Digital scopes have some limitations - and to really use them effectively, you do need to know a little about how they work and operate.? That being said, they can be valuable too - even a 5mhz digital scope can work with audio (and to a lesser degree with RF - low frequency stuff).? A 20mhz would work for older radios (with a lower IF), but a 20mhz _analog_ is far easier to use near the top end of its bandwidth than most digital scopes - and have a more accurate representation of the waveform at the upper end.? I'd suggest something at least 30mhz... if digital, go higher than that (better representation of the waveform).? For digital, a good rule of thumb is the bandwidth at least twice the signal you might want to check.
I've got a used analog (bought at a hamfest) which works good - yeah, there's a chance of a lemon but often they're quite rugged (and if they look good inside and out, you've got a pretty fair chance of getting a good one).? Usually a few simple tests can show if there are problems or not.? If it comes on, shows traces, and the seller can show a waveform (square wave is good), usually they're adequate for troubleshooting.? I think that there are lists on the internet that show what tests to do - and what sort of problems you're likely to find based on the make and model of the scope. IME, the usual failure is dried-out power supply caps.
Here is a list of suggested test equipment:
1. A very good DVM - be prepared to spend a fair amount on this. A
cheapo model will work, but the better the model, the more useful
you'll find it in the future.? (The one I have now - I've had for
almost 10 years, and if someone hadn't torched my shop, I'd still be
using models I'd had for years before that.)
2. Make a RF sniffer probe for it.? VERY useful for troubleshooting
radios.? You can use on-the-air signals or some other source
(mentioned later).
3. A directional wattmeter (aka SWR meter) - you can make one of these
if need be - even make one that works with the DVM.? This is
important - because a poor match puts transmitters in jeopardy. It's not about "Maximum signal out!!!", it protects the finals from
being overstressed!!!
4. The next on the list: a 50 ohm dummy load.? VERY important - you can
make one (just don't use wirewound resistors!).? I'd encourage
looking at kits, by the way - if you have any experience at all with
soldering (start with simple kits and you can develop adequate skill
rather fast).
Less critical but worth having.? Kits, by the way, do work... and you might know someone who has an old scope lying around that they don't have a use for.? I've got a couple of pieces of equipment I built from kits - and have considered others.
1. Here is where I'd put a scope - they may not be essential, but if
you have any experience at all with them, they're that useful (make
sure you have bandwidth in excess of the signal you expect to check).
2. Almost as important - a signal source.? There are DDO kits available
that are inexpensive and they do an adequate job (although the
signal isn't that clean/pure).
3. Make or buy a step attenuator (for the signal source) - if you don't
luck out and find one.
4. Here is where I'd put something like a VNA or other antenna checker.
5. It goes on from there.? I'd even suggest something like a "grid
dipper" or similar - they are VERY useful, especially when checking
things like toroids and caps.? I used to have one - and miss it.
6. Here's another good one - for checking many components.? It's called
a "zener Sweeper" - and I used to have one.? There may be other
little things like that.
7. I thought I'd mention a RF bridge.? I bought a wide-band bare-bones
one from China, and I'd previously built a dBm meter (combined chip
and components with an arduino).? You can combine these with a DDO
signal generator and do all sorts of neat stuff - even synthesize
something resembling a dipper!
8. The rest is per personal preference.? One more thing - don't stint
on the soldering iron.? Get a good one (you don't have to break the
bank to find a good one... temperature controlled and grounded). Ditto for small tools - a good wire nipper is very important
(especially for kits).
_VERY important - do your best to get manuals (including service if available) for everything_!!!? They can save tons of headache and heartache!
Good luck... and I hope this helps.
Bob
N4FBZ (First licensed 1980, General Radiotelephone {commercial radios} 1981.)
On 5/17/20 10:59 AM, ponton.leo@... wrote:

Very off topic. My mind is wandering since passing my foundation, getting my call sign and now waiting for a radio. The Baofeng I ordered at the beginning of April didn’t arrive (woop!) and I got a refund. The next day delivery FT-65 to replace it which I ordered on Thursday is coming on Monday. My uBitx is awaiting a despatch window. My CW isn’t good enough to use my Forty-9er yet. I can’t afford a FT-817.


