[RFI] Netgear GS724T switch

[gwj at me.com]

We have had no problems with any of the basic GigE Netgear switches at any of my stations, other than making sure to apply a choke to the DC output of the wall wart (or even better, find a model that runs on 12V if possible). In this case, we needed POE to power some cameras. That always has a certain level of risk with it since you’re really at the mercy of the power supply for the POE, whatever it may be. Whether it’s blind luck or quality EMC engineering on the part of Netgear, this one causes no problems.

-Gary NA6O

> On Jun 22, 2023, at 4:52 PM, <nlsa at nlsa.com> <nlsa at nlsa.com> wrote:
> 
> Gary –
> That’s encouraging!  Did you select the Netgear GS116PP intentionally or was it luck of the draw that you got an RF-quiet model?
> Best regards,
> Michael
>  
> From: gwj at me.com <mailto:gwj at me.com> <gwj at me.com <mailto:gwj at me.com>> 
> Sent: Thursday, June 22, 2023 4:20 PM
> To: rfi at contesting.com <mailto:rfi at contesting.com>; nlsa at nlsa.com <mailto:nlsa at nlsa.com>
> Subject: Re: [RFI] Netgear GS724T switch
>  
> Here’s a benchmark for you on low-RFI (at VHF) ethernet switches. At the W6TCP remote EME station (144, 220, 432, and 1296), we use a Netgear GS116PP 16-port POE unmanaged switch. There is zero RFI at this station. It has an external SMPS adapter that has 12 turns on a mix 31 toroid on the DC line but only to remove residual noise in the HF bands that might bother the other nearby HF station. We do not use shielded ethernet cables. I have checked carefully around all our equipment with a VHF sniffer probe (small loop) and proved that all conducted emissions are pleasingly low. Ian got himself WAS on 2m in exactly 365 days, and on 220 in just over a year… Not too shabby.
>  
> Gary, NA6O
> gwj at me.com <mailto:gwj at me.com>
> https://na6o.com <https://na6o.com/>
>  
> 
> 
>>  
>> Dear friends,
>> 
>> My remote 2m EME system is comprised of a number of modules (SDR,
>> transverter, SSPA, plus antenna and ventilation control modules, etc.), all
>> of which are linked to each other via a Netgear GS724T Gigabit
>> <https://www.netgear.com/business/wired/switches/smart/gs724tv4/ <https://www.netgear.com/business/wired/switches/smart/gs724tv4/>> "smart
>> switch."  All this equipment is located right underneath the EME antenna.
>> Despite abundant snap-on ferrite chokes and use of STP Cat6 cables
>> throughout, there is still considerable EMI from the switch and the Ethernet
>> cables connected to it.  Is there more that I can do to quiet the switch?
>> Alternatively, is there a network switch that is known to be RF-quiet?
>> 
>> Thanks,
>> 
>> Mike, W9IP