A lot of good stuff can be found here:
N5DUX Ham Radio PDFs
Including decent scans of Solid State Design for the Radio Amateur, QRP Classics, and some of the W1FB notebooks, now long out of print, but still very good practical reference material for the average, non technically educated, builder, imo.
spoiler alert: 40673, 2N2222A, MC1350 and even more zombie parts!
Win W5JAG
N5DUX Ham Radio PDFs
Including decent scans of Solid State Design for the Radio Amateur, QRP Classics, and some of the W1FB notebooks, now long out of print, but still very good practical reference material for the average, non technically educated, builder, imo.
spoiler alert: 40673, 2N2222A, MC1350 and even more zombie parts!
Win W5JAG
and here:
< Radio amateur bladen >
Watch the UKW-Berichte section. It's more about VHF & up and most in German,
but the circuits talk for themselves. There was "VHF Communications" also,
an English version.
A lot of mixers, IF amplifiers with 40673, Demodulators, AGC.
I need a reality check here, guys.
I need a better scope.
A boat anchor scope is out of the question - I've retired my old ones because my bench is too small.
I'm weighing one of the compact, imported, inexpensive ( < $300 ) hardware digital scopes, or the 10 bit Red Pitaya. I lean toward the Pitaya because: it's small, it will do some spectrum analysis which looks useful, and it could be an SDR IF when I get that far.
We've all seen my technical skills. Is adding the Red Pitaya into the mix at this point going to be too much? Would I be better off with hardware?
Win W5JAG
I need a better scope.
A boat anchor scope is out of the question - I've retired my old ones because my bench is too small.
I'm weighing one of the compact, imported, inexpensive ( < $300 ) hardware digital scopes, or the 10 bit Red Pitaya. I lean toward the Pitaya because: it's small, it will do some spectrum analysis which looks useful, and it could be an SDR IF when I get that far.
We've all seen my technical skills. Is adding the Red Pitaya into the mix at this point going to be too much? Would I be better off with hardware?
Win W5JAG
Hi W5JAG,
Go for the conventional 'scope. I bought a USB deal and ended up putting a nolder oscilloscope back in place. It's also very easy to damage USB type scopes. Much happier now.
I've had to keep an analogue scope along beside the digital one. Some things the digital oscilloscopes don't do well but analogue ones do. A sound card would be better for the other tests, like spectrum analysis.
-Chris
Go for the conventional 'scope. I bought a USB deal and ended up putting a nolder oscilloscope back in place. It's also very easy to damage USB type scopes. Much happier now.
I've had to keep an analogue scope along beside the digital one. Some things the digital oscilloscopes don't do well but analogue ones do. A sound card would be better for the other tests, like spectrum analysis.
-Chris
If Red Pitaya, then the 14 bit version, that's where the dynamic range
starts to get interesting. I have no idea of the quality of the Chinese scopes.
I have boat anchors all around & I want knobs on them.
I never got used to the HP16500 logic analyzer and its 4 scope channels.
All to be set up with the mouse. No, not 4 me.
I don't miss the analog scope any more. It collects dust.
regards, Gerhard
starts to get interesting. I have no idea of the quality of the Chinese scopes.
I have boat anchors all around & I want knobs on them.
I never got used to the HP16500 logic analyzer and its 4 scope channels.
All to be set up with the mouse. No, not 4 me.
I don't miss the analog scope any more. It collects dust.
regards, Gerhard
I agree that knobs beat menus like a full house beats two of a kind, but while my wife has a closet that is bigger than what I lived in all through college and professional school, my entire hobby existence is squeezed into an 8 x 12 foot room off the end of a detached garage. So, no boat anchors. I don't even have any of the Collins ham rigs at the house right now.
eBay was having a flash 15% off sale Friday afternoon and evening so I bought a compact "Hantek" 70 MHz DSO ( only 8 bit ) scope for $203 including shipping to my office. I don't have real high expectations for it. I just want to be able to look at some waveforms and measure some HF RF voltages with a reasonable degree of accuracy. The internet is full of blogs and videos of how to unlock it to 200 MHz, but none show any actual evidence that it really works and is accurate at that frequency, just conclusory statements. So 70 Mhz ish is all I really expect.
I haven't ruled out Red Pitaya - the Hantek would be in addition to the Pitaya, not in place of it.
