Date   

Re: Content flagged as objectionable

barry halterman
 

A one tube transmitter with a single 6146 was a popular design in the early 1960s.
Barry


On Sun, Aug 23, 2020, 6:25 AM Bob Lunsford via groups.io <nocrud222=yahoo.com@groups.io> wrote:
On Sunday, August 23, 2020, 2:02:49 AM EDT, s53c.lado@... <s53c.lado@...> wrote:


I apologize to reply to your message with an off topic question. Since English (American) is not my native language, I sometimes don't understand some references. I can relate to your mention of both one tube radios and 807 finals (I built both at age of 13), but I'd be glad if you explain what you mean by "MOPA design". I googled about that a little bit, but failed to find a meaningful explanation.

If I return to the topic, I absolutely agree with you that ham radio nowadays requires al least basic understanding of micro controllers and programming. Although C and C++ are not the only programming languages, they seem to be most used ones in micro controller area. Thus any kind of reference to Jack Purdum books covering C, C++ and ham radio are and should be most welcome in Bitx forums!


Integration of uBitx V6 board with Nextion kit from https://amateurradiokits.in/ #ubitxv6 #nextion

vu3gwn
 

Has anyone integrated uBitx V6 board with the kit from https://amateurradiokits.in/. Since the power /volume control, ptt, audio out and cw key along with Antenna connectors are soldered on the board unlike the V5 board, wanted to check how it has been handled. The kit is currently not compatible with V6 board. 

If anyone can share their experiences and or some photos how the integration has been done, it will help.

Thanks


Re: Content flagged as objectionable

Bob Lunsford
 

On Sunday, August 23, 2020, 2:02:49 AM EDT, s53c.lado@... <s53c.lado@...> wrote:


I apologize to reply to your message with an off topic question. Since English (American) is not my native language, I sometimes don't understand some references. I can relate to your mention of both one tube radios and 807 finals (I built both at age of 13), but I'd be glad if you explain what you mean by "MOPA design". I googled about that a little bit, but failed to find a meaningful explanation.

If I return to the topic, I absolutely agree with you that ham radio nowadays requires al least basic understanding of micro controllers and programming. Although C and C++ are not the only programming languages, they seem to be most used ones in micro controller area. Thus any kind of reference to Jack Purdum books covering C, C++ and ham radio are and should be most welcome in Bitx forums!


Re: kit-projects AGC with uBITX v5 - need help #v5

Vic WA4THR
 

I have a V4 and use and entirely different AGC system, so I can't help directly. There was at least one instance of that AGC board not working, which may have been due to a failed component, and an update to pull the AGC voltage from a different part of the circuit, not the Vol-H pin, that may be of use. See the following message:

https://groups.io/g/BITX20/message/69343?p=,,,20,0,0,0::Created,,kit+projects+v4+agc,20,2,0,31881810

=Vic=


Re: Content flagged as objectionable

 

We used 0A3/VR75 or 0B3 type of tubes not OA79 (typo)..


At 23/08/2020, you wrote:
Lado,
MOPA refers to a simple transmitter design that had a MASTER OSCILLATOR (MO) followed by a POWER AMPLIFIER (PA). Very often these were tubes like the 12BY7 as the oscillator followed by a beer bottle 807 as the power amplifier.Â
In india, a common design was to run the oscillator at 7 Mhz from an EF91, that was stabilized with an OA79. This was followed by a doubler/driver to 14 and a power amplifier on one or two 807s. This pushed out about 100 watts of CW.
- f

On Sun, Aug 23, 2020 at 11:32 AM <s53c.lado@...> wrote:


Re: Content flagged as objectionable

Terry VK5TM
 

Lado,

If you search using the term 'MOPA ham radio' you will get much better results to explain MOPA.

