Topics

RX sensitivity #v6

publique@...
 

Hello ! This is a very dummy question, but I can't really find the information... I would like to know what is the RX sensitivity of the ubitx ? I'm planning to use it (among other things) in my sailboat to receive weather forecast, but how good is the reception compared to a SDR (RTL-SDR, or even the more HF-oriented SDRPlay RSPDx), or to a HF transceiver from big brands ?

Many thanks !
73's from French Guyana ;)

Thomas

Richard
 

I do not have exact figures, however, the article in the description page says there is a usable signal at .1 uv .


On Sunday, March 1, 2020, 01:27:04 PM CST, publique@... <publique@...> wrote:


Hello ! This is a very dummy question, but I can't really find the information... I would like to know what is the RX sensitivity of the ubitx ? I'm planning to use it (among other things) in my sailboat to receive weather forecast, but how good is the reception compared to a SDR (RTL-SDR, or even the more HF-oriented SDRPlay RSPDx), or to a HF transceiver from big brands ?

Many thanks !
73's from French Guyana ;)

Thomas

_Dave_ AD0B
 

A number I don't have. But that said it is comparable to my other radios. The big advantage that it has over the sdr receivers is that it can transmit, also you don't need a computer to make it work. It doesn't have FM or real narrow filter for cw. Can receive AM on either side band. 
73
Dave
AD0B
Raduino bracket and Ham_Made_Keys

Curt
 

Thomas

Asshar does quote a perceived sensitivity somewhere, I am not recalling it. On HF its effectiveness in sensitivity should rival other rigs, except maybe at 24 and 28 MHz where is does not offer preamp. This analysis does assume a full sized antenna is available. If the antenna would he quite small, the design of a preamp could matter. Your matter could he complicated by the antenna and particular frequency.

Curt

Evan Hand
 

Thomas,

I would caution that the ubitx, while a good radio, that in my opinion it is really designed for two markets; the just starting out ham that cost is a large factor, and the tinkerer (like myself) that uses it to both learn and sharpen skills.

Reading between the lines of your message, I believe that a little bit higher end might be a better choice for the sailboat.  The one that comes to mind is the new MFJ G90 that is a Chinese import of the Xiegu G90.  I do not own one, so am only going by reviews that I have read and the specs.  The three that caught my eye were the 20 watts out, the built in antenna tuner, and the SDR based design.

With the above said, I concur with the others that have commented so far; receive compares favorably with my main go to rig (An IC-7300), and better than the Hermes HL2 (
that I have started to play with) for sensitivity.  The uBitx has nowhere near the number of modes and features as either the HL2 or the IC-7300.  I need to also say that I have not got consistent results from the different boards that I have bought at different times.  The last v5 board is by far the best, so would expect the v6 to be comparable.  The messages on this site do indicate the there may be variability between units within the same model, as some state having low receive volume and others great results.

The above are my personal views.  Others may be different, and that is OK.
73
Evan
AC9TU

David Nelson
 

just received new xiegu g90  and it is a very nice well made radio but I find it considerably  noisier than my ubitx v3.
That is on the same antenna. A vertical multi band. I am going to look into some audio filtering. I would love to try 
a nescaf if neqrp ever sells more kits. Just my experience.  Dave  kc2ipx

On Sun, Mar 1, 2020 at 3:34 PM Evan Hand <elhandjr@...> wrote:
Thomas,

I would caution that the ubitx, while a good radio, that in my opinion it is really designed for two markets; the just starting out ham that cost is a large factor, and the tinkerer (like myself) that uses it to both learn and sharpen skills.

Reading between the lines of your message, I believe that a little bit higher end might be a better choice for the sailboat.  The one that comes to mind is the new MFJ G90 that is a Chinese import of the Xiegu G90.  I do not own one, so am only going by reviews that I have read and the specs.  The three that caught my eye were the 20 watts out, the built in antenna tuner, and the SDR based design.

With the above said, I concur with the others that have commented so far; receive compares favorably with my main go to rig (An IC-7300), and better than the Hermes HL2 (
that I have started to play with) for sensitivity.  The uBitx has nowhere near the number of modes and features as either the HL2 or the IC-7300.  I need to also say that I have not got consistent results from the different boards that I have bought at different times.  The last v5 board is by far the best, so would expect the v6 to be comparable.  The messages on this site do indicate the there may be variability between units within the same model, as some state having low receive volume and others great results.

