Date   
Microphone choices

Michael Goins, k5wmg <wmgoins@...>
 

Looking to use my BITX on SSB and cw and trying to figure out a good mike for it, either hand or desk. Will likely take to Costa Rica later in the year and possibly leave there. Suggestions or where to look for more information?

Re: CW key sticking with Nextion LCD

Joe Puma
 

Which bitx are you using. I have uBitx and R52 is near audio predriver and its a 2n3904. How do I do this on a uBitx v3. I guess this is what we call a carrier burst?

 

Joe

KD2NFC

 



On Apr 9, 2019, at 12:34 PM, Sam Tedesco <stedesco619@...> wrote:

 

Hi Joe,

There was a blocking diode fix on r52 that fixed all of my cw issues. I'm going off of memory...but, I lifted r52, on side towards 2822 chip, add diode in series...cathode down to board. I run my delay 450-500

 

Re: v5 12m/10m Spectrums

Curt
 

Ron

thanks I found them.  see if your instrument under units can be changed from dB v to dB m.  I think that may change the result. 

Curt

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

John (vk2eta)
 

Thank you all for your replies. Much appreciated.

I will do more work based on your input and report back on the results.

73, John (VK2ETA)

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Jerry Gaffke
 

Maybe.
Except it is working just fine at the first mixer on thousands of uBitx's.


On Tue, Apr 9, 2019 at 02:07 PM, Dexter N Muir wrote:
It seems the slightest leakage from "open" unbalances the mixer -and an Arduino output doesn't deliver that cleanly. Physically switching the key, direct from the panel socket or by relay, may be the only way to get clean CW by this method.
73, Dex ZL2DEX

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Dexter N Muir
 

It seems the slightest leakage from "open" unbalances the mixer -and an Arduino output doesn't deliver that cleanly. Physically switching the key, direct from the panel socket or by relay, may be the only way to get clean CW by this method.
73, Dex ZL2DEX

Re: v5 12m/10m Spectrums

ronmhauser@...
 

Ok, zipped in files section, deleted from photos section

Re: v5 12m/10m Spectrums

ronmhauser@...
 

Gah!  I guess the website shrinks the file resolution, they are not readable.  Hm.  Maybe there is a way to upload the full resolution pics

v5 12m/10m Spectrums

ronmhauser@...
 

Hi everyone.  Someone, I think Curt, asked about spectrum results on 12m/10m which I had not looked at previously.  The screen caps are in Photos (not files) under my call, K0EIA.  If I am reading this right, 12m looks ok, 10m not quite.  I haven't done a build nor an analysis like this before, so let me know what you see.

My setup is an Analog Discovery 2 puck generating 20mV - 50mV pp at 1kHz on the terminals of the mic connector, and a clip lead to ground the PTT.  The AD2 also takes the spectrum off a 47dB tap on my dummy load, and I have a diamond antenna crossed needle swr meter that reads 0-20w.  I experimented with varying the microphone level from 50mW to 30-20mW, and varying RV1.  Max in the filename is RV1 turned maximum counterclockwise.

73
--Ron
K0EIA

Re: CW key sticking with Nextion LCD

Sam Tedesco
 

Hi Joe,

There was a blocking diode fix on r52 that fixed all of my cw issues. I'm going off of memory...but, I lifted r52, on side towards 2822 chip, add diode in series...cathode down to board. I run my delay 450-500

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Jerry Gaffke
 

John,

Topology is different between first and second mixers on the uBitx.
I'd do your mod as proposed, but cut traces to T4 pins 3,5 and 6.
Swap them so T4 pins 3,5 are in from R47, pin 6 is out to C211.

Not yet obvious to me why it would matter.
But Farhan likely made that first mixer at T2 different than all 
other mixers on the uBitx and Bitx40 for a reason. 

Jerry, KE7ER

Re: My wish list for ver. 6 of ubitx

Robert D. Bowers
 

There are hams who might be priced out of the market by that... hams who are technically competent but who are on very limited means.  That's the beauty of the Bitx radios... they're made to be modded, if that's what a person wants to do.  If not, they're good basic radios in themselves and for most people, affordable.

