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SSAs or Solid State Amplifiers are also referred to as IPAs or Intermediate Power Amplifiers. There are also SSPAs or Solid State Power Amplifiers. Most HPA manufacturers use an IPA for their Power Amplifier Tube (Klystron or TWT). The whole idea behind an SSA/IPA is to make a small signal large enough to saturate the power amplifier stage...in this case a Klystron or Traveling Wave Tube.
The SSA/IPA allows the Manufacturer to overcome most losses (Cables, Attenuators, Switches, Splitters, etc.) between an Upconverter/Exciter or RF Source and the HPA input.
The SSA will often have other items “built in” such as Pin Diodes for Inhibiting the RF, Electronic or Digital Attenuators for varying the output power up and down, and Crystal Diode detectors for monitoring the IPA/HPA power level. A failure on the part of some of these items may give the impression that the SSA has failed when that is not truly the case. Either way, your typical recourse is to repair or replace the unit.
The SSA itself is typically a fixed gain device. A failure of the SSA will likely affect the gain or stability of the amplifier’s output. Sometimes it will affect the operation of the Amplifier Tube itself; especially in the case of TWTs. If an SSA begins generating out of band signals, it will likely cause a TWT to defocus thus increasing the Helix Current. The net result is higher than normal Helix Current or Helix Current Trips.
Note: An unstable output or defocussed TWT need not be the result of a failed SSA. Many times this symptom is the result of external forces. Check for loose Cables or RF Connections between the RF Source and the HPA prior to assuming the HPA is bad. Also try changing the RF Source as Upconverters & Exciters have been know to fail as well. Loose Waveguide may cause your system to go into oscillation giving similar stability problems.
If your SSA Fails, usually your fastest means of repair is replacement. Your HPA manufacturer will usually have a unit on the shelf, however, there have been times that the needed model would be 1 or 2 weeks away from being on the shelf. Sometimes the Manufacturer or Green Satellite will have a loaner if you have them check out your SSA. With a little ingenuity, SSAs can be substituted if your model is obsolete. If a substitute or spare unit is available (or your not limited by time), your options expand to repairing the original SSA. One of the best places to have your SSA repaired is Panatron!
Panatron will typically give you a free analysis and warrant what they repair (not the whole unit) for life. They are a good company and have friendly and knowledgable people working there. I highly recommend them!!! Evaluation takes up to ten business days and the repair will take up to 3 weeks. Many times, they have replacements on the shelf for an even faster turnaround!
Panatron also has many other products that they manufacture. The link below will take you to their site. Tell them we sent you!
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