The above are my personal views.  Others may be different, and that is OK.
73
Evan
AC9TU

iz oos
 

I have ver. 3, ver. 6 should be even more sensitive. Ubitx is sensitive like other rigs. The difference between expensive and the least expensive radios is not on sensitivity. Even my portables, tecsun PL660 or Sargeant 909 are as sensitive as expensive rigs. Consider even portables with SSB like the Tecsun PL660 or the PL680. As receivers they work absolutely fine. I have used portables like these to decode FAX weather maps years ago and I found them nice.


Il 01/mar/2020 21:47, "David Nelson" <kc2ipx@...> ha scritto:
just received new xiegu g90  and it is a very nice well made radio but I find it considerably  noisier than my ubitx v3.
That is on the same antenna. A vertical multi band. I am going to look into some audio filtering. I would love to try 
a nescaf if neqrp ever sells more kits. Just my experience.  Dave  kc2ipx

On Sun, Mar 1, 2020 at 3:34 PM Evan Hand <elhandjr@...> wrote:
Thomas,

I would caution that the ubitx, while a good radio, that in my opinion it is really designed for two markets; the just starting out ham that cost is a large factor, and the tinkerer (like myself) that uses it to both learn and sharpen skills.

Reading between the lines of your message, I believe that a little bit higher end might be a better choice for the sailboat.  The one that comes to mind is the new MFJ G90 that is a Chinese import of the Xiegu G90.  I do not own one, so am only going by reviews that I have read and the specs.  The three that caught my eye were the 20 watts out, the built in antenna tuner, and the SDR based design.

With the above said, I concur with the others that have commented so far; receive compares favorably with my main go to rig (An IC-7300), and better than the Hermes HL2 (
that I have started to play with) for sensitivity.  The uBitx has nowhere near the number of modes and features as either the HL2 or the IC-7300.  I need to also say that I have not got consistent results from the different boards that I have bought at different times.  The last v5 board is by far the best, so would expect the v6 to be comparable.  The messages on this site do indicate the there may be variability between units within the same model, as some state having low receive volume and others great results.

The above are my personal views.  Others may be different, and that is OK.
73
Evan
AC9TU

Rick Tilton
 

Sorry but I was a techs home the other day working on some other stuff.  Showed him the ubitx.  He put it on his equipment to check SNR and it came out to 1 microvolt?  VERY high!  At 1/3 microvolt you could hear if someone had GREAT audio.   Yes we checked several times and checked SEVERAL other receivers to make sure we were reading correctly.  Suggestions?  I only see about two transistors or such in the rx section.  However, I did not get anywhere close to .01 microvolt?  I'm not the greatest tech but know enough to be dangerous somewhat.  Suggestions again or am I the only one seeing this? 


On Sun, Mar 1, 2020 at 2:27 PM <publique@...> wrote:

Hello ! This is a very dummy question, but I can't really find the information... I would like to know what is the RX sensitivity of the ubitx ? I'm planning to use it (among other things) in my sailboat to receive weather forecast, but how good is the reception compared to a SDR (RTL-SDR, or even the more HF-oriented SDRPlay RSPDx), or to a HF transceiver from big brands ?

Many thanks !
73's from French Guyana ;)

Thomas



--
73,

Rick WK4R

--
73,

Rick WK4R

MVS Sarma
 

Technical Specifications

The µBITX is an understandable radio and, hence, can also be a learning experience. The complexity is kept to a minimum so you can always repair and make changes if you so desire. The µBITX has a carefully thought-out operator interface. The tuning knob features many menu options available with a simple push on the tuning knob. From RIT, to dual VFOs, to the keyer, and many other features are all accessible from the tuning knob by simply pushing on it. There are intelligent defaults everywhere (these are easily overridden). Example : below 10 MHz, it auto-selects LSB and vice versa. To operate CW, you just press the morse key. Architecture The µBITX uses upconversion to the first IF of 45 MHz. This eliminates the need for a large number of band pass filters, keeping the design simple and virtually image free. The roofing filter at 45 MHz is 15 KHz wide. The signal is then down-converted to 12 MHz where a low ripple SSB filter with 8 crystals is used to provide a sparkling audio. The transmitter has push-pull PA using two IRF510s for a clean output. The low cost IRF510s are simple and inexpensive to replace should the need ever arise. Receiver :
  • Sensitivity: a 0.2uv signal is clearly audible
  • Selectivity: 2.4 KHz,  low ripple SSB filter with 8 crystals
  • RIT (Receiver Incremental Tuning)
  • Continuous coverage from 500 KHz to 30 MHz
  • Sideband selection
  • Detent-less encoder tuning. Tunes with larger step rates when tuned quickly
This info is there in hfsignals.com


On Mon, Mar 2, 2020 at 12:57 AM <publique@...> wrote:

Hello ! This is a very dummy question, but I can't really find the information... I would like to know what is the RX sensitivity of the ubitx ? I'm planning to use it (among other things) in my sailboat to receive weather forecast, but how good is the reception compared to a SDR (RTL-SDR, or even the more HF-oriented SDRPlay RSPDx), or to a HF transceiver from big brands ?

