Date   
Re: Has anyone built Ashhar's Specan?

Jerry Gaffke
 

An ADC on the audio with a simple program to do peak detection might do about as well as the ad8307 on the 12mhz IF.
But the ad8307 will give better dynamic range (unless you have an awfully nice ADC),
and the ADC would give the possibility of doing an FFT in software for very fine grained resolution.
I think.


On Wed, Jul 26, 2017 at 10:36 am, Jerry Gaffke wrote:
Maybe switch between the 45khz crystal filter, the 12mhz crystal filter, and analyzing the audio with an ADC.

Re: balanced modulator, D20 & schematic in general

Jerry Gaffke
 

Nope.
Here's a list of the minor differences between the Bitx40 schematic on hfsigs (no change since raduino introduced in Dec 2016) and what gets shipped:
    https://groups.io/g/BITX20/message/28827
Check the thread around it too for a few more hints about possible hacks you could do.
Could add Gian's rx pop fix to the list:  https://groups.io/g/BITX20/topic/5619768

Jerry, KE7ER


On Wed, Jul 26, 2017 at 10:48 am, Keith VE7GDH wrote:
so my question is really if there are updated drawings available.

balanced modulator, D20 & schematic in general

Keith VE7GDH
 

While I'm waiting for the replacement IRF510, I was
looking around at the circuit board on the BITX40. It
was purchased June 2. The schematic at hfsigs.com
shows a pot R106 between D15, D16 and the (pad/load?)
of R37, R38, R39. On the actual circuit board, I
don't see the pot at all. D15 and D16 are missing,
but I see a 3-pin device labeled D20, obviously in
place of D15 & D16. The circuit obviously works with
no adjustment, but I was just wondering if there
was a schematic available that reflected the
actual shipped boards?

Before hitting "send" I did a search and see that
David NA1MH asked about D20 back on May 31, and
got a reply from Mvs Sarma that it was a BAT54S,
so my question is really if there are updated
drawings available.

--
73 Keith VE7GDH

Re: Has anyone built Ashhar's Specan?

Jerry Gaffke
 

Maybe switch between the 45khz crystal filter, the 12mhz crystal filter, and analyzing the audio with an ADC.
Jerry, KE7ER


On Wed, Jul 26, 2017 at 10:17 am, Ashhar Farhan wrote:
you could just do rms of the audio. the main challenge would be that given 3 khz bandwidth, the 30 mhz scan would need a reading every 1.5 khz. that means, 20,000 readings for the full scan. it will take a long time. this ia why specans have variable bandwidths.

Re: Has anyone built Ashhar's Specan?

Ashhar Farhan
 

you could just do rms of the audio. the main challenge would be that given 3 khz bandwidth, the 30 mhz scan would need a reading every 1.5 khz. that means, 20,000 readings for the full scan. it will take a long time. this ia why specans have variable bandwidths.
- f

On 26 Jul 2017 10:35 p.m., "Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:
If I were to create a pcb for the uBitx, it would have pads for an optional ad8307 (or ad8310) after the crystal filter, just before the demodulator.  Drives an ADC pin on whatever processor you happen to be using, 10 bits of ADC is plenty.  So in addition to having an all band HF xcvr, would have a low grade Spectrum Analyzer.  That ad8307 could also be used as an S meter.  Removing a jumper at the input to the ad8307 and plugging in something like a scope probe it could be used as an extremely wide dynamic range RF probe for trouble shooting.  

Or maybe instead sample the output of the demodulator using a 24 bit ADC, use DSP techniques on one of the cheap ArmCortex Arduino compatible processors to do an FFT for fine grained spectrum analysis.  This would be more difficult to do right.

Of course, you would have to build two if you want to check emissions on your new uBitx.

Jerry, KE7ER

Re: Has anyone built Ashhar's Specan?

Jerry Gaffke
 

If I were to create a pcb for the uBitx, it would have pads for an optional ad8307 (or ad8310) after the crystal filter, just before the demodulator.  Drives an ADC pin on whatever processor you happen to be using, 10 bits of ADC is plenty.  So in addition to having an all band HF xcvr, would have a low grade Spectrum Analyzer.  That ad8307 could also be used as an S meter.  Removing a jumper at the input to the ad8307 and plugging in something like a scope probe it could be used as an extremely wide dynamic range RF probe for trouble shooting.  

Or maybe instead sample the output of the demodulator using a 24 bit ADC, use DSP techniques on one of the cheap ArmCortex Arduino compatible processors to do an FFT for fine grained spectrum analysis.  This would be more difficult to do right.

Of course, you would have to build two if you want to check emissions on your new uBitx.

Jerry, KE7ER

Re: On the subject of fake IRF510

chris gress <Chrisg0wfh@...>
 

I just ordered 2 of the ones with the display them China things don't last long I have found so I will have a back up they
Look cool anyway 

On 26 Jul 2017 13:57, "Curt M." <Kc3hjp@...> wrote:
After whatever went on with the first Bitx40 that I was shipped and especially after it appeared that the Radrino got whacked during troubleshooting when I switched from 12v to 13.8v I'm exclusively on 12V now.  I use the 15Ah Bioenno battery that I bought for my FT-817ND which puts out about 13.4v so I installed a voltage converter/stabilizer between the battery and the radio.  I set it for around 12.1v with no load.  See links below...

