DPD OMNI X just set up

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bobruzzo

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I finally got my OMNI X antenna and got it all put together and set up. VERY good build quality. I couldn't get it up as high as I wanted, but it's only maybe 18" lower than my discone. And I really had no way to separate it further from the discone unfortunately. Out of antenna space. But the omni works pretty well. One thing is I am wondering if this antenna may be somewhat directional? I monitor a P25 simulcast system here in RI. I have been previously using a DPD 800 mhz mag mount up on roof. Reception was GREAT with the mag mount. But the place I mounted it right on a ground plane with a weight in it to keep it in place, is not really suitable. See picture. That metal plate is a computer side cover bent into shape with a section of 2x3 screwed into bottom so it stays put. So far even in the last wind storms it didnt move.
Anyway I want to take that off roof and use it mobile maybe. So the only thing I noticed differently with the omni x was the PROVIDENCE system isn't as strong as it was using the mag mount. I thought MAYBE the omni may have a SLIGHT directionality to it. MAYBE the discone is too close. All the other zones on P25 come in loud and clear full scale. I am going to go out and TURN slightly the omni to see if that makes any difference. Originally I planned to mount that discone in the CENTER PEAK part of roof but stupid ladder isn't tall enough. Wife doesn't mind antennas as long as they stay where they are. But nothing attached to house. And I didnt want to have coax run longer than 50'. I am also at my height limit with these mounts. Can go up any higher without GUYING and LONGER COAX. Well anyway I will try some very slight turn of the omni to see if that changes anything on the Providence zone signal.
 

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thecop

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As an OmniX owner who is about to get the antenna outside and on a fiberglass telescopic mast for the first time, I’m very curious to find out what your results were.
Good luck!
 

bobruzzo

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As an OmniX owner who is about to get the antenna outside and on a fiberglass telescopic mast for the first time, I’m very curious to find out what your results were.
Good luck!
It's a pretty nice antenna. Built like a tank. VERY good reception. I was up and down ladder trying different heights and facing it a few different directions. I thought maybe if I actually lowered the antenna that might help one of my zones (P25 simulcast) come in a little better. Not a heck of a lot but after a lot of give and take I decided to put it back up to it's original height. I marked the mast with waterproof marker to get it exact. I got it up ONE INCH higher and it made a big difference! That zone is much more stable with the signal. One inch. Everything else is full scale. What is irritating is I live close to Providence and before the scanner couldnt even lock on to the control channel. The mag mount antenna actually gave a consistent solid signal. But I guess 800mhz radio waves with P25 are fickle. You need to putz around with antenna height/location.
I am happy with antenna. It has a decent bandwidth so I can even hear full scale the Newport Naval base in Newport (RI) which is blocked between me and there by a BIG HILL. The P25 Navy system is cool cause I can hear transmissions from the Greak Lakes, mid Atlantic coast....must have everything tied in together. There are some encrypted channels but mostly all open to hear. Antenna was easy to assemble if you take your time. All heavy duty parts.
 

JoshuaHufford

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I want to get a wide band antenna to put up at my house at some point and this one is on my list to consider.

Curious what kind of coax you are using?

Besides 800MHz what other ranges are you monitoring that it does well with?

Do you have anything to receive between 890-960MHz? I have stuff in that range I'd like to be able to receive and I'm curious how it would do.
 

bobruzzo

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I want to get a wide band antenna to put up at my house at some point and this one is on my list to consider.

Curious what kind of coax you are using?

Besides 800MHz what other ranges are you monitoring that it does well with?

Do you have anything to receive between 890-960MHz? I have stuff in that range I'd like to be able to receive and I'm curious how it would do.
I use both the Omni X and a discone, both work very well. The coax on both antennas is LMR 400. I'd even go to a higher type but the stiffness of the cable and cost is high. You should use good cable if monitoring up in the 800mhz range. When I bought my discone, it came with 60' of CRAPPY thin cable. I used it temporarily cause it was still winter and too cold to do much outdoor antenna work. When I did get the LMR400 shortly after it made a BIG difference. I am monitoring a P25 system here in RI. 800mhz. I also have the Newport Naval base on 380mhz and the omni picks up the signal 100%. Newport is just under 1 hour away from me with a big hill in the way. The omni doesnt do lowband.
I like the discone myself. It is up about 25' on back of garage. I can hear pretty good distances. I am on a small hill so that helps. Discones are a bit over $100....they have no gain but work a wide range of freqs....not REAL good on 800mhz though.
 

