Remember, I have preamp #1 ON. Virtually all my local noise originates
from the SMPSs in our new appliances (2014). Our mountain home was burned
completely down in the High Park Fire of 2012 here in N. COlorado (we lost
everything except the two vehicles, a very few clothes, and our puppy). We
rebuilt down here. The mountain house was built before all the Chinese
SMPSs with no attention paid to EMC invaded everything (from China, with
Love). Today, ALL appliances have them and appliances are exempted from
FCC rules.
We recently had to replace a refrigerator. Old was Samsung - little RFI.
The new one is made in the USA, Hotpoint. Once installed and plugged in,
160 and 75 meters became useless. I built a very aggressive CMC and
installed it in the line cord to the new refrigerator. Solved the problem
completely, well, almost..... Every new appliance has multiple Chinese
SMPSs in them. All are RFI sources. It's been a 6-year battle on my part
to deal with the RFI. Not to mention another hobby is radio astronomy
which is even more sensitive to RFI.
With no preamps turned on in the Icom 7300 (or 7610), my noise floor is S-0
(-100 dBm) or lower most of the time during the day. On 160 and 75 toward
evening, it comes up a bit, but that is just cosmic and atmospheric noise.
Dave - WØLEV
On Sat, Jan 23, 2021 at 12:07 AM Joe WB9SBD <nss@mwt.net> wrote:
> Hi Dave,
>
> Why do you have such a HIGH noise floor at all?
>
> Wow, It doesn't look low at all,
>
> My noise floor if it is any higher than a S 2 or 3 I shut the radio off!
>
> Joe WB9SBD
>
> On 1/22/2021 5:54 PM, David Eckhardt wrote:
>
> For those unbelievers in feedline chokes to properly treat CM energy on
> feedlines, I made some quantitative tests using my HF antenna and Icom
> 7300. So,...... have a read of the short attachment.
>
> I hope it leaves you with a belief in baluns (NOT transformers) and
> CMCs.
>
> Dave - WØLEV
>
> PS: After some 3-years, I still have not removed the clear plastic
> covering the surface of the touch screen.......
>
>
>
>
>
--
*Dave - WØLEV*
*Just Let Darwin Work*
Beware of cheap underperforming clones
As of 2022 there are many badly performing clones on the market. V2/3GHz NanoVNA uses parts like ADF4350 and AD8342 which are costly and clones have been cutting costs by using salvaged or reject parts.
See official store and look for V2 Plus4/V2 Plus4 Pro versions only to avoid getting a bad clone. We have stopped selling V2.2 versions since October 2020, so all V2 hardware that are not Plus or Plus4 are not made by us and we can not guarantee performance.
Click here to join and see most recent posts.
[nanovna-f] EFFECT OF CMCs and/or BALUNS on RECEIVED NOISE
David Eckhardt 2021/01/23 00:26
To reply to this topic, join https://groups.io/g/NanoVNAV2