I am wanting to run 2 scanners from my Omni X antenna. Do I need to split at the antenna and run 2 separate coax's into the house or can I split it after coax goes into the house? Also what items are needed for the splitting? Thanks. It will be about a 40 ft run from the antenna.
Best way to run 2 scanners off Omni X outside antenna?
- Thread starter shajoe44
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Markinsac
Member
Split once inside - something like this should work.
There are other devices similar on the market that allow splitting more devices.
There are other devices similar on the market that allow splitting more devices.
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Thanks
TailGator911
Silent Key/KF4ANC
You shouldn't lose too much signal with a 40-ft run, and keep in mind you will lose a little from the splitter. The best way will cost a few bucks if you install a distribution splitter that is amplified, such as the Stridsberg muliti-coupler. But just two scanners with a 40-ft run you should be ok with that 2-way splitter they sell at Scanner Master. Run your feed line in and install the splitter somewhere behind your desk. Try to keep the split feed coaxial at 3-4ft max.
JD
kf4anc
JD
kf4anc
When using a simple passive splitter, be aware that you will be losing half (or more) of the signal to each scanner. This would be in addition to the loss created in your 40' coax run. A better, albeit more expensive, solution would be to use a quality-built active device with just enough gain to compensate for the loss. Too much gain can result in excessive noise and/or IMD issues.
I agree, definately a good application for a amplified Stridsberg multicoupler. Pay now or pay later.
TailGator911
Silent Key/KF4ANC
I used a Channel Master 4-way passive splitter for years, 4 scanners off a Grove Scantenna when I built my first shack in Florida when I moved there in the 80s. I got great reception. When I splurged and spent the big bucks on a Stridsberg I wondered what all the hoopla was about. I did not notice any difference at first. Then, I noticed my S-meters hovering at 9 instead of 4-5 and I thought wow my signal is so much stronger. But, my reception was the same. I lived in Osceola county at the time (St. Cloud, near Disney World) amidst a good strong system. It was only when I moved to the coast on a barrier island that I noticed the difference. I could hear the Osceola system from my home on Merritt Island clear as a bell, so it did make a difference. As others have noted, might be overkill in the city with good signal already. As always, depends on your QTH, equipment, antennas, finances, etc. The Stridsbergs are expensive.
JD
kf4anc
JD
kf4anc
Ubbe
Member
Do not get that SP1300 splitter. It has a 5dB loss. Run a single coax from the antenna. A LMR400 have a 2dB loss at 900Mhz and costs $45 and a RG6 3dB loss at 900Mhz and costs $10 and then add connector cost and choose what you think would be most beneficial for you.
A standard scanner like Unidens traditional models have an impedance of
35 ohm at 750Mhz and
115 ohm at 800Mhz and
20 ohm at 850Mhz.
If a scanner are monitoring the 160MHz band it will at the 750MHz-900Mhz band have an impedance that goes from 5 ohm to 800 ohm depending of the frequency.
It's all over the place depending of the frequency.
An Omni-X are several dipole antennas in parallell, each tuned to it's own frequency band. A standard single dipole antenna are
75 ohm at it's tuned frequency, lets say it's 160Mhz and
600 ohm at 130Mhz and
350 ohm at 190Mhz and
10 ohm at 90Mhz and 220Mhz.
It's all over the place depending of the frequency and an Omni-X will have even more complex variations.
Get a $5 T-connector and split the coax to two scanners as any kind of impedance matching have no effect and loosing half the signal in a "proper" splitter are unneccesary. It could happen with some scanners that they emit som spurious signals out its antenna connector, so using an isolating splitter might be neccesary but will drop the signal to half strenght. A $10 CATV splitter have something like a 20dB attenuation of signals between scanners that are probably sufficient in most cases.