The SMD hot air thing doesn't even have a brand name, however, it works well - it has already removed those lightning blasted driver chips off the SteppIr board, as well as an RCA 40673 I found on a board from about thirty years ago, and some 3N202's and IF transformers from another board. I haven't tried the soldering iron - it came with some surprisingly fine point tips.
I played with the DG MOSFET board for a few days, and then completely dismantled it back down to parts, except for the hi / lo pass filter at the antenna input. I'm not sure if I am going to rebuild the perf board with diode mixers, or try some other active mixers on it.
I have a bunch of 7360 mixer tubes that I would like to play with. DF96 has a page on his website on tube mixers, including 7360. Most of it is over my head, however. I don't know how well a 7360 would take to square wave ish oscillator drive. I think that kind of drive is not ideal for the 40673 types, although it can be made to work.
Win W5JAG
Attachments
I have 3 scopes.
The old style analog Tek 2335 came dead from a flea market for $20. It now sees occasional bench use, but lives wired to a Vacuutrace. The tracer does not work well with modern DSO's.
My workhorse is a first gen TEK 2232 DSO with "analog" capability. It is the one seen in all of the Tubelab pictures. I purchased it dead from a Motorola scrap sale for $100 about 15 years ago. It turned out to be intermittent and a good whack made it work, although it spontaneously reboots whenever it feels like it. I got one of these on my bench at Mot when they first came out, and used one until I left the company, so I am familiar with it, all of it's quirks, and the ways it can fake out an inexperienced DSO user (aliasing).
I got a modern Chinese DSO about 5 years ago. I have seen identical looking scopes with a few different brand names on them. You can purchase the cheapest model and then apply an internet hack to "upgrade" it. My 70 MHz model now measures over 400 MHz at 3 db and has several new options including a spectrum analyzer. It's still only 8 bits, so the dynamic range is about 45 db. I use it for mostly low voltage stuff where the digital triggering and bus decoding is a great help. Its on my DIY Arduino compatible, digital, and analog music synthesizer bench.
Each scope seems to be a good fit for it's intended use. Just which one will be the RF workhorse? I don't know yet, but I'll probably go with the TEK 2232 since that's what I used at MOT, unless I needed to scope RF signals in the near 1 GHZ range......but nothing I have here can do that.
The old style analog Tek 2335 came dead from a flea market for $20. It now sees occasional bench use, but lives wired to a Vacuutrace. The tracer does not work well with modern DSO's.
My workhorse is a first gen TEK 2232 DSO with "analog" capability. It is the one seen in all of the Tubelab pictures. I purchased it dead from a Motorola scrap sale for $100 about 15 years ago. It turned out to be intermittent and a good whack made it work, although it spontaneously reboots whenever it feels like it. I got one of these on my bench at Mot when they first came out, and used one until I left the company, so I am familiar with it, all of it's quirks, and the ways it can fake out an inexperienced DSO user (aliasing).
I got a modern Chinese DSO about 5 years ago. I have seen identical looking scopes with a few different brand names on them. You can purchase the cheapest model and then apply an internet hack to "upgrade" it. My 70 MHz model now measures over 400 MHz at 3 db and has several new options including a spectrum analyzer. It's still only 8 bits, so the dynamic range is about 45 db. I use it for mostly low voltage stuff where the digital triggering and bus decoding is a great help. Its on my DIY Arduino compatible, digital, and analog music synthesizer bench.
Each scope seems to be a good fit for it's intended use. Just which one will be the RF workhorse? I don't know yet, but I'll probably go with the TEK 2232 since that's what I used at MOT, unless I needed to scope RF signals in the near 1 GHZ range......but nothing I have here can do that.
They are not made as a measurement device. Some may have low pass
filters above the audio range, no matter what the sampling rate is, or they
may be noisy as hell at 50 KHz. Some seem to be good.
Caveat emptor. Check what others use. 90 KHz should be possible with
the right device.
Windows sometimes thinks it must use them for music. I had a lot of
windows trouble with the DG8SAQ network analyzer that has USB audio
codecs of its own. Nice thing, nevertheless. I like it.
cheers, Gerhard
Moving away from zombie parts, here is 2N3823 JFET times two in a cascode configuration. I bumped into this circuit here:
http://kd1jv.qrpradio.com/swbcrx/AMSWBC.HTM .
