Diamond Discone coax upgrade

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w1av

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Finally, after over a year I replaced my original coax run and mast. Last January (2018) I bought a Diamond Discone antenna. It came with really thin cheap coax. I should have swapped that coax out to begin with. But, alas I used it anyway....local reception wasnt too bad. I also made a few vertical dipoles out of old aluminum stock. I had a bunch of 75 ohm TV coax so I used that for the dipoles. Dipoles were not up very high and received VERY well even tho coax was mismatched. But for receiving I doubt it mattered much on airband and vhf. One day I was messing around with my Radio Shack Pro 2055 trying to program some trunked Mass State Police freqs.....Those freqs are up in the 800 mhz range but I was hearing them on a VHF dipole! I live in Rhode Island with a sizeable hill to my east. I also noticed when I switch antennas to the discone I couldnt hear a thing on the trunked channels! I figured that cheap flimsy coax that came with the discone was garbage for sure. So I ordered a 50' length of LMR 400, the REAL stuff. And I also ordered 3 sections of 16 gauge mast at 5 feet long a piece. I replaced the crappy coax and the cheaper 18 gauge mast sections I bought at Lowe's. Got everything all put back together today and what a difference. I am hearing things that I previously couldnt hear. Even though the LMR is VERY stiff, it was still easily routed with gentle bends around corners. It seems very similar to the 9913 I used when I was into ham radio. I am still licensed but inactive. I had just enough of a cable run to go directly from antenna to radio with no slack! Perfect length. I may eventually put one of those vhf dipoles up again to use with an extra Uniden BC700a scanner in here. I was using that for monitoring ACARS. When I put the discone back up today I didnt bother to add the dipole to the mast. I gotta clean all the connections and then put it up. Anyway attached is a picture of antenna. I mounted it to back of garage. Unfortunately my ladder wasnt long enough to be able to mount brackets closer to the roof peak. And climbing on roof off limits. I was still able to get the new mast up a bit higher anyway. Going to store tomorrow to get grounding rod and wire.
 

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prcguy

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Nice to hear about an upgrade that has a good outcome. If you add a ground rod, NEC requires you to bond that rod to your house main electrical panel ground in a specific way. See NEC article 810 on the Internet for more info.

Finally, after over a year I replaced my original coax run and mast. Last January (2018) I bought a Diamond Discone antenna. It came with really thin cheap coax. I should have swapped that coax out to begin with. But, alas I used it anyway....local reception wasnt too bad. I also made a few vertical dipoles out of old aluminum stock. I had a bunch of 75 ohm TV coax so I used that for the dipoles. Dipoles were not up very high and received VERY well even tho coax was mismatched. But for receiving I doubt it mattered much on airband and vhf. One day I was messing around with my Radio Shack Pro 2055 trying to program some trunked Mass State Police freqs.....Those freqs are up in the 800 mhz range but I was hearing them on a VHF dipole! I live in Rhode Island with a sizeable hill to my east. I also noticed when I switch antennas to the discone I couldnt hear a thing on the trunked channels! I figured that cheap flimsy coax that came with the discone was garbage for sure. So I ordered a 50' length of LMR 400, the REAL stuff. And I also ordered 3 sections of 16 gauge mast at 5 feet long a piece. I replaced the crappy coax and the cheaper 18 gauge mast sections I bought at Lowe's. Got everything all put back together today and what a difference. I am hearing things that I previously couldnt hear. Even though the LMR is VERY stiff, it was still easily routed with gentle bends around corners. It seems very similar to the 9913 I used when I was into ham radio. I am still licensed but inactive. I had just enough of a cable run to go directly from antenna to radio with no slack! Perfect length. I may eventually put one of those vhf dipoles up again to use with an extra Uniden BC700a scanner in here. I was using that for monitoring ACARS. When I put the discone back up today I didnt bother to add the dipole to the mast. I gotta clean all the connections and then put it up. Anyway attached is a picture of antenna. I mounted it to back of garage. Unfortunately my ladder wasnt long enough to be able to mount brackets closer to the roof peak. And climbing on roof off limits. I was still able to get the new mast up a bit higher anyway. Going to store tomorrow to get grounding rod and wire.
 

