one HC-49S
>? ? ?(the short
>? ? ?crystal).? In a current shopping spree I find that the HC-49U has
>? ? ?practically
>? ? ?disappeared from the face of the earth.
>
>? ? ?But that may be a good thing.? Note:? the HC-49S crystal in the paper
>? ? ?had the
>? ? ?highest Q rating!!
>
>? ? ?Figure 1 in Chucks paper shows a HC-49U carefully taken apart. Try
>? ? ?to find
>? ? ?a photograph of a HC-49S.? I dare you.? Some take one apart and do
>? ? ?a high
>? ? ?resolution photo.? Please.
>
>? ? ?chuck
>
>
>
>
>
>
|
Re: Looking for 2N2/xx Unbuilt Kit
..muppet boards are intriguing. The closest I came was building the 4SQRP QRP Tuner where the reverse side of the front panel is, essentially, a muppet layout. It was one of those kits that just came together and the resulting product was a very useful tuner. If you do decide to do this, short but descriptive bulletins would be really appreciated. That said and with respect for projects taking over your life, I know documenting one for a blog adds an extra layer or two of complexity, but whenever it's convenient..? ?
?
And, you are correct, the interconnections are something to be considered. I am leaning towards mimicking the 1999 article with boards of the identical size so that, as completed, they could be laid together and "ground strapped" together and the? other interconnections could be imitated per the article.?
?
"...after all is said and done, more is said than done.."
~That's me alright!
?
--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."
|
Re: Looking for 2N2/xx Unbuilt Kit
As a halfway house between a builder designing their own board (which I agree would be quite a demanding task) and doing a Manhattan build, another approach could be to design a "muppet" board, which is a PC board without the holes. You solder the components directly to the copper tracks. It's Manhattan construction with a PC board instead of the pads. One could even base the layout on the published layout for the original 2N2 design. This would be perfectly acceptable for an individual builder to do as their own project if not shared with other builders. If attempted as a group project, we'd need to seek approval from Jim. As you say, the copyright as well as the respect for his work demand it.
?
I'm currently assembling a 2N2/20 from a kit. When done, I'm thinking of attempting a Manhattan build of a 2N2. I haven't tried it yet, as the thought of attempting such a project was a bit overwhelming, plus my interests went in other directions. If I do give it a try, I think I'll adopt a very low-pressure approach, building a section at a time, whenever I feel like it, with no expectation of timing for the end result. My builds used to take over my life, and I won't allow that to happen again :-) I was thinking of trying to achieve the same footprint as the Norcal kit board (3 1/2" x 5 1/2") by stacking two Manhattan boards, and building a similar-sized enclosure to the kit one, but out of PC board material. Holes would need to be drilled in the upper board to allow a screwdriver to reach the trimcaps in the lower board. I might be asking for trouble by even thinking of that approach..........
?
Your idea of building each section on a separate board sounds interesting.? All the interconnects could generate an extra complexity (power to each board, inputs and outputs for each board, etc). If you were really neat, you could use standard connectors, such as SMA for the RF, and perhaps some type of JST connector for the DC power. I don't know - it could get quite involved.
?
Dave
AA7EE
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Hello all,
The Sasquatch Stomp is just two weeks away.
Check it out at
If you need a?Sasquatch Number, or have made a request?and not received a response, please email skmcfee@...
Hope to work younin the Stomp.
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? FS: MTR 4Bv2.3 CW TRANSCEIVER
MTR 4B-V2.3 CW Transceiver. Great condition.?? These rigs are very rare. Only used indoors, in a dry, climate-controlled, non-smoking environment.
Great rig for QRP/P, Travel, SOTA.
Features & Specs:? - 4 bands 80/40/30/20
- Very low rcvr noise floor
- Low current for max battery life
- Wide operating voltage range (5.5-13v)
- Full 5w QRP gallon with 12V supply
- 2 line, backlighted, blue display
- SWR-RF power display? (no SWR meter needed in your pack!)
- Built in realtime clock
- Internal iambic B keyer - 5-31 WPM, in 1 WPM increments
- Straight key operation
- 3 CW message memories with beacon mode
- Sensitivity 0.5uV
- Rcvr audio bandwidth 400hz, centered at 600 Hz
- Rcvr current 27mA
- Xmit current 750mA max at 12 V input
- Xmit spurs -50dBc or better
- Antenna jack BNC
- Power jack 3.5mm with 2.5mm pin
- Works with standard TRS, high sensitivity earbuds with inline volume control (Koss, etc)
$400
Includes: - 18-inch power cord, terminated in PowerPoles
- Hardcopy instructions
Terms: - Local pickup near Pasadena, CA:? ? ?Cash
- Shipped to USA address:? ? ? ? ? ? ? ? ? PayPal F&F
PM or email (see my QRZ page) if interested. More pictures available.
73, Jay W6CJ
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Robin Midgett
Alan N8WQ
hwstar
Gary Freeman
k6whp
Jay W6CJ