Date   
Re: Tell me your favorite uBitx mods

Diver Martin <diver.martin@...>
 

The Teensy3.2 is a great little uC, I've used it in a lot of other projects.  Removing the leonardo and replacing with a Teensy would yield a price delta of about ~+$15, as the ATMega32U4 is about $4, popcorn components another $1, and the teensy3.2 is $20.  The downside to a teensy3.2 in this case is that it'll have to require some level shifting for the display and a few other things I think maybe, as it's a 3.3V output IO. (Unless the display and other things can tolerate 3.3V, which I haven't looked into)

On Mon, Jan 1, 2018 at 3:21 AM, gerrykav via Groups.Io <gerrykav@...> wrote:
I am planning on adding this audio filter/DSP project to mine... when I get it.

https://gi1mic.github.io/

/ Gerry




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: Variable power control

Daniel Isaza
 

Just a tought...

what happens if we reduce the voltage to the electret mic with a simple pot? distortion? variable power?

Dan

On Mon, Jan 1, 2018 at 4:09 PM, Clark Martin <kk6isp@...> wrote:
That’s easy enough to fix.  You put a power control pot (2 terminals only) between the +5V and the bias pot(s).  You set the power control to maximum and adjust each bias pot(s) for for the proper current draw.  Now you can turn down the bias / power, as you please.  But you can’t turn it up past “full”.

Clark Martin
KK6ISP

On Jan 1, 2018, at 11:54 AM, John Seager <jseager2009@...> wrote:

Arv, a) Happy New Year. b) Aside from using an attenuator, drive is controlled by
the preset RV1. This could be replaced by a variable pot., perhaps on the back panel. 
However I think it was Farhan who pointed out a long time ago that the only problem
with this is the temptation to keep turning it up!  73,  John  G0UCP




Re: Variable power control

Arv Evans
 

John  G0UCP

Agreed.  Some just can't have enough knobs and some percentage of those "must have
them turned to the right-most position". 

There is also the problem of change in operating parameters when power levels are changed
without a good idea of what the effect might be. 

Attenuators for QRP power levels are inexpensive and easy to build.  Add a switch or relay
and they allow the exciter to run at design specifications and still have controllable output. 

Using an attenuator on the input of a power booster helps insure that the impedances are
matched (maybe!) between exciter and linear amp.

HAPPY NEW YEAR! 

Arv  K7HKL
_._


On Mon, Jan 1, 2018 at 12:54 PM, John Seager <jseager2009@...> wrote:
Arv, a) Happy New Year. b) Aside from using an attenuator, drive is controlled by
the preset RV1. This could be replaced by a variable pot., perhaps on the back panel. 
However I think it was Farhan who pointed out a long time ago that the only problem
with this is the temptation to keep turning it up!  73,  John  G0UCP



On Monday, 1 January 2018, 17:05, Arv Evans <arvid.evans@...> wrote:



On Mon, Jan 1, 2018 at 9:19 AM, <ad4xx@...> wrote:
I'd love it if I could add a variable control to adjust output power on the uBitx.  After looking for solutions, I understand now that it's not a simple add of a potentiometer.  Anyone done this yet?




Virus-free. www.avast.com


Re: elves are at it

Dexter N Muir
 

> Would a bigger salary habe enhanced any thing of real importance?

Yes, Leland. It would have given (me anyway) more resources to do more and learn more, and more leisure to THINK.
73 de ZL2DEX

No TX #ubitx

joe kallo <quietglow@...>
 

Finally got around to putting my ubitx into a box, and I'm having trouble getting measurable output. I followed the bias tuneup procedure but when I got to the part where you HAAALLLLOWW into the mic and watch for deflection on the ammeter, I got none. I also didn't see any movement on the power meter/swr/dummy load. So I hooked up a cw key and confirmed: no measurable output when keyed down.

Where ought I to start troubleshooting?

Thanks much and 73

Joe KD9JLV

Re: No TX #ubitx

joe kallo <quietglow@...>
 

Should have noted: the radio does go into tx mode when the PTT is pressed and when the key is down. 

Re: Variable power control

Art Howard
 

I agree, attenuator would be the best/simplest option

On 1 Jan 2018 3:51 pm, "Daniel Isaza" <hk4dei@...> wrote:
Just a tought...

what happens if we reduce the voltage to the electret mic with a simple pot? distortion? variable power?

