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I wonder my BITX has less sensitivity or not.
I maesured it about -117dBm using my HP8656B SG.
Not reached to 120dBm. My K2 reached to -127dBm. hi...
How is your BITX?
ja9mat Hidehiko.
|
comparing to cost of K2, the sensitivity has reached almost the best value, I suppose.
sarma ?vu3zmv
On Tue, Jul 4, 2017 at 2:35 PM, <qrper72@...> wrote: I wonder my BITX has less sensitivity or not.
I maesured it about -117dBm using my HP8656B SG.
Not reached to 120dBm. My K2 reached to -127dBm. hi...
How is your BITX?
ja9mat Hidehiko.
|
Thats about 0.3uV, more than enough.
On 40M the atmospheric background noise is higher than this.
You need a K2 sensitivity when using a poor antenna like a
mobile one whose gain will be negative compared to a dipole.
I'll measure mine later and post, something else on my table!
73, Raj vu2zap
toggle quoted message
Show quoted text
At 04-07-2017, you wrote: I wonder my BITX has less sensitivity or not.
I maesured it about -117dBm using my HP8656B SG.
Not reached to 120dBm. My K2 reached to -127dBm. hi...
How is your BITX?
ja9mat Hidehiko.
|
OK thanks sarma and Raj,
Yes, -117dBm is enough for me.!
I only want to know the limitation of this simple receiver's sensitivity.
I'm waiting for Raj's measurement result.
ja9mat Hidehiko.
|
Good news for me! managed to fix my function Seimens generator. One white power bypass smd cap had a neat hole in it!
I connected the sig gen and found that I can hear the signal down to -130dbm. Sort of minimum signal I can hear while tuning
across the frequency.
Tune up and down the frequency while reducing the signal and you should get to a point where you cant hear the tone.
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At 04-07-2017, you wrote: OK thanks sarma and Raj,
Yes, -117dBm is enough for me.!
I only want to know the limitation of this simple receiver's sensitivity.
I'm waiting for Raj's measurement result.
ja9mat Hidehiko.
|
Hello Raj,
Really -130dBm?
It's great!
I will try again but I think I'm not able to hear -130dBm with my HP SG.
ja9mat
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Hide San,
I was just as surprised!
I had the volume cranked to full to hear it. When I connected the antenna back the volume of noise was deafening !
The amp capacitor C113 is connected. Monssons here and the noise is high!
I would do a static voltage check on RX chain. VFO and BFO level check too.
I have done a lot of mods to VFO (Analog) BFO.
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At 04-07-2017, you wrote: Hello Raj,
Really -130dBm?
It's great!
I will try again but I think I'm not able to hear -130dBm with my HP SG.
ja9mat
|
Can you describe the procedure you used?? dBm or
uV?
Did you use an output signal somewhere to monitor
with scope?
With SSB, how did you set up the modulation?? How
did you determine you were not \
hearing the signal at low levels.
I have 8648C Generator.?? I think my BitX has a
hearing problem?
Mike, WA6ISP
I wonder my BITX has less sensitivity or not.
I maesured it about -117dBm using my HP8656B SG.
Not reached to 120dBm. My K2 reached to -127dBm. hi...
How is your BITX?
ja9mat Hidehiko.
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
|
Hi Mike,
I used DBM on HP test set.
The output was by ear. Minimum discernable signal. Volume full!
This was not a Two tone ssb test.
Do a minimum discernable test, thats a level you can have a CW
qso.
Crank up the volume full and checck!
Cheers
Raj
At 04-07-2017, you wrote:
toggle quoted message
Show quoted text
Can you describe
the procedure you used??? dBm or uV?
Did you use an output signal somewhere to monitor with
scope?
With SSB, how did you set up the modulation??? How did
you determine you were not \
hearing the signal at low levels.
I have 8648C Generator.? ?? I think my BitX has a
hearing problem?
|
I found my HP Function Gen had dBm to -36.? My RF
Gen is out in a shed outside.
So I tried this with the 33220A Agilent.
With a fixed and variable attenuator, I can barely
hear -110.
I put 400 Hz AM modulation on and tuned Bit to
7.1000.? My Generator tuned to 7.0988 to hear a tone.
I probably am not calibrated.
I never have heard a signal, I have no antenna
and have just tried wire out the door.
I guess the Receiver is working?
Mike, WA6ISP
On 7/4/2017 7:32 AM, Michael Hagen
wrote:
Can you describe the procedure you used?? dBm
or uV?
Did you use an output signal somewhere to
monitor with scope?
With SSB, how did you set up the modulation??
How did you determine you were not \
hearing the signal at low levels.
I have 8648C Generator.?? I think my BitX has a
hearing problem?
Mike, WA6ISP
I wonder my BITX has less sensitivity or not.
