Best RF Multi-coupler money can buy

[blantonl]

I'm looking for a recommendation from the pros here.

I've had yet another Stridsberg Multicoupler die on me, this time the 16 port $900 big daddy, and while I love the Stridsbergs I suspect I blew a diode or fuse while doing some antenna work and cabling housekeeping. It powers up, but it's now RF deaf... so I've got an email into Stridsberg. It's been pretty dry and static electricity has been rampant. While I get it repaired, I'd like to take my multi-coupler installation to a next level.

Here's what I'm looking for.

1`) Prefer rackmount
2) Top of the line specs for port isolation and port DB Loss.
3) 16 output ports, but 8 ports is fine
4) N-connector input for the antenna. SMA or BNC outputs are fine.
5) 25-1000 MHz bandwidth support
6) Installed / Switchable FM BCB filters would be nice.

I have a winradio antenna switcher / multicoupler that is 4 antennas in and 8 ports out, however it is noisy and the power supply seems to blast noise on certain points of the UHF mil band, so I kind of like it but it could be better.

Let me know what you guys think.

 

[buddrousa]

Sir I have looked at this one but never tried any of their products.

Wideband RF Multicoupler - 16 Radios, Surge Protected, 50 Ohm

16 Port Active RF Multicoupler, ships now, free trial

www.digital-loggers.com

 

[AB5ID]

Sir I have looked at this one but never tried any of their products.

Wideband RF Multicoupler - 16 Radios, Surge Protected, 50 Ohm

16 Port Active RF Multicoupler, ships now, free trial

www.digital-loggers.com

Has been mentioned before results not favorable.

Digital Loggers 16 port Multicouplers

Has anyone tried one of the Digital Loggers 16-port multicouplers? I am thinking one of these might replace a pair of 8-port Stridsbergs... https://www.digital-loggers.com/multi.html

forums.radioreference.com

 

[Thunderknight]

Find out what Motorola or Harris use at sites. Trunked sites are usually built with a single receive antenna that is used for all the receivers.

 

[AM909]

I don't know if Chip Angle (now retired) built any broadband stuff, but it was well-thought-of, pioneering stuff in the 80s.

 

[buddrousa]

Has been mentioned before results not favorable.

Digital Loggers 16 port Multicouplers

Has anyone tried one of the Digital Loggers 16-port multicouplers? I am thinking one of these might replace a pair of 8-port Stridsbergs... https://www.digital-loggers.com/multi.html

forums.radioreference.com

Looks like they may no longer sell them

 

[prcguy]

Find out what Motorola or Harris use at sites. Trunked sites are usually built with a single receive antenna that is used for all the receivers.

That would be only one band and only the repeater input range, not VHF/UHF and 800 off one system.

 

[prcguy]

I approached Chip about designing and marketing a low noise high level broadband amp and he turned me down. I also approached the new owner of the company and he has not made any progress either.

There are off the shelf amplifiers and splitters that will give much better performance than any Stridesberg or similar device. Here are the parts I use although they are not mounted to anything at the moment. The amplifier IP1 is around 1 watt, the IP3 is 46dBm but the noise figure is a little high at 3.5dB, but you can't have low noise and huge signal handling in the same box. The divider has about 30dB isolation between ports at the lower end of the band and about 22dB at 800MHz. Overall there is about 1dB gain from input to output.

I could mount these to a rack with type N input or any other connector and maybe send to Lindsay for evaluation. Maybe.

I don't know if Chip Angle (now retired) built any broadband stuff, but it was well-thought-of, pioneering stuff in the 80s.

 

[vagrant]

@prcguy Which amplifier model is that?

 

[prcguy]

That would be the ZHL-1010. I keep a few spares although there might be a 20dB gain ZHL-2010 in there.

@prcguy Which amplifier model is that?

 

[blantonl]

Hmm, maybe I might go the route of purchasing a ZHL-1010 and a ZFSC-8-43+ and giving this a nice test here in the lab. They aren't that expensive.

I might just mast mount that ZHL-1010 in a weatherproof box and and power it using a Bias-T. Let me chew on this today.

There's also the option to go big and add a minicircuits remote controlled antenna matrix switcher that throw that into the mix for a much more flexible and high performance solution.

 

[prcguy]

I also have a spare MiniCircuits FM trap, the best I've ever tested and a manual 3GHz rated transfer switch to take it in and out of line. I could rack mount this stuff all wired with RG-142 coax and send it. If you like you can have it for the retail cost of the parts. I might even throw in an HP limiter for the preamp.

I've also done remote powered mast mount stuff and here is the latest version of mine, although I will be swapping out one of the preamps and filters soon.

Hmm, maybe I might go the route of purchasing a ZHL-1010 and a ZFSC-8-43+ and giving this a nice test here in the lab. They aren't that expensive.