I purchased two different ones to try.  With the first one which has a display, I set it for 12.1v and the voltage drops to just under 12v when I power the Bitx on.  When I key up and talk the voltage does not go any lower than the initial voltage drop.  Actually 12.1v was the highest I could get when adjusting the output because the device can only control at a minimum of 1v difference between the input and output.  not sure what happened to the other .2v but either way it seems fine.  What's nice is that this device gives you a pretty clear indication that you are really transmitting because you see the fluctuations in current as you are talking into the mic.  I haven't checked what happens to the voltage with the second one but measuring the power output of the Bitx on the Bird 43, the power output using either one shows that I'm putting out about as close to 6 watts as it could be without the needle actually covering the 6 indicator so I suspect that either of these are fine.  I built the radio with it only ever being a QRP radio so what appears to be about 5.9 watts is more than I was expecting.  Also, these devices do not appear to induce any type of noise into the receive or transmit of the radio.  For everyday use I may stay with the one that doesn't have the display because I can leave it connected to the battery at all times without the load of the LCD and backlight drawing from the battery.  Having the one with the display will allow me to have a quick indication of what's going on with the radio if I ever question if the final has gone defective.

https://www.amazon.com/gp/product/B01FQGFXS6/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 

https://www.amazon.com/gp/product/B00C0KL1OM/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 


Re: Has anyone built Ashhar's Specan?

ohwenzelph
 

My first concern: Getting some of the good authentic and correct parts at a reasonable price or suitable substitute is my initial concern. In particular the MAV11, ADE-1 and the correct version of the Si570, also suitable crystals. 
Have you built a Sweeperino?
jerry aa1of

Re: I7SWX PTT Pop Mute

Giancarlo
 

Hi,

thanks for reporting the trial of my muggested circuit and  the positive results
73

Gian
I7SWX

Re: On the subject of fake IRF510

Curt M.
 

After whatever went on with the first Bitx40 that I was shipped and especially after it appeared that the Radrino got whacked during troubleshooting when I switched from 12v to 13.8v I'm exclusively on 12V now.  I use the 15Ah Bioenno battery that I bought for my FT-817ND which puts out about 13.4v so I installed a voltage converter/stabilizer between the battery and the radio.  I set it for around 12.1v with no load.  See links below...

I purchased two different ones to try.  With the first one which has a display, I set it for 12.1v and the voltage drops to just under 12v when I power the Bitx on.  When I key up and talk the voltage does not go any lower than the initial voltage drop.  Actually 12.1v was the highest I could get when adjusting the output because the device can only control at a minimum of 1v difference between the input and output.  not sure what happened to the other .2v but either way it seems fine.  What's nice is that this device gives you a pretty clear indication that you are really transmitting because you see the fluctuations in current as you are talking into the mic.  I haven't checked what happens to the voltage with the second one but measuring the power output of the Bitx on the Bird 43, the power output using either one shows that I'm putting out about as close to 6 watts as it could be without the needle actually covering the 6 indicator so I suspect that either of these are fine.  I built the radio with it only ever being a QRP radio so what appears to be about 5.9 watts is more than I was expecting.  Also, these devices do not appear to induce any type of noise into the receive or transmit of the radio.  For everyday use I may stay with the one that doesn't have the display because I can leave it connected to the battery at all times without the load of the LCD and backlight drawing from the battery.  Having the one with the display will allow me to have a quick indication of what's going on with the radio if I ever question if the final has gone defective.

https://www.amazon.com/gp/product/B01FQGFXS6/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 

https://www.amazon.com/gp/product/B00C0KL1OM/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 

Re: Dynamic mic preamp?

 

I just put the stock mic back for now until I find something I like. I honestly just don't have anymore room in the case for that kind of add-on. If I went with smt it would cost me more to order the parts than I can spare at this time, was hoping for a simple 2n4401 or 2n3904 option but they all seem not be working right for this application.

Re: Dynamic mic preamp?

4Z1NT
 

What are the values of C4, R7, C8, R9?

On 25 July 2017 at 14:14, Jeff <jeff@...> wrote:
Here is the circuit using the SSM2167 I built that seems to work quite well. It has plenty of gain as well as a nice compressor. You can find more details here.

http://jeffcummingscom.000webhostapp.com/2017/06/02/more-additions-mic-compressor/



Jeff
N9ARZ


Re: IRF 630-IRF640 vs IRF510

Ashhar Farhan
 

You have to figure out if really the PA is blown. One way is to find out if the bias pot can increase the PA current from 0 to the required 100ma.
if that works, i would look for charred resistors around the driver and the predrivers.

- f

On Wed, Jul 26, 2017 at 2:22 AM, Lawrence Galea <9h1avlaw@...> wrote:
Heat, overvoltage, overcurrent, and in pa's high vswr / mismatching are deadly enemies of semiconductors 

On Tue, Jul 25, 2017 at 9:23 PM, Keith VE7GDH <ve7gdh@...> wrote:
Allison KB1GMX wrote...

