discone in attic- help !

[skanca]

have discone in attic, for best results should it be placed as high to attic roof as possible, or just sit on attic floor with bottom elements supporting it ?? secondly, does it have to still be attached to some sort of mast /pole ??? I have a large "s" hook already in attic roof approx 10-11 ft high, was thinking about just hanging antenna from that.. Any suggestions ?

 

[N_Jay]

have discone in attic, for best results should it be placed as high to attic roof as possible, or just sit on attic floor with bottom elements supporting it ?? secondly, does it have to still be attached to some sort of mast /pole ??? I have a large "s" hook already in attic roof approx 10-11 ft high, was thinking about just hanging antenna from that.. Any suggestions ?

With antennas height is everything.

If you are only getting another 4 feet, and you are happy with teh reception, then sitting on the floor is fine, but if you want all you can get you might as well hang it as high as you can.

Hanging it is fine.

 

[skanca]

ok thanks for the reply. Having some problem receiving 800mhz, thought alittle more elevation might do the trick. Other bands sound great, nice strong signals.

 

[jbstahr]

ok thanks for the reply. Having some problem receiving 800mhz, thought alittle more elevation might do the trick. Other bands sound great, nice strong signals.

Discones are usually great for UHF/VHF, but only moderate on 800Mhz. If your comms are mostly 800, its well worth it to buy a single-band antenna just for 800 Mhz.

 

[N_Jay]

ok thanks for the reply. Having some problem receiving 800mhz, thought alittle more elevation might do the trick. Other bands sound great, nice strong signals.

Discones are usually great for UHF/VHF, but only moderate on 800Mhz. If your comms are mostly 800, its well worth it to buy a single-band antenna just for 800 Mhz.

Discones are great over the band for which they are designed.

About the best they do is a 3:1 to a 6:1 band spread, no matter what the misleading advertising says.

Most scanner discones are not designed for 800 MHZ so that could be PART of teh problem.

How much and what type of cable do you have?

Cable losses can get very high at 800 MHz.

 

[bluecool]

Discone and RS Pro93

I too need help with the Discone Diamond and a RS hand held. I bought a Discone and could not get it to work with my RS Pro-93. Upon plugging it on, with an extra shielded coax, I immediatly lost all the NOAH weather channels. and started to get static on local freqs that are clear with the RS rubber duck. I did gain the CB freqs, which the scanner does not pick up with the ruber duck.

I was hoping to get in more rail freqs that I can only get when I am at my girlfriends house (one town over from mine, about 2 city miles). Instead, I get less channels. I was also hoping the Discone would help me get the Marine channels better.

I tried it out the 3rd floor window, in a 3rd floor bedroom, and now I am thinking of the attic as well, but I'm about to give up. I have another base station antenna as well (fiber vertical and aluminum radials) on the roof, and got the same results. urgh.

Any clues on what is happening and how to fix it?

Thanks
bluecool
(novice)

 

[N_Jay]

Re: Discone and RS Pro93

. . . Upon plugging it on, with an extra shielded coax, . . . .
I tried it out the 3rd floor window, in a 3rd floor bedroom, and now I am thinking of the attic as well, but I'm about to give up. I have another base station antenna as well (fiber vertical and aluminum radials) on the roof, and got the same results. urgh.

Any clues on what is happening and how to fix it?

Thanks
bluecool
(novice)

What do you mean by "extra sheilded coax"?

What type and how long is the cable?

Who put the connectors on.

The discone should work BETTER than the duck, when it is in about the same place as the duck.
If it doesn't then you have a cable, antenna or connector problem.
Fix that first before trying to find a "beter" spot for the antenna

 

[bluecool]

Thanks for the help.

--What do you mean by "extra sheilded coax"?
I first was using RG58, thought it was the problem and went to RS and bought a 5ft of RG8, the really thick stuff, which has a UHF Coax male on each end.

--What type and how long is the cable?
The new one is 5ft, the old was 10 ft and it was flimsy RG58. I could hear the static change by touching the cable. I tried this cable with the antenna out the 3rd floor windown and on a wooden stick in my 3rd fl bedroom. No difference, except out the window got a better CB reception.

Who put the connectors on.
Original and one adapter I put on. The original Coax UHF (S0239) is going into the female bottom of the Discone, on the other end of the cable I have an adapter changing it from Coax to BNC to attach to the scanner. I have tried three diff. adapters (from my drawer of gadgets) and none make a difference.

