How can I get a discontinued item?

SOURCE: Problem in RF Power Amplifier

Look in the "Radio Amateur's Handbook" and past issues of the QST magazine. There have been articles on design including schematics and circuit layout in past issues as well as the Handbook.

Here is a site for a kit for a 10 watt amp... it is for 2MHz to 30MHz, but you can add turns to the transformers to get performance at 1MHz.

http://www.kitsandparts.com/linearamp.php

There is adequate info for design at the site and parts callout and layout.

SOURCE: Would I need a mixer or amplifier with this

The unit has a built in mixer as well as individual outputs. You would need an amplifier/speaker that could receive from teh mixed output jack of this. Use BALANCED TRS cable.

SOURCE: Hi I have a vhf digitech AM-4071 wireless microphone system and the problem is that both microphones are going only through one RF, on the transmitter. The second mic goes but its not receiving on tr

You need to check that they are both operating on different channels there should be a switch or POT on the microphone and possibly one on the reciever. If they are static or preset you need to swap one for the other channel. Some (usualy cheap) mics have a preset or static channel often ch-A and ch-B, there should be one of each in the box. If you bought the extra body packs they will also come with the preset channels.
- thegorisb