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Author Topic: "Quiet" DSL Modem suggestions  (Read 18386 times)

Posts: 17

« on: May 08, 2012, 12:46:41 PM »

I'm looking for a replacement for my DSL modem, i.e. the network interface to the DSL network.  I had the Westell that I got from Verizon, but it pretty much obliterates 10m, and gives me S5 noise on 20 and 40.  A friend of mine had an extra DSL modem, and I've been playing with that, but it gives me S7 noise on 15m.

I also use 2 Linksys WTR54GL WiFi routers (I'm bridging the DSL modem).  One router is in the computer room, the other is in the TV room (repeater client).  They don't really give me any issues, despite having them both transmitting at 200mw instead of 70mw using DD-WRT.

So, I'm looking for recommendations for a DSL modem and/or a brand I should take a look at, so I can buy a new one.  Since I intend to bridge the DSL modem, I don't care if it has WiFi per se.

Also, I think part of the problem is the proximity of my antennas to the house.  I can't help that, it's just part of the equation.  Common-mode chokes on my antennas aren't helping with that noise.

So, if you would have any suggestions concerning specific devices or brands, positive OR negetive, I'm all ears.



Posts: 7718

« Reply #1 on: May 08, 2012, 02:53:40 PM »

Common-mode chokes on the DSL line is a possible solution.

Posts: 17

« Reply #2 on: May 08, 2012, 06:48:51 PM »

Thanks, I've tried that, but it didn't make any difference.  I've tried chokes on the phone wire and on the CAT-6 cable between the DSL modem, which is shielded, and the WRT54GL router.

The only other next step I can think of is to try powering the DSL Modem off of a 3A linear power supply.

But, I would rather find someone who has network equipment with minimal RFI, see what they're using.

Posts: 510

« Reply #3 on: May 08, 2012, 09:31:47 PM »

I assume the modem has a wall wart for a PS. Those are often the culprit. It was in my case when I had AT&T Uverse. Their crappy power supplies put out a lot of hash that was being radiated out the modem cables. Changing the PS helped a lot.

Try the linear.

Posts: 17

« Reply #4 on: May 14, 2012, 11:25:18 AM »

I found a decently quiet DSL Modem.  It's the Actiontec GT701D, sold by Amazon.

My WiFi network is now the two WRT54GLs and the Actiontec GT701D in transparent bridge mode.  I seem to have nearly eliminated RFI affecting reception due to my home network.

Posts: 2073

« Reply #5 on: May 19, 2012, 02:48:28 PM »

my shack is 40 feet as the Romex pulls from the DSL modem, a Zyxel 800, in a separate shed.  I pulled Ethernet out there.

due to internal wiring issues, I "home-run" wired the modem right at the demarc, and fed the house phone lines from the output voice port of the modem.  no hash on the ft890.

however, I did take precautions in the shack with the phone and dsl feeds... wrapping both lines around PC power supply toroids about 6 times (blue/white, probably a 61 mix) and using commercial surge suppressors on both.

as one of the DSL guys for one of the big-4 telcos, I'd recommend first putting an analog wall wart on the modem instead of the switching jobs used now.  failing that, start playing with toroids.  I'd wrap the Ethernet maybe 8-10 turns, and then I'd start looking at the internal stats of the modem (most are accessible from your browser at private address .  you want to look at the WAN link error and up/down speeds.  when you start winding toroids in frustration with the DSL modem input lead to the phone system, wind 4 or 5 turns and recheck those WAN link speeds.  keep winding UNTIL you start cutting the retrained speed down, then STOP.  you won't get any more benefit, and that's the point at which you will precipitously lose DSL capability (as in no-train) with a few more turns.  might want to back it off a couple turns if you start to drop the speed.

some DSL service equipment (DSLAMs) have built-in "hamband" filters in their software that were mainly designed to stop interference with AM signals.  the provider could try turning that on in software.  what it will do is seriously chop your maximum speed, and won't make a difference in the DSL modem interfering with your hamming.  it's designed to keep neighbors surfing.  and in that case, the real fix is probably changing the demarc from carbon or varistor protectors to gas tubes, and fixing ground issues.
« Last Edit: May 19, 2012, 02:56:34 PM by KD0REQ » Logged

Posts: 6252

« Reply #6 on: May 20, 2012, 04:27:59 PM »

Get you a twelve volt battery and power the modem from that to see if that makes a difference.  I think you'll find that the modem wall wart is putting most of the hash on the lines.

I got tired of the playing Verizon was giving me and powered the modem off a 5 watt CB power supply I had kicking around.  Got rid of just about all the noise problems I had.  YMMV.  Good luck and 73!
« Last Edit: May 20, 2012, 04:32:35 PM by K1CJS » Logged

Posts: 1

« Reply #7 on: May 25, 2012, 03:10:17 PM »

Ray I use a netgear wireless router/modem which sits within a foot of my TS-450s and my FT-950 and I have no noise.  I operate 80 thru 10 with no problems.  My amps sit within three feet of the router/modem and I have no problem with the netgear.  It is also an easy router/modem to configure. Good luck and hope you have sucess.  73...Dick N6EB

Posts: 1

« Reply #8 on: May 27, 2012, 09:48:23 PM »

9A4TA Misa shows how he solved a QRM issue caused by network device:

Perhaps it could inspire you Smiley

Posts: 6

« Reply #9 on: June 25, 2012, 07:44:40 PM »

I tried chokes also, and while chokes helped, the best improvement
was when I went into the computers network properties and changed the speed from 100 mb to 10 mb. It's listed as "speed & duplex" in the advanced configuration settings.
It made a very noticeable difference and since I have 5 meg DSL,
slowing the wired connection down from 100 to 10 did not
make any speed difference. The modem (or a router) will negotiate
with the computer for the fastest speed allowed by the computer.

It's worth a try.

Richard / K4RTS

Posts: 2243

« Reply #10 on: July 01, 2012, 08:46:31 PM »

I must be lucky for once (it's about DAMN TIME!) Grin
We have TV/Phone/Net bundling and the
modem for my shack sits at MOST two-three
feet from mt PROII, K2, and TS-940S.....and just
under 4 feet from my venerable A "ARRIS
I get zero noise in my receivers and no
TVI, RFI, or phone interference.

This modem is labeled "ARRIS". No Wall Wart
with this one, it runs off of 120vac and the plug to
the modem is one of those "universalinternational" jobs.
Interestingly, it has a light on it labeled "Battery" so
must be have built in UPS. Do most Cable Mobems have this?
Actually, there are two lights. One labeled "Battery 1 and Batter 2"
but "Battery 2" is never on.

Well I've been working now for 20 minutes with the
the AC line unplugged and no difference in receiver noise
on the few bands I've checked, and Net and Phone
service is working. Interesting. I might take the lid off this
one and see what kind of battery it uses

I used to think Murphy lived in my shack
for periods of time, that's how many and
varied complaints I received or problems

Guess a dodged a bullet with this modem business.
(Still gonna keep my head down though)  Cool

Good luck with your modem difficulties.
73,, Ken AD6KA

Posts: 960

« Reply #11 on: July 08, 2012, 04:31:21 AM »

N9YNG seems to have found his problem.
I had a similar situation with a router that had birdies all over 20M. I bought a very nice Netgear router with wireless capabilities and it is in a metal box. Not plastic like all of our other electronics seem to be.
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