Proposed new antenna setup

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w1av

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I currently am using a Diamond discone up about 20' mounted on back of garage (detached) with a 60' coax run. I am thinking the coax that came with this antenna is not too good...thin rg58 or something. After using this setup for one year, evaluating, I find I have plenty of regular analog signals from all over to listen to. All vhf and uhf.
I don't have digital capabilities (yet) but there are LOTS of standard FM signals to listen to. Scanners are basic Bearcat Uniden BC700A and BD350A.
What I am thinking is better coax. With a 60 foot minimum run maybe the LMR 400 would do the trick and new antenna I am looking at is the Diamond X200a. I've used amateur antennas as monitoring antennas before and they have much better gain that the discone. And seeing that I am only really listening to vhf/uhf, this would suit my purposes better. I dont really want to go over the 8' height of the X200a. I live in a reasonable good location on small hilltop. Here is picture of what my setup is.
The small vertical dipole is cut for aviation band. I live only a few miles from airport and can hear tower ok. Plus I couldnt raise it up much higher. My room is where the coax goes in thru window. Wife said I can do what I want on garage but not house. And I cant climb anymore so getting up on roof is a no go. I live in Cranston RI and like to listen to the police/fire over in eastern Mass. Most are on UHF and I can hear them OK but with crappy thin coax and a no gain antenna I think I can do better. Plus I have 2 HUGE hills to the east and west of me. Luckily signals get thru ok. Nothing to the west to listen to. Its all mostly north, south and east.

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Peerlessk

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LMR-240f is an option also . Your setup close to mine . If you were going to go the height of 60 or more I would say LMR-400 but in this case 240f is great . The discone really works like most of them out there on the market . Someone reading this is going to argue this . But if your not transmitting then they all do the same thing . Wide band . The fault of your setup would more than likely be the coax .
 
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w1av

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Yeah I did have the ground attached to the bottom of mast down to copper rod in ground but when I repainted garage wall, I took the ground off cause it was in my way so I will re attach when I go back out.
 

Ubbe

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If you are monitoring 450Mhz signals you only have 1/4 of the signal left after a 60' lenght of RG58. At 800Mhz it will be 1/10 left for the scanner to use. At 150MHz you only cut the signal in half so that are acceptable.

There's no reason to not switch to RG6 coax. It is not as good as LMR400 but better than LMR240 and conciderable less costly and easier to install and to put connectors on. RG6 has 2,7dB loss at 450Mhz and LMR400 has 1,6dB using 60 feet coax and RG58 has 7dB.

/Ubbe
 

Frankhappyg

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That’s to bad you can’t mount to the side of the house where your window is.
Your run would be less then 12 feet.


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KB4MSZ

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I'm somewhat new to the scanner world, although I do plan to buy one soon to augment my mobile Ham station. My intention is to install it behind the seat of my truck, and then it will just run mostly unattended and full time. I assume the current draw isn't going to be a problem, I have had cross-band repeaters operating overnight without issue.

The thought I had with W1AV's situation is that if the scanner is mostly an unattended appliance that you just listen to, maybe it would be possible to install the scanner in the garage and use some sort of wireless transmission to send the audio output to the house. This would both greatly shorten the coaxial line, and it would also permit listening to the scanner most anywhere in the house as well. Just a thought.
 

nyair1

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Diamond discone is a really good all around antenna. I wouldnt change it out. Best to get better cable for it and if you can get it up higher and put your ground back on. You can also get rid of the top whip on it. Thats only for low band.

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krokus

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If you are changing things out, what about a tripod on the roof, on the breezeway? That would shorten your run by quite a bit.

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w1av

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Diamond discone is a really good all around antenna. I wouldnt change it out. Best to get better cable for it and if you can get it up higher and put your ground back on. You can also get rid of the top whip on it. Thats only for low band.

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Yes this was one of my first considerations. But I am still torn with the fact that the discone has NO gain, while the Diamond X200a HAS gain (on both vhf/uhf). And I have used amateur radio verticals as scanner antennae in the past with very good results. Plus I also agree that replacing the coax may be good too. But I don't really want to have to take this thing down more than once cause I have bad left shoulder.
 

w1av

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If you are changing things out, what about a tripod on the roof, on the breezeway? That would shorten your run by quite a bit.

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I originally thought of that till wife reminded me about all the new vinyl siding we had done! She said garage is fair game though so I figured I may have a 50' run, but also can mount more than 1 antenna. I wish I could get up on roof and use chimney....I'd be able to get more height. But my climbing days are over. As you can see the roof pitch near my room is very steep. I tried getting up there last year but there is nothing to grab onto to hoist myself up.
 

w1av

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If you are changing things out, what about a tripod on the roof, on the breezeway? That would shorten your run by quite a bit.