If you really need best signal possible for weak signal hunting, then get a low noise mastmounted preamplifier. It will feed an almost constant impedance to the coax and will also compensate for any coax losses and splitter losses and improve scanners signal/noise ratio and will improve sensitivity. A CATV splitter at the other end of the coax will mellow out the impedance variations between scanners and a variable attenuator between CATV splitter and coax are crucial to adjust the signal to a lower level where it doesn't give intermodulation or desense problems.
/Ubbe
A standard scanner like Unidens traditional models have an impedance of
35 ohm at 750Mhz and
115 ohm at 800Mhz and
20 ohm at 850Mhz.
If a scanner are monitoring the 160MHz band it will at the 750MHz-900Mhz band have an impedance that goes from 5 ohm to 800 ohm depending of the frequency.
It's all over the place depending of the frequency.
An Omni-X are several dipole antennas in parallell, each tuned to it's own frequency band. A standard single dipole antenna are
75 ohm at it's tuned frequency, lets say it's 160Mhz and
600 ohm at 130Mhz and
350 ohm at 190Mhz and
10 ohm at 90Mhz and 220Mhz.
It's all over the place depending of the frequency and an Omni-X will have even more complex variations.
Get a $5 T-connector and split the coax to two scanners as any kind of impedance matching have no effect and loosing half the signal in a "proper" splitter are unneccesary. It could happen with some scanners that they emit som spurious signals out its antenna connector, so using an isolating splitter might be neccesary but will drop the signal to half strenght. A $10 CATV splitter have something like a 20dB attenuation of signals between scanners that are probably sufficient in most cases.
If you really need best signal possible for weak signal hunting, then get a low noise mastmounted preamplifier. It will feed an almost constant impedance to the coax and will also compensate for any coax losses and splitter losses and improve scanners signal/noise ratio and will improve sensitivity. A CATV splitter at the other end of the coax will mellow out the impedance variations between scanners and a variable attenuator between CATV splitter and coax are crucial to adjust the signal to a lower level where it doesn't give intermodulation or desense problems.
/Ubbe
If you're in an area with strong signals and close by systems and a good antenna you probably don't need a preamp to over come loss from cables, connectors, adapters, etc. If reception is good on your routine frequencies, a stronger signal usually won't make it better. But often people will find other signals they never knew were there before. This is especially applies when searching out new signals and using Discovery mode or even Close Call.
Yes Stridsbergs are expensive, that one of the reason I just purchased my first one recently after wanting one for about 40 years! Not all couplers are created equal, Stridsberg actually uses Amphenol BNC connectors and I'm confident the internal components are of better quality, lower noise than what you might find in cheap imports. Stridsberg's products are Made In The USA! That still means something to me and I support them.
I would also consider a Stridsberg amplified splitter for the OP. For me it would have to be a very high level, low noise figure preamp with only about 10dB gain and I would feed that to a high quality 4-way 50 ohm splitter. I would also try to put the preamp at the antenna and also use a good FM trap filter and/or other filtering to keep unwanted stuff out of the preamp. The Stridesberg products work fine in most areas but I'm afraid it would get overloaded where I live.
I was worried about overload where I live but I don't use it on 700-800MHz because I'm saturated by about 10-12 towers on the Macomb MPSCS system so signals are already strong. Many long time users of the Stridsberg MCA204M told me the amplification is just enough to overcome typical loss introduced my cables, connectors and adapters. I think they're right.
I'm using it on my DPD MilTenna OMNI antenna followed by a PAR FM & Intermod filters primarly for Civ/Mil-air bands feeding a BCT15X for Selfridge ANG and a BCD536HP for anything in the air using Zip Cod/Radio scanning. Works great and has made a great difference especially with reception of the base itself at Selfridge.
One word of caution this can become addictive and more scanners could be in your future. The OMNI X is awesome for me. Love it! I also use the EDA Electroline Drop Amps 8 port version. They are cheap and do a great job. Find them on Ebay all the time. They only amp 3.5db and each port is isolated so you won't experience back signals from one scanner to the other. What happens is once a signal is un-squelched on one scanner then all of a sudden the other is doing the same thing. They start to act like twins. Best to have port isolation so each scanner can do it's own thing. I currently run 11 scanners on one antenna the DPD Log Periodic. I use the Omni X (MilAir version) on remote setups. Good luck and let us know how you like the Omni X.
