Thanks for the feed back DigitalRocks, my hope is that by not pointing at any Detroit stations this should keep the over loading to a minimum. I seems that people realy like or dislike these Antennacraft pre amps.

I am sad to report the loss of my Research Communications pre amp today.
I returned from work this afternoon and turned on the television and there was the dreaded snow on most analog stations. I knew right away, as I have experienced this before, that my mast head unit has fryed.
There was passing thunder showers this afternoon, and in the past I usually just turn off the preamp and unhook the coax to the antenna when I expect bad weather. Guess what I did not do today.
I am just totally crushed.
Just in case someone asks, yes the antenna is properly grounded. I assume there was just to much static in the air and the resistors blew.
I will be taking a few days to mourn then run with my KitzTech which I own.

Mark

Update: 6:30 PM
Ah you all know me, I would not be able to sleep without fixing it so I went to the roof and confirmed the correct voltage on the coax so I know it was not a power supply issue. As hard as it was, out came the preamp and inside I replace the power supply section with my Kitz Tech preamp I had laying around. Volia I'm back in business. Erie, Youngstown, and Cleveland are back, so are my analogs.
Still ,I will be able to sleep tonight at the very least.

Update 2:
From the Research Communications web site, they state that they have a standard twelve month parts and labour warranty. Hope they honor this.

Sorry to read that, PanaMark :eek:

I wonder if a simple, short ground jumper around RC preamps would be overkill?

Do you have the power supply of the preamp plugged into a surge protector? I've got almost everything electronic plugged into these things around the house after losing a few items in a thunderstorm once.

Very sad news. :(

Will there be a memorial service before the burial? ;)

__________________________________

Is your antenna mounted near any high trees, etc, that the lightening could have flashed over to the antenna? Seems odd that it would just kill the preamp and not do any damage to other sensitive equipment.

That's a tough blow, Mark. Sorry to hear about it...

Jase, with your CN tower set-up, you must have been hit or nearly hit by lightning. Are you doing anything special to protect your pre-amp? Or maybe the CM7777 is one tough cookie?

I'm fortunate in that I have lots of mature trees in the immediate area that "compete" for height with my tower. Or I've just been lucky. Probably the latter.

In terms of amp protection, I've done nothing special. The 7777 is mounted directly to the mast, without any ground line by-pass. I've never unplugged the coax during a storm.

Though I have pondered replacing my amp with an RC--so this development with Mark's amp does interest me, as Kitchener (like most of Southern Ontario) also gets its fair share of storm activity throughout the summer.

One thought I had: The RC ships with an optional resin/PVC/non-metallic box, which I believe Mark is using. I wonder if using a metal box, mounted to the mast, would offer greater protection?

I was thinking about it today, and my antenna is the highest point in the immediate area. The subdivision is fairly new so there is no mature trees nor taller structures so I'm sure it is a haven for strong build up of static during thunderstorms. I am rethinking the grounding strategy as the pre amp mast is ahead of the ground block on the other side of the rotor.
I feel strongly that this was weather related and not from overload.
I have received an email from England stating they will be honoring the repairs.

I cannot help but wonder it all the precautions I have taken regarding the past storms have helped, ie turning off PS and unhooking the coax.

This is the same as the Winegard preamp issues I had previously, as in those cases I lost the preamps masts after storms also.

can you piggy back over the rotor to ensure a bonding ground to the top portion of the rotor to eliminate static build up, or do I have enough grounding as it exsists?

The RC amp has a metal exterior, which presumably has continuity with the coax shielding (outside of F spigots to coax). Even if you didn't have the antenna mast grounded, at the very least the coax ground should prevent static-related failure.

Mark, I know you've got the antenna grounded, but have you got a grounding block/arrestor installed before the coax enters your home? (you may have answered this before, if so, apologies for the redundant question)

And is there continuity between the amp and the mast ground?

I just find it odd this has happened twice...

To me, if your tower is indeed the highest point around ya, the best protection from lightning is to create a halo of protection
above ya. A Lightning Rod may be needed for that.