And I agree with everyone else in that there is a lot of crossover between micro processors, software and ham radio that mention of Jack's books makes sense in this forum to me.
--
https://www.vk5tm.com


Re: Content flagged as objectionable

Ashhar Farhan
 

Lado,
MOPA refers to a simple transmitter design that had a MASTER OSCILLATOR (MO) followed by a POWER AMPLIFIER (PA). Very often these were tubes like the 12BY7 as the oscillator followed by a beer bottle 807 as the power amplifier. 
In india, a common design was to run the oscillator at 7 Mhz from an EF91, that was stabilized with an OA79. This was followed by a doubler/driver to 14 and a power amplifier on one or two 807s. This pushed out about 100 watts of CW.
- f

On Sun, Aug 23, 2020 at 11:32 AM <s53c.lado@...> wrote:

I apologize to reply to your message with an off topic question. Since English (American) is not my native language, I sometimes don't understand some references. I can relate to your mention of both one tube radios and 807 finals (I built both at age of 13), but I'd be glad if you explain what you mean by "MOPA design". I googled about that a little bit, but failed to find a meaningful explanation.

If I return to the topic, I absolutely agree with you that ham radio nowadays requires al least basic understanding of micro controllers and programming. Although C and C++ are not the only programming languages, they seem to be most used ones in micro controller area. Thus any kind of reference to Jack Purdum books covering C, C++ and ham radio are and should be most welcome in Bitx forums!


Re: Content flagged as objectionable

otalado
 

I apologize to reply to your message with an off topic question. Since English (American) is not my native language, I sometimes don't understand some references. I can relate to your mention of both one tube radios and 807 finals (I built both at age of 13), but I'd be glad if you explain what you mean by "MOPA design". I googled about that a little bit, but failed to find a meaningful explanation.

If I return to the topic, I absolutely agree with you that ham radio nowadays requires al least basic understanding of micro controllers and programming. Although C and C++ are not the only programming languages, they seem to be most used ones in micro controller area. Thus any kind of reference to Jack Purdum books covering C, C++ and ham radio are and should be most welcome in Bitx forums!


Re: Relay for antenna tuner output?

Clark Martin
 

Use the some model of relay as in the antenna tuner. If it isn’t adequate, the tuner is in trouble.



Clark Martin
KK6ISP

On Aug 22, 2020, at 9:06 PM, Rob French (KC4UPR) <kc4upr@arrl.net> wrote:

I use one of those N1DDC-style automatic antenna tuners from Russia (eBay) with my uBITX. I've been thinking about building a dummy load into the antenna tuner case (or even external for that matter, with a BNC), and making it so that:

(a) I can select between the dummy load or the antenna via a pushbutton, and

(b) Anytime the tuner is turned off, it will automatically switch to the dummy load, as a modest safety measure.

Does anyone have a recommendation as to the type of SPDT relay that I should use for this? What parameters do I need to consider? Obviously voltage level (accounting for both max power output, and high SWR conditions), but is there anything else? Anything for maintaining impedance? (I'm guessing not really, at HF. But I don't know.)


Relay for antenna tuner output?

Rob French (KC4UPR)
 

I use one of those N1DDC-style automatic antenna tuners from Russia (eBay) with my uBITX.  I've been thinking about building a dummy load into the antenna tuner case (or even external for that matter, with a BNC), and making it so that:

(a) I can select between the dummy load or the antenna via a pushbutton, and

(b) Anytime the tuner is turned off, it will automatically switch to the dummy load, as a modest safety measure.

Does anyone have a recommendation as to the type of SPDT relay that I should use for this?  What parameters do I need to consider? Obviously voltage level (accounting for both max power output, and high SWR conditions), but is there anything else?  Anything for maintaining impedance?  (I'm guessing not really, at HF.  But I don't know.)

Thanks!
-Rob KC4UPR


Re: kit-projects AGC with uBITX v5 - need help #v5

Rob French (KC4UPR)
 

One more solicitation for help, hoping someone has some thoughts.  Big picture, I don't *seem* to get any AGC response either due to the audio input to the AGC (which does register an S-meter reading, though not with DC voltage levels that I would expect), or even with +3V applied directly to the Common pad.  Doesn't seem to be any attenuation.  Again, for the first part (control voltage from the audio), I have a buffer and audio preamp that I use for line-out, and even when that thing is clipping the audio, it doesn't seem to have any effect on the AGC (and the control voltage doesn't seem to get above 0.5 VDC).