The Discone seems to perform no better than the rubber duck.

The seller I bought it from gave me the following advice via an e-mail.

"The best coax is going to LMR400 if you can get it. You can use any good 50 ohm coax with a solid shield. Try not to use the Radio shack RG8 or RG58, I've had trouble with them. Try the antenna without the vertical whip to see if that will bring in the NOAA channels. It sounds right that you are receiving CB and not the higher frequencies. Lossy coax will do that. Get just enough coax to run from where you want the antenna to where you will be using your scanner."

Thanks
bluecool
Boston, MA[/i]

 

[N_Jay]

Thanks for the help.

--What do you mean by "extra sheilded coax"?
I first was using RG58, thought it was the problem and went to RS and bought a 5ft of RG8, the really thick stuff, which has a UHF Coax male on each end.

--What type and how long is the cable?
The new one is 5ft, the old was 10 ft and it was flimsy RG58. I could hear the static change by touching the cable. I tried this cable with the antenna out the 3rd floor windown and on a wooden stick in my 3rd fl bedroom. No difference, except out the window got a better CB reception.

Who put the connectors on.
Original and one adapter I put on. The original Coax UHF (S0239) is going into the female bottom of the Discone, on the other end of the cable I have an adapter changing it from Coax to BNC to attach to the scanner. I have tried three diff. adapters (from my drawer of gadgets) and none make a difference.

The Discone seems to perform no better than the rubber duck.

The seller I bought it from gave me the following advice via an e-mail.

"The best coax is going to LMR400 if you can get it. You can use any good 50 ohm coax with a solid shield. Try not to use the Radio shack RG8 or RG58, I've had trouble with them. Try the antenna without the vertical whip to see if that will bring in the NOAA channels. It sounds right that you are receiving CB and not the higher frequencies. Lossy coax will do that. Get just enough coax to run from where you want the antenna to where you will be using your scanner."

Thanks
bluecool
Boston, MA[/i]

10 feet of cable should not make any difference.

Discones (true discones) don't have a top whip. Thatis a trick to try to get them to work at lower frequencies. I don't know what the effect is on the higher frequencies, but O am sure it would not be good.

Something is not right.

I would guess the antenna is shorted or the center conductor is open (in the cable or in the antenna.

 

[bluecool]

Sounds like I got ripped off. this was called a Delux Discone. It has 6 points on the horizontal plane, and four radial legs that hold it up, and one sticking out the top going straight up.

Here it is:

http://cgi.ebay.com/ws/eBayISAPI.dl...&ssPageName=STRK:MEWN:IT#ebayphotohosting

 

[N_Jay]

Sounds like I got ripped off. this was called a Delux Discone. It has 6 points on the horizontal plane, and four radial legs that hold it up, and one sticking out the top going straight up.

Here it is:

http://cgi.ebay.com/ws/eBayISAPI.dl...&ssPageName=STRK:MEWN:IT#ebayphotohosting

Double check how you put it together. Maybe you missed an insulating washer?

I have seen antenna shorts occur when parts are over tightened.

 

[Concrete1]

Re: Discone and RS Pro93

I too need help with the Discone Diamond and a RS hand held. I bought a Discone and could not get it to work with my RS Pro-93. Upon plugging it on, with an extra shielded coax, I immediatly lost all the NOAH weather channels. and started to get static on local freqs that are clear with the RS rubber duck. I did gain the CB freqs, which the scanner does not pick up with the ruber duck.
I was hoping to get in more rail freqs that I can only get when I am at my girlfriends house (one town over from mine, about 2 city miles). Instead, I get less channels. I was also hoping the Discone would help me get the Marine channels better.

I tried it out the 3rd floor window, in a 3rd floor bedroom, and now I am thinking of the attic as well, but I'm about to give up. I have another base station antenna as well (fiber vertical and aluminum radials) on the roof, and got the same results. urgh.