nyair1

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Finally, after over a year I replaced my original coax run and mast. Last January (2018) I bought a Diamond Discone antenna. It came with really thin cheap coax. I should have swapped that coax out to begin with. But, alas I used it anyway....local reception wasnt too bad. I also made a few vertical dipoles out of old aluminum stock. I had a bunch of 75 ohm TV coax so I used that for the dipoles. Dipoles were not up very high and received VERY well even tho coax was mismatched. But for receiving I doubt it mattered much on airband and vhf. One day I was messing around with my Radio Shack Pro 2055 trying to program some trunked Mass State Police freqs.....Those freqs are up in the 800 mhz range but I was hearing them on a VHF dipole! I live in Rhode Island with a sizeable hill to my east. I also noticed when I switch antennas to the discone I couldnt hear a thing on the trunked channels! I figured that cheap flimsy coax that came with the discone was garbage for sure. So I ordered a 50' length of LMR 400, the REAL stuff. And I also ordered 3 sections of 16 gauge mast at 5 feet long a piece. I replaced the crappy coax and the cheaper 18 gauge mast sections I bought at Lowe's. Got everything all put back together today and what a difference. I am hearing things that I previously couldnt hear. Even though the LMR is VERY stiff, it was still easily routed with gentle bends around corners. It seems very similar to the 9913 I used when I was into ham radio. I am still licensed but inactive. I had just enough of a cable run to go directly from antenna to radio with no slack! Perfect length. I may eventually put one of those vhf dipoles up again to use with an extra Uniden BC700a scanner in here. I was using that for monitoring ACARS. When I put the discone back up today I didnt bother to add the dipole to the mast. I gotta clean all the connections and then put it up. Anyway attached is a picture of antenna. I mounted it to back of garage. Unfortunately my ladder wasnt long enough to be able to mount brackets closer to the roof peak. And climbing on roof off limits. I was still able to get the new mast up a bit higher anyway. Going to store tomorrow to get grounding rod and wire.
I used the bury-flex lmr400 cable on mine. Its very flexible if you ever need to get anymore.

Sent from my SM-G920V using Tapatalk
 

Ubbe

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Yes, hight is everything for antennas. The first part that clears your own roof and neighbours roof are the most important one and the next part above that will clear trees and other terrain obstacles. More height will also isolate more from the interferencies that generates from electronic devices in the house. The improvement you got have probably nothing to do with coax. At 900MHz and 50 feet the LMR400 attenuates 2dB and the RG6 3 dB.

/Ubbe
 

FKimble

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Next time get the LMR-400F (flex). Almost same specs just a lot more user friendly when not running it straight up a tower or mast. Also you may want to get a short jumper, as in 3 feet maybe, to take the strain off the antenna connector on the radio.

Frank KK4YTM
 

w1av

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Got the grounding all done today....8' long copper rod hammered into ground with heavy gauge copper wire and heavy duty clamps.
 

w1av

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Yes, hight is everything for antennas. The first part that clears your own roof and neighbours roof are the most important one and the next part above that will clear trees and other terrain obstacles. More height will also isolate more from the interferencies that generates from electronic devices in the house. The improvement you got have probably nothing to do with coax. At 900MHz and 50 feet the LMR400 attenuates 2dB and the RG6 3 dB.

/Ubbe
The antenna definitely clears many rooftops here with exception of a few 2 story homes, but they are not near me. I have 2 large hills to the west and east of me but they are at a good distance away. I stripped off the black covering on that cheap coax that came with the discone and I was right. It was VERY flimsy, crappy braid was thin and you can see the dielectric under it..
 

Ubbe

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I missread. I thought you had RG6 to start with but it was probably low quality RG58 and that makes a big difference at 800MHz and 50 feet to swap to something else. You went with LMR400 but that is only a 1dB difference to a more managable RG6 and if you want to save some money in the process.

/Ubbe
 

hsdtech

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I don't ground my antennas or masts. I just unhook my outdoor antennas AND any AC power to my radios during bad weather.
 

w1av

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And you DID bond that to the house electrical ground.

The house electrical ground is quite a distance from where I mounted/grounded this antenna. The antenna is mounted to my detached garage (in back) and grounded to 8' copper rod directly below mast. If I could have mounted antenna(s) on my CHIMNEY which is the ideal spot, I could have run ground directly down from chimney cause house elec. ground is right there next to chimney. Unfortunately roof is off limits!! I posted pics of the ground points further down in here in thread.
 

w1av

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Here is a detailed closer look at how I grounded the mast/antenna. I added my VHF airband dipole back up on mast. I know it is low on mast but I live pretty close to state airport and can hear tower from here even with antenna low. Plus I couldnt reach up much further anyway! The electrical wiring (lights) in garage are run over to main house to fuse panel in basement. Garage doesnt have its own panel. There is a small light and electric garage door openers. Chimney is not visible in the pics but thats where the house ground is waaaay over on other side of main house. There is an HDTV antenna on a short mast in my junk pile in one of the pictures. I planned on using it as experimental scanner antenna and it works really good turned sideways (vertical plane). But it is a real flimsy design with limp plastic parts that wont stand up to weather. Somebody gave me the antenna. I might scavenge the aluminum parts off it to make something else.
 