I did check the +12V input and the regulator +5V output on the AGC board, those are both fine. 

Thanks,
-Rob KC4UPR


Re: Have an older Bitx40 to sell? #bitx40

Ted
 

Scott, Mike,

Emails sent.  Thanks.



Ted
K3RTA


uBitx V6 . 2 board connectors #ubitxv6 #ubitx-help

vu3gwn
 

AFAIK, 

P1 is power
P2 is Antenna
P3 is ???
P4 is Speaker
P5 is ???

Also,

1. if we use P2 should we remove the BNC soldered? 
2. Should we remove the On off/Volume connector if we use P1?

Any help is appreciated.

Thanks,
VU3GWN


Re: Content flagged as objectionable

Laurence Oberman
 

All Jack's Books are all invaluable. I would ignore the odd complaint
and keep the reviews and updates about Jack's books coming.
Jack gives us way more than he receives,
I have not seen anything from the complainer yet in terms of
contributions and help.
Jack, thanks for all you do

Regards
Laurence

On Sat, Aug 22, 2020 at 9:15 AM Nigel <zs6rn@rotherham.co.za> wrote:

Hi all :-)

Have not seen the 'objection' but will nevertheless add my 2c in that if Jacks latest book is only a fraction of the help to those seeking explanations regarding 'C' (I am unlikely to be needing as is 'not my core interest') that his Arduino book for Amateur Radio has been for me (purchased couple of years ago), then I would support the 'spreading the word' re upcoming availability for sure.

Stay safe and as always remember to KEEPSMILING!

73 Nigel ZS6RN ex G8DEV a l-o-n-g time ago



Re: Have an older Bitx40 to sell? #bitx40

Scot McMath
 

Ihave a Bitx 40 too that’s available. QRZ Wb7AVU

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Ted via groups.io
Sent: Saturday, August 22, 2020 2:48 AM
To: BITX20@groups.io
Subject: [BITX20] Have an older Bitx40 to sell? #bitx40

 

For a project, hoping to find an older model with 10-turn POT for tuning rather than a raduino (if i understand the lineage of the radio correctly).   Anyone?


Re: Have an older Bitx40 to sell? #bitx40

Mike Davis <maddmd818@...>
 

I have one that is 2 or 3 years old. It's in a rather large case and I also have a spare board with some parts removed, a spare microphone, extra mic elements and more odds and ends. It works fine, but I'll need to keep the battery that is inside the case. You can email me. My QRZ email is good. WA1MAD


Re: Content flagged as objectionable

Nigel ZS6RN
 

Hi all :-) 

Have not seen the 'objection' but will nevertheless add my 2c in that if Jacks latest book is only a fraction of the help to those seeking explanations regarding 'C' (I am unlikely to be needing as is 'not my core interest') that his Arduino book for Amateur Radio has been for me (purchased couple of years ago), then I would support the 'spreading the word' re upcoming availability for sure.

Stay safe and as always remember to KEEPSMILING! 

73 Nigel ZS6RN ex G8DEV a l-o-n-g time ago 

 


Have an older Bitx40 to sell? #bitx40

Ted
 

For a project, hoping to find an older model with 10-turn POT for tuning rather than a raduino (if i understand the lineage of the radio correctly).   Anyone?


Re: Horton hears a uBITX WSPR 18,127,200 times per year = another sticky relay (again...)

Richard Spohn
 

The 4states qrp group "Magicbox" TR switch (long-time unobtainium, unfortunately) was a totally electronic qrp TR switch utilizing mosfets for switching. It was and is the best non-mechanical TR switch ever, and amazed that it is no longer available -- Rich WB2GXM

Sent from my MetroPCS 4G LTE Android device

------ Original message------
From: Bob Lunsford via groups.io
Date: Fri, Aug 21, 2020 7:01 PM
Cc:
Subject:Re: [BITX20] Horton hears a uBITX WSPR 18,127,200 times per year = another sticky relay (again...)

