MW.E.c. and E.U. a2 for operation

[Quatsch]

Wunderbar! I admit a modicum of jealousy.

[17thairborne]

Thank you for your support. Now if only I knew what I was doing here

[Quatsch]

Here's a vid to get you started;
https://www.youtube.com/watch?v=F4-5QV6J4XM

And some more info I'm sure you've already seen;
http://www.la6nca.net/tysk/mwec/

I wonder how well it will do ssb signals, being that I don't know if you can vary the bfo to one side or the other of the filter skirt, or if the bfo is always going to be in the middle of the filter passband or offset by the cw offset? The radio covers the 160m HAM band, and the utility band between 160m and 3000KHz where ssb and fsk and/or psk signals can be found. Should be a great dx machine for the ranges it covers. Also, before hooking it up and pressing the on switch, I'd look at the voltages coming from the power supply, if the power supply can be run without a load to make sure they're what the radio is supposed to see. Some power supplies don't regulate well without a load so that should be taken into consideration. Otherwise, I say hook it up and press the button! Oh yeah, you need a speaker or headset and an antenna.

[17thairborne]

Thanks. Great vid. Is that your radio?

It should be no problem powering up the Umformer and checking the output with a multimeter, but I'm not sure what to use to try a load.

What is the simplest type of antenna to use?

[17thairborne]

How readily available and expensive are the transmitters? I have only found one for E1250 Ouch

[Quatsch]

Thanks. Great vid. Is that your radio?

It should be no problem powering up the Umformer and checking the output with a multimeter, but I'm not sure what to use to try a load.

What is the simplest type of antenna to use?

Sadly, not my vid, I can only afford American radios so far.... but I do have a nice 1936 Ta.P morse key by Lorenz.
I'd just check the pins in the power supply output for their respective voltage to ground and place the voltmeter leads accordingly, then check it. If it has close to the desired or expected voltages then just plug it into your radio and see how she plays. Also, I would be building or buying a solid state power supply for the radio, but that's just me.

As for an antenna, I suspect a few feet of wire will do well for simple testing, but a proper antenna would result in "more better" radio. An outdoor antenna with proper lead in to avoid picking up in home radio noise makers would do you well. It could be as simple as a "long wire" out to any available support, or even a loop of wire around the house under the eaves. I try to feed all my antennas via coax to help reduce in home noise pickup, some in home devices such as pcs. tvs, and the various wall wart power supplies make a tremendous racket on the radio waves in some cases.

Examining the typical antenna deployed with such radios will give you an idea as to what antenna/impedance it was designed to work with. Apparently this radio was common to command vehicles so investigating command vehicle antennas is warranted, as well as any information on antennas employed in stationary listening posts or command centers as they might also employ the same type of radio. I suspect that funksamler will know exactly what antenna types this set was designed for.

[17thairborne]

Thanks for the information. Over the next week or so I will get busy and check the tubes and pins and the umformer. Perhaps I know someone in town who has access to a tube tester.

[hcs]

Thanks. Great vid. Is that your radio?

It should be no problem powering up the Umformer and checking the output with a multimeter, but I'm not sure what to use to try a load.

What is the simplest type of antenna to use?

If you feel ready to check the umformer with a load, then connect a 5Kohm(5000 ohm) at least 3,5 watt power resistor(MUST be a power resistor!!!), between pin 4 and 5 at the umformer output. This will load the 130V output, to the specified current at 26 mA. The resistor will get hot!!!
Or was it the transmitting output you wanted to check?

[Funksammler]

You can check the Umformer unloaded, the output voltage will be a bit higher (about 150 Volt) but that should not be a problem. Looking at both the Umformer and receiver they seem to be restored/serviced, indicating that this came from a former radio collector's collection. So I would have no problems hooking this up after some simple initial checks.

I would first test the umformer unloaded. Just connect the two contacts on the back to a car battery and plug in your cable. Use a little wire to connect contacts 1 and 3 in the plug, this should close the starter relay and the Umformer should start to run. Listen carefully to the noise of the umformer, it should make a pleasant hum. If it squeaks or rumbles, runs irregularly the umformer will need some work. With a multimeter, measure the voltages in the plug.