TailGator911
Silent Key/KF4ANC
Umm "addictive" being the key word here. Once you are bitten, you will turn, and never look back har-har
There's no cure but sometimes you can releave anexity buying another antenna!
The Stridsberg specs are quite poor in the world of preamps. There is no difference in choosing a preamp vs a multicoupler when it comes to IP1 (compression point) and IP3. Ideally both numbers would be at least 10dB higher than what Stridesberg advertises, otherwise a good amount of customers will experience IMD with lots of ghost signals throughout the bands created inside the multicoupler. CATV amplifier/splitters are not the answer either and their specs would not be much different than a Stridesberg.
If a Stridesberg doesn't work out I have a good combination of preamp, divider and FM trap filter I can share that works in my difficult RF hell.
If a Stridesberg doesn't work out I have a good combination of preamp, divider and FM trap filter I can share that works in my difficult RF hell.
A lot of those specs are over my head, but it works for me. I saw your creation in another thread if that's the one you're refering to? I'd have to come out of retirement to afford all the components!
Yea, the MiniCircuits ZHL-1010+ is $150, but it will put out about 1 watt with a noise figure less than 3.5dB. Then a suitable 4-way divider is another $98 for a ZFSC-4-1-BNC, but you can find them or similar units on Ebay in the $20 range.
With the Stridesberg 4-port multicoupler running $185 new, you could put together a much better version for maybe $63 more using new parts listed above, or with used parts much less than a new Stridesberg. Stridesberg sells a 700MHz and 800MHz low noise preamp, which has terrible specs and cost more than the wide band MiniCircuits amp. These preamps have wimpy little 1dB compression points of 12dBm and the noise figure is nothing special.
The Stridesberg multicoupler is an ok solution for many people, but I'm a little underwhelmed with their price vs performance.
With the Stridesberg 4-port multicoupler running $185 new, you could put together a much better version for maybe $63 more using new parts listed above, or with used parts much less than a new Stridesberg. Stridesberg sells a 700MHz and 800MHz low noise preamp, which has terrible specs and cost more than the wide band MiniCircuits amp. These preamps have wimpy little 1dB compression points of 12dBm and the noise figure is nothing special.
The Stridesberg multicoupler is an ok solution for many people, but I'm a little underwhelmed with their price vs performance.
This is what I am needing to accomplish, I have a DMR system that I like to monitor on my TRX1 and this is hooked to the Omni X antenna. I am trying to get the best reception possible on my second scanner, a whistler 1040 that I broadcast a 453.350 agency on raadio feed. This agency is a little scratchy at times when using an all band antenna indoors. They have a North and South channel. When on south channel the broadcast is crystal clear. It's when the north channel is used that I need help with. This agency comes in perfect on the TRX1 hooked to outside antenna. Thats why I was wanting to hook both scanners to the Omni X. I love this antenna. I am picking up things I haven't before. I live out in a rural area so no city overloads.
You can save about $40 if you opt for the 2-Port device, @ $148.00 or save about $110.00 if you buy a 2-Port passive (no preamp) coupler. However you'll probably regret it soon when you want to add that 3'rd or 4th scanner down the road. Buy once, cry once! 
Ubbe
Member
Then the first thing you should try are a simple T-connector to split the coax into two and feed both scanners. There's a high probablility that it is the only thing you'll need to do.
Stridsberg should really try to redesign their multicouplers so that the amplifier are a seperate box, with a diod switch to engage an internal FM trap filter when the 12v power are switching polarities and a relay function that bypass eveything at power loss, that can be installed at the antenna and power feed from the splitter box, that has a switch to select different dB levels depending of coax loss, still at the other end of the coax. It makes much more sense and all the coax and connector losses will be converted to gain that improve reception compared to a passive antenna/coax system.
/Ubbe
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