It is attributed to W7ZOI, but it is not described in "Introduction to Radio Frequency Design" which I belatedly discovered on my bookshelf, or "Solid State Design for the Radio Amateur". There is a lot of information on JFET mixers in the former.
The repair parts for the SteppIr are still in my Mouser shopping cart, and with the FT-950 still toast, my subjective point of reference is lost, so I can't say whether this is better, worse, or just a sideways move from the usual dual gate MOSFET mixer. It does work.
Some of the broadband transformers and other parts are starting to trickle in, so this may or may not be tinkered with further. The new scope should be here next week, that should help a lot.
Win W5JAG
http://kd1jv.qrpradio.com/swbcrx/AMSWBC.HTM .
It is attributed to W7ZOI, but it is not described in "Introduction to Radio Frequency Design" which I belatedly discovered on my bookshelf, or "Solid State Design for the Radio Amateur". There is a lot of information on JFET mixers in the former.
The repair parts for the SteppIr are still in my Mouser shopping cart, and with the FT-950 still toast, my subjective point of reference is lost, so I can't say whether this is better, worse, or just a sideways move from the usual dual gate MOSFET mixer. It does work.
Some of the broadband transformers and other parts are starting to trickle in, so this may or may not be tinkered with further. The new scope should be here next week, that should help a lot.
Win W5JAG
Attachments
Modest SMD success. The motor driver chips in the SteppIR controller have been replaced, and it and the antenna appear to be back in proper working order.
Some of the SMD stuff is trickling in, so the first question is ... how do you store this stuff ? I'm getting 1206 parts, and they are still absurdly small. I bin, bag, or sack my leaded through hole parts, not sure if that is the best way to deal with the SMD parts, or if there are other solutions.
I like the cheap DSO, and was pleasantly surprised to see it can do some limited and crude psuedo spectrum analysis. It looks like this Hantek can do about 60 dB of dynamic range, so somewhat useful. I darn near took off for Dayton Friday, but didn't, so now I'm trying to use that to rationalize getting a real spectrum analyzer.
As always, it would have been cheaper just to buy a radio.
Win W5JAG
Some of the SMD stuff is trickling in, so the first question is ... how do you store this stuff ? I'm getting 1206 parts, and they are still absurdly small. I bin, bag, or sack my leaded through hole parts, not sure if that is the best way to deal with the SMD parts, or if there are other solutions.
I like the cheap DSO, and was pleasantly surprised to see it can do some limited and crude psuedo spectrum analysis. It looks like this Hantek can do about 60 dB of dynamic range, so somewhat useful. I darn near took off for Dayton Friday, but didn't, so now I'm trying to use that to rationalize getting a real spectrum analyzer.
As always, it would have been cheaper just to buy a radio.
Win W5JAG
Hi W5JAG,
Leave them in the tape. I used plastic bins for resistors, one per drawer and I stick the tape smds in with the other resistors.
It took three 60 drawer cabinets to store all the 5% resistors, money very well spent as it only takes me seconds to find the right resistors. Of course now I have non-standard metal film 1% resistors, so those live in a bag in two bins. Complete PITA to deal with. But with new odd values showing up all the time, I can't really use the drawer system unless I simply bought all of them. Had I the money, I would have done exactly that. Special capacitors are handled the same way. Normal capacitors are in ... drawers! The only sane way to store your parts really.
-Chris
Leave them in the tape. I used plastic bins for resistors, one per drawer and I stick the tape smds in with the other resistors.
It took three 60 drawer cabinets to store all the 5% resistors, money very well spent as it only takes me seconds to find the right resistors. Of course now I have non-standard metal film 1% resistors, so those live in a bag in two bins. Complete PITA to deal with. But with new odd values showing up all the time, I can't really use the drawer system unless I simply bought all of them. Had I the money, I would have done exactly that. Special capacitors are handled the same way. Normal capacitors are in ... drawers! The only sane way to store your parts really.
-Chris
If they came from Mouser or Digikey, I leave them in the original packaging. Some of the Mouser labels fade, so write the important stuff on the label with a Sharpie. Find a suitable storage box for the packages. I use plastic Christmas ornament boxes. Cheap at Walmart on Dec. 26.
If they are loose parts I use two methods.
