Diamond Discone N --->no coils STILL DEAD

[CookeCityScanner]

Hey guys, I am new to this forum so bare with me. I am also relatively new to scanning. I have attached some photos of my two antennas I have erected. One is a RS discone and one is a Diamond Discone with N connectors. The RS uses RG 58/u w/ pl259s and the Diamond uses 9913 w/ Ns. I am using a Uniden 898T at the moment. I live right outside of Yellowstone National Park so I can pick up all sorts of park frequencies as well as frequencies (through repeaters) from Cody, Wyoming. I got the scanner because I wanted to listen in on any law enforcement activity in the area. The stock whip antenna picked up a few signals but not much. I then bought the RS Discone and erected it and WOW Im getting tons of stuff I never got before. For example I was never able to pick up the NOAA WX bands until I was about 50-60 miles from my current location with the stock antenna. Oh also I have never even tried the scanner on the Diamond antenna yet which has FAR superior cable according to many of you especially for some of the higher frequencies.

Anyway maybe you guys could tell me some extra things I shoudl do for safety or anything else that might come to mind. Both masts are 1/2" steel. At the top I had to use like a 1 foot LP pipe section to get the Ubolts tight. The RS is the one coming through the roof but on the outside of the building and the Diamond is located on the backside of the riser on that other building. My only fear with the RS mast is that it is 2 10' sections and the union may be a weak point. My main concern is right now they are just up there. How should I ground them. I understand lightning is lightning and they will be destroyed but a groud also gets rid of static discharge as well as I understand.

If anyone on here is from these parts let me know of something interesting I might want to listen to. So far Im getting all the park stuff which is mainly in the 160-170 and then the gmrs etc. As well as some 800mhz+ stuff. I also can get the WX as well. I dont get anything on the RR Marine News or AIR bands though but maybe where I am I shouldnt be anyway.

Also to be clear yes the two antennas are on two seperate buildings, one across the street from the other. I plan on putting an el cheapo RadioShack Pro 83 Handheld on the RS antenna with the RG58U and putting the Uniden which I have far more programmed into on the Diamond with the 9913. Also on the building with the diamond I have a 450-470 yagi coming with a 40 watt amplifier for a Motorola Handheld programmed for a science study frequency. The normal handhelds are 4 watts and do pretty well so Im excited about that as well. ALSO I am making another post about an antenna I have that I have no clue what it is for which may or may not go on that building as well.

 

[CookeCityScanner]

More Pictures

Here are more pictures.

 

[CookeCityScanner]

More Pictures

More Pictures

 

[twolf816]

what kind of pole is that you are using as a mast? ive been looking for one but all the ones ive seen that are taller than 15ft tend to bend horribly. correct me if im wrong, but that looks a lot taller than 10 or 15 feet.

 

[CookeCityScanner]

Its 1/2" steel pipe. I was attempting to use 3/4" pipe but that gets REALLY heavy even with two people trying to put it up. The 1/2" is sold in 21' sections and it does have some sway to it but once you get the first bit of it secured well it seems to hold up well. There is probably 15'at least of unsecured mast on both buildings. If you can purchase the 21' sections do that instead of using two 10' sections and a union. The RS mast has a union which does create a weak point. We have had some pretty strong wind gusts since Ive put them up though.

Ill add that the installation of the RS antenna dropping through the roof hole was much easier than the other. The other pipe swayed A LOT and it took muscle but you prepare first. Screw in a couple 1/2' pipe holders on one side and bend them out a little and try to get it in there as quick as you can. I had a drill with screw already to go to get that first holder tightened down. After that you are good. Get about 5-6' of it secured. I wouldnt want to go much taller than that with that pipe. I guess thats where towers and thicker more eyesore piping comes in.

 

[CookeCityScanner]

Anyway back to grounding. I should ground the rod for sure Im guessing. Would just copper from 12/2 run down to a spike in the ground work for this, or to a connector the phone or satellite guys use. Just connect the wire has high up on the mast as possible or what?

