I have, in the lab,
freq standard
voltage standard
resistor standard
all within 0.1% or better.? NIST traceable.
All I'm lacking is capacitor and inductor standards.
I found the following on ebay and just for its looks
alone I'm willing to eat up 10% of my remaining budget
for parts to get one.? You have to appreciate the design.
IMHO.
<>? 16.5nF 1%
Needed for multiple L/C meter checking.? I used to
have some 104.0pF 1% caps, but can't find them.
Inductors may be more of a problem.
Ideas?? Anyone else obsessed?
--
chuck adams, aa7fo
QRP WAS 17m started Apr 2, 2025
WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN
PA,CA,CO,WI,NE,ID,IL,NC,NY,AL
DXCC W,VE,JA,PY,ZL
|
I recommend looking at Lapidary cutting blades as they are the thinnest.? They
are used for cutting banded agate, ruby, sapphire and other precious stones
and they don't want to waste precious material.? They do come in 7" diameter
and will fit a number of common saws.? Been there. Done that.
Good idea Igor.
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On 4/14/25 23:57, Igor Katkov via groups.io wrote: I don’t know why I’ve not thought of it before. A Diamond blade from a wet saw, installed in a wood saw, goes through FR4 like a knife through butter.
--
chuck adams, aa7fo
QRP WAS 17m started Apr 2, 2025
WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN
PA,CA,CO,WI,NE,ID,IL,NC,NY,AL
DXCC W,VE,JA,PY,ZL
|
Jim,
Thanks for the info!
I got those caps in my cart.
Alan, N8WQ
On 4/13/25 14:59, Jim Kortge, K8IQY via
groups.io wrote:
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Alan,
This is what Mouser has:
-200 PPM tempco, so should work fine where the older polystyrene
caps were used for VFO temperature compensation.
72/73,
Jim, K8IQY
On 4/13/2025 1:58 PM, Alan N8WQ via
groups.io wrote:
Gang,
Does anyone have a good source of polystyrene capacitors to
point me to?
I need a 330pF cap for my current project, plus some spares :)
Thanks...
Alan, N8WQ
|
I don’t know why I’ve not thought of it before. A Diamond blade from a wet saw, installed in a wood saw, goes through FR4 like a knife through butter.
?
|
This time I am sharing my latest project on Github:
?
If you, like me, don't like the low gain and hiss of LM386 as the AF amplifier of your receiver project, try this design.
It has extra gain, matching the lower level of simple DC receivers, a nice active LPF based on the idea from Ashhar VU2ESE, and a TDA2822 PA.
All parts can be from Aliexpress and the PCB can be ordered from JLCPCB, for a total BOM of a (very) few dollars per board if you build 5 and chose the cheap shipping option (I know, I know, not for long...). Assuming you already have resistors and capacitors.
Well, maybe the MMBT3904 input transistor should be a genuine one for guaranteed low noise, but even that is not critical.
It can also be built using TH parts and your favorite construction technique.
One thing that is missing is AGC. I tried a few simple options to keep the complexity and the cost low, but didn't like any of them.
?
73, Mike AF7KR
?
|
Re: BPF for DC receiver video
My solution is based on testing of toroids is that they do have
external fields.
?
In a 10M radio I needed small bandpass filter but the toroids
did interact if too close.? MY solution (since they were t37 size)
was old HC6U crystal cans, unsolder the top and save it.? Wrap
the wound toroid in card stock strip so there would not be
metal contact to the windings.? Mount the cans to copper clad
board?open end up by soldering.? Leads out the top allow for tuning
and coupling connections.??
?
The added capacitance would make them move down in frequency
but since they were externally tuned that was easy to adjust.? Filter
performance with cans shielding them was excellent.? The
result was very compact as well.
?
?
Allison
?
|
Re: Earliest example of Manhattan construction?
My earliest project using manhattan variant was 1973, summer.
?
I was building a few bits for testing UHF RF source, UHF Preamp,
and some repeater bits (for commercial 464mhz).? By then I had
years of dead bug builds.? I added strips of G10 copper clad for?
things like power busses, and stripline RF interconnect (at UHF!).
