Freq range of radio greater than freq range of antenna - any possible problems ?

GKLdiy88

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Don't bother with a 4ft ground rod, 8ft minimum as mentioned. Here is something to think about, grounding per NEC is for human safety and not necessarily for lightning protection. It would be very difficult and expensive to build a grounding system that might survive a direct lightning hit so maybe its best to accept that fact and just ground for human safety.

That should be satisfied with a ground block or lightning arrestor in the feedline which is grounded to the house AC panel ground with 10ga or larger copper wire per NEC. The mast will then be grounded via the feedline and that should satisfy NEC. Anything beyond this is $$ that will not do anything to protect against a direct lightning hit, unless you take the big step and hire an outside professional firm and spend a lot of $$.
Thanks, I had heard about it being very expensive to protect from a direct hit and mostly might only see that on commercial installations rather than private homes. I just wish my service ground was not so far away from where the 8 foot grounding rod needs to be put under where the antenna mast will be as it will be about a 50 foot run of ground wire to go from the back of the house around a corner to the front where the service ground is at.
 

prcguy

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Thanks, I had heard about it being very expensive to protect from a direct hit and mostly might only see that on commercial installations rather than private homes. I just wish my service ground was not so far away from where the 8 foot grounding rod needs to be put under where the antenna mast will be as it will be about a 50 foot run of ground wire to go from the back of the house around a corner to the front where the service ground is at.
Its not uncommon to run the ground wire from an antenna or satellite dish across the roof and down if its a shorter path. Its also good to keep the ground wire external of the house. Your ground rod at the base of the mast requires at least #6 copper wire to bond to the main house ground rod but if you didn't have that ground rod the NEC requirement for grounding the antenna or feedline to the main house ground is #10 copper wire.
 

GKLdiy88

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Just wanted to see if anyone has had any actual experience using these two products at the links below, I wish I could just buy the top of the line more expensive versions, but I really need to try to stay within a fairly tight budget after all I already spent on hobby stuff so far since January.

XRDS -RF CB Coax Cable 12FT, KMR 400 UHF Coaxial Cable PL-259

XRDS-RF UHF Lightning Arrestor PL-259 Lightning Surge Protector

I have a Comet GP-1 antenna I am waiting to put up and need the 12 ft coax to go from the antenna to where the other cable will come out of the house with the surge protector connecting the two.
 

mmckenna

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Just wanted to see if anyone has had any actual experience using these two products at the links below, I wish I could just buy the top of the line more expensive versions, but I really need to try to stay within a fairly tight budget after all I already spent on hobby stuff so far since January.

XRDS -RF CB Coax Cable 12FT, KMR 400 UHF Coaxial Cable PL-259

Never used it. What worries me about it is that they are using the "KMR400", like they want you to think it's similar to LMR400. LMR-400 is pretty stiff and wouldn't be rolled into a tight coil like it shows on the Amazon page. To me, that's a red flag.

I get the budget issues, though. For a short run, do the best you can.
 

GKLdiy88

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Never used it. What worries me about it is that they are using the "KMR400", like they want you to think it's similar to LMR400. LMR-400 is pretty stiff and wouldn't be rolled into a tight coil like it shows on the Amazon page. To me, that's a red flag.

I get the budget issues, though. For a short run, do the best you can.

Thanks, I know that 100% of Amazon reviews might not always be trustworthy but it does have a 4.6 out of 5 rating.

It's just that places like DX Engineering want to charge high prices for a short piece. (with shipping it would be about $60 for just a 12 foot piece)
 

mmckenna

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Thanks, I know that 100% of Amazon reviews might not always be trustworthy but it does have a 4.6 out of 5 rating.

It's just that places like DX Engineering want to charge high prices for a short piece. (with shipping it would be about $60 for just a 12 foot piece)

The problem with Amazon reviews is that you have no idea what the buyers are comparing it to.
The cable should work fine for most uses. But how it compares to other cables would take someone knowledgeable and having the right test equipment.

Essentially the Amazon reviews are only good for "Some random dude on the internet claims…."
 

GKLdiy88

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The problem with Amazon reviews is that you have no idea what the buyers are comparing it to.
The cable should work fine for most uses. But how it compares to other cables would take someone knowledgeable and having the right test equipment.

