I apologize for coming straight out of the box with a question which has probably been answered, however I cannot find the solution for this problem.
I have a cmm site which has been hit by lightning twice in the last 8 months, both times coming in through the gps side of things, and taking out the cmm. I have been researching lightning arrestors for the GPS cable, and this is the best I have come up with
http://www.tessco.com/products/headerPr … rchField=1
any other suggestions would be appreciated.
sir yes sir. We currently are looking into the same thing as we have had 2 lightening strikes in 8 months as well. As soon as we know something we will let you know, on the flip side, you do the same? 
You make me giggle Jamie. On a side note, Celerity’s equipment and mine are co-located, therefore the same problem did happen at the exact same time.
Your kidding? Ohhh thats right… your from DEL-CO. Hey I have a new number, you called the wrong number this morning. I have a solution I do believe so lets discuss it sometime. Call me - 496-9899.
TONY -
Try this… We are going to use one of these to test at our Sunbury test site to see if it causes any issues. This might be our solution:
http://altelicon.zoovy.com/category/lig … operation/
We use the N-Female to N-Female Bulkhead
FYI: Whatever you use needs to be able to pass DC voltage.
I’ve been supplying the following protector for several years with no deaths of equipment…
Motorola p/n RRX4059A (Polyphaser MR50LNZ+15) List $can’t find it…approx. $100 or thereabouts.
Good luck, 8)
Keir
I appreciate all the advice. I have been working on RF communications for 15 years now, and in that time I have used several mfg’s of lightning arrestor. PolyPhaser has been the most reliable in my experience although they are more expensive. I have already ordered the DGXZ+06NFNFA model. According to what few specs I can find on GPS this arrestor should be fine, its a DC pass, multi-strike arrestor with a freq range of 800 - 2500Mhz. the one thing I could not find is the voltage pass requirements for the antenna, I am assuming it is 6 volts.
Keir,
I did find the MR50LNZ+15 at tessco for $78 (gold pricing). This model is designed to pass 15 volts, so if the one I ordered does not work I will re-order this model.
My final concern on this, is signal loss. Theory goes… for every connector in a cable you lose 3db of gain. I use LMR-400 for the gps cabling however I am afraid I may have to re-mount my GPS closer to the CMM to compensate for the extra connectors. This will work itself out when the parts are in though.
FWIW: We have a GPS antenna with 25’ of LMR400 and a coupler and it works fine.
I don’t have to tell you GOOD WRAPS! The mount for the GPS makes it hard to get a really good seal (dumb design).
I don’t seem to any problems sealing the GPS antenna.
Just un screw the large locking nut from the GPS and slid it over the cable, then screw the connector onto the GPS unit then wrap electrical tape from the bottom of the heat shrink on the connector all the way up to the GPS antenna, then wrap mastic rubber tape over the same area, making sure to squeeze out all the air bubbles. Then starting from BELOW the heatshrink on the connector do 3 passes with heavy electrical tape, once up to the GPS then back DOWN to below the rubber mastic then back up again)Make sure the first pass of electrical tape is loose and the last 2 or as tight as you can get them. Then slide the locking nut up and tighten it down to the mount.
I worked for a guy in Tennessee who taught me a really cool trick to sealing RF connectors.
1. make wrap with electrical tape, in the normal direction
2. reverse direction, so that the sticky side is out.
3. wrap the desired arear with sticky side out.
4. layer of mastic… rubber sealant. what ever you want to call it
5. finish with electrical tape in normal direction.
Advantage:
If you ever have to cut the seal on the antenna, one clean cut, and you dont have any cleanup of the connectors to do!
Yup that’s right Tony,
Thing is you need to to make 3 passes with the electrical tape after you put the MASTIC on. Start at the bottom and then go up and then down again, this will create a shingleing effect.
I installed this polyphaser:
http://www.tessco.com/products/headerPr … rchField=1
and it worked flawlessly. Prior to polyphaser install, 9 satelites tracked after: 9 still.