well,
the situation here is a bit close. I have 12.6 Kv lines directly behind the hose. THe neighbors have outdoor florescent lights (and there are even 2 bug zappers). I have checked and there are at least 14 wi-Fi access points within 400 feet of me. THe house itself has 2 AP devices, about 300 feet of LAN cable, 2 switches and 6 computer systems (the room mates have 3 desktop systems). I have 3 laptop machines, 2 of which are turned off. Half the lights in here are of the tube variety (those stupid cheap made "green lamps"). all of these make some noise. As a result, I also have to have an MFJ 2500 series antenna noise cancellation unit in operation here just to remove all the electrical noise. THe power lines are the worst of it.
Basically, I am using every trick I can find to reduce or eliminate noise before it hits my radio.
-eric
On Feb 1, 2014, at 5:49 PM, John Miller wrote:
> I actually never have lived in a place with a lot of noise. It's funny,
> when I first was a ham, I was living with my parents, in the woods pretty
> much with over a hundred feet between houses, well over 100 feet and all
> woods behind me. Next place, in a neighboring town I was in an apartment in
> the center of town, surrounded in a factory, houses, other businesses, a
> place that converts vans to wheel chair vans and works on them, still never
> had any noise for what ever reason and there you could about reach out and
> touch the neighbors. Now I'm in a trailer park and we're not much further
> away form each other I have a light off and on buzz here that my noise
> blanker takes out and other than that, again very quiet. 2 meters I have
> noise but I couldn't care less about that and even that is rare. I don't
> know why I'm that lucky. I spent 2 months with my in-laws at one point,
> there, I had a +40 noise level from 160 through 70 CM, I could get on GMRS,
> and 900 MHz from there, that was about it and no filtering remotely helped
> that but that was an area with all businesses and apartments above them once
> in a while.
> ----- Original Message -----
> From: "eric oyen" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Saturday, February 01, 2014 7:00 PM
> Subject: Re: Low Pass Filter
>
>
>> the funny thing is that low pass filters operate bi-directionally. If =
>> your radio produces harmonics that interfere above its normal operating =
>> range, then mix down products from sources above HF would also cause =
>> interference on HF. THese mix down products are often caused by =
>> interactions within the first stage of the IF in your radio. SO, using a =
>> filter eliminates a lot of that from getting to your radio (thus =
>> reducing or eliminating the problem).
>>
>> I have an FM radio station transmitter site less than 3 miles from me =
>> producing several thousand watts. without the filter, I hear what sounds =
>> like FM modulated signals in a couple of bands. I put the filter in =
>> place, and those signals disappeared. THere are other sources (such as a =
>> wireless Access point, LAN switches and cable modems'DSL modems that =
>> produce signals that can show up in HF directly. Filtering these is a =
>> bit harder. I am having to use ferrite beads on the power leads and also =
>> on the LAN cables to try and minimize some of these issues. I have only =
>> been partially successful. I still get a lot of birdies in the 10 meter =
>> band (around 28.5). I am going to acquire a portable shortwave receiver =
>> and try to track these signals to their source and see what I can do to =
>> remove them.
>>
>> -eric
>>
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