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737mech

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How's the upgrade working for you? I enjoy seeing people making improvements but sometimes they get caught up and forget to report how well it worked. It looks great!
 

prcguy

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Certain things are a must do like bonding the ground rod to the house electrical panel with the specified size wire. If not then why bother grounding at all? Its not doing anything useful the way you have it.

The house electrical ground is quite a distance from where I mounted/grounded this antenna. The antenna is mounted to my detached garage (in back) and grounded to 8' copper rod directly below mast. If I could have mounted antenna(s) on my CHIMNEY which is the ideal spot, I could have run ground directly down from chimney cause house elec. ground is right there next to chimney. Unfortunately roof is off limits!! I posted pics of the ground points further down in here in thread.
 

JoshuaHufford

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Certain things are a must do like bonding the ground rod to the house electrical panel with the specified size wire. If not then why bother grounding at all? Its not doing anything useful the way you have it.

So how far away do you need to be before you don't need to bond everything together? Obviously you can't bond your grounding system to your neighbors.
 

prcguy

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If you add a ground rod that is electrically connected to anything that runs off common AC power in your house, you need to bond that ground rod to the house electrical entry point. NEC specifies a minimum of #6 copper wire for this and there are length limitations where you must upsize that wire if the run is over a certain distance. There is no provision for not bonding a ground rod to the electrical entry point due to distance.

If you've ever watched a DirecTV installer put a dish in, they survey the house for two things, a clear shot to the satellites and a short run of ground wire to the electrical panel not to exceed about 30ft.

If your chimney is an ideal spot for a shorter run of coax and ground wire, I would find a way to get the antenna there and ground it to code at the minimum.
 

w1av

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If you add a ground rod that is electrically connected to anything that runs off common AC power in your house, you need to bond that ground rod to the house electrical entry point. NEC specifies a minimum of #6 copper wire for this and there are length limitations where you must upsize that wire if the run is over a certain distance. There is no provision for not bonding a ground rod to the electrical entry point due to distance.

If you've ever watched a DirecTV installer put a dish in, they survey the house for two things, a clear shot to the satellites and a short run of ground wire to the electrical panel not to exceed about 30ft.

If your chimney is an ideal spot for a shorter run of coax and ground wire, I would find a way to get the antenna there and ground it to code at the minimum.

Wow this totally makes sense. I wanted to use chimney originally. But I have bad shoulder and cant climb. I suppose I could get somebody to do it. We have a friend who is an electrician who is younger and able to climb. I will make him an offer to install antennas on chimneys. I need to get a strap mount but they are easy to order from Amazon. All I really use is 2 antennas, the discone and my home made dipole for vhf. Plus chimney mount will give me a few more feet higher. The house electrical ground is directly below the chimney in ground. I am no electrician but as a side note, is it possible to use the ground side of electrical connection in garage? There is switch for garage door openers and light. Could I run a copper ground wire to that? It would be a short run maybe 10 or 12 feet from mast. Just as a temporary measure for now till summer when I can schedule roof climbing.
 

prcguy

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In your case the chimney sounds like an ideal place for an antenna based on short grounding distance and a shorter coax run plus the height. Don't take my advice on grounding, go by the NEC Article 810 specs and here is one of many papers on the subject.
http://www.reeve.com/Documents/Articles Papers/Reeve_AntennaSystemGroundingRequirements.pdf

Wow this totally makes sense. I wanted to use chimney originally. But I have bad shoulder and cant climb. I suppose I could get somebody to do it. We have a friend who is an electrician who is younger and able to climb. I will make him an offer to install antennas on chimneys. I need to get a strap mount but they are easy to order from Amazon. All I really use is 2 antennas, the discone and my home made dipole for vhf. Plus chimney mount will give me a few more feet higher. The house electrical ground is directly below the chimney in ground. I am no electrician but as a side note, is it possible to use the ground side of electrical connection in garage? There is switch for garage door openers and light. Could I run a copper ground wire to that? It would be a short run maybe 10 or 12 feet from mast. Just as a temporary measure for now till summer when I can schedule roof climbing.
 

ridgescan

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prcguy-w1av asked if he could ground to the electrical at the garage, which I assume leads to house electrical via conduit> So wouldn't that conduit essentially act the same as running a ground wire, but even better if that conduit runs underground to the house? And I also am assuming his garage electrical is already bonded to house electrical.
 
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