I still do that.? Have a few pieces I built from back then, still
work too.? I've found if the rule of short leads (except
bypassed power and maybe audio) is the absolute rule.
?
Its not so new? and the method I use for one off and
quick builds.
?
?
Allison
|
Re: Anyone built Charlie Morris ZL2CTM Simple SSB Transceiver?
Daniel
?
You are getting a decent feel for components in vogue. G QRP might still have a utility to design low pass filters. Info is still around.?
?
Many filters can be constructed with T50-2 toroids. Many transformers use FT37-43 etc.?
?
When time is scarce build something small. A regen receiver. A xtal controlled transmitter. A vfo just for the experience. You can also build small circuits like an audio amp, and reuse them.?
?
Perhaps get stuff to build a PLL before they go extinct.?
?
Here I am building a qmx plus. And going through my stuff to refine a homebrew Ozark Patrol regen. If I can't find the little variable caps I had in Maryland I will put a second cap in series to reach my target.?
?
Curt
?
|
Re: looking for parts polystyrene capacitors
Has anyone here ever heard of:
?
?
They are a good source of ferrites and other toroids and many other
common parts people use.
?
?
Allison
|
Hi
?
I uploaded some OHR Qrp Manuals in Files Section. Still I do not have any:)
?
Regards and 73s de TA0G
Hakan GUNER
|
Thanks.? I have the manuals, but it would be nice to get them
from some one else to make sure they match.
It is appreciated.? Thanks for the help.
toggle quoted message
Show quoted text
On 4/14/25 07:55, bill K7WXW via groups.io wrote: I have an OHR 500, the DDS that goes with it, and a WM-1 that I have picked up along the way.? I will go through my manuals and scan/upload any that aren't on archive. org.? Thanks Chuck!
73 Bill K7WXW
--
chuck adams, aa7fo
QRP WAS 17m started Apr 2, 2025
WAS-17 QRP --> TX,FL,SC,GA,OK,AR,KS,AL,AZ,MN
PA,CA,CO,WI,NE,ID,IL,NC,NY,AL
DXCC W,VE,JA,PY,ZL
|
Re: looking for parts polystyrene capacitors
The question is, what kind of poly?
Polystyrene (what we all want) or one of the much more common types, Polyester or Polypropylene?
?
I would be shocked to see polystyrene capacitors on Amazon, Aliexpress, OR Temu.
They are obsolete and I've only seen them NOS on eBay, or other NOS suppliers.
|
Re: Anyone built Charlie Morris ZL2CTM Simple SSB Transceiver?
I've not built it, but if you have a nano vna you can build the same filter he built, and just remove 2-3 windings at a time to get into the 3.9-4.0 range instead of 3.5-.3.6. I doubt a complete redesign is needed. On Mon, Apr 14, 2025 at 7:35?AM Daniel KK4MRN via <daniel-kk4mrn.skipper529= [email protected]> wrote:
Hello,
Has anyone built the Simple SSB Transceiver that was shown on the blog and videos by Charlie Morris, ZL2CTM?
Any suggestions?
?
?
While I was trying to figure out what parts to get for various projects I wanted to work on, I realized that he was targeting a portion of 80m from 3.5 MHz - 3.6 MHz for the Band Pass Filter.? But in the USA, I cannot do 3.5 MHz - 3.6MHz because no voice mode is allowed on that portion in my region.?
?
So, I need to move this up. ? And really, since this will be QRP, I do not expect to be getting any DX. And since I would share this with others, most hams would have a General. ? And I probably be more interested in targeting 3.8 - 4.0 MHz since this is where I hear most things anyways. ? So, this is where I need to learn how to do some of the same math he shows in his videos and his blogs to come up with his Band pass filter and IF Amp, etc.?? So, my center frequency for a band pass filter would be 3.9MHz.??
?
I looked on kitsandparts for their low pass filter board only and looked at it.? And its links and led me to LTspice which is free so I downloaded it.? So, I will try to reproduce what Charlie did first.? Then proceed with my own stuff.
?
I wanted to get toroids from kitsandparts.? But now I am not so sure.? Because now I will need to re-think the project for my region.
If I go with the NE5334 preamp and LM380 amp ICs, they both can be found at Mouser in stock.
?