Any clues on what is happening and how to fix it?
Thanks
bluecool
(novice)

ASSuming your coax isn't shorted or bad, one possibility that no one has mentioned is that the discone is actually Doing it's job, pulling in more signal & causing an "overload" or "De-sense" of the scanner/receiver.
All the signals you mention that got "worse" ( Rail, Marine, NOAA), are all in the 155-165 Mhz range & there could be some sort of paging transmitter or other signal(s) in the area that are overloading the scanner, which doesn't happen on the rubber duck.
This would also explain why CB (27Mhz) signals did get Better with the discone, since 27Mhz is very far from 160Mhz & is less likley to be affected.
Also, You said you tried 2 completley different base antennas, & had the same problem at these VHF frequencies, only when hooked up to them, so it sounds like a base antenna at your location is causing overload.

 

[NorwalkRXing]

hey Bluecool, I can relate to exactly what your going through..Unfortuneately, Ive been down the same road with buying stuff on ebay, like Discone antennas , and good coax cable, with prices that seemed too good to be true, and was promised that these products would preform as good , if not better than the higher priced proffesional versions...Well, I've learned my lesson after waisting all that money. I've learned in this hobby, that "Quality Equipment" is not cheap, and to save yourself the hassle, and waisting money by buying the quality equipment from the begining...Now in no way am i saying that someone cant get a good deal on quality equipment on ebay, I'm merely stating that in this time and age, the consumer gets what he pays for...basically in a nut shell, If I could do it all over again, I would most definately spend the extra cash to get the best coax, and best antenna... On a side note, after trying, the RS discone, and 2 others that I purchased on ebay, I finally broke down and purchased a Diamond Discone, and 65' of RG-6/QS....for me this setup is awsome!...but after hearing such good remarks about Times Microwave LMR-400 cable, I purchased some this morning...the price to me seems fare..65' with connectors and shipping came to $77...something just tells me that i should have purchased the LMR from the begining...A lesson learned !!!

 

[BIONIC_TEXAN88]

blue cool, i bought that exact antenna off ebay last month and have good results w/ it. definately better than the rubber ducky. i used rg6 and mounted it 20' in air using 3/4" conduit. i would check your threaded connection on top of the antenna (where it all comes together on the mounting bracket)

 

[Highlander_821]

I think that something is *wrong* with either the antenna or the connectors on your coax. It might be overload or desensing the receiver, but I would check everything out thoroughly.

 

[bluecool]

Great replies. Thanks everyone.

I will double check for the washer. It seemed so simple to put together, how could I mess it up? I guess the washer could be in the wrong spot. Also, it sounds like I am having the overload like you say, what can I do about that? Someone on another site reocommended buying an FM trap and something else (another RS gadget) to fix the problem. Well, maybe this antenna and my RS hand held are jsut not meant to be married?

Great feedback everyone.

bluecool

 

[bluecool]

blue cool, i bought that exact antenna off ebay last month and have good results w/ it. definately better than the rubber ducky. i used rg6 and mounted it 20' in air using 3/4" conduit. i would check your threaded connection on top of the antenna (where it all comes together on the mounting bracket)

Yes Bionic Texan, I read your other post just now and I was stunned that we bought the same antenna from the same seller. He has been great with e-mail communication and trying to help me figure out why the antenna was not working. Thanks for sharing your story - gives me hope. What scanner are you using?

bluecool

 

[TeRayCodA]

Get a voltmeter/ohmmeter,ohm out the antenna(cone radials should NOT short to the disc,or the vertical element)

Then assemble the coax onto the antenna,check continuity on the connector(outer) that goes on the scanner(shield),to the cone radials(should be shorted)

Check continuity against the connector outer(shield) to the disc(should be open),as with the top element/whip.

Center conductor to disc elements/whip should be shorted.

Now,check continuity between the center conductor,and shield.

-Or could you bychance have a bad bnc connector on your scanner?
Have you tried any other scanners with this antenna?

Even with the ones that I have built,I have never had this problem.

 

[Concrete1]

The fact that you had the same problem with both the discone & "a different" base scanner antenna makes it doubtful that you messed up building both antennas to the point that they both lost all VHF receive..
I would suspect either the coax, if it was common to both antennas, or a de-sense problem.
A good thing to try for de-sense would be a variable attenuator. These are made for TV, & will have "F" connector in/out, but they will allow you to set the amount of attenuation, usuall between 0-25dB or so, and are relatively inexpensive, & I have seen them work.
An FM trap would only be good if the problem is caused by a close FM radio Broadcast station, otherwise they are useless.

 

[Highlander_821]

You could mess around with the attenuator on the Pro-93 as well.