Question:  I want to run DC on the coax, or use a pre-amp near my antenna.  Which arrestor should I use?

Answer: Pick the right frequency range (HF, VHF/UHF), then pick unit with a -PP (Power Pass) suffix.  

Question:  What is the difference between the M-301 and M-300?  There's only a small differnce in the listed frequency range.

Answer: That's true, the only real difference is the M-300 goes a bit lower.  We decided to keep both models as they have been in production since the 90's rather than eliminate one of them.

Question: Why would I choose a QRP model?

Answer: All coax aarrestors use a gas discharge tube as PART of their defense against power surges.  GDT's are specified based on the voltage they will pass; when this voltage is exceeded they "activate" and conduct to ground. This GDT has to be rated high enough in order to allow the transmitting power through the unit without accidentally activating (which would give you instantaneously high SWR and make your radio unhappy), but still low enough to be effective at stopping a surge.  If a station is 10w or less all the time, it would be benefical to have this GDT rating as low as possible.

Question:  What are the two screws/nuts on the sides of the case for?

Answer: They are the connection to ground.  Either one can be used (there are two simply for orientational convenience.) Since the entire case is ground, mounting it on a conductive surface such as in an entry panel, which is then in turn grounded, is also good.

Question:  What is the dB loss through the arrestor?

Answer:   When ANYTHING is put into the radio circuit it introduces some amount of loss.  Adding a longer coax, adding connectors, arrestors, etc. all add some degree of loss.  Having said that, most of these items add a minuscule amount of loss (escpecially at HF freqeuncies).  Our arrestors have less than 0.1dB through them, which is difficult to measure, let alone hear.