HAM Radio and the Corona Virus.

The western world is closing down, for a while.
The Corona virus crisis has hit us all.
As someone in the rather vulnerable group I have, essentially been in isolation for a week now. Not quite, because this week I had appointments at the hospital for a blood test and subsequent CT-scan, as part of the follow-up on a cancer I had treated - successfully - in 2018.

Since I was out, I did go to the pharmacy, too, just to get supplies of medicine I have been using regularly, especially a means to reduce the effects of pollen allergies.

This crisis may take longer than we might expect, for me, at least, I will hesitate to venture much out into the world (or even in my own country), until we have seen and tested a successful treatment or a vaccine is available.

What does that mean to me? I am fortunate enough to have retired, so there is no **need** to go out much. I can get food supplies and other necessities delivered to my door. Even then, I should be careful not to be infected from the delivery people. The most essential company has already initialized measures in that respect.

Here is the thing for me. I am generally used to living on my own, and have not gone out among people a lot. Yes, sometimes I have gone for a larger event, but that is all on hold now.

This is why I like having HAM radio as my interest, among others I can pursue alone. But with HAM radio, I am still in contact with other people on a daily basis, probably even more so because we are all at home most of the time.

So if I can avoid getting infected I will get through that crisis. Others may not be so fortunate.

To everyone in doubt: If you are an essential part of health care and other necessary functions, take all possible precautions to stay healthy. Many others should be working from home, if at all possible, and so help reducing the spread of the virus. Those of us who are vulnerable due to age or previous sickness, stay home if at all possible, and help in any way you can, those who need it.

We will all need to stand together (with a distance) to get through this. If we do, most of us will be there on the other side, if not, we will see much fewer people succeeding.

Analog Vs Digital Multimeters.

When should one use analog, and when digital meters for (mainly) voltage and current measurements?

To me there is an easy answer.

If I am adjusting something for maximum or minimum values, the analog meter wins every single time. It is much easier to see when the max/min values are reached with a "moving needle" meter.

Will I go without the digital multimeter? No way. It makes for an easy measurement of more or less static values.

So yes, I have a set of digital multimeters with Volt/Ampere/Ohm measurement, and one with capacitance measurement.

A cheap Chinese PCB module serves as L-C meter, down to most of the values I need to measure, about 1pF and some nH (I need to test the latter).

I just took out 2 museum pieces: Unigor multimeters. Good quality analog meters for V/A/Ohm, all the way into the Mohm range. The only thing is the battery needed for resistance measurement. Most modern meters use AA or AAA cells, or a 9V battery. Those 2 meters use 1.5V D-size cells. Now I need to find out if I can still get those. If not, I will have to find/make an adapter.

OK, the resistance measurement on the analog meter is not that important, but why not restore the full function of those museum pieces?

Apart from the multimeters I still have 3 excellent analog meters: An AC (milli)volt meter with high impedance input, a DC (milli)volt meter, and a Bolometer with a thermistor probe for up to 10GHz, one that needs care, not exceeding 10mW input to the probe, in order to keep the meter functional. More than 10mW, even for a short while, and the probe burns out.

A set of older (second hand) attenuators (for use with the Bolometer (power meter)) will have to be tested, but I have some, at least, new ones that should be good for low power measurements, up to 1/2 - 1W.

With access to the test equipment I should now be able to do a bit of home construction activities again, be it kit building or fully home made circuits.

Update:
I found an adapter for mounting AA batteries in the Unigor meters.
One of the Unigor multi-meters is now in working order. Ranges:
10uA - 1A
100mV - 1kV (DC and AC (the AC is probably not precise in the lower ranges))
Resistance measurement not very precise, but for that the digital multimeter will probably work better.
The other meter probably requires disassembly. If I get it back in order, I can measure up to 10A with that one. This is for later.

Desk With Test Equipment.

Finally, I did a bit of tidying in the upstairs shack.
The shack has two desks, one should be dedicated to test equipment, the other should be used for some radio and computer equipment.

I almost cleared the upstairs desk for the test equipment. At least, the desk can now be used for more extensive testing than with the rudimentary set of test equipment at the ground floor radio (shack) desk.
Test equipment available for use at the desk:
- HP DC voltmeter
- HP AC voltmeter
- HP432 bolometer w/10GHz probe
- spectrum analyzer 10 - 1700 MHz w/tracking
- Marconi transceiver tester
- Tektronic 2 channel oscilloscope, 60MHz
- Velleman frequency counter
- modulation meter
- handheld multimeter, V/A/Ohm
- old Trio AF signal generator
- Fluke V/A/ohm, not functional, will need check and repair, if applicable
- Of course, (Velleman) soldering iron w/ power supply and multimeter
- a diode power meter built by a friend. can do 10GHz/max 100mW

There is more to come, e.g. a bit of test equipment/accessories for microwave and other measurements, such as:

- low frequency function generator and mini (cheap Chinese LF) oscilloscope kit

- modified satellite or MMDS down converters for converting microwave signals down to the range of the spectrum analyzer or frequency counter(s)

- VNAs (mini or Nano) for circuit/antenna testing (gain/frequency characteristics, SWR etc)

- directional couplers for 1.3, 2.4 and 10GHz

- Accessory mini frequency counters

- reference frequency generator ( TCXO, OCXO, Rubidium or GPS controlled)

- crystal tester(s)

- and more, to be described later