Sequencing relay operation in a logical way does also make sense. When I worked at IBM, an engineer told me that they have to do that or risk a lockup from signals from different sources getting to a control gate at the same instant, causing "digital confusion." Therefore, they had to keep this in mind when designing circuits.

Funny thing is they called a "race problem" where signals raced to an entry point for the flow and it messed up the timing. Therefore,they placed resistors and capacitors at strategic places to avoid the problem.

Good thing about this forum is that when a question comes up from someone in the group, people start thinking about it and keep coming up with good ideas to try for a fix to the problem. Some thing that come up are not of direct or immediate interest to me but I read them anyway and learn thing I never heard of before.

Bob — KK5R

On Friday, August 21, 2020, 6:49:32 PM EDT, Arv Evans > wrote:


Bob

On further thought, it might be possible to use an RC 
network on each gate so that operation could be a 
staged sequence.

Arv
_._

On Fri, Aug 21, 2020 at 2:54 PM Bob Lunsford via groups.io yahoo.com@groups.io> wrote:
Now THAT is a good idea. No wiping needed. Would be similar to steering diodes, etc. Good thinking. Would take some tricky switching (with transistors) logic but it seems logical so, why not?

Bob — KK5R

On Friday, August 21, 2020, 3:36:59 PM EDT, Arv Evans <arvid.evans@...> wrote:


Bob

I wonder if anyone has looked into solid-state relays to see if P and N type MOSFETS might be used to make up an arc-resistant relay?

Arv
_._


On Fri, Aug 21, 2020 at 12:58 PM Bob Lunsford via groups.io yahoo.com@groups.io> wrote:
If the failure is due to excessive voltage, more voltage than the design favors, then the increased voltage can cause arcing regardless of how small and this can affect the relay's ability to carry current. Doing it thousands of times complicates it.

Where inductance is involved, it is even more apparent. To reduce this to a minimum is the goal of designers.

The fact that you key the transmitter before speaking and release the PTT after you finish speaking is of course normal and natural. Still, if there is less than perfect conduction in the contact, this can be complicated with the modulation, even if minuscule.

After a few hundred thousands of this occurring, then number of operations may well be a factor.

You are doing all you can do correctly what you must so it still must be the relay as it is the only moving part involved. I do not think it's the mechanical movement, if it's a contact/conduction matter, but of the current going through the contact which apparently is reaching its design 'operations before failure' maximum. Therefore, I suggest you prepare to replace the relay/s.

It is not you, it's a relay problem. Minimizing the problem only prolongs the inevitable.

Bob — KK5R

On Friday, August 21, 2020, 2:05:08 PM EDT, Bob Fischer, Fischer Technical Services <fischertek@...> wrote:



I believe "voice modulation" has little or no effect on the life of my T/R relays.
I don't think it matters if I use "peak" or "average" values of the modulated waveform to calculate current interrupted by the relay contacts.
I key the transmitter before I start speaking and release the PTT after I have finished speaking.
Just a guess on my part is the most common mode of failure for these relays is either "abrasive wear" or "mechanical fatigue."
Bob
WB8BEL


From: "Bob Lunsford via groups.io" yahoo.com@groups.io>
To: "BITX20@groups.io" <bitx20@groups.io>
Sent: Friday, August 21, 2020 1:38:22 PM
Subject: Re: [BITX20] Horton hears a uBITX WSPR 18,127,200 times per year = another sticky relay (again...)


Due to the wiping action of relay contacts when they make-break, "double tapping" the mic causes the ptt operation to better keep the contacts clean. In fact, doing it about ten times before talking into the mic would improve the wiping of the contacts. Some early designs of reed switches when asked to carry current were famous for "welding" the contacts because they were more designed for switching data signals which are relatively small current pulses.

