Date   

Re: RX sensitivity #v6

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


Re: Any interest in uBITX Net

Martin Potter <ve3oat@...>
 

Maybe it's propagation of I am too far away from everyone, but I heard no one. Lots of adjacent activity (7278) and I called CQ BITX once on 7277 but there were no replies. I also called twice on 7275, which seemed clear at the time, but heard no response there either.

I recently changed the mic element in my cheap Baofeng microphone, replacing it with the element from the QRP-Kits mic kit. Wonder if it has improved the audio quality at all.

73,
... Martin VE3OAT


Re: Any interest in uBITX Net

David Nelson
 

got contesters on 277  kc2ipx


On Sun, Mar 1, 2020 at 3:13 PM Mick <Mgsebele@...> wrote:
Anybody on 40m ssb 7277? @20:12 itch


Re: Any interest in uBITX Net

Mick
 

Anybody on 40m ssb 7277? @20:12 itch


Re: RX sensitivity #v6

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


Re: Good spot to insert audio preamp on V6 #v6

 

I decided that I would go another direction for my low audio problem, instead of trying to insert a preamp I just am using the uBitx's audio amp as the preamp to a TDA2030 module, it works so much better. See picture attached as to how I mounted it. I screwed the chip to the side of the cabinet to keep the chip cool.

Joel
N6ALT


Re: RX sensitivity #v6

_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


Re: RX sensitivity #v6

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


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


Re: Efficient speaker for low volume #audiocircuit #ubitx

Jack, W8TEE
 

FWIW, I find Parts-Express to be a really good and responsive company. I've purchased quite a few items from them, including a cheap solder station (<$15.00) and cheap speakers and have been happy with the products and their service.

Jack, W8TEE


On Sunday, March 1, 2020, 10:09:26 AM EST, Mark Muller <markvmuller@...> wrote:


Great idea, Don. If you're looking for a smaller speaker with high sensitivity in the audio frequency region, you might give this one a try.

https://www.parts-express.com/2-mylar-cone-full-range-waterproof-speaker-d0050008nm14bar--289-204

Looking at the sensitivity graph, it might sound pretty "bright" - you won't get much bass, but it cuts off fairly sharply after 6 kHz, so maybe that will be OK?

Can't beat the price!

73's de N5KNG (Mark)

--
Jack, W8TEE


Re: Setup mode #v6

Reed N
 

Holding the tuner button down when powering on goes into the three cal serial mode, not into the menu. Might still do what you need, but isn't necessarily the same.


Reed


Re: Only noise when connected to the antenna #v6

Jonathan Kayne, KM4CFT
 

I have published a YouTube video that goes through my findings. I was also trying to explain how the circuitry works. I show spectrum analyzer readings as I explain it so it might help.
https://youtu.be/pQb-sM8slCg

Curt, I did indeed check each oscillator and they were all working as expected. In fact that was the first thing I checked when I started troubleshooting. I also observed that the LO would appear at the output of the mixer due to nonlinearities of the mixer. 

Evan, I have tested up to the product detector stage. It is of course possible that one of the transformers isn't working properly, but I will say that I checked the product detector by inserting a 1 kHz -50 dBm (that's the lowest the function generator could do as the Agilent I was using for testing is 100 kHz minimum and had to switch to the lower frequency SG) into the audio side and it mixed the baseband up to 11 MHz. The weird thing about that was that the signal appeared to be amplified and not attenuated (by about +28 dBm if I remember correctly) maybe that signal generator wasn't as accurate as the Agilent...

-Jonathan, KM4CFT


Re: Signal pathway highlighted on schematic

Joe Puma
 

Thanks for providing this. 



On Mar 1, 2020, at 10:55 AM, _Dave_ AD0B <davesters@...> wrote:

Here is the signal pathway for a V3 uBITX
--
73
Dave
AD0B
Raduino bracket and Ham_Made_Keys
<ubitxv3s.pdf>


Re: Efficient speaker for low volume #audiocircuit #ubitx

Don - KM4UDX
 

I've always had a thing for clear speakers...I mean how cool is that...hahaha.

There is a price to be paid for that great small form factor...the efficiency is 84 dB 2.83V/1m.

The bigger non-transparent speaker with large magnet efficiency is 96 db...so the difference between the two (84-96) is 12 db gain going from smaller to larger.

But the Mylar speaker is the small bomb.


Re: Signal pathway highlighted on schematic

_Dave_ AD0B
 

Here is the signal pathway for a V3 uBITX
--
73
Dave
AD0B
Raduino bracket and Ham_Made_Keys


Signal pathway highlighted on schematic

_Dave_ AD0B
 

This one is for a uBITX V6

--
73
Dave
AD0B
Raduino bracket and Ham_Made_Keys


RTC07S Si531 DDS VFO

e78cb@...
 

Dear friends, I need help..

I accidentaly burned out Si5351 chip on Raduino on my BITX 40 kit TRX. So I removed Arduino and I decided to use RTC07S DDS VFO from hambuilder.com instead.
It all turned on and I set up IF to 12MHz and it is on frequency BUT there emerged two problems:

1. My BITX is on USB modulation at all times! As you know BITX 40 shoud run on LSB as it was before with Raduino DDS.. I do not know how to correct this.. I tried to switch DDS contacts opposite to get opposite V from DDS in my thinking logic but I got too low gain to hear it.. What do you suggest?
RTC07S has a LSB and USB BFO outputs, but I switched only VFO outputs to DDS on BITX as it only gives some signal.. Does BITX has BFO outputs and can I connect RTC07S to it..I dont know..

2. I get annoying buzz signall at all times in speakers, when DDS runnig.. Hopefully this is more easy to reslove, but I had no idea at the moment...

Thanks for any solution or guidance..

Vule, E78CB





Efficient speaker for low volume #audiocircuit #ubitx

Mark Muller
 

Great idea, Don. If you're looking for a smaller speaker with high sensitivity in the audio frequency region, you might give this one a try.

https://www.parts-express.com/2-mylar-cone-full-range-waterproof-speaker-d0050008nm14bar--289-204

Looking at the sensitivity graph, it might sound pretty "bright" - you won't get much bass, but it cuts off fairly sharply after 6 kHz, so maybe that will be OK?

Can't beat the price!

73's de N5KNG (Mark)


Re: #v6 software #v6

Juha Lindfors
 


Here is link to the Reeds site.

Juha oh8cw

su 1. maalisk. 2020 klo 16.20 Mark Spohr (mhspohr@...) kirjoitti:

Here's the thread on Reed's code.
The forum search function works pretty well.

https://groups.io/g/BITX20/message/75230


Re: #v6 software #v6

Juha Lindfors
 

That's Ashhar's github site?

Juha oh8cw

su 1. maalisk. 2020 klo 16.20 Mark Spohr (mhspohr@...) kirjoitti:

Here's the thread on Reed's code.
The forum search function works pretty well.

https://groups.io/g/BITX20/message/75230