Should I also put an inline arrestor of some sort. I read about wanting to discharge any built up static because it can effect signal quality. Would just grounding the rod do this or do I need to do that in the coax somewhere. Thanks for all the help.

Should I could also just run copper wire from the rod to sheet metal screw in the roof or is that just a really STUPID idea. Up here everyones rooves are metal anyway.

 

[Al42]

Anyway back to grounding. I should ground the rod for sure Im guessing. Would just copper from 12/2 run down to a spike in the ground work for this, or to a connector the phone or satellite guys use. Just connect the wire has high up on the mast as possible or what?

Number 12 will disappear if the antenna across the street gets hit - you want at least #6 for ground wire, larger if you can get it. You want it connected from the pipe (the bottom is fine) directly (no bends) to a ground field - a few 10 foot rods covering as large an area as you can - all connected with the same at-least-#6-wire.

Should I also put an inline arrestor of some sort. I read about wanting to discharge any built up static because it can effect signal quality. Would just grounding the rod do this or do I need to do that in the coax somewhere.

Yes, you want a static supressor (like a Blitz-Bug) on the coax cable, as close to the building entry point as possible, grounded to a ground rod as close as possible. Don't forget a drip loop - let the coax droop lower than the entry point, so rain drips off outside the building. While you're making the drip loop, make it about 5 turns of coax about a foot in diameter - that forms a pretty good choke at lightning frequencies - a nearby strike or a very small direct strike might be stopped by the choke. (Not stopped enough to protect the scanner, but enough to protect the building and the cable.)

Should I could also just run copper wire from the rod to sheet metal screw in the roof or is that just a really STUPID idea.

Not stupid, just a way of asking for a new house. (Or wings and a harp if you're in the building when it's struck.)

Up here everyones rooves are metal anyway.

And pretty well insulated from ground, so not a problem as far as lightning is concerned.

 

[CookeCityScanner]

Ok thanks that advice helps A LOT.

NOW Ive got a new problem. I just went a put the BCT8 on the Diamond with the 9913 cable which as Ive said before I was excited since it should get even better signals. Well guess what. I get NOTHING. Its connected everywhere just fine.

The pics show the mount and the wire runs down the building. It is held near the 1/2" mast (in a few spots) by the 3/4" pipe holders but not like horribly pinched. Once it enters the house it is coiled up a lot before it gets to the BNC connector. Its a 100' long cable. I have some solder on connectors coming to cut it to the length needed, and use the rest of the cable on another antenna, but for now it SHOULD work how it is right?


Im getting no signals with it. I came back to the RS Discone on the RG 58u and everything works fine. Does this tell me my cable is bad?

The cable is labeled "DAVIS RF 50 OHM 9913 TYPE CABLE" or something close to that. Is this a knockoff of the Beldin (sp?) stuff or what? The connector on the Diamond is an N and the BNC on the other end of 100' is compressed on.

 

[Al42]

Once it enters the house it is coiled up a lot before it gets to the BNC connector.

One turn? 100 turns? Coiling the wire forms a choke - something RF doesn't go through. Just for giggles, as someone who used to work for me used to say ... run the cable straight - out a window and back if that's the only way you can run it - and see if that improves things. If not, measure the resistance between the center pin and shield - there shouldn't be any. (And from the center of one connector to the center of the other connector should be almost a dead short - only a couple of ohms at most.)

Im getting no signals with it. I came back to the RS Discone on the RG 58u and everything works fine. Does this tell me my cable is bad?

No, it tells you something is wrong, but not what's wrong. It could be a bad connection or a bad antenna.

The cable is labeled "DAVIS RF 50 OHM 9913 TYPE CABLE" or something close to that. Is this a knockoff of the Beldin (sp?) stuff or what?

Exactly. It could be RG-8U, or something even worse. 9913 type means "something like 9913". That could mean multi-shield, 50 ohm or just "coaxial cable with black outer insulator". IOW, it doesn't mean anything more than "cable made by Davis".