Some circuits have caps across the contacts to buffer/absorb any arcing no matter how small. The capacitor in older auto distributors that are across the "points" were there to keep away any arcing which carbonized the points, per mechanics of that era, keeping them from being ineffective when switching the ignition coil's primary. The points did not depend on a wiping effect to keep them clean.

Smaller relays may not be depending on the wiping action as much as the relays used in the RF section of tube-type HF amplifiers. Larger relays had much less problems with relay contacts than smaller ones because there is more wiping action with them than with smaller relays.

Since we cannot access the relays on the uBITX radio, then we must resort to other ways to fix this where it may be a problem to those who use the radio more than others. We must depend on what little wiping action is available OR resort to using a relay socket where this relay may need replacing and unsoldering them repeatedly is undesirable. Therefore, we need to know which relay is the culprit and not put in a socket for relay/s where it is not necessary.

I also wonder if socket pins could be soldered into the board and using these instead of a much larger socket considering that the pins are few and distant from each other. A socket shell could also include a wire lock to keep the relay in place, however.

With voice modulation, there are definite peaks that don't show up with average measurements. This may be why the problem seems to show up with SSB more than with other modes.

These are some thoughts I have on this, no recommendations are being offered.

Bob —  KK5R

On Friday, August 21, 2020, 12:39:15 PM EDT, Don - KM4UDX <dontay155@...> wrote:


Bob -- yes. SSB voice exacerbates the sticky relay phenomenon (VESRP).  I get it on any band. I'm getting good at double PTTing at the end of every SSB TX, and keeping my fingers crossed that the RX mode is operating in all its glory after the double tap. Sort of like double clutching a truck transmission during a shift. Hahah. 

I learned to be very humble 'bout my diagnostic powers. No matter how much I wish it otherwise, 95% of observed faults are my own. 

With the mighty uBITX, working, building, experimenting, playing, upgrading and adjusting lead to ample amounts of near daily humiliation upon the continuing discovervy that "oh, I guess I caused that problem..."


Re: Horton hears a uBITX WSPR 18,127,200 times per year = another sticky relay (again...)

Bob Lunsford
 

Sequencing relay operation in a logical way does also make sense. When I worked at IBM, an engineer told me that they have to do that or risk a lockup from signals from different sources getting to a control gate at the same instant, causing "digital confusion." Therefore, they had to keep this in mind when designing circuits.

Funny thing is they called a "race problem" where signals raced to an entry point for the flow and it messed up the timing. Therefore,they placed resistors and capacitors at strategic places to avoid the problem.

Good thing about this forum is that when a question comes up from someone in the group, people start thinking about it and keep coming up with good ideas to try for a fix to the problem. Some thing that come up are not of direct or immediate interest to me but I read them anyway and learn thing I never heard of before.

Bob — KK5R

On Friday, August 21, 2020, 6:49:32 PM EDT, Arv Evans <arvid.evans@...> wrote:


Bob

On further thought, it might be possible to use an RC 
network on each gate so that operation could be a 
staged sequence.

Arv
_._

On Fri, Aug 21, 2020 at 2:54 PM Bob Lunsford via groups.io <nocrud222=yahoo.com@groups.io> wrote:
Now THAT is a good idea. No wiping needed. Would be similar to steering diodes, etc. Good thinking. Would take some tricky switching (with transistors) logic but it seems logical so, why not?

Bob — KK5R

On Friday, August 21, 2020, 3:36:59 PM EDT, Arv Evans <arvid.evans@...> wrote:


Bob

I wonder if anyone has looked into solid-state relays to see if P and N type MOSFETS might be used to make up an arc-resistant relay?

Arv
_._


On Fri, Aug 21, 2020 at 12:58 PM Bob Lunsford via groups.io <nocrud222=yahoo.com@groups.io> wrote:
If the failure is due to excessive voltage, more voltage than the design favors, then the increased voltage can cause arcing regardless of how small and this can affect the relay's ability to carry current. Doing it thousands of times complicates it.

