This is a NEW old stock linear Class AB amplifier pallet which covers the frequencies of 175 to 230 MHz and will put out 75 Watts. This uses a +27.5 volt power supply on the RED wire which also needs to have a .3 ohm 10 watt resistor in series with the power lead for collector current monitoring and which also limits the voltage at full rated output to 26 volts. This needs at least a 6 amp 28V (normally adjusted to 27.5V) power supply for operation as it draws around 5 amps at 75 watts of output. This also needs a +5V power supply capable of about 200 ma on the blue wire with a recommended 5 ohm 10 Watt in series resistor for bias current monitoring. This can be a simple 7805 regulator (with an input filter cap of about 470 uF@35V) off the main 27.5V supply, ONLY if adequate heat sinking is provided for the regulator as it will dissipate around 4.5 watts. Otherwise I would use a separate +5V supply. These series resistors for the main supply and the bias supply are typically mounted right next to the amplifier and are usually the Dale RH – 10 type.These were designed to be a linear drive amplifier for the upper VHF TV channels 7-13 but go up into and past the 1.25 Meter Ham band. The picture of the wattmeter shows 75 watts output. I was using a test frequency of 225 MHz for the pictures. As you can see from the picture with the module bypassed with a BNC barrel, the input power was then around 7 watts. These typically have 10 dB minimum of gain in the 174-230 MHz range, although the gain is higher in the middle of the band by about 3 dB. I have tested these amplifiers and they are all in working condition. A small heat sink is included but the amp is not mounted yet just in case you want to put it on your heat sink. You will need to drill and tap the heat sink I provide to mount the amplifier and 5 Volt regulator. If you require a continuously, always on output, I recommend a different heat sink and I do have several beefier ones I can sell at an additional cost. I also always recommend using a cooling fan with any high power RF amplifier, on any heat sink.
The very large heat sink in the picture with the watt meters AND the second module I used to the drive amplifier are NOT included in this listing, just the small heat sink and ONE 75 watt module.
You should be very happy with this amplifier and I am offering a 14 day right of return. However, this item should be returned in WORKING condition and will be tested upon return. Due to the possible unstable nature of external circuits this amplifier may be connected to, if this amplifier is returned failed due to an improper application, miss-matched loading, over driving, an inquiry will be started to determine the cause of failure before any refunds will be issued. If negligence has been found NO refund will be issued. I have worked with these modules for years and failures are not normal under the proper working conditions. I do have several circulators/isolators in this band also available for sale in my items should you wish to protect it from any unforeseen circumstances.I will offer a discount on both if purchased together. Please contact me in advance of your purchase so we can come up with a price of each and you would then make the offer on each item which I would in turn accept.
I also have several of these modules in used condition which I will be placing up on soon. If you are interested in these before I get them listed let me know by contacting me and I\'ll try to get them up quickly. Reason being is I need to test them first.
Thanks,
