Shielded Ethernet Switch Recommendation

Doug Wilson

Hi,

I was having big rfi problems with SmartSDR and the 6600M (mostly transmit cutout) that have been completely solved with a Palomar 6600 kit and DX Engineering filters on the ethernet cable to the radio and computer.

Now I've noticed a spike every 60 khz or so on 20m that is stronger on the hexbeam than the efhw but present even with the antenna disconnected. Some searching reveals this could be unshielded cat5 but could also be the unmanaged switch I'm using.

Any recommendations on a shielded 10 port switch, or other solutions? I understand this could be several other things and I can work further to hunt it down. I'm in a pretty quiet rural setting with no neighbors closer than 1/2 miles so it's something here. So I thought I would try the experience base here for easiest fix first. The 61khz spacing sounds like the switch, cat5 or both but I don't know.

Thanks

Mike-VA3MW

Doug,

It is likely from wall cubes, or something like a cordless drill charger. You may have to kill the power to the house and run the radio on battery while turning on 1 thing at a time.

I doubt it is from the station power supply.

73

Mike-VA3MW

Hi Doug

If they are every 60Khz or so, it is likely a switching power supply.

I bet they look like this. This is at my remote. I have to go track them down.

Doug Wilson

Mine are not that pronounced (maybe half the db) and do not have that double spike. I'm using two Samlex 1235P-M power supplies and they could definitely be the source.

I switched off the non radio power supply and the spikes were unchanged. However shutting off the tuner showed an 8db noise floor drop on the hexbeam.

Doug Wilson

Thank you Mike.

frc2302

Sorry to resurrect an old thread, but just wanted to mention that you should be careful with shielded ethernet cables. Ethernet is ground-isolated by design, which in our case is a good thing. Adding a shield, if it is connected at both ends, may give you a ground loop, which may create new problems at best, or be dangerous at worst.

I found that fiber is pretty cheap for small runs. You can isolate your ham gear from the rest of your network for under $100, including a pair of media converters, the necessary transceivers, and a length of fiber. That's the route I went, and it is of course immune to RF, ground loops, and surges.

Mike-VA3MW

BTW, I am going to write this up in detail. First, the DX Engineering ISO filters did nothing to help in my situation. YMMV.

I was dealing with the picture you see above with the feed to my tower (Shield CAT 6) being the problem. I did spend all day Saturday working on it. I got rid of a lot of the noise by changing the Switch to ProSumer switch (TP-Link TL-SG1024DE), but the noise continues.

I will be changing it to Fiber once I get back from Dayton.

Mike

KI5RLR

https://community.flexradio.com/discussion/comment/20603130#Comment_20603130

Mike - What fiber to ethernet converters did you end up using in your setup? Thanks

Peter K1PGV

the feed to my tower (Shield CAT 6)

By changing to fiber, you eliminate the lightning/static problem on those cables as well. This is probably the most common reason commercial users do outdoor fiber runs (like between buildings).

The biggest problem with fiber is you have to buy pre-built cables of the “right” length. Putting connectors on fiber requires considerably more tools and skill than crimping an RJ45.

I’m eager to read about people’s experiences with the various GBE to fiber converters that are available. I’ve long wanted to isolate my lab with fiber.

John K3MA

I sold some surplus fiber gear a while ago after setting up my network. I did not think it necessary to have fiber gear that was all current technology (insert high price) and as such I looked for older commercial-grade equipment that was being swapped out by large companies and picked up several HP Procurve 2524 switches and some TrendNet TFC-1000MFC fiber converters. These use the older style SC type fiber connections. I successfully and easily set up fiber networking to the Flex equipment using either two of the TrendNet converters (one on each end) or the HP switch on one end and TrendNet converter on the other end.

The upside is you get very good commercial-grade equipment and the cost is very low. I did the entire setup for less than $75 including 100 feet of fiber cable. I just did a quick look on eBay and some of this exact equipment is still listed with prices for the converters around $20 and the HP switch for around $40. I see on Amazon that SC to SC fiber cable is about $50.

One thing I would mention if doing this now. At least a year or two has passed since I originally did the conversion and more modern gear for reasonable budget prices might have come out on the surplus market so you might benefit from doing some window shopping on eBay.