Essentially the Amazon reviews are only good for "Some random dude on the internet claims…."
Not to be confused with "Some random dude on radioreference.com giving you advice about coaxial cable…." ;)
:LOL:

That is why I was hoping someone on the forum might have had actual experience with how either product worked.

Even if it is not as good as the high priced versions, is it at least reasonably good enough to still be worth getting.
 

mmckenna

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I ran 50 feet of Radio Shack(!) RG-8 for my GMRS base for a long time. Yeah, it wasn't "perfect", but it did exactly what I needed it to. A few people tried to shame me for it, but that's OK. It connected the radio to the antenna and I was able hear and talk to the people I needed. Budgets matter, especially when there is a significant other involved.

I think you'd be just fine with that cable.
 

GKLdiy88

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I ran 50 feet of Radio Shack(!) RG-8 for my GMRS base for a long time. Yeah, it wasn't "perfect", but it did exactly what I needed it to. A few people tried to shame me for it, but that's OK. It connected the radio to the antenna and I was able hear and talk to the people I needed. Budgets matter, especially when there is a significant other involved.

I think you'd be just fine with that cable.

Thanks for sharing your RG-8 story, my wife has been pretty patient with my hobby spending, but I still need to do my part in trying to be budget minded, while still getting stuff worth getting.

Any hobby would not be anywhere as much fun if my wife was upset from me spending way too much over budget on hobby stuff :LOL: My wife does not mind me having a hobby at all, but I can appreciate needing to try to keep the spending within reason.

Like some hobbies, this is one of those hobbies where "odds and ends" can start adding up fast :LOL:

It is a hobby though that can be enjoyed on a fairly modest level, or for those who can afford it at a level that might cost more than both of our cars :LOL:

Hey, if any of us won the "Publisher's Clearing House Sweepstakes" we might consider getting the most powerful radios allowed with the highest antenna tower allowed and a state of the art setup to rival a commercial setup :LOL:

Anyhow, I have learned to be content and enjoy what I can afford and still have fun regardless ! :D
 

mmckenna

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Anyhow, I have learned to be content and enjoy what I can afford and still have fun regardless ! :D

That's the most important part. This can easily turn into a very expensive hobby.
I limit myself with it, but that's easy to do because I usually get my fill of radio stuff at work, plus I have some cool takehome radios.

A simple base radio and a good antenna will be rewarding on its own. Use whatever coax you can get your hands on, and do what grounding you can. It doesn't need to be perfect, just safe.

And by all means, keep the Minister of War and Finance happy, lest you be doing KP for the next 10 years.
 

GKLdiy88

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That's the most important part. This can easily turn into a very expensive hobby.
I limit myself with it, but that's easy to do because I usually get my fill of radio stuff at work, plus I have some cool takehome radios.

A simple base radio and a good antenna will be rewarding on its own. Use whatever coax you can get your hands on, and do what grounding you can. It doesn't need to be perfect, just safe.

And by all means, keep the Minister of War and Finance happy, lest you be doing KP for the next 10 years.
:LOL:

Thanks for the encouragement, I am leaning towards getting that cable, now I just need to be sure this part is okay to get -

XRDS-RF UHF Lightning Arrestor PL-259 Lightning Surge Protector

I'll be researching it more later.

......hey, as long as I watch the budget for hobby stuff and I don't let my hobbies keep me from doing my chores and household projects my wife doesn't mind my hobbies at all :D
 

mmckenna

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That protector will probably be just fine. Like prcguy said above, there's not much you can reasonably do to protect against a direct strike, at least not in the hobby realm.
Your goal is to get stuff properly grounded per code, and protect your home from a nearby strike.
 

GKLdiy88

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That protector will probably be just fine. Like prcguy said above, there's not much you can reasonably do to protect against a direct strike, at least not in the hobby realm.
Your goal is to get stuff properly grounded per code, and protect your home from a nearby strike.
Thanks again, and I do plan on grounding both the mast and the protector to a rod below the mast as well as a wire to bond that rod to the main service ground, definitely want to be safe !
 

mmckenna

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Thanks again, and I do plan on grounding both the mast and the protector to a rod below the mast as well as a wire to bond that rod to the main service ground, definitely want to be safe !

