Here I want to pay attention everyone, who is going to organize such expeditions on the very important moment of operation of equipment in them. The equipment on expeditions is powered up only one time, right at the beginning of expedition. It is powered up, but is not turned off! Equipment should work round day. It concerns to ALL equipment, but especially it concerns to tube equipment. A transceiver, a power amplifier can work in a room conditions within many years. But it can leave out of operation in other day of forwarding operation in field condition. So, the tube transceiver, despite of my protests was out-of-operation. The AC - main transformer (it was self-made) from this transceiver strongly buzzed and hindered to sleep.

Other day in the morning, after attempt to switch on this transceiver it was emitted smoke, sparkle, and has ceased to work. My attempts to repair it have not crowned by success. I could restore service capability only on reception. At switching on of the transceiver on transmission in it in several places there was an arc and gradually burned "superfluous" details in different places of the transceiver.

It is necessary to note in this connection, that it is not necessary to recognize schedule to manufacture repair of equipment in expedition conditions. As displays my experience it is impossible to take with itself all details for the repair. All the same, something can not take with itself, or there will be a failure again of installed detail, and the transceiver will leave out of operation. Simple it is necessary that the apparatus did not break during expedition. The principal preventive measures of thus consist that it is not turn off from operation.

If the apparatus at the connection in expedition has worked, let's it works and further. Only we switch off the apparatus, as inevitably it would be suction of it inside of moisture. On Ai - Petri , to a night cloud lowered and the damp in our room became close to 100 %.

The unturned transceiver was cooled, and there were conditioned for condensation of a moisture inside it. As a result of it drop of a water which were in air, are drained inside the transceiver, sit down on its details, and wet a dust, which inevitably is present on high-voltage circuit parts. This dust became conducting, and at high voltage switching on has taken place where breakdown of this dust, where a current leakage through moist dust tracks.

If an apparatus warm, permanently works, the moisture inside it is not condensed even in conditions 100 % of air humidity. From behind inside heat emitted by operation of the apparatus, its details all time dry up. The conditions for condensation of a moisture inside the apparatus do not arise. As a result of it the tube transceiver or the power amplifier can work on expedition even is strongly moist conditions rather long time.

In this causing I want to remind one of the old operating instructions of tube transmission -receiving equipment on radiocenters. There is forbidden to turn off tube equipment, even if it is not used for operation. If it is possible to do for un using gear it is only to remove anode voltage, abandoning live heats of valves. And only for holding repair or preventive operations, the equipment is turned off from main. I saw on these centers radio receivers, live more than 20 years back, and not turned off all this period. Even the valves in some receivers changed, not turning off receivers from main! This specificity of tube equipment maintenance on transmission -receiving centers. But, we this instruction have not executed.

So, the tube transceiver any more was not subject to restoring in our conditions (now this transceiver afteraW3 substitution of the several burned down details quite normally works). For operation from expedition on HF ranges we still had radio set R-143 and two of my transceivers on 160-80 meters and on 40 meters. We have removed the tube transceiver, have got my transceivers and have manufactured their hook up. These transceivers were repeatedly tested by me on different my expeditions. They have worked and on Ai-Petri!

What still surprises by DC (direct conversion) transceiver operation (my transceivers are direct conversion transceiver) from mountain expedition is a full absence of a background of an alternating-current in head-phones by their operation. In city conditions a DC transceiver often works with strong background of an alternating-current, also receives a harmonics of powerful radio sets operating in city. Far from cities, where there is no all of this interference, DC transceiver works fine!