You should measure +12 V between pins 2 and 1 and about +150 V between pins 4 and 5.

Have a good smell after running for a while, you should not smell burning or get a pugnent smell of faulty capacitors.

As a next step, I would remove all the valves from the Mw.E.c and connect the plug. Now you should be able to start the Umformer by turning the volume knob to the right. The switch may be a bit dirty, but after moving it a few times the umformer should reliably switch on and off.

Have a look at the valve schematic in post #5, these show the connections looking from the bottom upwards, so you have to mirror these when you are looking from the outside in. With the umformer switched on:
- Measure the voltage across the middle two of four contacts, this should be the filament voltage of 12 V
- Measure the anode voltage between the right of four contacts and the contact left key slot. These voltages should be between 60 and 150 volts, dependent on which valve you measure (note that the 2nd heterodyne stage only works in band II).

Again use your sense of smell, there should be no strong smells.

Next, check the valves. You will probably not have a valve tester available, but you can at least measure that the filaments are intact. Just measure the resistance across the two middle of four contacts. If you measure an open circuit, you will need a new valve.

Stick the valves back in, connect your headphones and use a piece of wire to an antenna antenna (a meter of wire will be ok at this stage, but the longer your antenna the better). When you are ready for the big moment, switch on the receiver and wait a minute or so for the valves to heat up. If the receiver works you will start hearing a hissing sound. Touch the antenne connection with your antenna wire, you should hear a loud scratching sound in your headphones as you do this. When you hear this scratching the receiver is working in principle. Now fix the antenna and turn the tuning knob to see if you can pick up any stations. Start playing with the other controls to see what happens. On "Tg" you should hear a beeping noise with your reception which disappears on "Tn". Switching on the "Tonsieb" will make the noise duller.

If it doesn't work there are some other measurements to determine the area of the fault, but it looks like the set should be in working condition.

Have some fun!

Funksammler

[Funksammler]

Ah, and first of all, check your headphones. Put them on your head and measure the resistance between the two pins with a multimeter. Not only should you measure resistance but you should hear a scratching sound as you touch the pins....

regards,

Funksammler

[17thairborne]

Funksammler,
You have laid out a superb plan for me to follow. I will report on progress within the next 2 days. Much to do today and out of town tomorrow, and so I will wait until I can dedicate a few hours to comfortably accomplish these tests. I sincerely appreciate all of the advice you and Quatsch have provided.

On another note, I am looking at your frame you fabricated for the Befehlspanzer. Very nice . I hope some day to make something like that for my set up. I have just learned how to weld, and it will make a fun learning experience.

[17thairborne]

I garnered a few hours this evening and tested the tubes as recommended by Funksammler and inspected the sections with the covers removed. Here are the tube results. The image was taken on slow shutter speed, so the LCD screen was changing during exposure.

Tube 14: 65Ω HF stage
Tube 15: 55Ω 1st Heterodyne stage
Tube 16: 64Ω Mixing stage
Tube 17: 99Ω 2nd Heterodyne stage
Tube 18: 99Ω IF stage
Tube 19: 101Ω IF stage
Tube 20: 103Ω De-modulator
Tube 21: 55Ω Push-pull amplifier
Tube 22: 63Ω Final amplification stage

[17thairborne]

Here is the interior shot of the left side (as viewed from the rear standing on end) of the case with the sockets for tubes 14,15 and 16.

This is the HF stage, the 1st Heterodyne stage and the Mixing stage. (HF stufe, I Uberlagerungsstufe, Mischstufe)

[17thairborne]

This is the section what contains the 2nd heterodyne stage with tube 17. Note the 353kHz quartz crystal correctly labeled as component 155.

[17thairborne]

Here is the interior of the IF stage (Zwischenfrequnzstufe) showing the sockets for tubes 18 and 19.