Best RF Multi-coupler money can buy

[blantonl]

Give me your thoughts on the Omni-X for VHF/UHF. I have to put mine up. I'm assuming the direction of the elements can cause some of its omni pattern getting shifted a bit, but wouldn't think it was not that significant.

I think there is some directional lobes in the receive performance of this antenna, subtle, but there. The antenna is extremely well built and for all intents and purposes has performed wonderfully. I’ve had the antenna for probably 7 years now and it’s still in great shape, even through multiple super hot S Texas summers.

it has been installed on a home with tile roof and one with metal roof, and I’ve found I’ve had to orient it to maximize its reception for the stuff I monitor.

 

[Mike_G_D]

For me everything in the 700/800/900 bands were good until some huge wide band signals showed up recently in the roughly 718 to 768MHz band. The carriers are about 10MHz wide each on my receivers spectral display. Today they are running about -30dBm on the spectral display and for a 10MHz wide carrier the peak power is much higher. I don't know the RBW of my receivers spectrum analyzer and will have to measure the exact levels on a real spectrum analyzer.

QUOTE="bearcatrp, post: 3627589, member: 53377"]
Not to intrude on your conversation but from reading this thread, seems like 5G is going to be an issue for us scanners. Please elaborate.

FWIW - I see/experience similar where I am too.

-Mike

 

[vagrant]

Thank you for confirming what I thought about that antenna due to the design. I considered purchasing one, but wondered about directivity. I tested a Scantenna ST2 for a while and it was directional, so back up went the reliable discone for the 100~500 stuff. I may end up trying an Omni-X one day anyways.

I think there is some directional lobes in the receive performance of this antenna, subtle, but there.

 

[N9JIG]

I have an Omni-X in my garage, it will probably go in the attic this week as I just got the coaxes run today. I am pretty sure that it has a flattened Figure-8 pattern to it so when I do install it I will be sure to place it near the attic hatch and so that I can turn it.

I might try to convince my HOA that it is really a TV antenna and put it outside but I am not sure I want to poke the bear. They have been pretty relaxed with me so far.

 

[krokus]

I might try to convince my HOA that it is really a TV antenna and put it outside but I am not sure I want to poke the bear. They have been pretty relaxed with me so far.

Run a lead from your multi coupler to your TV. Then it is your TV antenna, even if you are not watching OTA.

 

[Tim-B]

What is the advantage of using the type of antenna that Mr. Blanton ordered? I looked at that antenna and it costs $2,000 and has unity gain. Is is just the ruggedness and ability to transmit with high wattage over several bands that you are paying for?

Edit: on wait, I looked again and see that it is not unity gain but 0 decibels over a dipole. If it works as well as a dipole but across many frequencies and is very rugged and long lasting then I can see the benefit. Are there other benefits that I overlooked?

 

[buddrousa]

The OMNIX is less than $200 if that is what you are talking about.

 

[Ubbe]

The OMNIX is less than $200 if that is what you are talking about.

He's refering to Mr. Blanton's statement of replacing his Omi-X with a discone ANT280S at $2.000

Looking at that discone it says 118-3000MHz at SWR 1.5:1 or better. But then it says 118-137 at SWR 1.8:1
It looks to have the standard dimension as most other discones at $100 so should perform just the same. There's no magic built into it, it just are built to last for ages and take on a tornado or two. That support ring at the end of the top and bottom elements are a great help that can be done to any discone to make them a lot stronger.

/Ubbe

 

[prcguy]

The ANT280S also has 12 skirt radials which is more than a typical scanner Discone and there might be more top hat radials, all leading to more efficiency. It looks like the skirt radials run up to some kind of radome below the top hat and its possible the top part of the skirt is solid sheet metal and if so that would increase efficiency in the upper frequency ranges.

A typical Discone design uses close to an equilateral triangle for the bottom skirt and it looks like the ANT280S is a little taller than it is wide. Some companies have changed the formula to alter the radiation pattern or to optimize the frequency range and hopefully the ANT280S has a good lobe at the horizon over the entire range of 118 to about 960MHz or what you would want for scanner use.

He's refering to Mr. Blanton's statement of replacing his Omi-X with a discone ANT280S at $2.000

Looking at that discone it says 118-3000MHz at SWR 1.5:1 or better. But then it says 118-137 at SWR 1.8:1
It looks to have the standard dimension as most other discones at $100 so should perform just the same. There's no magic built into it, it just are built to last for ages and take on a tornado or two. That support ring at the end of the top and bottom elements are a great help that can be done to any discone to make them a lot stronger.

/Ubbe

 

[mmckenna]

I have an ANT-280 on one of my high sites at work, and it out performs the Diamond I have. Not a side by side comparison, but it does work well for what it is.

And it is built like the proverbial brick $#!† house.

 

[prcguy]

Maybe you or Lindsay can run an A/B test between the Telewave and a more common Discone like the D130 or Radio Shack and give us the results. I have an old R/S I could send to either one of you for testing.

I have an ANT-280 on one of my high sites at work, and it out performs the Diamond I have. Not a side by side comparison, but it does work well for what it is.

And it is built like the proverbial brick $#!† house.

 

[vagrant]

Ohh...I'd like to see those results. I sense this is about to be moved to its own thread.

Maybe you or Lindsay can run an A/B test between the Telewave and a more common Discone like the D130 or Radio Shack and give us the results. I have an old R/S I could send to either one of you for testing.

 

[mmckenna]

Maybe you or Lindsay can run an A/B test between the Telewave and a more common Discone like the D130 or Radio Shack and give us the results. I have an old R/S I could send to either one of you for testing.

I have a Diamond D-130N at my house, just need to pull it down some day and do some testing.

 

[RFI-EMI-GUY]

You might look out for surplus multicouplers from repeater sites. Often they are very wideband construction. I have one of these and it has a Watkins Johnson wide band amplifier module inside.

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[Ubbe]

...some kind of radome below the top hat and its possible the top part of the skirt is solid sheet metal and if so that would increase efficiency in the upper frequency ranges.

Yes. The 12 elements will be very close together forming a solid skirt, if it isn't already are solid metal behind the radome. To get up to 3GHz it needs to be a very small gap between top and bottom elements and would need some sort of support of a non-metallic material to make it much stronger in that thin neck where the RF signal are taken from.

If doing A/B test, remember to slowly turn a discone between the degrees that corresponds to half the distance between elements. 22 degrees for a 8 element design. The efficience of a discone will pretty much be the same max value for all discones but the gap in the horizontal angle where it degrades will be larger with fewer and thinner elements. Wrap a discone in aluminium foil, to make it look solid, for a C test.

/Ubbe