I'd like to connect equipment to a coaxial surge protector. Is it needed for a properly grounded coaxial cable? How much attenuation does a typical coaxial surge protector cause over the range of frequencies it will pass?
APC has a unit that says "Insertion Loss: 0 dB to 3.0 dB over rated frequency range" in their documentation.
BlackBox also has a unit that says: "Low signal loss." Read into that what you will.
I don't think you'll have major loss... I already did it for one of my client and I didn't notify any performance downgrade on an internet connection before or after the cable plug in the surge protector. The speed test was the same after as before so...
I highly recommend the TII Network Technologies Surge Protector http://a.co/1QyT9fK
Downstream Signal strength dropped less than 0.5 dBmV and Upstream return signal remained the same +/- 0.25 dBmV and SNR remained about the same +/- 0.50 dB. That's very good. This should be installed where your cable enters the home or business (usually outside) before the splitter (if any).
This MUST be grounded or it just won't work. It's a fact of electrical engineering. Attach in place of your existing ground block outside at the point of entry. This is a gas discharge arrester. These tubes divert the extra current to ground. They do this by using an inert gas as the conductor. When the voltage is at a low level the makeup of the gas is such that it is a poor conductor. When the voltage surges above that level, the electrical power is strong enough to ionize the gas (plasma), making it a very effective conductor. It passes on current to the ground until the voltage reaches normal levels, and then becomes a poor conductor again (i.e., it resets itself).