Stridsberg MCA216M

[N9JIG]

I currently have 4 8-port active multicouplers (MCA208M) as well as a pair of passive MCA204's. They work great for their intended applications. I now however have need for more than 8 ports off a single antenna. While I have been encouraged to roll my own with parts from Mini-Circuits (and am investigating doing so) I like the plug and play of the Stridsbergs. so am considering the MCA216M. At $800 though it is a steep price, even for me.

I have a question about the MCA216M first: Is the preamp set to amplify directly from the RF input or is it split before the amplifier?

I ask this as the notes on their web page say that you can use a passive MC to feed 2 Actives. While I have tried this and it works well, the signal strength and quality is somewhat less than from using the MCA208M directly connected to the antenna. I have some weak signal targets that just do not receive as well when I use the passive to feed a pair of active MC's.

If the MCA216M is amplified directly from the antenna input prior to any splits then it should perform better for me that using a passive to feed two active MC's, as well as simplify my installation that requires 12-16 ports.

Does anyone know whether the MCA216M is amplified AFTER being split to two 8-port parts or before? If you have one could you pop off the cover and see how the input is wired (or even post a picture of the interior here)?

(I sent this question to Stridsberg and of course never heard back.)

 

[Ubbe]

There's no reason to amplify after a split and not before it. Stridsberg use a GaAs pHEMT amplifier that has some 20dB gain and then reduce it's signal to let it be +3dB at each output. It uses transformers that has one input and two outputs and those outputs goes to another pair of transformers to make it a 1-4 splitter. Then you can add 4 more transformers to those outputs to get 8 outputs and finally add 8 more transformer to get 16 outputs. All those transformers makes it expensive.

The loss are 3dB for each transformer the signal has to pass so will be 9dB for 1-8 and 12dB for 1-16 so still gain left to compensate for the losses when the signal doesn't need to be reduced much at all in a 1-16 splitter.

/Ubbe

 

[prcguy]

If you amplify after splitting all that loss will be added to the system noise figure and reception would be degraded, so no respectable company would amplify after splitting.

 

[N9JIG]

There's no reason to amplify after a split and not before it. Stridsberg use a GaAs pHEMT amplifier that has some 20dB gain and then reduce it's signal to let it be +3dB at each output. It uses transformers that has one input and two outputs and those outputs goes to another pair of transformers to make it a 1-4 splitter. Then you can add 4 more transformers to those outputs to get 8 outputs and finally add 8 more transformer to get 16 outputs. All those transformers makes it expensive.

The loss are 3dB for each transformer the signal has to pass so will be 9dB for 1-8 and 12dB for 1-16 so still gain left to compensate for the losses when the signal doesn't need to be reduced much at all in a 1-16 splitter.

If you amplify after splitting all that loss will be added to the system noise figure and reception would be degraded, so no respectable company would amplify after splitting.

This is exactly as I think but just wanted to confirm that the MCA216M does exactly that. The reason I suspect it might not is that they suggest using a passive to feed 2 active multicouplers for the same effect, that leads me to think they might have just placed two 8-ports with separate amps in a single package.

 

[Ubbe]

If you split a signal it gets reduced 3dB so that 3dB are added to the noise figure that are 3dB, or if it was 3,5dB NF for a 1-4 mulcticoupler. So if they split and use two circuit boards of a 1-8 splitter then its noise figure would be 6dB. Noise figures doesn't matter if you always receive strong signals higher than -95dBm. If you are into weak signal monitoring than you have to pay attention to the total noise figure in the whole receive chain.

/Ubbe

 

[N9JIG]

If you split a signal it gets reduced 3dB so that 3dB are added to the noise figure that are 3dB, or if it was 3,5dB NF for a 1-4 mulcticoupler. So if they split and use two circuit boards of a 1-8 splitter then its noise figure would be 6dB. Noise figures doesn't matter if you always receive strong signals higher than -95dBm. If you are into weak signal monitoring than you have to pay attention to the total noise figure in the whole receive chain.

/Ubbe

I get that but my question is whether the MCA216M amplifies the signal before any splitting (like the MCA208M does) or if it passively splits before two separate amplifiers.

• If they amplify first and then split into 16 ports once then it should work fine for me (and better than their suggestion to use a passive MC to feed two active's). This (to me anyway) would be a true 16-port multicoupler.
• If they amplify first, then split into two then each of those gets split 8 ways then there might be issues or might not be.
• If they split into two first, then amplify into 2 8-port splitters then there will be an even higher reduction, the same as if I used a passive MC to feed two actives. This (to me) would be a pair of 8-ports in a single box with an internal splitter feeding each, which I can replicate with my existing passive and active MC's.

 

[Ubbe]

better than their suggestion to use a passive MC to feed two active's

They probably suggested that as it could be what they are doing in the MCA216. It takes exactly twice the 12VDC power of an MCA204 or MCA208, minus 20mA for one power LED less, and they say that MCA216 uses dual amplifiers and it has the exact same specification as their single amplifier multicouplers.

So everything indicates that they passively split 1-2 and feed two MCA208 circuit boards that have their amplifiers set to a 3dB higher gain to compensate for the extra loss. You can see that you have 4 ports on each side like a MCA208 and then a bigger gap and then 4 more ports at each side, like if you have two MCA208 circuit boards next to each other inside it. Its noise figure would have told us their design solution, a value that Stridsberg do not state for their multicouplers.

/Ubbe

 

[prcguy]

I get that but my question is whether the MCA216M amplifies the signal before any splitting (like the MCA208M does) or if it passively splits before two separate amplifiers.

• If they amplify first and then split into 16 ports once then it should work fine for me (and better than their suggestion to use a passive MC to feed two active's). This (to me anyway) would be a true 16-port multicoupler.
• If they amplify first, then split into two then each of those gets split 8 ways then there might be issues or might not be.
• If they split into two first, then amplify into 2 8-port splitters then there will be an even higher reduction, the same as if I used a passive MC to feed two actives. This (to me) would be a pair of 8-ports in a single box with an internal splitter feeding each, which I can replicate with my existing passive and active MC's.

I will put $$ on they are amplifying first then splitting, they would be out of business if they split before the amplifier. It doesn't matter if they split to two after the amplifier then to two 8-way splitters for 16, that's similar to what is inside a passive 16-way splitter anyway. They should only have one amplifier to make up for total splitter loss, which is 12-13dB for 16-way.

 

[Ubbe]

The gain of one amplifier supports a 16 ports design, but they use a dual amplification solution and only logical explanation for that, and that they also state they only build after they get an order, very few are sold, and can deliver in a couple of days, are that they use their already ready built 8 port circuit boards that have their own amplifier, no triple amplifier design mentioned.

Stridsbergs multicouplers have always been a medium signal strength design, not for weak signal and neither for strong signal as it overloads too easily, that are outperformed by many TV antenna amplifiers at 1/4 of the cost. But you get a plug&play splitter with BNC connectors ready to be used and will be suitable for most users.

/Ubbe

 

[N9JIG]

I will put $$ on they are amplifying first then splitting, they would be out of business if they split before the amplifier. It doesn't matter if they split to two after the amplifier then to two 8-way splitters for 16, that's similar to what is inside a passive 16-way splitter anyway. They should only have one amplifier to make up for total splitter loss, which is 12-13dB for 16-way.

That's what I figured.

I am keeping an eye out on the parts to make my own. I might end up just buying the stuff new from Mini-Circuits, if I do it would be pretty much a wash, except for the jumpers as I don't have enough SMA-BNC or SMA to N ones. I should get better performance than I would with a Stridsberg anyway.