[rslaback]

We bought our house a couple years ago and I set up the rooftop antenna just in time for fall football season in 2014. It's an 80 mile antenna with a mast mounted CM-7778 mounted to a rotator.

The following spring we lost the first preamp in a thunderstorm. I went to watch some tv the other day and found that the second preamp was now not working either. I'm open to any suggestions on increasingly the longevity of my equipment (or a suggestion to a better shielded design).

 

[rabbit73]

The 7778 was redesigned when PCT bought out Channel Master, and reports seem to indicate that it has a higher failure rate than the original 7778. The failure is usually in the front end of the preamp from EMP or static discharge. The failure can also be in the power supply if there is an intermittent short in the coax. Do you know which part failed?

Is the coax grounded to the house electrical system ground with a grounding block? Is the mast also grounded to the house electrical system ground with a separate 10 gauge copper wire?



Where are you located?

You might need to switch to an Antennas Direct Juice preamp.

A coax surge protector can be inserted between the antenna and the preamp input, but they sometimes degrade the weak signals because there is device connected between the coax center conductor and the shield.
https://www.amazon.com/TII-Broadband-Cable-Lightning-Protector/dp/B0016AIYU6

http://www.tiitech.com/products.php?cat=7

http://www.tiitech.com/repository/datasheetlibrary/210_212.pdf

http://www.tiitech.com/repository/installationsheetlibrary/92219901-tii_210&212_InstNt.pdf

Some low noise figure preamps (Kitztech & Research Comm) have a higher failure rate because the front end uses a device that is more sensitive to static discharge; that's the trade off.

I lost a computer during an August storm. It was off and plugged in to a good surge protector power strip that was also off. I now uplug it when not in use.

 

[Calaveras]

I lost a couple of preamps in thunderstorms on top of a tower because I was using a fiberglass mast which insulated the antennas and preamp from the tower. The coax was connected to the bottom of the tower. I added a wire from the preamp case (which was metal) to the top of the tower so that the coax at the top and the bottom of the tower was at the same potential. I haven't lost a preamp since.

Perhaps you have something similar going on.

 

[holl_ands]

I would recommend inserting a Holland Electronics GRB-AR Gas Tube Spike Arrestor on the INPUT of the Preamp: [Do NOT confuse with "GRB-AR" from PDI.]
http://www.hollandelectronics.com/catalog/upload_file/Filters-Cable_Drop_Protection.pdf

More on this subject, incl. WHY the GRB-AR is your best choice vs MOV type Surge Protector Device [which degrades RF signal over time]:
http://www.digitalhome.ca/forum/186...gh-attic-antenna-side-side-2.html#post1463911

Of course you should already have an AIR GAP Spark Suppressor as part of the NEC Code mandated Ground Block at the Coax entry point to the structure and you should be using an OUTDOOR Balun [Low Loss Philips or Channel Master are recommended], which is SUPPOSED to have DC Connectivity between the 300-ohm Twin-Leads and the 75-ohm Shield in order to drain off Static Electricity buildup on the ACTIVE (only) Antenna Elements [worth rechecking with a VOM].....and of course a Grounded Mast to drain off Static Electricity buildup on the Mast and whatever Antenna parts are connected to the Mast.

 

[rabbit73]

Of course you should already have an AIR GAP Spark Suppressor as part of the NEC Code mandated Ground Block

The mandated ADU does not contain a spark gap, even in the Listed models. It is nothing more than an F-81 with provisions for grounding
http://www.commscope.com/catalog/broadband/product.aspx?id=19
http://www.3starinc.com/single_port_coaxial_cable_ground_block_si-gb-50l.html
http://www.techtoolsupply.com/2-Port-3Ghz-Grounding-Block-p/grb-2dhr.htm