The circuit was designed with the IRF510 as it is
available and works. If you substitute it's at your
own peril or for you own edification.

The IRF510 is cheap to replace. I'm starting to think
that perhaps I should just stick with it! Perhaps I just
got unlucky with the first one.

I was in a QSO that was probably 15+ minutes long
when my output dropped. It was the typical QSO with
about 50% RX / 50% TX. I wasn't monitoring temperature,
but could that have been enough to make the 510 unhappy?

--
73 Keith VE7GDH





Re: Dynamic mic preamp?

Jeff
 

I just found them on Ebay you might look at 172308533782 this is the seller I used. the9ARZy come all together and you just snap off what you want to use.
Jeff
N

Re: On the subject of fake IRF510

1practical.man
 

Amen Dr Fred. Stopping the leak is of great concern. Wound contamination is way down the list. I am personally grateful for the fancy new hemostatic bandages and tourniquet, along with the medics who trained us to use them. Real lifesavers. Everyone who drives a car should keep em on hand and be trained in using them.  Car accidents maim far more people than interpersonal violence. 

Of course, we all have radios and cell phones to summon help. (Just to keep this radio related). 

On Jul 25, 2017, at 18:59, Dr Fred Hambrecht <AAR4MI@...> wrote:

Having been on the receiving end of a “War lead bullet”, I can assure you lead contamination was my very last worry. Repairing the hole was of much greater concern.

 

v/r

Fred W4JLE

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Tuesday, July 25, 2017 13:01
To: BITX20@groups.io
Subject: Re: [BITX20] On the subject of fake IRF510

 

A billion cars burning roughly 1000 gallons/yr is an awful lot of CO2 even if it is relatively benign (it is not:  https://xkcd.com/1732/).  And more than a little noxious crap.  To say nothing of all the jet fuel and spills and wars.  That gunfire is a far bigger source of lead in the environment than electronics hobbyists, if you really care about lead.


On Tue, Jul 25, 2017 at 09:24 am, Andrew Krause wrote:

Meh... if your car is maintained, the only thing coming out of your tail pipe is plant food (CO2 and Water). 

Re: Microphone bypass cap

Steve Greer
 

Thanks everyone who replied.  I don't use the electret mic I use an old turner super sidekick and I replaced the cap with 1000000 uf in series not parallel as stated on hfsigs and I got a good audio report so it was getting dc voltage in the audio circuit causing the muffling.  All seems to be good now.  The 200 watts bitx is back on the air. Thx group 73 KM4OUS

Re: On the subject of fake IRF510

Jerry Gaffke
 

No argument here.
I owe you a beer and more should we ever meet, whatever war that was.
I was lucky enough to come of age at the end of the Vietnam War (the American War to some), 
right about when they shut down the draft. 

Jerry


On Tue, Jul 25, 2017 at 04:00 pm, Dr Fred Hambrecht wrote:
Having been on the receiving end of a “War lead bullet”, I can assure you lead contamination was my very last worry. Repairing the hole was of much greater concern.

Re: On the subject of fake IRF510

Dr Fred Hambrecht
 

Having been on the receiving end of a “War lead bullet”, I can assure you lead contamination was my very last worry. Repairing the hole was of much greater concern.

 

v/r

Fred W4JLE

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Tuesday, July 25, 2017 13:01
To: BITX20@groups.io
Subject: Re: [BITX20] On the subject of fake IRF510

 

A billion cars burning roughly 1000 gallons/yr is an awful lot of CO2 even if it is relatively benign (it is not:  https://xkcd.com/1732/).  And more than a little noxious crap.  To say nothing of all the jet fuel and spills and wars.  That gunfire is a far bigger source of lead in the environment than electronics hobbyists, if you really care about lead.


On Tue, Jul 25, 2017 at 09:24 am, Andrew Krause wrote:

Meh... if your car is maintained, the only thing coming out of your tail pipe is plant food (CO2 and Water). 

Re: raduino v1.20.1 (respect frequency limits) released

César EA3IAV
 

Installed! I feel like it works much better! 
Thank you

Re: On the subject of fake IRF510

Andrew Krause
 

All of those assertions are demonstrably false, but this is not the forum for that. 


On Tue, Jul 25, 2017 at 1:00 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
A billion cars burning roughly 1000 gallons/yr is an awful lot of CO2 even if it is relatively benign (it is not:  https://xkcd.com/1732/).  And more than a little noxious crap.  To say nothing of all the jet fuel and spills and wars.  That gunfire is a far bigger source of lead in the environment than electronics hobbyists, if you really care about lead.


On Tue, Jul 25, 2017 at 09:24 am, Andrew Krause wrote:
Meh... if your car is maintained, the only thing coming out of your tail pipe is plant food (CO2 and Water). 




--

Andrew Krause
General Class Amateur Radio License: KM4ZJO
andrew.krause@...
(404) 732-2369