JoshuaHufford

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That is the reason I'm wondering about the Omni-X, curious if it does better than a discone at 890-960MHz. I'm wondering if I would be better off with a Discone and 900MHz antenna then use a diplexer, but if I could do it with one antenna that would be nice.
 

bobruzzo

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That is the reason I'm wondering about the Omni-X, curious if it does better than a discone at 890-960MHz. I'm wondering if I would be better off with a Discone and 900MHz antenna then use a diplexer, but if I could do it with one antenna that would be nice.
Thats a hard question to answer. Well the omni is specifically tuned to the bands it operates on, where a discone is not tuned to anything specific. But discones suffer once you start moving up to 800mhz. The omni is tuned to 800mhz so one would assume it hears better than discone. All the towers are sorta close to me so I cant really compare both antennas. It depends on what you listen to. I listen to everything from vhf high to 800mhz. I use the omnix for my P25 800mhz systems. The discone is used for the conventional police, fire, etc.
 

Ubbe

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There's no tuned elements in a Omni-X that receives 800Mhz. It's just a big metal peice in the air for that band, but size matters when it comes to antennas. The aluminium tubes that sits on the plastic tube are tuned to around 400Mhz and are so wide in size that it perhaps covers a hundred MHz wide frequency range. The X elements are tuned for VHF-Air and VHF 150-170MHz.

/Ubbe
 

bobruzzo

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There's no tuned elements in a Omni-X that receives 800Mhz. It's just a big metal peice in the air for that band, but size matters when it comes to antennas. The aluminium tubes that sits on the plastic tube are tuned to around 400Mhz and are so wide in size that it perhaps covers a hundred MHz wide frequency range. The X elements are tuned for VHF-Air and VHF 150-170MHz.

/Ubbe
I use my omni x strictly for P25 800mhz trunking system here in RI. It sure does pick up the towers well enough. Maybe too well cause I noticed the simulcast issues are a little worse on the Providence zone compared to when I use my 800mhz mag mount. Maybe the omni x being up high could be getting overloaded cause the towers are not far from here. I anticipated getting an sds200. I have the money in bank just waiting for me to pull the plug. Not sure yet cause of the 2 issues I have read about. The "hum" and the display problem. Maybe wait till June of July when some new batches come out. They are on back order from most places anyway.
 

cmed325

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I recently put the same antenna up on a 10 ft mast on my chimney,,Im in a gully anyway so any improvement would be noticed, I have to say that i have not noticed any real difference between this, A discone or an ST-2 that i had up before it,,Im looking forward to the new improved ST-2 when it come out.
 

bobruzzo

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I recently put the same antenna up on a 10 ft mast on my chimney,,Im in a gully anyway so any improvement would be noticed, I have to say that i have not noticed any real difference between this, A discone or an ST-2 that i had up before it,,Im looking forward to the new improved ST-2 when it come out.
I did an A/B with the omni and my discone. Discone is up a little higher. I noticed the omni picked up some things stronger than discone and vice versa. But I am using the omni strictly for the P25 systems in RI. I was REALLY hoping I'd finally be able to pull in the Bristol County Mass state police trunk. Nope! STILL can't get it without lots of static. It sucks because I used to be able to hear them loud and clear with just a simple 1/2 wave VHF homebuilt vertical dipole! They must have cut power way down or something.
 

Ubbe

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It sucks because I used to be able to hear them loud and clear with just a simple 1/2 wave VHF homebuilt vertical dipole! They must have cut power way down or something.
A dipole will work better than a discone or an Omni-X at 800MHz. Try and set one up again, as a test, and with coax that doesn't attenuate too much at the lenght and frequency used. If it works better you could use a diplexer to have the Omni-X go up to 500MHz and then the diplexer will use the dipole for anything above 600MHz.

You can build your own diplexer if you gut out a cheap metal box, like a $5 CATV splitter, and solder together a couple of coils and capacitors for $5 and use the many online web based calculators to get the values and how to connect it together.

/Ubbe
 

bobruzzo

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A dipole will work better than a discone or an Omni-X at 800MHz. Try and set one up again, as a test, and with coax that doesn't attenuate too much at the lenght and frequency used. If it works better you could use a diplexer to have the Omni-X go up to 500MHz and then the diplexer will use the dipole for anything above 600MHz.

You can build your own diplexer if you gut out a cheap metal box, like a $5 CATV splitter, and solder together a couple of coils and capacitors for $5 and use the many online web based calculators to get the values and how to connect it together.

/Ubbe
Like I said, the dipole I was using at the time was cut for VHF HIGH! I tried making an 800 mhz vertical dipole but gave up due to lack of material.
 

vagrant

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I would really like to see the 225-900 MHz spread, perhaps the VSWR from 220 ~ 1000 MHz. Additionally, I think the SWR of its advertised range would be helpful for many 118 ~ 900 MHz. Tell us about your coax type, coax length and any adapters you may have inline too please as I presumed it is deployed on a mast. If you want to give us additional readings, it will be appreciated.

Thank you
 
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