I might just mast mount that ZHL-1010 in a weatherproof box and and power it using a Bias-T. Let me chew on this today.

There's also the option to go big and add a minicircuits remote controlled antenna matrix switcher that throw that into the mix for a much more flexible and high performance solution.

 

[AM909]

...
I might just mast mount that ZHL-1010 in a weatherproof box and and power it using a Bias-T. Let me chew on this today.
...

Chip makes a big deal about getting that low noise-figure close to the antenna, where it'll do the most good. We did it once on ham (VHF hi) and saw good results at a low-level site, where we could get away with not filtering in front of it. That amp sounds like it'll take a whole bunch of signal into it and stay linear, and so could be worth trying, depending on your environment. Most commercial installs I saw didn't bother with the extra hassle of tower-mounting, but again, most made use of some band filtering in front out of necessity. YMMV. We look forward to hearing about the results.

 

[prcguy]

If your using the smaller Angle Linear preamp like in the picture below, those are not very good by today's standards with an IP1 around 12dBm and noise figure .5dB at UHF. You can do better with a MiniCircuits for much less $$. The larger amps pictured were the best in the land mobile business at the time having an IP1 around 25dBm and a NF around .8dB at UHF. These were not cheap preamps and I think they cost close to $300.

A current MiniCircuits ZX60-P103 will cover VHF and UHF with a NF under .5dB and a 1dB compression of 22dBm, not bad for $89 retail. This is a very good choice for a repeater front end with lots of sharp preselection in front of the preamp and that is what the Angle Linear preamps were designed for. The ZX60-P103 may work for some as a broad band amp on a Discone with no filtering but for others it will fail miserably. This is where you give up some NF specs and go with a more bullet proof ZFL-1010 or possibly a ZFL-2010 if you need more gain.

Chip makes a big deal about getting that low noise-figure close to the antenna, where it'll do the most good. We did it once on ham (VHF hi) and saw good results at a low-level site, where we could get away with not filtering in front of it. That amp sounds like it'll take a whole bunch of signal into it and stay linear, and so could be worth trying, depending on your environment. Most commercial installs I saw didn't bother with the extra hassle of tower-mounting, but again, most made use of some band filtering in front out of necessity. YMMV. We look forward to hearing about the results.

 

[blantonl]

I also have a spare MiniCircuits FM trap, the best I've ever tested and a manual 3GHz rated transfer switch to take it in and out of line. I could rack mount this stuff all wired with RG-142 coax and send it. If you like you can have it for the retail cost of the parts. I might even throw in an HP limiter for the preamp.

I already placed this order today:

1x ZBSF-95-N+ (FM Trap)
1x ZFSC-8-43+ (Power Splitter / Combiner)
1x ZHL-1010+ (Preamp)

The FM trap in my setup is critical. I'm going to get these on the bench and see what's up.

Maybe if you build me something rack mounted I'll drive this POS up to you some point soon in DFW (that we spoke about a while back) 🤣

 

[prcguy]

Aah yes, I remember the two story spaghetti Discone. Not sure I have room for that in my life at the moment or a way to hide it from the wifee.
I do all my assembly in So Cal but will be in TX here and there.

You might find you don't need an FM trap with the big MiniCircuits amp, its much harder to drive into IMD land compared to most I've tested.

I already placed this order today:

1x ZBSF-95-N+ (FM Trap)
1x ZFSC-8-43+ (Power Splitter / Combiner)
1x ZHL-1010+ (Preamp)

The FM trap in my setup is critical. I'm going to get these on the bench and see what's up.

Maybe if you build me something rack mounted I'll drive this POS up to you some point soon in DFW (that we spoke about a while back) 🤣

View attachment 115632

 

[dlwtrunked]

I already placed this order today:

1x ZBSF-95-N+ (FM Trap)
1x ZFSC-8-43+ (Power Splitter / Combiner)
1x ZHL-1010+ (Preamp)

The FM trap in my setup is critical. I'm going to get these on the bench and see what's up.
...

That is the best FM Trap I have found but the ZHL-1010+ does not impress me with its noise figure being larger than I normally accept.

 

[dlwtrunked]

Aah yes, I remember the two story spaghetti Discone. Not sure I have room for that in my life at the moment or a way to hide it from the wifee.
I do all my assembly in So Cal but will be in TX here and there.

You might find you don't need an FM trap with the big MiniCircuits amp, its much harder to drive into IMD land compared to most I've tested.

But he might drive the receiver into IMD land without the trap.

 

[blantonl]

I also ordered a Telewave ANT280S Discone today as well.

I’m using a dead Multicoupler as an excuse to just go nuts and make some investments in my overall Antenna infrastructure.

 

[prcguy]

The ZHL-1010 noise figure is the same as most Stridesberg products.

That is the best FM Trap I have found but the ZHL-1010+ does not impress me with its noise figure being larger than I normally accept.