What's Your Noise levels?

Lasse Moell

Just saw a post regarding noise levels.. Lets see what others measure. Use 100 Hz BW and read the average level in dBm (I'm using DDUtil), make sure it's an empty spot! Do note time when sample is taken.
---------------------------
28 MHz -132 dBm 2el Yagi
24 MHz -133 dBm   "
21 MHz -130 dBm   "
18 MHz -128 dBm   "
14 MHz -123 dBm   " (ant to northwest)/-117 dBm (ant to southwest)
10 MHz -122 dBm   Dipole
7 MHz -108 dBm     Dipole statics/thunder
3,5 MHz -108 dBm inv L
1,8 MHz -104 dBm inv L

All measured at 21 local, still daylight. QTH just outside of city center (suburban).
Anyone care to share your levels? Do not forget to mention where you are located i.e. city/suburban or rural. Remember increasing RF gain can improve readings!

dlwarnberg

40 meters, DX Engineering 4 square receive array... pic.. rural 

dlwarnberg

How about 80 meters no RF Gain?

Lasse Moell

David, thanks for posting. maybe you misunderstood what I want... Setting a 100 Hz wide passband filter makes it easy to calculate and compare to other settings, and of course not having a station/signal in the passband only noise, and use dBm rather than S-units. What I forgot to account for is the "antenna factor" i.e. a receive only antenna may have good SNR but pick up lot less energy, hence very low noise floor. By using the transmitting antenna (and telling what type) it is possible to compare with others.

dlwarnberg

simply trying to help get the conversation started

Mark_WS7M

All with 80m loop, coax feed, 2.5:1 balun and PalStar HF Auto tuner with antenna tuned:

12:00Z, location is suburban/rural.  IE on the edge of town near a large open space.  Underground utility wiring.

3.5: -100
7: -110
10: -119
14: -116
18: -119
21: -117
24: -119
28: -126

Lasse Moell

Mark, that is some 10 dB worse than me! I have spent a fortune on ferrites to make sure it's just the antenna and not the feeder that is receiving. BTW today 7 megs are a bit more normal here reading  -116 dBm.

John KB4DU

So, at 1700 UTC, Inverted V at 25ft, Tuner set to matched condition, I get:
80M  -105
40M   -105
20M   -115
15M   -120
10M  -122

Living right next to an Army post doesn't help.

Lasse Moell

John, I live just next to air force base. See the jets taking off from my kitchen all day long Helicopers can be a bit annoying as they hover for hours. I had a problem with 9th overtone on 14.040 hitting one of the tower comms channels, causing thie squelch to open and close as I was transmitting this drove the ops nuts, distance to their ground tx/rx-site is 1/4-mile  This was lilkely due to passive intermod, and I never found the non-linear source. Spent several days running all over with portable spectrumanalyzers, directive antennas and such.So I often try to avoid this frequency, just to keep them happy. They know where I live....

K3DCW

Here's my numbers for my 6700 tested here in Maryland in a large-lot (avg. 2 acre) suburb in rural area at 1645 local time / 2045 UTC.

Antenna is a Marconi T with the vertical element going up about 90' and a 265' top over radials and a 500 sq ft. ground screen. All utilities underground and house apx. 130' from antenna base.

All measurements done in CW mode, 100Hz bandwidth, no preamp and with antenna tuned using internal ATU.

Band        Measurement           
10m         -124dBm
12m         -118dBm
15m         -125dBm
17m         -124dBm
20m         -126dBm
30m         -123dBm
40m         -117dBm
60m         -121dBm
80m         -114dBm
160m        -112dBm

Lasse Moell

Looks pretty quiet to me, especially the low bands! I am sure your numbers would be even better on 20-10 meter if you invoked the preamp, as I bet you are limited by the radio NF. I do hear/see a big improvement by using the pre-amp, especially on 10,12 and 15 meter.

K3DCW

Indeed, some of the numbers are around -140dBm with the preamp on. However, I wanted to give a good even baseline knowing that I can always improve from that if needed.