Dan

On Mon, Jan 1, 2018 at 4:09 PM, Clark Martin <kk6isp@...> wrote:
That’s easy enough to fix.  You put a power control pot (2 terminals only) between the +5V and the bias pot(s).  You set the power control to maximum and adjust each bias pot(s) for for the proper current draw.  Now you can turn down the bias / power, as you please.  But you can’t turn it up past “full”.

Clark Martin
KK6ISP

On Jan 1, 2018, at 11:54 AM, John Seager <jseager2009@...> wrote:

Arv, a) Happy New Year. b) Aside from using an attenuator, drive is controlled by
the preset RV1. This could be replaced by a variable pot., perhaps on the back panel. 
However I think it was Farhan who pointed out a long time ago that the only problem
with this is the temptation to keep turning it up!  73,  John  G0UCP




Re: #ubitx Re: Ubitx only on preorder now #ubitx

Art Howard
 

109 ground shipping ?

On 1 Jan 2018 1:51 pm, "chris gress" <Chrisg0wfh@...> wrote:
I ordered mine last night and got the HF signals email today I an on pre order got it for the 109 dollar price so I am happy 
Chris G0WFH 

On 1 Jan 2018 19:16, "B C" <k9wis@...> wrote:
Just got an email from hf signals acknowledging my order and payment on Dec 14th, two weeks ago...No indication of when they will ship..
Brian K9WIS



Re: Selecting the correct BFO frequency

Kerr Smith
 

Thanks for the replies - will adjust the BFO so it sits at 20dB down the edge of the filter - I will try lowering its frequency first and see how it goes, I tried changing the capacitance in series with the crystal as a quick test and this did alter its frequency so I will look in to this more tomorrow.

The circuit for the BFO I am using is the one shown in figure 18 of the following site:

http://www.nutsvolts.com/magazine/article/bipolar_transistor_cookbook_part_5

This receiver is planned to be a completely handmade version - my last creation was a Bitx20 using a si5351 and this works very well, it has a display screen, rotary encoder tuning as well as memory - I spent far longer on writing the software than in making the actual circuit (every time I thought I was finished I had another idea for an extra feature).

For this receiver I am trying to design it as much as possible by hand so I can learn more about how to do this. I only have a few bits left such as the second mixer, another RF amplifier and the audio amplifier - I already have working versions of the mixer and tuned RF amplifier so these just need duplicating.

Just to clarify - will it matter if I decide to put the BFO above or below the center frequency of the crystal filter - this is just going to be a receiver for 40m, there will be no transmitting circuits?

Re: #ubitx Re: Ubitx only on preorder now #ubitx

Andrew Farkas <afarkas@...>
 

I ordered mine on the 12th of December and it's due here in VA3 land on Jan 3rd. I ordered it and had it sent DHL for Christmas and later on found out they were previously sold out. 
If I'd known they were sold out I would've just had it sent India Post since I'll probably get dinged for the duty coming into Canada. I'll take the hit though for this uBitx. I was going to buy an FT817ND last year. I figure I'm saving myself at least $700 to $1000 Canadian.
Works for me! 
Thank you Mr. Ashar Farhan!

On Jan 1, 2018 2:51 PM, chris gress <Chrisg0wfh@...> wrote:
I ordered mine last night and got the HF signals email today I an on pre order got it for the 109 dollar price so I am happy 
Chris G0WFH 

On 1 Jan 2018 19:16, "B C" <k9wis@...> wrote:
Just got an email from hf signals acknowledging my order and payment on Dec 14th, two weeks ago...No indication of when they will ship..
Brian K9WIS




Re: Tell me your favorite uBitx mods

K5ESS
 

There are many 3.3v 16 X 2 displays advertised on Ebay.  Practically giving this one away.

https://www.ebay.com/itm/DC-3-3V-HD44780-1602-LCD-Display-Module-16x2-Character-LCM-Blue-Blacklight-NEW-/162222360139?hash=item25c534c64b

Mike

K5ESS

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Diver Martin
Sent: Monday, January 1, 2018 3:33 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Tell me your favorite uBitx mods

 

The Teensy3.2 is a great little uC, I've used it in a lot of other projects.  Removing the leonardo and replacing with a Teensy would yield a price delta of about ~+$15, as the ATMega32U4 is about $4, popcorn components another $1, and the teensy3.2 is $20.  The downside to a teensy3.2 in this case is that it'll have to require some level shifting for the display and a few other things I think maybe, as it's a 3.3V output IO. (Unless the display and other things can tolerate 3.3V, which I haven't looked into)

 

On Mon, Jan 1, 2018 at 3:21 AM, gerrykav via Groups.Io <gerrykav@...> wrote:

I am planning on adding this audio filter/DSP project to mine... when I get it.

https://gi1mic.github.io/

/ Gerry



 

--

Martin Held - AE7EU

http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: Tell me your favorite uBitx mods

Diver Martin <diver.martin@...>
 

Figured out what my plan was on that front.  I want to re-use as much of the raduino as possible, so one thing I did to make my life easier was to use a 74HC595 shift register, frees up IO's, and uses ones I've already got to level shift up to 5V for the IO expanders (the relays are all 5V that I'm using / have already designed in).  This way, the stock display module that comes with the raduino can be used.