My newest radio (Bitx40) - I'm not interested in modding, but I did add a noise filter/agc (external).  There is one mod that I might make if it's not already done (the radio was given to me, otherwise I couldn't have afforded it)... eliminating "VFO gallop".  Otherwise, I want it like it is.  That's my preference (I'm not even going to update the firmware from stock).  Others... prefer to make all sorts of changes.  More power to them!

I hold to the KISS adage (Keep It Simple Stupid), and since I don't do CW (neurological damage makes copying code... unreliable), don't need almost all of the mods available.  My radio is going to be used for portable/emergency work (and as a backup rig if the TS-520 doesn't work) - plus if I can ever start making contacts, QRP work.  (I rarely have time to try to make contacts, and hearing people making calls is even rarer.)  If I can ever get the ignition noise problem in our van isolated and eliminated, I would likely use it for mobile work.

Bob

N4FBZ



Re: My wish list for ver. 6 of ubitx

Curt
 

Iz

If I were Farhan - I would move on to other things!  Let's see what's in the future -

Given that we have thousands of v3, v4 and v5 around the globe -- I suggest that some merchant(s) kit 'the essentials.'  Its not like me not to comment (and think some) - here goes --

1) separate relays were used at the input and the output of the LPF, to be fully sure I exploit the filters at their potential;  -- I like the idea of separate relays.  I am blessed to be using such a board designed by a gracious list member -- now we just need someone to kit it for sale -- it works very well. 

2) add the possibility to add an RX preselector in the chain;  maybe my antennas are too small because I really don't need it.  okay I don't plan to use the rig in CQWW -- its fine 99% or more of the time. 

3) AGC.  I really like the simple VK3YE AGC - its working wonderful and requires NO changes in the board.  2 transistors - build it your favorite homebrew style - okay 2 key things to source - a LDR (aka photoresistor) and a bright LED.  the former from junkbox, the latter from some device that broke.  (I will confess I am still having trouble getting the ND6T to do anything in my rig -- trying to use it to feed S-meter.  it seems to work for everyone else - stay tuned to see what I may be missing)


4) RV1 externally adjustable - my no change to board here - just move it to the front or back panel.  now - do you or I have the wisdom to use it without a spectrum analyzer?  I am doubting it in my case! 

5) op-amp output for SDR receiver/panadapter.  me I would have said a SCAF audio filter.  but again, this is easy to add.  someone who never does CW might not need it at all, but I do use it some on SSB.  one could mount a simple board on its connector to host this.  Sunil may be taking notes! 

6) switchable RF finals and separate very low power output to drive V- U external transverters without the need of attenuators.   sure I thought about this!  well if a V6 would obsolete our rigs (I don't see this coming anytime soon!) -- we just need to cut away the PA's and build our own V/U machine.  perhaps when Farhan & friends launch their second satellite the V/U uBITX will land on planet earth. 

PS - I think we still lack much data on how much as been solved by v5.  honestly I think I prefer the narrower filter in v4 for SSB.  I can recount that trying some v5 changes in my v4 did not help much.  at the moment I am viewing my v4 as 'the glass more than half full' -- I am clean on all CW bands, and on SSB all the way up to including 17m. 

the uBITX remains a rig for the whole planet - the adventure does continue. 

73 Curt

CW key sticking with Nextion LCD

Joe Puma
 

I recently installed the 5” Nextion on uBitx Rig. I noticed that on the 10 meter band the CW key sticks when pressed and there is a noisy tone that goes along worn it. I guess this is RF getting in the line. If I disconnect LCD from power it goes away. I’ve been trying out .1 uf caps on things I seem to be having RAF issues with and it’s been fixing it with great success. So for the keyer I put a cap over the blue wire going to LCD and ground. It stopped the sticky CW key and I don’t hear the squealing RF in the signal.