Mike-VA3MW

I never did go to Fiber.

Since I had AC Power going to the base of the Tower, I just used a pair of TP-Link Power Line devices which moves IP over the powerline.

In the other direction, 300', I ran RG6X with MoCA media converters on each each. It gave me just shy of 1Gbit/sec.

As for Switches, I use TP-Link business office managed switches. They are in a metal case. The managed switch helps me find switch ports that are flapping.

K1UO Larry

I am surprised that using the TP-Link power line devices didn't create noise on your HF frequencies. They certainly did here. So much so that I had to remove them and come up with another solution.

Mike-VA3MW

If they did, I didn't hear them and they were below my noise floor. But, I don't see any noise or birdies related to them.

My noise continues to be wall warts as I find them.

frc2302

In case it's useful, I went with a pair of these: https://amazon.com/gp/product/B003CFATL0/ and https://amazon.com/gp/product/B003CFATYW/. That isolated the ham network segment nicely.

FWIW, even copper ethernet is supposed to be ground-isolated, though some manufacturers do not seem to know that. Sticking with reputable brands is key. I still would want surge protection, which I get for free with fiber, but I think ground loops shouldn't be an issue even with copper (unless you are using shielded cable, in which case you do need to design carefully and connect the shield only at one end).

frc2302

Oh and this: https://www.amazon.com/gp/product/B00M1C0186/

runs nicely off my shack power via this: https://amazon.com/gp/product/B00C66JTPI/

which lets me expand while maintaining my isolation downstream of the fiber.

Peter K1PGV

@frc2302 Thank you for those pointers. Really, much appreciated.

I've gone ahead and ordered some of those TP-Link RJ45 to SFP converters that you suggested. I chose to go BiDi simplex single mode fiber, though (I bought these Ubiquity SFPs https://www.amazon.com/gp/product/B072FHMZHZ/).

We also agree on our choice of GBE switches. Long ago I standardized on HP ProCurve switches for both office and home use. When they no longer made those, I went on a long, error prone, sort of random-walk of the available switches. I finally arrived at the Netgear ProSAFE line of switches, and have now standardized on those (which are surprisingly good quality for the money).

For the benefit of anybody else who might be considering doing a fiber run to isolate their shack: After spending waaay too much time looking into this, I came to the conclusion that you really want to use armored LSZH fiber because it's far too easy to damage most non-armored cables (as you're pulling it through a wall, or even running it around you basement).

Again, @frc2302, thanks for your pointers.

frc2302

I'm glad it was useful. Re: damaging fiber - gray 1/2" PVC conduit is cheap (and paintable, if it matters); I use it anytime the cable is leaving the rack.

Peter K1PGV

 gray 1/2" PVC conduit is cheap... I use it anytime the cable is leaving the rack.

Yeah, for ME, conduit isn't worth the effort for 30m runs in my basement (especially given that having conduit now creates the problem of actually pulling (or blowing) the fiber through the conduit). I found some awesome armored, pre-terminated, single mode armored cable on Amazon that's apparently made with ClearCurve LBL: https://www.amazon.com/dp/B0BP1Z6D8P -- Shockingly inexpensive, and definitely good stuff.

frc2302

https://community.flexradio.com/discussion/comment/20609408#Comment_20609408

Thanks for the tip. That could be useful for me too.

frc2302

Oh, man. I feel sheepish.

A year after buying that Netgear switch, which runs on 9v, and the buck converter to go with it, I discovered that the SMC 8505T runs directly on 12v, and I already have two of them in my junk box. $20 on eBay if anyone else wants one!

https://www.ebay.com/itm/144709403367

(I'm not the seller. I'm keeping mine.)

Peter K1PGV

SMC makes (er, made?) a good product. I think they're out of the switch business now, aren't they?

I'm not sure where their switches are made, though. For me, it's got to be TAA/NDAA compliant, or it doesn't get on my network. Just, you know, personal paranoia. Too many stories of commodity devices "phoning home" or launching bot-net attacks... 😥

frc2302

Peter - in general, I share your paranoia; however, the SMC switch above is old and "dumb" (unmanaged, no connectivity of its own), so I doubt it's an exfil threat.

Mike-VA3MW

Peter, I agree with the above commenter.