Cheap multicoupler.

[crazyboy]

Hi. I was wondering where I can get a cheap multicoupler. I need four ports.(sc200,bc 142xl,pro97) I need it to be under 100 dollars. Anyone know where I can get one used maybe? thanks.

 

[Al42]

Does it have to be a multicoupler? Would a splitter do?

 

[N_Jay]

Does it have to be a multicoupler? Would a splitter do?

And the difference would be?

 

[crazyboy]

I dont know the difference but..I dont want to use a tv splitter because I dont want to have a f-uhf & then a uhf-bnc. I'd like it to have just bnc's on it. I will mainly be scanning vhf & uhf but a some 800 will be mixed in there to.

 

[Al42]

Does it have to be a multicoupler? Would a splitter do?

And the difference would be?

"Splitter" usually refers to the resistive network one buys at Radio Shack for a few bucks. "Multicoupler" could be something that works much better, but costs a lot more.

 

[DaveH]

The common CATV splitter usually isn't just resistors. There's a wideband transformer in there.

Dave

 

[bsavery]

Crazyboy.... stick with the multicoupler search. Or bite the bullet and buy a new one. Even the best CATV splitter has 7.5db of loss per port.

Toss in the loss from the impedence mis-match and that's enough to kill off just about anything not transmitting from your driveway!

Bob

 

[DaveH]

Crazyboy.... stick with the multicoupler search. Or bite the bullet and buy a new one. Even the best CATV splitter has 7.5db of loss per port.

Toss in the loss from the impedence mis-match and that's enough to kill off just about anything not transmitting from your driveway!

Bob

A 2-port splitter has 3.5-4dB loss per port. As I have stated, 3dB of this is due to splitting power 2 ways. A perfect 4-port splitter would have 6dB loss per port; a real one higher.

The impedence mismatch thing is part of a long-standing misconception. There will be an additional small loss due to mismatch, which I admit I didn't mention, but it is not going to outright kill any reasonable signal. It is the same flawed argument such as against using 75-ohm coax.

Agreed, the high-grade multicouplers may be worth the money for those who need them. The cheap approach may work fine and save a pile of money, and it is a small investment.

Dave

 

[Al42]

Agreed, the high-grade multicouplers may be worth the money for those who need them. The cheap approach may work fine and save a pile of money, and it is a small investment.

Which is why I asked. The RS 15-1235 (4 port, which is what crazyboy wants) is only $10. If it works he saved some money - if it doesn't he can return it.

 

[N_Jay]

Crazyboy.... stick with the multicoupler search. Or bite the bullet and buy a new one. Even the best CATV splitter has 7.5db of loss per port.

Toss in the loss from the impedence mis-match and that's enough to kill off just about anything not transmitting from your driveway!

Bob

NO they don't.

I decent qualliy 2 way is 3.5 or so.

The loss from the mismatcc would only be a concern if teh antenna system is a consistant 50 ohm, which a wide band antenn is NOT!.

 

[crazyboy]

Thanks, ill continue the search.

 

[ka5s]

Hi. I was wondering where I can get a cheap multicoupler. I need four ports.(sc200,bc 142xl,pro97) I need it to be under 100 dollars. Anyone know where I can get one used maybe? thanks.

Here's a 8 way 10MHz - 1 GHz SMA conector spltter for $50 or so.
http://cgi.ebay.com/ws/eBayISAPI.dl...;item=3814261126&rd=1&ssPageName=WD1V

4 way 2-2000 MHz Type N
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=73169&item=7520687898&rd=1

4 way 5-500 MHz:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=73170&item=7520674131&rd=1

4 way SMA 2-2000 MHz
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4660&item=7520421585&rd=1

 

[bsavery]

Crazyboy.... stick with the multicoupler search. Or bite the bullet and buy a new one. Even the best CATV splitter has 7.5db of loss per port.

Toss in the loss from the impedence mis-match and that's enough to kill off just about anything not transmitting from your driveway!

Bob

A 2-port splitter has 3.5-4dB loss per port. As I have stated, 3dB of this is due to splitting power 2 ways. A perfect 4-port splitter would have 6dB loss per port; a real one higher.

He asked about a 4 port, so I didn't mention what a 2 port loses. "a real one higher" Higher... like the 7.5db figure I quoted off the face of the RS 4 port splitter I have sitting here in front of me maybe?

The impedence mismatch thing is part of a long-standing misconception. There will be an additional small loss due to mismatch, which I admit I didn't mention, but it is not going to outright kill any reasonable signal. It is the same flawed argument such as against using 75-ohm coax.

It's not a misconception, it's an actual fact. Yes, the loss will vary based on the frequency, but nonetheless, there will be loss.

Add up the loss numbers for each item... cable loss, splitter loss, antenna and scanner connector insertion loss, impedence mismatch loss... and your close enough to 9-10 db loss that you might as well stick with the stock antenna!

Agreed, the high-grade multicouplers may be worth the money for those who need them. The cheap approach may work fine and save a pile of money, and it is a small investment.

May, but not likely. You might hear strong signals, but that's about it. Then you'll be back here asking about an amp!

Besides, if you can afford 4 scanners and are that serious about the hobby, why not spend the extra money and do it right!

Bob


Dave[/quote]

 

[bsavery]

NO they don't.

I decent qualliy 2 way is 3.5 or so.

Which I would have said if he'd asked about a 2 way splitter. He asked about a 4 way, so I stated the loss for a 4 way splitter.

The loss from the mismatcc would only be a concern if teh antenna system is a consistant 50 ohm, which a wide band antenn is NOT!.

It's not constant, agreed... but how much does it really vary? I'll bet from 100-900 mhz it'll be closer to 50 than 75.


Bob

 

[Al42]

The loss from the mismatcc would only be a concern if teh antenna system is a consistant 50 ohm, which a wide band antenn is NOT!.

It's not constant, agreed... but how much does it really vary? I'll bet from 100-900 mhz it'll be closer to 50 than 75.

I think I'd have to go with both of you on this one. The receiver may be closer to 50 ohms across its entire design range (the design engineer has a bit of control over that, and the front end can easily be kept tuned) but the antenna impedance "curve" will probably resemble a fractal image.

 

[N_Jay]

NO they don't.

I decent qualliy 2 way is 3.5 or so.

Which I would have said if he'd asked about a 2 way splitter. He asked about a 4 way, so I stated the loss for a 4 way splitter.

Sorry missed that, but the same applies, a 4 port multicoupler will have about 7 dB of loss, regardless of the quallity.

The loss from the mismatcc would only be a concern if teh antenna system is a consistant 50 ohm, which a wide band antenn is NOT!.

It's not constant, agreed... but how much does it really vary? I'll bet from 100-900 mhz it'll be closer to 50 than 75.

Bob

You wopuld lose that bet.

Go look at the spects. They are 2:1 or even 3:1 over their specified range.

Impeadance mismatch losses are probabaly under 1 dB.