The brown paper coin envelopes are what I used at work. The little stuff has no markings and we needed the actual part value as well as the Motorola part number, so the paper envelopes work. I used a plastic food storage container as a tray to heep the envelopes vertical, and made cardboard dividers to keep them organized. I put three of these inside a desk drawer so all my parts were available with minimal chance of spilling. Each individual envelope can be removed, used and then returned. It just takes discipline to keep them organized.
Another common storage system is the pill organizers used by older people. They come in strips of 7 days or longer. Glue a bunch of these to a suitable substrate (1/4 inch plywood) and make labels for each component value. Make sure that the organizers you choose will stay shut, and open without undue force. Organization is easy, and all the component values are visible. The disadvantage, you will be very unhappy if you drop the whole thing and half the containers fly open.
I still have thousands of SMD stuff in both storage systems, and haven't decided which way to go going forward, since I haven't done much SMD stuff since leaving Mot, but that's about to change. I'm leaning toward the envelopes, since I dropped one of the pill boards and lost half the parts.
How was Dayton? I got up Friday morning, realized it was that weekend, and was prepared to pack up the XYL and five year old and mad dash road trip to Ohio, but the local QRN convinced me otherwise.
So I mowed all weekend.
So far, I have left them on their tape / packaging from Mouser, and was going to put them in the equivalent bin or drawer with their leaded semiconductor equivalents.
But my bins for caps, resistors, inductors, and such are overflowing with leaded parts, I am just out of room. I think the envelope idea is a good idea. I'll just have to find room for the containers of envelopes.
How do you test these things for value / working order? I'm getting the semi's from reputable vendors like Mouser to try to avoid specification issues, but I figured it would be safe enough to stock up on passives on the cheap from eBay.
Win W5JAG
So I mowed all weekend.
So far, I have left them on their tape / packaging from Mouser, and was going to put them in the equivalent bin or drawer with their leaded semiconductor equivalents.
But my bins for caps, resistors, inductors, and such are overflowing with leaded parts, I am just out of room. I think the envelope idea is a good idea. I'll just have to find room for the containers of envelopes.
How do you test these things for value / working order? I'm getting the semi's from reputable vendors like Mouser to try to avoid specification issues, but I figured it would be safe enough to stock up on passives on the cheap from eBay.
Win W5JAG
Hi W5JAG,
You test them with an LCR meter and a surface mount test jig. The main problem with Ebay parts are that they are either over the storage date (end caps won't solder well anymore in a solder bath), or there is something wrong with them. That means out of tolerance parts, or parts defective in one or more characteristics. Of course they could be a closing sale of a contract manufacturer or just really low quality junk.
-Chris
You test them with an LCR meter and a surface mount test jig. The main problem with Ebay parts are that they are either over the storage date (end caps won't solder well anymore in a solder bath), or there is something wrong with them. That means out of tolerance parts, or parts defective in one or more characteristics. Of course they could be a closing sale of a contract manufacturer or just really low quality junk.
-Chris
I have bought a lot of ebay parts, and I have really no complaints.
Definitely not lo quality junk but Yageo, Kemet, Panasonic and the other
usual suspects. I usually hand solder them without problems, although
I can do vapor phase, but I do that normally only when BGAs are involved.
For parts that are important, I just have restocked the capacitors
with NO0 / C0G parts from DigiKey from 0p5 to 100n. I would never use
100n NP0 for decoupling, the large values are costly and do not bring
any advantage over X7R. But for time constants, they are OK.
For Resistors, I have bought a Susumu kit of thin film 0.5% devices.
Normally I use 0603. That still fits nicely into the grid given by SO-8
chips (50 mil). 0402 makes it uneasy to route signals below the chip
resistors. The Kits turned out to be a mix of 0603 and 0805, with
some parts of the spectrum over-represented. The parts are in little
glass bottles , and I co-habitated 0805 and 0603 parts in the same
bottles and recycled the emptied ones for 49R9, 100R, 200R and such,
what a RF guy needs (terminations of transformers, splitters, combiners etc...).
The glass bottles are nicely aligned in plastic boxes and the boxes are
in a crate. (Is that the right word? Please bear with me, I have to think in
a foreign language
) PS
By the work of Pavel Denim, the Red Pitaya can now do the job
of a vector network analyzer to 60 MHz or so. I just did read that,
no test from my side, I have a ZVB-8
Cheers, Gerhard DK4XP