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Yes I originally was going to put a tripod on roof of garage but my stupid ladder doesnt extend far enough to get up there. Unfortunately the breezeway roof is also off limits. I didnt wanna press my luck trying to negotiate too much since I have total freedom with garage for mounting. The thing is in the past I averaged out most of my coax runs were around 50' give or take. And I always had good reception in other places I have lived. 50' isn't too bad but I really think my main issue is the crappy coax that came with that discone. I probably should have ordered better coax before putting it up. But I figured for the cost of the antenna, the coax that came with it should have been good. But it probably is junk. I get better reception on some freqs with that homebrew dipole! And I am using cable TV coax (75 ohm) with very good results. I read that for recieving, 75 ohm cable is fine and it works pretty good with that dipole.
 

w1av

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Diamond discone is a really good all around antenna. I wouldnt change it out. Best to get better cable for it and if you can get it up higher and put your ground back on. You can also get rid of the top whip on it. Thats only for low band.

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What I might end up doing is still getting that vertical X200a with new coax run. Then I will replace coax for the discone and use that for my aircraft monitoring. Yeah that top whip isnt really needed cause there isnt any lowband activity around here. And the discone is so lightweight I could set up a new spot for it and try to get it up higher. I am looking at 2 or 3 ten foot sections of chain link fence top rails. Bracket them to garage wall. But not sure how flexible those pipes are. The 10' galvanized ones better but heavier and costly.
 

prcguy

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Ham antennas like the X200 work as advertised within the ham bands but if you go too far out of band all bets are off and the Discone may work better. I've noticed this on 162MHz weather channels where a broad band no gain antenna outperforms a high gain but narrow band ham antenna. The Discone will be hard to beat for VHF and UHF air bands.

Fence top rail comes in 21ft lengths and I'm currently using one of those to hold up the end of a 133ft wire antenna where the first four feet are bolted to a cinder block wall. It bends a little but its better than three separate sections joined together.

What I might end up doing is still getting that vertical X200a with new coax run. Then I will replace coax for the discone and use that for my aircraft monitoring. Yeah that top whip isnt really needed cause there isnt any lowband activity around here. And the discone is so lightweight I could set up a new spot for it and try to get it up higher. I am looking at 2 or 3 ten foot sections of chain link fence top rails. Bracket them to garage wall. But not sure how flexible those pipes are. The 10' galvanized ones better but heavier and costly.
 

nyair1

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Yes this was one of my first considerations. But I am still torn with the fact that the discone has NO gain, while the Diamond X200a HAS gain (on both vhf/uhf). And I have used amateur radio verticals as scanner antennae in the past with very good results. Plus I also agree that replacing the coax may be good too. But I don't really want to have to take this thing down more than once cause I have bad left shoulder.
Ive been using a ST4 discone for 20+ years with great results. I have davis bury flex rg8 coax about 50ft length in my run. Antenna is about 30ft in the air. If you cant go up on the roof anymore try looking for someone that installs tv antennas and have them give you a estimate on getting it up higher or maybe check with a local.ham radio club. Lots of times they have someone or members that can still climb roofs. Just a few ideas.

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w1av

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Ham antennas like the X200 work as advertised within the ham bands but if you go too far out of band all bets are off and the Discone may work better. I've noticed this on 162MHz weather channels where a broad band no gain antenna outperforms a high gain but narrow band ham antenna. The Discone will be hard to beat for VHF and UHF air bands.

Fence top rail comes in 21ft lengths and I'm currently using one of those to hold up the end of a 133ft wire antenna where the first four feet are bolted to a cinder block wall. It bends a little but its better than three separate sections joined together.

Yeah that is probably true with going outta bands on ham antenna. I guess the "Q" of antenna is specifically for those intended bands. The more I am reading on here the more I am inclined to at least replace coax and try to gain a few more feet of height with discone. That route HAS to be better than what I have been using the past year. I was also thinking of making a dual band dipole for vhf/uhf since I get great results from my homebrew vhf dipole. But building those dipoles is a real pain.
 

Ubbe

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It is the wind resistance that strain the installation much more than any weight of the antenna can do.

I have a 5/8 GP antenna for VHF air and a amateur dualband diamond X510 and the X510 are the same, if not better, than the 5/8 in vhf airband. It seems to work really good in all VHF-UHF bands outside of the amateur frequencies.

/Ubbe
 

w1av

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It is the wind resistance that strain the installation much more than any weight of the antenna can do.

I have a 5/8 GP antenna for VHF air and a amateur dualband diamond X510 and the X510 are the same, if not better, than the 5/8 in vhf airband. It seems to work really good in all VHF-UHF bands outside of the amateur frequencies.

/Ubbe

Well my thinking is the frequencies outside the ham bands I listen to are not really that far away from the ham bands. When I was an active ham back 20 years ago, I always used ham antennas for my scanners. I did notice that the amateur gain antennae worked a little better than a standard scanner antenna. But also there are alot of variables too. Location. I live in an acceptable spot for adequate reception. However there is a big rise in the land to my east....then it slopes down low again. I like listening to the Massachusetts communications on 855 Mhz. Up on the hill, it comes in strong....but it doesnt even break squelch at home. I am in Rhode Island, center of state. That Mass frequency has a TON of action....Maybe an 800mhz BEAM antenna would help but they are too expensive. Well there is still plenty of analog stuff available....more than my scanner will hold in memory.
 
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