Where inductance is involved, it is even more apparent. To reduce this to a minimum is the goal of designers.

The fact that you key the transmitter before speaking and release the PTT after you finish speaking is of course normal and natural. Still, if there is less than perfect conduction in the contact, this can be complicated with the modulation, even if minuscule.

After a few hundred thousands of this occurring, then number of operations may well be a factor.

You are doing all you can do correctly what you must so it still must be the relay as it is the only moving part involved. I do not think it's the mechanical movement, if it's a contact/conduction matter, but of the current going through the contact which apparently is reaching its design 'operations before failure' maximum. Therefore, I suggest you prepare to replace the relay/s.

It is not you, it's a relay problem. Minimizing the problem only prolongs the inevitable.

Bob — KK5R

On Friday, August 21, 2020, 2:05:08 PM EDT, Bob Fischer, Fischer Technical Services <fischertek@...> wrote:



I believe "voice modulation" has little or no effect on the life of my T/R relays.
I don't think it matters if I use "peak" or "average" values of the modulated waveform to calculate current interrupted by the relay contacts.
I key the transmitter before I start speaking and release the PTT after I have finished speaking.
Just a guess on my part is the most common mode of failure for these relays is either "abrasive wear" or "mechanical fatigue."
Bob
WB8BEL


From: "Bob Lunsford via groups.io" <nocrud222=yahoo.com@groups.io>
To: "BITX20@groups.io" <bitx20@groups.io>
Sent: Friday, August 21, 2020 1:38:22 PM
Subject: Re: [BITX20] Horton hears a uBITX WSPR 18,127,200 times per year = another sticky relay (again...)


Due to the wiping action of relay contacts when they make-break, "double tapping" the mic causes the ptt operation to better keep the contacts clean. In fact, doing it about ten times before talking into the mic would improve the wiping of the contacts. Some early designs of reed switches when asked to carry current were famous for "welding" the contacts because they were more designed for switching data signals which are relatively small current pulses.

Some circuits have caps across the contacts to buffer/absorb any arcing no matter how small. The capacitor in older auto distributors that are across the "points" were there to keep away any arcing which carbonized the points, per mechanics of that era, keeping them from being ineffective when switching the ignition coil's primary. The points did not depend on a wiping effect to keep them clean.

Smaller relays may not be depending on the wiping action as much as the relays used in the RF section of tube-type HF amplifiers. Larger relays had much less problems with relay contacts than smaller ones because there is more wiping action with them than with smaller relays.

Since we cannot access the relays on the uBITX radio, then we must resort to other ways to fix this where it may be a problem to those who use the radio more than others. We must depend on what little wiping action is available OR resort to using a relay socket where this relay may need replacing and unsoldering them repeatedly is undesirable. Therefore, we need to know which relay is the culprit and not put in a socket for relay/s where it is not necessary.

I also wonder if socket pins could be soldered into the board and using these instead of a much larger socket considering that the pins are few and distant from each other. A socket shell could also include a wire lock to keep the relay in place, however.

With voice modulation, there are definite peaks that don't show up with average measurements. This may be why the problem seems to show up with SSB more than with other modes.

These are some thoughts I have on this, no recommendations are being offered.

Bob —  KK5R

On Friday, August 21, 2020, 12:39:15 PM EDT, Don - KM4UDX <dontay155@...> wrote:


Bob -- yes. SSB voice exacerbates the sticky relay phenomenon (VESRP).  I get it on any band. I'm getting good at double PTTing at the end of every SSB TX, and keeping my fingers crossed that the RX mode is operating in all its glory after the double tap. Sort of like double clutching a truck transmission during a shift. Hahah. 

I learned to be very humble 'bout my diagnostic powers. No matter how much I wish it otherwise, 95% of observed faults are my own. 

With the mighty uBITX, working, building, experimenting, playing, upgrading and adjusting lead to ample amounts of near daily humiliation upon the continuing discovervy that "oh, I guess I caused that problem..."

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