Though, that is pretty dang cheap :)

On Mon, Jan 1, 2018 at 3:00 PM, K5ESS <k5ess.nothdurft@...> wrote:

There are many 3.3v 16 X 2 displays advertised on Ebay.  Practically giving this one away.

https://www.ebay.com/itm/DC-3-3V-HD44780-1602-LCD-Display-Module-16x2-Character-LCM-Blue-Blacklight-NEW-/162222360139?hash=item25c534c64b

Mike

K5ESS

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Diver Martin
Sent: Monday, January 1, 2018 3:33 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Tell me your favorite uBitx mods

 

The Teensy3.2 is a great little uC, I've used it in a lot of other projects.  Removing the leonardo and replacing with a Teensy would yield a price delta of about ~+$15, as the ATMega32U4 is about $4, popcorn components another $1, and the teensy3.2 is $20.  The downside to a teensy3.2 in this case is that it'll have to require some level shifting for the display and a few other things I think maybe, as it's a 3.3V output IO. (Unless the display and other things can tolerate 3.3V, which I haven't looked into)

 

On Mon, Jan 1, 2018 at 3:21 AM, gerrykav via Groups.Io <gerrykav=yahoo.co.uk@groups.io> wrote:

I am planning on adding this audio filter/DSP project to mine... when I get it.

https://gi1mic.github.io/

/ Gerry



 

--

Martin Held - AE7EU

http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?




--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

#ubitx Power output on 40 / 80 m with high current levels #ubitx

Alex - PA1FOX
 

Hi all,

I'm working on my uBitx which is completely homybuilt, so not the currently sold PCB version. By building it from scratch you encounter a lot of interesting things and learn a lot about it. Receiving of the rig is very good now but I am struggling with the TX. When aligned for output power of 8 watts, using a sine wave generator and full modulation level, the rig draws about 3,5 amps of current on 40M. At 80M, power output increases to about 12 watts, but current jumps up to around 4 amps. Sometimes my IRF's get killed at that level. There's now way so far I've got it set to say 8 watts with less than 2 amps of current. Things I've done so far are:

Play around with the HF power gain pot RV1 in combination with more audio drive level
Play around with the IRF's bias adjustment. Setting it too high will give a current thermal runaway and a fried IRF within a second. Careful with that...
Output toroids of the IRF balance, changed the windings bifilair, trifilair en more in both directions, so in fact play around with the output impedance with the IRF's see. The trifilair original option seems to be the best bet, but with these high current values. Toroid is a 37-10 with 7 windings trifilair.
Changed the emitter resistances on the 2N2219 to decrease the input power.

I've measured the LPF and it has a cutoff at 7300 KHz so that should be fine.
Testing done at 12volts, when at 13,8 volts, the output power and IRF amp values increase dramatically (got over 16 watts of RF) but this often kills one of the IRF's. No way I would keep the IRF's alive on 24 volts.
I don't have the LPF's for the higher bands in place yet, but it seems that at 20m and higher the overall gain of the TX chain decreases. When measured WITHOUT LPF (yes on dummy load, for sure) output power decreases to less than a single watt... This could also be an effect of the bidirectional part of the TX chain where the gain decreases with higher frequencies. For now I'm concentrating on the difference between the behaviour at 40 and 80 meters.

Could it be I am just using a wrong brand of IRF's? I have a load coming in from a second supplier to check.
Any other ideas? I have got rechargeable batteries built into my rig and they would last much longer if I could keep the total peak current below 2 amps.

Oh by the way, I've got a very large cooling heat sink and never got it really hot, just 'warm' 

Lovely experimental rig!

73, Alex
PA1FOX

Re: #ubitx Re: Ubitx only on preorder now #ubitx

Ken
 

Andrew

You shouldn't be dinged for customs as we have an exemption up to a limit.

