I like old devices and for a long time I worked with them and I also constructed some of them (ocilloscopes, frequency counters, signal generators. But as the time was gone, I couldn't withstand and I bought some of the newer ones. The first two are of that sort and I have a big enjoyment to work with them. Another benefit is more place on the desk.
To achieve the maximal enabled precision with a measurement device a calibration is needed using an accurate and calibrated device or another exact resource. If we have a four digit device or a 0.05% device we don't have automatically also a 4 digit or a 0.05% precision. So it can happen, that although we read 4 digits, one or two least significant digits are "house numbers". But for most practical measurements it would be enough.
click on picture to enlarge it.
UNI-T UTD2102CEL digital storage ocilloscope (DSO).
100 MHz 1 GS/s 2 channel, max.input sensitivity: 1mV/div with 1:1 probe, 10mV/div with 1:10 probe.
On USB key saved display values as bitmap(BMP) files: waveform, waveform values of this meas.
Bought: April 2012 at TIPA.
Rigol DG-4062 2 channel function / arbitrary waveform generator.
500MS/s, 60 MHz-sinus, 25 MHz-square, 1 MHz-ramp, 15 MHz-pulse. Modulation, sweep, burst,...
Bought: May 2012 at Rekirsch elektronik.
Hantek 2D72 3 in 1.
Ocilloscope two channels till 70MHz, 250MSa/s, Waveform generator sinus till 25MHz, output impedance 50Ω, Multimeter.
Display resolution 320 x 240 pixels. Powered with 2 x 18650 Li-ion replaceable recharchables with a charger. Bought in 2020.
Bandwith reduced down to 6 MHz with 1x probe.
Max. input sensitivity is with 1x probe 10mV/div and 100mV/div with 10x probe.
The probe has at 1x an input capacitance of 60pF, the other used probe 80pF.
Capacitive impedance of 80pF at 10 MHz is 200Ω
So we use 10x for higher frequencies and impedances with 10 times less sensitivity.
Or we can use an active probe.
I have tested such an active probe from ebay at 455 kHz and 10 MHz.
Active probe gave with both frequencies half of the amplitude, as we can see from the pictures below.
This active probe comes from ebay as RF Aktive Sonde 0.1 - 1500 MHz.
It has a SMA female connector on the PCB.
Channel 1 - blue color is standard probe, channel 2 - yellow is the active probe.
The standard probe 1:1 at 10 MHz was not applicable because of small input impedance.
We see, that the active probe has about 1:2 lost of sensitivity ratio.
Same result gave Hantek 2D72 scope.
Vector network analyzer NanoVNA-F
Works from 10kHz till 1500 MHz. There are many articles about usage of this device.
It uses rectangular signal 400mV p-p and for higher freq. harmonics, start-stop in 1s for 100 points.
See the varying rectangular output signal of nanoVNA at the attached scope:
At the first picture setting start 10 kHz and stop 100 MHz with C and L in series test circuit from the demo board.
At the second picture IF filter for MW radio CENTER 455kHz SPAN 400kHz. Yellow trace: S11 IMAG, green trace: S11 SMITH.
At the third picture resistnce 22Ω and capacitance 39nF in series. S11 yellow trace format REACTANCE and S11 blue trace format RESISTANCE. In SMITH diagram upper values is the reactance calculated to capacitance.
Left: Orion KTS Type TR-4202 Servoscope(Hungary)-tube 100 kHz ? prepared for Jan H.
Middle up: 2 pieces of H313 (N313) USSR 1MHz, Middle down: own construction 1 MHz.
Right: Saga (C1-94?) Lithuania - 10 MHz.
Two C1-94 10 MHz oscilloscopes with some differencies at the front panel and different names.
The older one named Tektronex is from 1985, the newer named Saga from 1994.
P6105: 10x, 100MHz, 13pF, 10Mohm. P6109: 10x, 150MHz, 11.8 pF, 10Mohm. P6408: Word recognizer.
Function generator, 0-20 MHz with wobbel facility.
Applied: IC MAX038, and a video OpAmp for achieving 50 ohm output imp.
A ready-made freq.counter unit for showing the generated frequency.
Saw tooth generator for testing circuits 35 Hz-125 kHz (based on viewing the distortion of the saw tooth). Applied: Only transistors and passive elements, without any IC.