Question regarding "splitter"

[conve36]

My situation:

I have a PDI "splitter" that looks just like the one in the picture.

It says "Mega Splitter" "2-Way 5-1000Mhz"

I have one antenna line coming in and connected to the "input".

It has 2 other connectors that each say 3.5dB and have 2 scanners hooked up to there. One scanner monitors an 800mHz trunked system and the other monitors mostly UHF conventional channels. I dont seem to have much of any signal loss in the 800Mhz freqs using this splitter or a "T" connector and any antenna I use... (trying to get the most out of the UHF area...)

My question: (regardless of what frequency bands I listen to)

Is it better to use this "splitter" than to use a PL-259 or BNC "T" connector?

Can this "splitter" be used the opposite way? As in hooking up 2 antenna's on the bottom connectors and one scanner to the "input"?

Should I hook up a ground to this splitter? (Will it make a difference?) I have it grounded at the antenna..

And yes I know this is NOT the best way of using 2 scanners with on antenna or vice versa, but I am working with what I have at the moment...

Thanks everyone!

 

[blueangel-eric]

there was a thread last week about this same thing and many more threads about every other week. There is a sticky at the top of the forum about this too. please take the time to look before posting.

 

[conve36]

Those posts get way off subject , there are hundreds of threads about the same subjects and people always post the same comments as you just did. I was just looking for a quick answer to MY situation. Isnt that the point of these forums? Your comment was not helpfull nor was it necessary. And my question about what these forums are for is rhetorical... Lets not get off the main subject of this thread

 

[zzdiesel]

I've noticed that attitude on multiple message boards over the years. It would have been just as easy for them to answer your question if they knew or ignored it if they didn't. This subject is very interesting to me as well. The scanner antenna multicouplers are so damned expensive. I need to run two scanners on one antenna now and then it will be three in a couple of months.

 

[conve36]

I've noticed that attitude on multiple message boards over the years. It would have been just as easy for them to answer your question if they knew or ignored it if they didn't. This subject is very interesting to me as well. The scanner antenna multicouplers are so damned expensive. I need to run two scanners on one antenna now and then it will be three in a couple of months.

This is working for me right now, I would recommend you try things for your self. You can get one of these splitters super cheap from WalMart, if you dont like it, take it back...

And I notice no difference when using RG-6 (tv cable) compared to RG-8

 

[zzdiesel]

Thanks. I found a three way cable splitter in my parts drawer. This splitter is weird. It has two output ports marked -7.5 db and the other one is marked -3.5 db. I wonder which ones would be better for scanners. I have to go to Radio Shack this morning to get a couple of cable connecter converters to go from F to BNC.

 

[blueangel-eric]

Those posts get way off subject , there are hundreds of threads about the same subjects and people always post the same comments as you just did. I was just looking for a quick answer to MY situation. Isnt that the point of these forums? Your comment was not helpfull nor was it necessary. And my question about what these forums are for is rhetorical... Lets not get off the main subject of this thread

this post is on the same page did you see it? http://www.radioreference.com/forums/showthread.php?t=124779

it talks about the same thing.

 

[gmclam]

Splitters

Is it better to use this "splitter" than to use a PL-259 or BNC "T" connector?

Yes.

Can this "splitter" be used the opposite way? As in hooking up 2 antenna's on the bottom connectors and one scanner to the "input"?

From the splitter's standpoint; some can be used in reverse and some can not. However, the mixing of two signals, such as from two antennas, is tricky and most likely will not get you what you want.

Should I hook up a ground to this splitter? (Will it make a difference?) I have it grounded at the antenna..

Signal-wise it makes little difference. If your antenna gets struck by lightning, it could make a huge difference. But then again, I suspect you have the splitter fairly close to your scanners, and the path to ground would not be shorter than through the scanners even if you did have a wire connected.

And yes I know this is NOT the best way of using 2 scanners with on antenna or vice versa, but I am working with what I have at the moment...

Actually that's exactly how I have 2 scanners connected to the same outside antenna.

This splitter is weird. It has two output ports marked -7.5 db and the other one is marked -3.5

What makes you think it is weird? When you split a single signal into two paths, each is attenuated 50% (or 3dB). Because there is also loss in the connections, and perhaps the splitter may not be 'perfect', the loss there appears to be 3.5dB. Now take one of those signals and split it again. You end up with one output at -3.5dB and two at -7.dB .. or in that case -7.5dB. If it was a 4-way splitter, the other port would have been split and all outputs would be attenuated somewhere between 6dB & 8dB.