I maesured it about -117dBm using my HP8656B SG.
Not reached to 120dBm. My K2 reached to -127dBm. hi...
How is your BITX?
ja9mat Hidehiko.
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
|
Considering my old Collins receiver has a 1 or 1.5mv sensitivity, the BitX is super sensitive! I haven't checked it on the service monitor yet tho.
Vince,
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On 07/04/2017 05:16 AM, Mvs Sarma wrote: comparing to cost of K2, the sensitivity has reached almost the best
value, I suppose.
sarma
vu3zmv
On Tue, Jul 4, 2017 at 2:35 PM, <qrper72@...
<mailto:qrper72@...>> wrote:
I wonder my BITX has less sensitivity or not.
I maesured it about -117dBm using my HP8656B SG.
Not reached to 120dBm. My K2 reached to -127dBm. hi...
How is your BITX?
ja9mat Hidehiko.
--
Regards
Sarma
--
Michigan VHF Corp.
|
I can confirm Raj's -130. I just hooked up my Motorola R-2200 service monitor to my BitX. At -130 I could detect the signal was there and could probably work a CW station at that level. At -131 I can't say for sure I was still hearing it. The lowest it will go is -137 and I definitely didn't hear it there!
Vince.
toggle quoted message
Show quoted text
On 07/04/2017 10:47 AM, Raj vu2zap wrote: Hi Mike,
I used DBM on HP test set.
The output was by ear. Minimum discernable signal. Volume full!
This was not a Two tone ssb test.
Do a minimum discernable test, thats a level you can have a CW qso.
Crank up the volume full and checck!
Cheers
Raj
At 04-07-2017, you wrote:
Can you describe the procedure you used?? dBm or uV?
Did you use an output signal somewhere to monitor with scope?
With SSB, how did you set up the modulation?? How did you determine
you were not \
hearing the signal at low levels.
I have 8648C Generator.? ? I think my BitX has a hearing problem?
--
Michigan VHF Corp.
|
I hear nothing that low, -110, I flip in another
10 and it is gone?
My BitX has Ear Wax!
Mike, WA6ISP
On 7/4/2017 4:25 PM, Vince Vielhaber
wrote:
I can confirm Raj's -130.? I just hooked up my Motorola R-2200
service monitor to my BitX.? At -130 I could detect the signal was
there and could probably work a CW station at that level. At -131
I can't say for sure I was still hearing it.? The lowest it will
go is -137 and I definitely didn't hear it there!
Vince.
On 07/04/2017 10:47 AM, Raj vu2zap wrote:
Hi Mike,
I used DBM on HP test set.
The output was by ear. Minimum discernable signal. Volume full!
This was not a Two tone ssb test.
Do a minimum discernable test, thats a level you can have a CW
qso.
Crank up the volume full and checck!
Cheers
Raj
At 04-07-2017, you wrote:
Can you describe the procedure you
used??? dBm or uV?
Did you use an output signal somewhere to monitor with scope?
With SSB, how did you set up the modulation??? How did you
determine
you were not \
hearing the signal at low levels.
I have 8648C Generator.? ?? I think my BitX has a hearing
problem?
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...
|
Hope the signal generator is not in parallel with antenna.
Try with another cable. Many times I have been chasing ghosts when the
problem was a frayed connection in the BNC.
Same thing happened with BITX40 the first time!
or is it Bi'swax ?
Cheers
Raj
At 05/07/2017, you wrote:
toggle quoted message
Show quoted text
I hear nothing that
low, -110, I flip in another 10 and it is gone?
My BitX has Ear Wax!
Mike, WA6ISP
On 7/4/2017 4:25 PM, Vince Vielhaber wrote:
I can confirm Raj's -130.? I just hooked up my Motorola R-2200
service monitor to my BitX.? At -130 I could detect the signal was
there and could probably work a CW station at that level. At -131 I can't
say for sure I was still hearing it.? The lowest it will go is -137
and I definitely didn't hear it there!
Vince.
On 07/04/2017 10:47 AM, Raj vu2zap wrote:
Hi Mike,
I used DBM on HP test set.
The output was by ear. Minimum discernable signal. Volume full!
This was not a Two tone ssb test.
Do a minimum discernable test, thats a level you can have a CW qso.
Crank up the volume full and checck!
Cheers
Raj
At 04-07-2017, you wrote:
Can you describe the procedure
you used??? dBm or uV?
Did you use an output signal somewhere to monitor with scope?
With SSB, how did you set up the modulation??? How did you determine
you were not \
hearing the signal at low levels.
I have 8648C Generator.? ?? I think my BitX has a hearing problem?
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID?
"MotDog@..."