The connector on the Diamond is an N and the BNC on the other end of 100' is compressed on.

No way to tell what's happening except by actually measuring, and measuring with an ohmmeter is only looking for gross problems - but at least it would eliminate a shorted or open cable. (Are you sure the antenna isn't shorted or open?)

 

[CookeCityScanner]

THere is probably 20 coils. Id bet 65 feet at least of unused cable. I wonder if this would have that big of an effect.

On the RS Discone setup there are probably about 10 coils with the RG58u cheapo wire and it seems to do well.

I also used that RG8/u thicker wire for a test on that other "unknown" antenna thread and it was basically coiled as tightly as it came in the box (50' so 20 coils or so) and i got a reception on 46 mhz with that.

This 9913 was just DEAD.

I dont see how the antenna would be shorted or anything. The only difference in setup is that this one is a Diamond antenna with a different cable and connector. Masts are same exact setup. Maybe the coils are the problem since with the RS setup Im only using 50' of cable. Id hate to have to take this thing down to test the cable. This SHOULD be a better setup than the RS Discone setup. I hope the cable is decent, I bought it through a popular "sponsor" on here. I guess I even thought itd be the beldin but whatever.

Do you guys like to use only lrm400 and solder/compress your own connectors mainly or what?

 

[TeRayCodA]

Good pics;but how do you keep those from bending under the wind?And it looks like an environment for icing too.I would at least use some 1&1/4" galvanized pipe(more rigid)
What is the other short pipe clamped with the other discone?
My thoughts are:you are adding more weight at the top where it gets top-heavy in high winds.I have used the 1&1/4"galvanized "top rail"of a chain link fence(10ft lenghts)-light weight,that fits into one another,at 20ft lenghts with a discone.
It looks like the 1/2"pipe would get too heavy.

 

[CookeCityScanner]

The top rail was my next thought but I couldnt get any. The pipe at the top of BOTH discones is short LP gas pipe segments. It was just to make it large enough to tighten down the U Bolts They seem to hold up well in the wind. Its snowed on them already believe it or not. A few days ago we had 10" and its June .

Ill probably look into what you said for my next setup.

What effect will the icing have and more importantly what could really be done about it if anything?

 

[CookeCityScanner]

I cut the coiled up unneeded portion off and used it for somethign else as described in another thread.

I then soldered on a UHF to BNC adapter and tried the Diamond again. I have no coil or uneeded wire now. Its still dead as a doorknob.

 

[Al42]

Time to take the cable down and measure it with the ohmmeter. Hot to hot, ground to ground and hot to ground. Should be very low, very low and very high. (Very low is a couple of ohms. Very high is infinity.)

 

[CookeCityScanner]

I still havent gotten around to taking down the ScannerMaster Discone and trouble shooting it. Its been BUSY. I did get a chance to ground the mast of the RS Discone antenna and I could SWEAR it improved reception a little. Static on some channels seemed to clear up a little. Then I heard griping about the routing of my ground copper wire so I rerouted it and it seems like not quite as good as reception as the original routing. Its still great reception. Just wondering if grounding the mast could really affect it that much and have the straightest simplest route could help even that much more.

Also like I mentioned before I have a pro83 as asecond scanner. I use the BCT8 mostly. The first day I got the pro83 it picked up the WX frequencies and seemed to do pretty good with most others. (I had to go 50-60 miles before to even start getting WX frequencies with the BCT8 and stock antenna) Once I put the RS Discone on the BCT8 wow what a difference. Anyway the pro83 doesnt pick up anything any more it seems. All functions work fine just no sensitivity. Is the radio broken or what. I hook it up to the same antenna so its not that.

 

[N_Jay]

Once it enters the house it is coiled up a lot before it gets to the BNC connector.

One turn? 100 turns? Coiling the wire forms a choke - something RF doesn't go through.

This is incorrect.

The choke formed by coiling Coax cable will stop common mode RF and RF running on the shield, but will not affect the signal IN the coax.

However the extra 65 Feet of cable does not do any good.