I'm fortunate that I live in a place where lightning storms are extremely rare. I still ground my stuff at home, and absolutely do at work.
Lightning can do a lot of damage, even nearby strikes. It doesn't play by our rules, though, so doing the best you can is a good plan.
 

GKLdiy88

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I'm fortunate that I live in a place where lightning storms are extremely rare. I still ground my stuff at home, and absolutely do at work.
Lightning can do a lot of damage, even nearby strikes. It doesn't play by our rules, though, so doing the best you can is a good plan.
I agree, lightning storms are fairly rare in our local area, but not totally unheard of, but I'd rather have things properly grounded too anyhow.
 

K7MEM

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It was a dark and stormy night....

The only thing predictable about lightning is it's unpredictability. You shouldn't be afraid of lightning, as long as you are prepared. If there is a storm heading your way, disconnect the coax from your radios. You don't even need a close encounter with lightning to generate damaging static and surge. Blowing winds and dry conditions is all you need. A surge protector will help protect against this static.

I use to live in a rural area in Northern Arizona, near the Grand Canyon. Our altitude was about 5,300 feet ASL. I had a 5BTV that was mounted at the top of a 18' section of 2" iron pipe. That put the top at around 40'. The antenna worked well but one stormy day, I forgot to disconnect the coax from my radios. A nearby strike generated so much static that the 80 Meter resonator exploded into thousands of little tiny pieces, spread over about a 50' radius. The rest of the antenna survived, but the tuner that was connected to the end of the coax, was turned into scrap metal. There were a few extra holes in the case and everything inside was welded together. Luckily, the tuner saved my radio from damage.

Now that was just a nearby hit. I have also observed direct hits. Direct hits are difficult to watch without dark sunglasses or a welding mask. The fireball is very intense. I have seen a direct hit reduce a 50' tree to ashes, in minutes. If it hit an antenna, it would be total scrap metal.

As I said in the beginning, don't be afraid, be prepared.
 

GKLdiy88

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It was a dark and stormy night....

The only thing predictable about lightning is it's unpredictability. You shouldn't be afraid of lightning, as long as you are prepared. If there is a storm heading your way, disconnect the coax from your radios. You don't even need a close encounter with lightning to generate damaging static and surge. Blowing winds and dry conditions is all you need. A surge protector will help protect against this static.

I use to live in a rural area in Northern Arizona, near the Grand Canyon. Our altitude was about 5,300 feet ASL. I had a 5BTV that was mounted at the top of a 18' section of 2" iron pipe. That put the top at around 40'. The antenna worked well but one stormy day, I forgot to disconnect the coax from my radios. A nearby strike generated so much static that the 80 Meter resonator exploded into thousands of little tiny pieces, spread over about a 50' radius. The rest of the antenna survived, but the tuner that was connected to the end of the coax, was turned into scrap metal. There were a few extra holes in the case and everything inside was welded together. Luckily, the tuner saved my radio from damage.

Now that was just a nearby hit. I have also observed direct hits. Direct hits are difficult to watch without dark sunglasses or a welding mask. The fireball is very intense. I have seen a direct hit reduce a 50' tree to ashes, in minutes. If it hit an antenna, it would be total scrap metal.

As I said in the beginning, don't be afraid, be prepared.
Thanks for sharing that !
 

GKLdiy88

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Seems like I sometimes keep seeing some things that I sometimes wonder if it is "optional" or an "absolute must"....

.......for instance a "balun" I will be installing a small modest "Comet GP-1" antenna, would a "balun" fall under optional or not necessary for a "Comet GP-1" ?
 

AK9R

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Balun is short for "balanced-unbalanced". The basic answer is that if you are feeding a balanced system (two wires separated from each other) with an unbalanced feedline (coaxial cable), you need a balun to connect the two. There's much more theory behind that answer that others here can expand on for you.

The antenna you mention has a coaxial feed point, i.e. unbalanced. You will be feeding it with a coaxial cable, i.e. unbalanced. Therefore, a balun is not necessary. That said, in some situations, a choke may be necessary in some situations to keep RF off of the feedline or an "un-un" may be necessary to transform between two unbalanced transmission lines.

The radials on that antenna, the three "spikes" that jut out at the base of the antenna, should keep the RF off of your feedline.
 
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