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Re: [RFI] Internet Modem / Router Cable Length and RFI

To: rfi@contesting.com
Subject: Re: [RFI] Internet Modem / Router Cable Length and RFI
From: "Roger (K8RI)" <k8ri@rogerhalstead.com>
Date: Thu, 04 Jun 2015 15:41:35 -0400
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
It could be luck, it could be connected to the purpose of the computers, or both. I do a lot of photography and AVI work, hence, the massive amount of storage.

I think the following are important for good relations between computers and ham stations. I've also noted some comments from others who have no problems and they too were using fairly high end power supplies..

I do a bit of flight simming as I was a pilot. Several of the sims are very good for IFR practice, have excellent scenery and very realistic flight controls and responses. That takes some powerful processing and video cards. In turn the video cards and top end processors require a lot of power, so the power supplies I purchase tend toward the top end. (200 to 220 watts for the CPU and as much as 300 watts for a single video card)

All of this means I often spend as much for individual components ( memory/RAM, Video cards, motherboards, cases, and power supplies) as many do for the entire computer as communications do not normally require a lot of power. Typical computer use (excluding gaming) takes little computing power and that includes streaming video.

I do go through a lot of components aiming for better performance. I've had power supplies quit when I added one more fan that only used 5 watts. Hence the present use of 850 watt power supplies with active power factor correction. I'd much rather have lots of excess power than not nearly enough

Each computer is powered off its own dedicated UPS which has built in filtering for both the power and the network as well as voltage spike protection. I'm moving to "line conditioners" with full time, true sine wave generators. These will run both the rigs and computers. The power to the ham station and computers are dedicated and run parallel from the breaker panel to the outlets in the den to eliminate, or minimize induced differential voltages.

The cases have conductive air filtering in and out so the cabinets are "relatively" RF tight.

I said I have not added any external filtering, but I do purchase components with both RF ingress and egress in mind My biggest fear, other than induced voltage from lightening, is the trend (or move) to wall warts. Even those are plugged into the UPS that feeds the individual computer. A wall wart with 6 to 8' of lead wire to the load can make for quite an antenna.

The network (modem, router, and switch are also powered from a dedicated UPS.

IOW I have resorted to good design practice for the entire station and interfacing with the computers. The power to the den is also according to good practice. In many cases it has taken several years to get things done, or modified in the case of house wiring. Permits are $25 for each circuit breaker added. Inspections are free.

Most have not been expensive changes to implement, but are often time consuming and may require building permits with the required inspections. Fortunately I live in an area where we can do the work ourselves even if it has to meet code. However, the computers, due to their intended use have not been cheap. OTOH as a side effect, those requirements may be what has kept me RFI free. Of course the next piece of equipment my shoot down that theory.

Because of induced voltages from lightening, I'd like to go wireless at least to the shop. With the servers located next to the router and smart switch I may be able to do that. Before the servers, I had the database spread across the network and when massive transfers may take 4 or 5 hours on a gigabit network, wireless becomes impossibly slow, particularly when I see 10, 12, or more networks that the router sees competing for space. Now I no longer need that capability.


Roger (K8RI)

On 6/4/2015 12:41 PM, Jim Brown wrote:
On Thu,6/4/2015 3:06 AM, Roger (K8RI) wrote:
I'll repeat, I have 2 130'runs of CAT-5

Hi Roger,

Emissions from equipment can vary widely from one piece of equipment to another. I'd say you're very lucky to have selected equipment that has no emissions. :) Every piece of wired Ethernet equipment I've owned has birdies around 14,030 and 21,052, and around the bottom end of 10M CW. Broadband noise on 6M and 2M is also common.

73, Jim K9YC
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