 

[kb2vxa]

Hi cook the scanner and all,

Mott The Hoople?

To put it all together in one neat package, first your problem could be twofold. If the coax passes the ohm meter test you probably forgot an insulating spacer when you assembled the antenna, it's supposed to read open for DC. That whip on the top is just a bit troublesome and where it's mounted could lie the short.

As for grounding, think of it as lightning protection only. They're giving good advice but I see no reason to coil the coax. Use the heavy wire and connect it to the bottom of the mast, no point in using more than you need, the mast conducts electricity. AVOID THAT ALUMINIUM GROUNDING WIRE, in time it corrodes, becomes stiff, snaps and is useless. Use solid copper, lightning doesn't like stranded. (Surface area vs. the skin effect when each strand is considered as an individual conductor as lightning sees it.)

There are always differing opinions with regard to lighning protection but I take my tips from broadcast engineers. Now since you're not going to use 4" solid copper strap one considers what may happen to a conductor when 50KA passes through it for about 1/10 of a second. You don't have to worry the grounding wire will light up like a fuse but it can. In that case a plasma conduit is formed which is a better conductor than the wire was (actually a superconductor) so in any case barring the unforseen the stroke will be harmlessly dissipated to earth.

Now we get to the mast, right, the union is the weak point and I mean WEAK. Now trot on down to the electrical supply house ruler in hand and get enough lengths of heavy wall aluminium EMT of varying sizes to make a telescopic mast. The next smaller diameter slips into the next larger one and so it goes, but the actual diameters both inside and outside make no freakin' sense which is why you brought the ruler. Nope, measure the 1" stuff and you won't find 1" anywhere on it. When you get home slip one inside the other for about a foot, drill and pin with stainless hardware to make the whole thing rigid. Well, sometimes it's better to assemble as you go but I'm not looking at your place up close and personal, the pix tell me squat. (;->) The weight will be at the bottom diminishing as you go up and it's very strong, you won't need to guy it unless you're building a broadcast tower.

From what you wrote you're using the very WORST thing imaginable, galvanized steel water pipe or something like it. The clue was in the length of the sections, 20' for pipe, 10' for EMT. You say you're busy, well get busy and take it down before nature does it for you. Not only is the union where it will rip apart but pipe bends with less pressure than you think, a long time ago I found out the hard way. To make a long story short, I put up a CB antenna for a friend, violent storm hit over the weekend and when I returned the next week I found a steel pretzel with what was left of the antenna stuck to one end. You'd be surprised how easily I bent it back with my bare hands to get in in the truck and haul the mess away.

I hope you find this compilation of their suggestions mixed with mine helpful and good luck with your skyhooks.

 

[CookeCityScanner]

Thanks for the advice. Yes Im using galvanized water pipe. One of them doesnt have a union its just 20' and its seen some pretty strong winds so Im not to worried. The other does have a union but still seems to be doing welll who knows. From now on though Ill do as you say. Actually my next mast will be a short 3-4' section of PVC for a directional yagi Ive got. Once I get the ScannerMaster Disone problem figured out.


Quick question. Im goign to go with the ohm meter real quick. If I just take the BNC end without taking it down and test from the center conductor to the shield which SHOULD give nothing. If I get somethign I know there is a short somewhere (probably at the antenna).

 

[CookeCityScanner]

Well I took down the Scanner Master discone and guess what... the compressed N connector had pulled off the wire. I reconnected it and taped it up good. Then I did a test with the ohm meter. center conductor to center conductor I got a little reading. center conductor to ground i got nothing which SHOULD be perfect right? Anyway I hooked it up to the scanner and voila its working. BUT its not working as good as the RS Discone setup is. It wont pull in channels that the other will. This makes no sense. The two antennas are probably 100' apart, the ScannerMaster is probably a good 5' higher AND it has better cable. Im stumped.

 

[K5MAR]

Did you check ground to ground?

I'd be really suspicious of that connector at the top, it shouldn't have come apart, and since it did, I gotta wonder. :?

Mark S.