So, I’m tinkering with circuits, arduino and so on. Of course whenever I google something there’s an oscilloscope in the article. Since I was a kid I thought I needed one but they’re pricey. Does anybody know....are those twenty-odd quid digital things any good? e.g. JYE Tech DSO138 Mini Digital Oscilloscope. I’ve heard good things about the NanoVNA and I wondered if these little ‘scopes are reasonable in the same way.

Or maybe I’d be better getting and old style big box scope from eBay and hope it works (“Spares only, turns on, but no way to test it” is the standard disclaimer)

Better still, what do people recommend for basic test equipment?

Go to a hamfest in your local area when they return ??.? It may be hit-or-miss if you find an oscilloscope but if you ask around I'm sure someone will have one that they will sell for a reasonable price or since you're starting out sometimes a freebie comes along that works.? It can be a great source for other test equipment also.? If you buy an oscilloscope locally at least you can try it out and make sure it works. I have found eBay to be really hit or miss and usually much too expensive for test equipment.? To get started a 20 megahertz analog scope is just fine and usually they're quite inexpensive.? Most of us didn't have anything better than that until the rash of cheaper Chinese scopes became available a few years ago.? They just cost too much for the experimenter back in the day.? If you can find a used? Rigol Ds1102E scope they make an excellent entry-level scope. Just don't pay too much for it. $100-$150 would be about the max for it since the newer?DS1054Z?is out and commonly available for $350. And for that money it must have all the probes included!??

Hopefully you'll be able to find what you need. One thing to remember at hamfests some people price their stuff realistically and it always is a good idea to offer less for the item than the asking price. Most people come down somewhat.? Do a little research and see what things are selling for on websites like eham or qrz.? You always run into the seller though that will not come down in price and their asking price is just ridiculous ie eBay prices and higher.? Just move on to the next table.? Not everyone is trying to find a sucker.? ?

randy.ab9go@....

This message sent to you from my mobile device via speech-to-text technology.

For me, the basic is:
1 - DMM
2 - An SWR/Power meter
3 - A 100Mhz or better oscilloscope
4 - A PC

Nice to have if you are going to do surgery, PA mods, or antenna experiments:
1 - An SDR Play RSP1A with a -50 DB tap and step attenuator to use as a Spectrum Analyzer (SA)?
2 - NanoVNA or Antuino (from HF Signals)
3 - 50MHz signal generator

Really nice to have:
1 - 2 GHz spectrum analyzer (Sigelent or Rigol)

All of the DSO Oscilloscopes that I have seen are only good to 1 MHz or so.? You really need the 100 MHz to do testing on a superheterodyne transceiver like the uBITX.

I have been pleasantly surprised by the flexibility and usefulness of the SDR Play RSP1A as a SA.? Of course, I would really like a Sigelent or Rigol SA, just not ready to spend $1,000+.

Above are my thoughts, others may be different, and YMMV.
Good Luck
73
Evan
AC9TU

Very off topic. My mind is wandering since passing my foundation, getting my call sign and now waiting for a radio. The Baofeng I ordered at the beginning of April didn’t arrive (woop!) and I got a refund. The next day delivery FT-65 to replace it which I ordered on Thursday is coming on Monday. My uBitx is awaiting a despatch window. My CW isn’t good enough to use my Forty-9er yet. I can’t afford a FT-817.

So, I’m tinkering with circuits, arduino and so on. Of course whenever I google something there’s an oscilloscope in the article. Since I was a kid I thought I needed one but they’re pricey. Does anybody know....are those twenty-odd quid digital things any good? e.g.?JYE Tech DSO138 Mini Digital Oscilloscope. I’ve heard good things about the NanoVNA and I wondered if these little ‘scopes are reasonable in the same way.

Or maybe I’d be better getting and old style big box scope from eBay and hope it works (“Spares only, turns on, but no way to test it” is the standard disclaimer)

Better still, what do people recommend for basic test equipment?

?

?

“A single light can banish the darkness”

Lux e tenebris?

"A fool stares?at the finger that points at the moon"
I Ching