73

Ken VA3ABN

On Mon, Jan 1, 2018 at 5:58 PM, Andrew Farkas <afarkas@...> wrote:
I ordered mine on the 12th of December and it's due here in VA3 land on Jan 3rd. I ordered it and had it sent DHL for Christmas and later on found out they were previously sold out. 
If I'd known they were sold out I would've just had it sent India Post since I'll probably get dinged for the duty coming into Canada. I'll take the hit though for this uBitx. I was going to buy an FT817ND last year. I figure I'm saving myself at least $700 to $1000 Canadian.
Works for me! 
Thank you Mr. Ashar Farhan!

On Jan 1, 2018 2:51 PM, chris gress <Chrisg0wfh@...> wrote:
I ordered mine last night and got the HF signals email today I an on pre order got it for the 109 dollar price so I am happy 
Chris G0WFH 

On 1 Jan 2018 19:16, "B C" <k9wis@...> wrote:
Just got an email from hf signals acknowledging my order and payment on Dec 14th, two weeks ago...No indication of when they will ship..
Brian K9WIS





Re: #ubitx Re: Ubitx only on preorder now #ubitx

John Miller
 

I ordered one the 15th, I have no clue when it will come in. I was hoping for Christmas but knew it wasn’t likely. Oh well, gathering a lot of good info on this list and looking forward to when it does actually get here.

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Ken
Sent: Monday, January 01, 2018 6:45 PM
To: BITX20@groups.io
Subject: Re: [BITX20] #ubitx Re: Ubitx only on preorder now

 

Andrew

 

You shouldn't be dinged for customs as we have an exemption up to a limit.

 

73

 

Ken VA3ABN

 

On Mon, Jan 1, 2018 at 5:58 PM, Andrew Farkas <afarkas@...> wrote:

I ordered mine on the 12th of December and it's due here in VA3 land on Jan 3rd. I ordered it and had it sent DHL for Christmas and later on found out they were previously sold out. 

If I'd known they were sold out I would've just had it sent India Post since I'll probably get dinged for the duty coming into Canada. I'll take the hit though for this uBitx. I was going to buy an FT817ND last year. I figure I'm saving myself at least $700 to $1000 Canadian.

Works for me! 

Thank you Mr. Ashar Farhan!

 

On Jan 1, 2018 2:51 PM, chris gress <Chrisg0wfh@...> wrote:

I ordered mine last night and got the HF signals email today I an on pre order got it for the 109 dollar price so I am happy 

Chris G0WFH 

 

On 1 Jan 2018 19:16, "B C" <k9wis@...> wrote:

Just got an email from hf signals acknowledging my order and payment on Dec 14th, two weeks ago...No indication of when they will ship..
Brian K9WIS


 

 

Re: Tell me your favorite uBitx mods

AndyH
 

On Mon, Jan 1, 2018 at 01:15 am, Dave Bottom wrote:
Hi Martin,
 
 A Second Story is a neat idea that could eliminate wiring with a suitable case that can take advantage of PCB mounted connectors.
Here's my wish list...
 
Important:
1) Well the top of my list is a really effective AGC.  This is what separates a really great rig from a really good rig.
The basic MicroBITX so reminds me of my SBE SB-33 (1966 - mobile rig) it is the audio derived AGC. 
Back in the day Collins S-Line had great (but complex) AGC that worked(s) great, but..
Nearly every Heathkit SSB rig back in the day had great AGC whether it was a tube HW-12 or a solid state HW-104.
Check out the HW-104 AGC system...
 
2) Solid CW Keying and for a paddle
 
3) USB interface to rear panel -  One big reason for this kit is to become proficient working with software.
 
4) Well if those are done an S-Meter is nice.
 
Nice to have:
4) Momentary button to toggle between VFO A and VFO B.  If you work split this is really necessary (Yes, I chase DX on QRP)
 
5) Mic Pre-Amp and Mic Gain -  I added this tonight with the PCB temporarily stuck on the rear panel (all my jacks are on the rear panel out of the way of knobs. 
It helps a little so I don't feel like I have to climb in the Mic, however a Speech Compressor might be more worthwhile.  Being able to use typical Electret Condenser Mics (e.g. ICOM radios) it needs more gain and an adjustment even if a PCB mounted internally accessible set and forget pot.
 
6) Keying interface for a Linear.  Band data and keying - This baby will drive an RF-KIT 2K+ LDMOS linear to legal limit. (when life is too short for QRP)
 
When you have nothing better to do:
7) VSWR Bridge with Display for forward/reflected power.  The tuner gets a lot simpler and an external tuner may not need power (manual tuner).
 