Now on 18mhz when I key the CW keyer I hear some hiss when I unkey during that delay time which is 600ms. I also see other weird things that happens during that 600ms delay. When RF was getting in even though it didn’t make the key stick during that delay time, my power and swr goes up briefly. I can make the delay be 0 and be done with it. I only use the CW keyer to trigger my auto tuner so I don’t need the delay but that odd surge in power and swr makes my auto tuner retune after I let go of the CW keyer. It makes using it a tuner tigger useless.

Normally during that delay you dont see any signal but if there is RF in the chain it seems to discharge it back out onto the antenna port during that delay process. This causes the auto tuner to tune.

I’ve only noticed it with the 5” LCD installed.

Jow
KD2NFC

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

 

John,

Try a higher value for R104 like 100K preset or pot. The current the diodes need to conduct is very small IMHO.

Raj

At 09/04/2019, you wrote:
Thank you for the reply Dexter.

The strange thing is that the control voltage at the mixer swings from a virtually zero value (0.2mV DC on key up) and a full conduction value at 245mV DC on key down.

The 245mV value did not change significantly when I reduced the R105/R104 values so it seems to indicate that the mixer diodes are fully conducting on Key down as expected.

Also something I didn't mentioned before: when I disconnect the wire between T4(3,5), that is the clock #1 mixer, and R105 I get no unbalancing of the mixer and a very weak transmitted signal as expected on key-up (or key-down for that matter as it is disconnected).

So it is as if the clock #1 mixer would be much more sensitive to unbalancing than the clock #2 mixer.

Scratching my head on this one.

73, John

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Ted
 

John,

RE:  "The 245mV value did not change significantly when I reduced the R105/R104 values....."

If you're looking for a power change via R104, you must increase that resistance value (from the stock 2.2k up to to 3k, 5k, 8k, etc) in order to decrease CW power output.  I've shorted R104 outright, and power remains at its full potential. Only by increasing value does anything move away from stock output there.

Just making sure that you're getting to where you meant to be on this.



Best regards,

Ted
K3RTA

Re: My wish list for ver. 6 of ubitx

Dennis Zabawa
 

Ver. 5 cleverly upgraded previous versions tackling most of the  issues. In any case I would move for a ver. 6 if:
1) separate relays were used at the input and the output of the LPF, to be fully sure I exploit the filters at their potential;
**** Definitely *****
2) add the possibility to add an RX preselector in the chain;
***** No *****
3) AGC
***** Definitely *****
4) RV1 externally adjustable
***** No *****
5) op-amp output for SDR receiver/panadapter
***** No *****
6) switchable RF finals and separate very low power output to drive V- U external transverters without the need of attenuators. 
***** NO *****
Of course I would not pretend to stay in the same price range.

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

John (vk2eta)
 

Thank you for the reply Dexter.

The strange thing is that the control voltage at the mixer swings from a virtually zero value (0.2mV DC on key up) and a full conduction value at 245mV DC on key down.

The 245mV value did not change significantly when I reduced the R105/R104 values so it seems to indicate that the mixer diodes are fully conducting on Key down as expected.

Also something I didn't mentioned before: when I disconnect the wire between T4(3,5), that is the clock #1 mixer, and R105 I get no unbalancing of the mixer and a very weak transmitted signal as expected on key-up (or key-down for that matter as it is disconnected).

So it is as if the clock #1 mixer would be much more sensitive to unbalancing than the clock #2 mixer.

Scratching my head on this one.

73, John

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

John (vk2eta)
 

Thank you Ted.

That may well be my final option.

I was hoping for a software controlled power level as I already do in with the SSB signal by using the gentle (relative to an audio passband) slope of the 45Mhz filter to flatten the power output over the 80m-10m range.

But I can live with say 2 watts for tuning at 80M and 1 watt at 10M. Still very usable and low enough to safeguard the finals during tuning.

73, John

Re: Trial to control CW power (and reduce harmonics as a result) by unbalancing the 2nd mixer #ubitx

Dexter N Muir
 

A possibility for the CW just changing amplitude: is the 'unbalancer' driven from an Arduino output? That could be going from low to high - either of which would unbalance. I'm not an Arduino expert, but could that output be configured to be "off=open"? The alternative would be a transistor in there to make it go either (the greater) to open.
73 de ZL2DEX