As for static buildup, followed by sudden discharge, may be able to do a little research on how we used to deal with it on Antenna Tuners a while back (in my previous life). If memory serves me correctly, we used to use some Shottky Diodes in the antenna tuner's directional coupler circuit, and they'd blow up occassionally from static out in the field. I may be able to dig up the exact circuitry that was involved, cause I vaguely remember a Mod that helped prevent and it did seem to help.

i.e. - worst case was, replacing the diodes, and back in business, instead of it building up so much and whacking everything else.

damn...gettin too old to remember that far back...

Jase as per the picture, with exception I have since replaced the rubber boot with 3M rubber tape on both ends. Also this is just under the roof vent and I have verified that no water is collecting or pooling there.

http://www.digitalhome.ca/forum/picture.php?albumid=120&pictureid=1202

also I have the roof vent lifted up so the coax is bent on one side, when the vent is brought back down it does not bend.

Naturally, like everyone else, I'm sorry about your RC. Glad to see it's getting repaired/replaced.

I'm certainly no expert but I would hazard that a lightning strike generates a tremendous amount of RF engery at all frequencies and a nearby strike could easily overload any preamp momentarily. A check with some neighbors if there was a strike close by may be a thought.

With the care you've taken with your installation, judging by the photos you've posted, I doubt you would have overlooked grounding. <- a compliment:)

quick addition: you guys were busy while I was typing this eh?

hmm, extra overload to an already overload circuit. I can buy that theory.
Indeed we were barnstorming there.

what I was recalling is a balanced circuit on the antenna side, static would buildup on the the antenna, and discharge internally in our antenna tuner, thus destroying some sensitive electronics inside...
There was something we had changed in the product to help bleed off the static buildup slowly (safely)...That's what I'm havin trouble recalling.

Cause it sounds like that may be what happened. Just thinkin if there was a direct strike nearby, u'd KNOW it (some other evidence nearby). Static in the air slowly building up when thunderstorms are nearby is a pretty common cause of destroying electronics. That Pre-Amp you have likely has a highly sensitive active device of some sort inside...(GASFET, whatever....)

If anything comes back to me I'll let ya'll know in here...

Edit: No, I don't think so. Was more to it than that, cause it's essentially an RF network in question.
I sent an email to an old buddy, asking for details and a drawing, he'll remember...
\/\/\/\/\/\/

is it a MOV, cause I have tons of those in my work truck that I use on low voltage 24 volt AC circuits to reduce premature failure on sensative A/C electronics from ie: brown outs?

Well, Mark, it certainly looks like you've done everything right with regards to your setup; you've done your research and know what you're doing. I suppose you'll just have to wait for the post-mortem on the amp from RC to get confirmation of static damage...

Mark you were asking about jumpering around a rotor and I know people who have done that so consider it as an option.

Make any sense to ya?
The typical Static/Surge suppression / grounding blocks are usually mounted near
where the cables enter the building, which is too late for ur pre-amp input.

Would it be possible to fabricate from a little bud box with Female F-Connectors,
and use really short Jumper Cables between antenna, ur bud box, and the pre-amp
input. Inside the bud-box install a couple 10 Mohm resistors in parallel.
That should bleed off any static buildup, without disturbing the low impedance
of ur antenna. Install the contraption on top of the tower (assuming that's
where the pre-amp is).

Short length of
To Preamp RG6 Center To Antenna
Conductor Only

5-10 Mohm Resistor
to ground

Any decent amp will have a Shottky Diode or something similar to protect it from static discharge. A concern I had with the bow tie M4 antenna was that there is no way to discharge static except through the preamp. (A folded dipole grounds itself to the mast but a bow tie does not.) To overcome that, I attached a grounding block to the mast before the preamp. Small in-line surge protectors are also available if extra protection is desired (I believe they often contain a Shottky Diode.) I used #8 wire for grounding the mast, instead of the smaller stuff that most antenna suppliers sell. #10 solid should also be adequate but I wouldn't use #10 stranded or smaller. Tall towers and masts require much heavier conductors and much better grounding methods than a 6' grounding rod sold by most OTA retailers.