Noisy receive
|
Just playing with the K3 V my IC-7300, No preamp in both and the K3 shows S5-7 of noise level whereas my 7300 shows S0, with Preamp 1 in the 7300 it shows about S5, I know im in the city and a very noisy environment but is it just that the K3 is so much more sensitive, or is it something else
Adrian G0KOM |
|
|
|
mikerodgerske5gbc
Yeah it’s more sensitive/hot.
toggle quoted message
Show quoted text
I wish mine had a 20db attenuator. Some say it’s not sensitive enough on 10 but I’ve not noticed anything, maybe a little quiet on 10&6. I prefer to use lo/hi cut on ssb with hi cut around 2500 especially on USB, cuts that nasty hiss down. 73 Mike R 7! Absolutely Awesome On Mar 12, 2023, at 11:49 AM, Adrian G0KOM <adrian@...> wrote:
|
|
|
|
ve3ki
Don't let the S-meter readings mislead you. Icom calibrates their S-meters differently from Elecraft.
toggle quoted message
Show quoted text
In the K3, each S-unit is 6 dB. S9 is -73 dBm. Thus, S5 in the K3 is around -97 dBm. In Icom rigs, on the other hand, each S-unit is 3 dB. So, S1 in the Icom is -97 dBm, the same as S5 in the K3. Band noise levels below about -100 dBm simply don't show up on the Icom's S-meter, unless the preamp is on. The S-meter in the Icom reads differently when the preamp is on than when it is off, i.e. the S-meter reads the signal strength after the preamp, not the signal strength at the antenna terminal. Therefore the S-meter in the Icom reads higher with the preamp on than with it off. So, if you pay attention to the S-meter, Icom radios seem much quieter than the K3 (band noise reads much lower). They also seem more sensitive in the limited sense that the S-meter reading swings more in the presence of a signal, and on a quiet band you can hear signals that don't even move the S-meter, but it's not a real difference in performance, just a difference in how the S-meter is calibrated. 73, Rich VE3KI On Sun, Mar 12, 2023 at 12:49 PM, Adrian G0KOM wrote:
Just playing with the K3 V my IC-7300, No preamp in both and the K3 shows S5-7 of noise level whereas my 7300 shows S0, with Preamp 1 in the 7300 it shows about S5, I know im in the city and a very noisy environment but is it just that the K3 is so much more sensitive, or is it something else |
|
|
|
Sandor Wetsel
Short answer is the K3 is that much more sensitive. Sandor KG4FET On Sun, Mar 12, 2023, 11:49 AM Adrian G0KOM <adrian@...> wrote: Just playing with the K3 V my IC-7300, No preamp in both and the K3 shows S5-7 of noise level whereas my 7300 shows S0, with Preamp 1 in the 7300 it shows about S5, I know im in the city and a very noisy environment but is it just that the K3 is so much more sensitive, or is it something else |
|
|
|
Charlie T, k3ICH
A radio’s “Sensitivity” can be too high. A good example is if your S-meter reads zero with no antenna connected, but S-7 when it is, you have TOO-MUCH sensitivity, which will only contribute to overload when a stronger than “weak” signal is received.
73, Charlie k3ICH
From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of Sandor Wetsel
Short answer is the K3 is that much more sensitive. Sandor KG4FET
On Sun, Mar 12, 2023, 11:49 AM Adrian G0KOM <adrian@...> wrote:
|
|
|
|
Mike - K8CN
Don, W3FPR wrote about 'noisy K3' many years ago.
You might want to read his explanation of how AGC
settings can cause the radio to appear 'noisy.'
Look down the menu on the left hand side of the
web page.
73,
Mike, K8CN
From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Charlie T, k3ICH <pincon@...>
Sent: Sunday, March 12, 2023 2:22 PM To: Elecraft-K3@groups.io <Elecraft-K3@groups.io> Subject: Re: [Elecraft-K3] Noisy receive
CAUTION: This email originated from outside of the University System. Do not click links or open attachments unless you recognize the sender and know the content is safe.
A radio’s “Sensitivity” can be too high. A good example is if your S-meter reads zero with no antenna connected, but S-7 when it is, you have TOO-MUCH sensitivity, which will only contribute to overload when a stronger than “weak” signal is received.
73, Charlie k3ICH
From: Elecraft-K3@groups.io <Elecraft-K3@groups.io>
On Behalf Of Sandor Wetsel
Short answer is the K3 is that much more sensitive. Sandor KG4FET
On Sun, Mar 12, 2023, 11:49 AM Adrian G0KOM <adrian@...> wrote:
|
|
|
|
Look at the numbers on the Sherwood Engineering Receiver Data chart. The manipulation of the preamp has a lot to do with the noise that one hears. In many cases, hams are noted to adjust their receivers for excessive gain. I've observed in some cases where hams use the Attenuator and the Preamp at the same time. Never could understand that rationale.
Rob Sherwood has a good paper on Receiver Adjustment for Optimum Performance. 73 Bob, K4TAX |
|
|