Mike@...
|
Namaste Raj,
?bee's wax never disturbed any RF or IF coils in the past, to best of my memory. ?Hope that could not be a reason please, regards ?sarma ?vu3zmv
On Wed, Jul 5, 2017 at 11:45 AM, Raj vu2zap <rajendrakumargg@...> wrote:
Hope the signal generator is not in parallel with antenna.
Try with another cable. Many times I have been chasing ghosts when the
problem was a frayed connection in the BNC.
Same thing happened with BITX40 the first time!
or is it Bi'swax ?
Cheers
Raj
At 05/07/2017, you wrote:
I hear nothing that
low, -110, I flip in another 10 and it is gone?
My BitX has Ear Wax!
Mike, WA6ISP
On 7/4/2017 4:25 PM, Vince Vielhaber wrote:
I can confirm Raj's -130.? I just hooked up my Motorola R-2200
service monitor to my BitX.? At -130 I could detect the signal was
there and could probably work a CW station at that level. At -131 I can't
say for sure I was still hearing it.? The lowest it will go is -137
and I definitely didn't hear it there!
Vince.
On 07/04/2017 10:47 AM, Raj vu2zap wrote:
Hi Mike,
I used DBM on HP test set.
The output was by ear. Minimum discernable signal. Volume full!
This was not a Two tone ssb test.
Do a minimum discernable test, thats a level you can have a CW qso.
Crank up the volume full and checck!
Cheers
Raj
At 04-07-2017, you wrote:
Can you describe the procedure
you used??? dBm or uV?
Did you use an output signal somewhere to monitor with scope?
With SSB, how did you set up the modulation??? How did you determine
you were not \
hearing the signal at low levels.
I have 8648C Generator.? ?? I think my BitX has a hearing problem?
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID?
"MotDog@..."
Mike@...
|
I have a much simpler test for sensitivity. I have done careful research and decided that there are a lot more stations that I can hear than stations that can hear me! I wish the folks running the kilowatt transmitters would pay as much attention to the capabilities of their receivers (and ears) as they do to their transmitters.? OK, I'll get off the soapbox now!
--
John - WA2FZW
|
The term I heard is "alligators"!
Very big mouth and small ears!
IMHO high power is useful in controlling a pileup or in bad condition skeds!
Raj, vu2zap
toggle quoted message
Show quoted text
At 05/07/2017, you wrote: I have a much simpler test for sensitivity. I have done careful research and decided that there are a lot more stations that I can hear than stations that can hear me! I wish the folks running the kilowatt transmitters would pay as much attention to the capabilities of their receivers (and ears) as they do to their transmitters. OK, I'll get off the soapbox now!
--
John - WA2FZW
|
YEP!? Had a QSO with a guy in Alabama, he was running 500W, I was running 5W. ?20M SSB.
Says a lot- my rig probably cost less than his microphone. ($65 for a Bitx20 V3SBL1 and a junked SSB CB for the crystal filter)
73 Larry KB3CUF
On Wed, Jul 5, 2017 at 9:31 AM, Raj vu2zap <rajendrakumargg@...> wrote: The term I heard is "alligators"!
Very big mouth and small ears!
IMHO high power is useful in controlling a pileup or in bad condition skeds!
Raj, vu2zap
At 05/07/2017, you wrote:
>I have a much simpler test for sensitivity. I have done careful research and decided that there are a lot more stations that I can hear than stations that can hear me! I wish the folks running the kilowatt transmitters would pay as much attention to the capabilities of their receivers (and ears) as they do to their transmitters.? OK, I'll get off the soapbox now!
>--
>John - WA2FZW
|
One need to retune ( 27 pf variable trimmer + one air wound LPF coil ) ?BPF if antenna is not 50 ohm, long wire is not 50 ohm... was talking about old 2.2uh inductors,?
Didn't tested 6 uh inductance BPF yet...
On Jul 5, 2017 7:36 PM, "Larry Acklin" < acklin@...> wrote: YEP!? Had a QSO with a guy in Alabama, he was running 500W, I was running 5W. ?20M SSB.
Says a lot- my rig probably cost less than his microphone. ($65 for a Bitx20 V3SBL1 and a junked SSB CB for the crystal filter)
73 Larry KB3CUF
|
?Low pass filter in BITX works best with 50 ohm input, otherwise sensitivity will suffer...
With long or short wire I always had to retouch my BPF...
On Jul 7, 2017 1:15 AM, "Sandeep Lohia" < sandeeplohia12@...> wrote: One need to retune ( 27 pf variable trimmer + one air wound LPF coil ) ?BPF if antenna is not 50 ohm, long wire is not 50 ohm... was talking about old 2.2uh inductors,?
Didn't tested 6 uh inductance BPF yet...
|
Hidehiko Komachi - JA9MAT
Raj vu2zap