[MRCA] Today's noise report

[Ray Fantini]

Solution to all noise problems. First, locate the source of noise and turn off. I have found TV sets in other rooms, displays on computers and the new GE washing machine all produce noise but with planning or maybe coordination that can be overcome. Second, bigger and higher antennas. Short or vertical antennas suck, dipoles cut for the band work for me. Also into this whole thing of using ferrite chokes at the feed point of the antenna and good cables from the antenna to the radios to minimize signals induced in transmission lines but sometimes think that's all just to try to make me feel like I am doing something when perhaps I am not and third, pray to the propagation gods. If it's a good day the signals are all S over and on a bad day noise is all you hear. That's just how it is.
I have my little PRC-20/6 Sunair portable transceiver that I will be using remotely with a portable dipole when the weather gets better. The transceiver works well off its internal battery running just twenty watts at home hooked to the dipole that I use for sixty but looking forward to operating from remote location where there is no local interference and seeing what that's like. The object is not only to be heard but also to hear everyone else. Can do it from the home QTH when conditions are good and expect no less from in the field. Will see what happens.

Ray F

From: mrca-bounces at mailman.qth.net [mailto:mrca-bounces at mailman.qth.net] On Behalf Of Al Klase
Sent: Tuesday, March 18, 2014 3:55 PM
To: mrca at mailman.qth.net
Subject: Re: [MRCA] Today's noise report

Hello Eugene,

While we're on the subject, it's a good idea if we're talking about something like the same thing.

Wikipedia's S-meter article states that by International Amateur Radio Standards S-9 = 50 uV in 50 ohms, and an S-unit is 6 dB.  Here's their table:

[cid:image002.jpg at 01CF42CA.0A1F1570]
And from a handy calculator:  http://www.giangrandi.ch/electronics/anttool/decibel.html

1 uV = 0 dBuV = -107 dBm

I've been unhappy with my noise level on 5357 KHz.  It's a constant S-5 on the pencil-drawn sticker around the S-meter on my Transworld TW-100, that I had calibrated with my HP-8640 signal generator.  This agrees with the S-5 reading on my Icom R-9000 and the -96 dBm (11 dBuV) reading on my HP 3586 Selective Level Meter.  I'm only able to do what it do here on 60M because I use a Timewave DSP-59+ audio processor to beat back the noise.  Noise here is mostly white noise, and I've been unable to reduce it.

Your 35 dBuV noise level (-72 dBm) is almost exactly S-9, which likely leaves you pretty deaf.

You've like heard all the fixes.  Get started.


With apologies for the technoweenie freakout, 73,
Al



On 3/18/2014 12:25 PM, W2HX wrote:
I did some calculation to quantify the noise at my qth.  Today the noise as shown on the receiver is a healthy 35 dBuV (receiver's meter is dBuV instead of an "S" meter) which equates roughly to 56 uVrms (microvolts RMS) at the antenna connector.  Better than usual which is a robust 40 dBuV or about 100 uVrms!  So needless to say, no M&S joy today :(

Time to work toward tracking down the source of the noise and getting it eliminated. And in the meantime, I will likely install a receiving H loop.  I've also read good things (believe it or not) about the MFJ-1025 noise canceller. Anyone ever try such a thing?

73 Eugene W2HX





______________________________________________________________

MRCA mailing list

Home: http://mailman.qth.net/mailman/listinfo/mrca

Help: http://mailman.qth.net/mmfaq.htm

Post: mailto:MRCA at mailman.qth.net



This list hosted by: http://www.qsl.net

Please help support this email list: http://www.qsl.net/donate.html



--

Al Klase - N3FRQ

Jersey City, NJ

http://www.skywaves.ar88.net/


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20140318/abda81a3/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image002.jpg
Type: image/jpeg
Size: 16851 bytes
Desc: image002.jpg
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20140318/abda81a3/attachment-0001.jpg>