Oh, wait, didn't you do that one already?  LOL
 
Dave WI6R

On Sun, Dec 31, 2017 at 6:29 PM, Diver Martin <diver.martin@...> wrote:
Hello all,
 
As I'm doing a motherboard mod, I'm looking to incorporate a bunch of mods into one PCB.  Right now, what I've got going are the following:
 
* A tuner + SWR Bridge (phase detector maybe?)
* A spot for an RTL-SDR (blogV3) dongle
* AGC Modifications
* Integrating LCD and headphone/mic/BNC/Power/etc jacks into the PCB
 
Other things I've thought about, space depending:
 
*Adding in footprints for a chinese AD9850 DDS module for one of the clock signals
 
I would like to hear the top mods you've done, and what you'd love to see integrated into a motherboard PCB that fits on top of the uBitx.  Battery charger?  Battery adapter? I dunno, bring it on!  If you have a favorite AGC mod, please tell me about it, and make some suggestions as well.  This is not promising to be a cheap kit, and full of SMT, but something I might make available.
 
Happy new year,
 
--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

 

 

 



 
--
73 Dave WI6R

#ubitx IRF510 concerns, different modes #ubitx

Ghericoan
 

I have yet to get my ubitx yet, as I am on the preorder list. But I was wondering if there is a way to back the power output down to five watts to save the heat stress on the IRF510s. I am looking to do digital modes like PSK31, WSPR, and possibly playing around with SSTV.

Just concerned on how to go about assembly once the unit is here because I want it to be solid for digital modes. I have already ordered spare MOSFETs, but would rather not get into the habit of replacing them.
--
----------
N5WLF, Greggory (or my nickname, Ghericoan)
General Class, Digital Radio Hobbyist

Re: #ubitx IRF510 concerns, different modes #ubitx

Gordon Gibby <ggibby@...>
 

Greggory --- it won't be nearly the problem you're thinking....


Just tone down the audio level into the mic if you want a lower power level.   With single side band, that proportionately reduces your output.    ​It is as  easy as that.    I haven't used these rigs a ton yet, but I've made multiple digital connections (WINLINK, ALE) and no problems at all with the finals.   


gordon




From: BITX20@groups.io <BITX20@groups.io> on behalf of Ghericoan <boakawizkid@...>
Sent: Monday, January 1, 2018 7:18 PM
To: BITX20@groups.io
Subject: [BITX20] #ubitx IRF510 concerns, different modes
 
I have yet to get my ubitx yet, as I am on the preorder list. But I was wondering if there is a way to back the power output down to five watts to save the heat stress on the IRF510s. I am looking to do digital modes like PSK31, WSPR, and possibly playing around with SSTV.

Just concerned on how to go about assembly once the unit is here because I want it to be solid for digital modes. I have already ordered spare MOSFETs, but would rather not get into the habit of replacing them.
--
----------
N5WLF, Greggory (or my nickname, Ghericoan)
General Class, Digital Radio Hobbyist

Re: Got Mine Built #ubitx

Terence Taylor
 

OK, here is the file to use for laser/cnc cutting of the case I made. I cut in out of 1/8" (3mm) MDF. Since that is a little too thick for the supplied  jacks, you may need to glue the jacks into the from panel or use a Forstner bit to create a recess for the retaining nuts.

Re: Selecting the correct BFO frequency

Jerry Gaffke
 

It definitely matters if the BFO is above or below the crystal filter passband.

I was talking both transmit and receive in that last post, but the math is the same regardless of which direction the signals travel.
If you want a BFO slightly lower in frequency than the crystal filter, the 10mhz crystal filter will be receiving a 10mhz USB signal.
So to compensate, must run the VFO at 17mhz, on the high side of 10mhz crystal filter, which flips things so that you will be receiving 7mhz LSB signals.
A 17mhz analog VFO is possible, but will be tricky to get stable enough.

The parallel resonant frequency of a crystal is a few khz above the series resonant frequency, that may be the key to using
a 3mhz analog VFO with your 10mhz crystal filter to receive a 7mhz LSB signal.
It is the series resonant frequency that is used by your crystal filter, and by many oscillator circuits.
So I'd fiddle around with the circuit in figure 18 of the nutsvolts.com link you posted to get a BFO above your crystal filter.
And/or look this over: http://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/radcom/2001/05/page63/index.html

 


On Mon, Jan 1, 2018 at 02:54 pm, Kerr Smith wrote:
Just to clarify - will it matter if I decide to put the BFO above or below the center frequency of the crystal filter - this is just going to be a receiver for 40m, there will be no transmitting circuits?