Anyways, I like the video how he went about designing it.? I like the use of the double-balanced diode mixers.? Except, I want to do Manhattan construction on island pads instead of strip board.
?
Anyhow, I maybe over my head and need to learn the electronics math and theory here.? But I thought I would see if others have tried first.? I am willing to do my home work.
There are some radios I have built to compare to in the past like Curt's transceiver and Norcal 40A / 40B.? So, there might be things there I could learn from including its book EOR.
?
Charlie did mention he used the book Solid State Design for the Radio Amateur as a guide.
?
Anyways, when I was at Adafruit, I noticed they were low on their Si5351A breakout boards.? So, I ordered some.
?
I liked how Charlie Morris showed the math how he determined values he got.? So, that is a good starting point for me.? I just got to figure out where he got that from.
?
I even looked at the band pass/low pass filters at QRP Labs, but they take about a month to come from Turkey - and that is during good times.? Not sure how things would be now.?? I do have a low pass/band pass filter from them for 40m but not 80m.?? But the filter is centered for CW - not SSB voice portions of the band.
?
Thanks,
Daniel KK4MRN
?
|
I have an OHR 500, the DDS that goes with it, and a WM-1 that I have picked up along the way.? I will go through my manuals and scan/upload any that aren't on archive. org.? Thanks Chuck!
?
73 Bill K7WXW
?
|
Anyone built Charlie Morris ZL2CTM Simple SSB Transceiver?
Hello,
Has anyone built the Simple SSB Transceiver that was shown on the blog and videos by Charlie Morris, ZL2CTM?
Any suggestions?
?
?
While I was trying to figure out what parts to get for various projects I wanted to work on, I realized that he was targeting a portion of 80m from 3.5 MHz - 3.6 MHz for the Band Pass Filter.? But in the USA, I cannot do 3.5 MHz - 3.6MHz because no voice mode is allowed on that portion in my region.?
?
So, I need to move this up. ? And really, since this will be QRP, I do not expect to be getting any DX. And since I would share this with others, most hams would have a General. ? And I probably be more interested in targeting 3.8 - 4.0 MHz since this is where I hear most things anyways. ? So, this is where I need to learn how to do some of the same math he shows in his videos and his blogs to come up with his Band pass filter and IF Amp, etc.?? So, my center frequency for a band pass filter would be 3.9MHz.??
?
I looked on kitsandparts for their low pass filter board only and looked at it.? And its links and led me to LTspice which is free so I downloaded it.? So, I will try to reproduce what Charlie did first.? Then proceed with my own stuff.
?
I wanted to get toroids from kitsandparts.? But now I am not so sure.? Because now I will need to re-think the project for my region.
If I go with the NE5334 preamp and LM380 amp ICs, they both can be found at Mouser in stock.
?
Anyways, I like the video how he went about designing it.? I like the use of the double-balanced diode mixers.? Except, I want to do Manhattan construction on island pads instead of strip board.
?
Anyhow, I maybe over my head and need to learn the electronics math and theory here.? But I thought I would see if others have tried first.? I am willing to do my home work.
There are some radios I have built to compare to in the past like Curt's transceiver and Norcal 40A / 40B.? So, there might be things there I could learn from including its book EOR.
?
Charlie did mention he used the book Solid State Design for the Radio Amateur as a guide.
?
Anyways, when I was at Adafruit, I noticed they were low on their Si5351A breakout boards.? So, I ordered some.
?
I liked how Charlie Morris showed the math how he determined values he got.? So, that is a good starting point for me.? I just got to figure out where he got that from.
?
I even looked at the band pass/low pass filters at QRP Labs, but they take about a month to come from Turkey - and that is during good times.? Not sure how things would be now.?? I do have a low pass/band pass filter from them for 40m but not 80m.?? But the filter is centered for CW - not SSB voice portions of the band.
?
Thanks,
Daniel KK4MRN
?
|
Re: looking for parts polystyrene capacitors
I asked Grok and it pointed me to Parts Connection among others. Appearently out of Canada. They seem to have lots of polys for sale: | |
Alan N8WQ
Matthew McDevitt N3AZ
bill K7WXW
Don K5DW
Jim Kortge, K8IQY