 

[zzdiesel]

What makes you think it is weird? When you split a single signal into two paths, each is attenuated 50% (or 3dB). Because there is also loss in the connections, and perhaps the splitter may not be 'perfect', the loss there appears to be 3.5dB. Now take one of those signals and split it again. You end up with one output at -3.5dB and two at -7.dB .. or in that case -7.5dB. If it was a 4-way splitter, the other port would have been split and all outputs would be attenuated somewhere between 6dB & 8dB.

I didn't word that very well. I simply didn't understand it and called it weird. I do thank you for explaining things for me. My two radio's seem to work the best on the -7.5 db ports.

 

[hoser147]

I have 6 scanners thru a splitter with no issues.........

 

[gmclam]

I didn't word that very well. I simply didn't understand it and called it weird. I do thank you for explaining things for me. My two radio's seem to work the best on the -7.5 db ports.

Consider for a moment how good of reception most people get with their hand-held scanners and the stock rubber antennas they come with. Now take that same 'sensitive' scanner and connect a powerful outdoor antenna to it. There are lots of cases where people end up with TOO MUCH signal. The scanner will typically adjust the signals it is receiving so that the strongest is where it wants it. So it does not surprise me if they work better on the lower signal level ports.

 

[blueangel-eric]

The scanner will typically adjust the signals it is receiving so that the strongest is where it wants it.

I am not sure what you mean in this sentence. the scanner doens't adjust anything. a strong signal shows up however or whereever it wants depending on the quality of the receiver. a strong signal can bleed over on other frequencies. the scanner doen'st adjust and tell it what freq to receive the strong signal.

 

[gmclam]

I am not sure what you mean in this sentence. the scanner doens't adjust anything. a strong signal shows up however or whereever it wants depending on the quality of the receiver. a strong signal can bleed over on other frequencies. the scanner doen'st adjust and tell it what freq to receive the strong signal.

Receivers have AGC (automatic gain control) which adjusts all signals in the frequency span it is receiving in. So a strong signal can make the weak weaker. Some of these scanners certainly don't have great AGC, and that's why they give us an ATTenuator function.

Regardless of AGC action, certainly an extremely close or powerful signal can bleed over onto adjacent frequencies. Theoretically however, the ability to select a desired signal over an undesired signal is a function of the receiver. In other words; good quality receivers will get less bleed over than cheap receivers.

If you do a little searching here at RR, you'll find there are often people who want to add RF amplifiers to their antennas feeding their scanners. Unless someone is in the boonies away from all RF sources, this usually has a negative effect. All it takes is one power signal from something like a paging system and it overloads the scanner. Of course this can happen without an external amplifier .. so having LESS signal often makes things work better.

 

[smokeyjones666]

Your 'weird' splitter is what we referred to in the cable industry as an 'unbalanced' 3-way, essentially the equivalent of hooking up a 2-way splitter to one of the outputs of another 2-way splitter - you get -7db on two ports and -3.5db on the remaining port.

Compare to what we always called a 'balanced' 3-way splitter that was -5.5db on each of the three ports. How these were different internally I couldn't tell you, I never bothered to cut one open and find out.

I have no idea if 'balanced' or 'unbalanced' were the proper names for these things, but that's what it said on the requisition forms so that's what we called them.

We had both of these types of 3-way splitters available in large quantities. I usually made sure I had at least a handful of 'unbalanced' 3-ways in my truck to aid in resolving reception problems in homes where there were multiple splitters located throughout the building.

 

[zzdiesel]

Thanks for info, Smokey. I used the splitter for several hours yesterday. It was killing the reception on my BCT15. I finally took it out of line. I figure the only thing I'll be satsified with is one of the high dollar multicouplers. I listen to too many distant trunking towers.

 

[blueangel-eric]

Receivers have AGC (automatic gain control) which adjusts all signals in the frequency span it is receiving in. So a strong signal can make the weak weaker. Some of these scanners certainly don't have great AGC, and that's why they give us an ATTenuator function.

Regardless of AGC action, certainly an extremely close or powerful signal can bleed over onto adjacent frequencies. Theoretically however, the ability to select a desired signal over an undesired signal is a function of the receiver. In other words; good quality receivers will get less bleed over than cheap receivers.

If you do a little searching here at RR, you'll find there are often people who want to add RF amplifiers to their antennas feeding their scanners. Unless someone is in the boonies away from all RF sources, this usually has a negative effect. All it takes is one power signal from something like a paging system and it overloads the scanner. Of course this can happen without an external amplifier .. so having LESS signal often makes things work better.

I once had a RS Pro82 or was it 83, the little cheap one, and it recieved quite pleasing. i lost it and got the Pro97 and it costs lots more but the reception was terrible. it overloads and desenses big time. sure it had a ATT but then that would cut everything back too much. i listen to the RR's and need all the signal i can get since that isn't on repeaters.