Many thanks !
73's from French Guyana ;)

Thomas

_Dave_ AD0B
 

Hi Rick Perhaps you might want to cross your eyes and look again at the  2 transistors in the receive circuit.  Most ubitx have 7 transistors and op amp in the receiver. If you can hear a signal at 1/3rd of a microvolt then where does the 1μV come in.

To the OP:
If you are looking for a radio for a boat you might think of something that will work in a rough wet environment. Ask Jeanne Socrates as she knows something about ithttps://www.qrz.com/db/VE0JS  Of course she may have been given that radio for publicity. Caveat emptor.

73
Dave
AD0B
Raduino bracket and Ham_Made_Keys

Bill Leaming
 

On 3/1/2020 1:26 PM, publique@... wrote:

Hello ! This is a very dummy question, but I can't really find the information... I would like to know what is the RX sensitivity of the ubitx ?
I had my uBITX on my service monitor yesterday and found clear signal all the way down to .1 uV...
As a comparison, my new Icom 7300's sensitivity for the same clarity of signal is .17 uV.

ajparent1/kb1gmx
 

On Sun, Mar 1, 2020 at 03:30 PM, Rick Tilton wrote:
He put it on his equipment to check SNR and it came out to 1 microvolt? 
Likely with a 10db S+N/Noise  and for HF 1uv is not that bad. 
That a signal and noise that is greater by 10DB than just the
noise output alone.   That means at about 10db less signal you
may still hear it (maybe weakly) which is still good.

FYI: a lot of well known radios .5uv for 10dbS+n/n is a very common
number.  Why not better?  At HF galactic and man made noise is 
sufficiently high enough that that will (very) easily be heard on a
receiver of that sensitivity.

The figure given in the published spec is really MDS of .2uV. as in
minimum discernible signal (enough to raise the average signal plus
noise level by 3DB).  That's actually pretty good.  For the test set
that may work out to a noticeably higher number (typically does).

>>> I did not get anywhere close to .01 microvolt?
RX sensitivity of .01uV, seriously?  getting .1 is very good,
but .01uV would be very hard to achieve.

Experience and reading specs for many radios would give
and idea of what normal and expected is.  Being inexperienced 
by your own words you do not have an idea of normal or expected.
Also measurements and measurement methods are well standardized
so those that understand them know what it means and how it was
arrived at.

 Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

ajparent1/kb1gmx
 

For many years when young and limited test gear if a receiver
had greater noise on an antenna than a dummy resistor it was
deemed more than sensitive enough for HF use.

Many years later, with access to the needed gear,  measuring such
a receiver was very educational.  Often I'd had striven for sensitivity
that was far more than needed and one such radio easily hit better
than commercial numbers for sensitivity.   Which by the way is 
easier to achieve than selectivity and overload performance.

Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

Joe Puma
 

Its always refreshing to see Allison popup out of the blue  =)

 

Hi Allison!

 

Joe

KD2NFC

 

Sent from Mail for Windows 10

 

From: ajparent1/kb1gmx
Sent: Wednesday, March 4, 2020 2:49 PM
To: BITX20@groups.io
Subject: Re: [BITX20] RX sensitivity #v6

 

On Sun, Mar 1, 2020 at 03:30 PM, Rick Tilton wrote:

He put it on his equipment to check SNR and it came out to 1 microvolt? 

Likely with a 10db S+N/Noise  and for HF 1uv is not that bad. 
That a signal and noise that is greater by 10DB than just the
noise output alone.   That means at about 10db less signal you
may still hear it (maybe weakly) which is still good.

FYI: a lot of well known radios .5uv for 10dbS+n/n is a very common
number.  Why not better?  At HF galactic and man made noise is 
sufficiently high enough that that will (very) easily be heard on a
receiver of that sensitivity.

The figure given in the published spec is really MDS of .2uV. as in
minimum discernible signal (enough to raise the average signal plus
noise level by 3DB).  That's actually pretty good.  For the test set
that may work out to a noticeably higher number (typically does).

>>> I did not get anywhere close to .01 microvolt?
RX sensitivity of .01uV, seriously?  getting .1 is very good,
but .01uV would be very hard to achieve.

Experience and reading specs for many radios would give
and idea of what normal and expected is.  Being inexperienced 
by your own words you do not have an idea of normal or expected.
Also measurements and measurement methods are well standardized
so those that understand them know what it means and how it was
arrived at.

 Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO