Date   
Re: QST September 2019 pg42 to 47

Jack Purdum
 

See below:
Jack, W8TEE

On Thursday, August 22, 2019, 1:48:25 PM EDT, Dr. Flywheel <Dr.Flywheel@...> wrote:


Everyone is entitled to their own opinion. The real question is what works in real life. Here are a few points to think about for people who insist on living in a virtual world:
  1. Many people use torrents to download books, in order to preview their content. Are you really saying that people only use torrent sites to preview books? Far and away most are using the site to get a free book and have no intention of paying for it regardless of its worth. To think otherwise is woefully naive. This is due to the fact that public libraries are limited in their ability to purchase and keep all the books in the world in their limited physical space. Do not assume that if someone downloads your book, they actually keep it forever. What difference can it possibly make whether they keep a free download book or not?
  2. I like previewing books prior to purchase. I also like physical books and my house is filled with them. I always purchase my books at bottom dollar, either "pre-owned" or "old stock". I use eBay, Amazon, B&N, etc for my purchase. As an author, you will not see a dime coming back to you through my purchase. However,  if you buy a used copy, at least someone bought the book and the author was paid for that copy. If you rip off a copy or someone gives you a file that contains the book, my guess is that copy has never been paid for.;
  3. Publishing for FREE has never stopped me from doing just that. If you are using the Internet, if you are using an Intel-based PC, if you are using Linux, if you are using an Android smart phone, if you are using WiFi technology, than you are using code, tools, and documents that I authored and/or contributed to maintain. I have never seen a dime coming back to me for my contributions, neither do I expect remuneration or royalties for my work. All of my work, including that in the Arduino Projects book is Open Source for both the hardware and software. So, in one sense I am paid for it, but in another I receive nothing for it. You're free to write what you want and disseminate it in whatever format you wish. However, publishers expect a return on their investment and I see nothing wrong with that.
  4. Many publishers act as a Mafia to squeeze a significant $$ by guarding the gates to publishing and physical distribution. When I went to college, my books cost between $3 and $10 each (Dover Edition). What is the justification for charging between $100 and $300 for a book used for educating university students and then changing the book edition every year to prevent resale of books (recycling)? There are many places where students can buy used books at reasonable prices. Perhaps one reason books are so expensive at university books stores is because publishers are getting ripped off by torrent sites. It could be a chicken-egg thing.
  5. Limiting information flow to the public will never work in today's world. the capabilities are there to distribute and share information by electronic means. This levels the playing field for all participants. The capabilities are orders of magnitude stronger than any laws on the books, as well as the ability to enforce such laws. Authors are better off being benevolent (open source) or offer their products at an enticing and fair price, or ask for voluntary pay from the consumer. There are already many people who take such attitude and being successful at dealing with reality. Do you get to determine "fair price"? Or perhaps the costs of development, editing, printing, binding, marketing, distribution and other costs play a more important part in determining a fair price. How do you know what my time is worth? Hint: You don't have a clue.
  6. Student debt in the U.S.A is already $1.48 TRILLION. great part of that is attributed to the cost of books Bullshit.. Someone is getting rich in this system and typically it is not the authors. Agreed, and torrent sites play a significant role.
 The world is constantly changing and sticking to old guns does not pay off. I suggest to stop whining and get on with your regularly scheduled programming...

--Ron   N7FTZ

On Thu, Aug 22, 2019 at 9:57 AM Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
This is an issue that hits home for me. One of my publishing companies has 3 people who's only job is to shut down torrent sites that allow free downloads of their books. Two years ago, they closed down over 2,000 sites that were downloading copyright material. They estimate that for every book I sell, three are downloaded illegally. We've even had universities point their students to these sites. It's impossible to stop them because the capital costs are little more than the cost of getting a domain name.

True, I'm out the royalties lost, but that's not the real cost of downloading/copying copyright material...regardless of the country's laws about it. The real cost are the books that don't come to the market because authors now know it's simply not worth the effort. If I were in it just for the money, I would have stopped writing around the turn of the century. We've even had readers on this site give the URL's of where my books can be downloaded free of charge. Since there is no way to stop them, my attitude now is: If you illegally download the book and read it, and decide it was worth it, then buy a copy of the book. I doubt there are many who follow this plan, but what else can an author do? It's a rock-hard-place situation.

Jack, W8TEE

On Thursday, August 22, 2019, 11:38:17 AM EDT, Arv Evans <arvid.evans@...> wrote:


The issue of posting something that might be under copyright does come up fairly frequently.
When this happens a lot of bandwidth is usually taken by those who charge in to protect the
copyright or patent, and not much ever comes of it.  Most do not know, or do not want to
admit, that for over half of the world copyrights and patents are irrelevant and are not enforced.
This makes it difficult or impossible to police violations in those countries.   Posting protected
material on a global forum like the BITX20 group seems to be a gray area because the person
posting the material may be in one of the unenforceable areas but the post can be read by
persons located in an enforceable area.  Best we can do is to ask that you do not post protected
material, and to remove those posts when it happens. 

Arv  K7HKL
_._


On Wed, Aug 21, 2019 at 11:00 PM kh6sky <kh6sky@...> wrote:
I have asked for permission from the ARRL to post an article from the early 60's and they refused to grant.  I am not optimistic about anything recent.  I have noted that QST authors sometimes post their articles on their own websites, for which I suppose they have permission, but don't know if it would be a work-around to go though the author and ask him to post it here.

Re: WSPR and APRS mobile

John (vk2eta)
 

Hello Ted,

Have you looked at JS8CALL?

It works on minimal HW like a PI, reports positions to APRS, allows precise locations with a variable length maiden locator format, uses the FT8 modulation for very low snr exchanges and it's messages simply spans as many 15 seconds transmit sequences as required.

73, John

Re: QST September 2019 pg42 to 47

Dr. Flywheel
 

Everyone is entitled to their own opinion. The real question is what works in real life. Here are a few points to think about for people who insist on living in a virtual world:
  1. Many people use torrents to download books, in order to preview their content. This is due to the fact that public libraries are limited in their ability to purchase and keep all the books in the world in their limited physical space. Do not assume that if someone downloads your book, they actually keep it forever.
  2. I like previewing books prior to purchase. I also like physical books and my house is filled with them. I always purchase my books at bottom dollar, either "pre-owned" or "old stock". I use eBay, Amazon, B&N, etc for my purchase. As an author, you will not see a dime coming back to you through my purchase.
  3. Publishing for FREE has never stopped me from doing just that. If you are using the Internet, if you are using an Intel-based PC, if you are using Linux, if you are using an Android smart phone, if you are using WiFi technology, than you are using code, tools, and documents that I authored and/or contributed to maintain. I have never seen a dime coming back to me for my contributions, neither do I expect remuneration or royalties for my work.
  4. Many publishers act as a Mafia to squeeze a significant $$ by guarding the gates to publishing and physical distribution. When I went to college, my books cost between $3 and $10 each (Dover Edition). What is the justification for charging between $100 and $300 for a book used for educating university students and then changing the book edition every year to prevent resale of books (recycling)?
  5. Limiting information flow to the public will never work in today's world. the capabilities are there to distribute and share information by electronic means. This levels the playing field for all participants. The capabilities are orders of magnitude stronger than any laws on the books, as well as the ability to enforce such laws. Authors are better off being benevolent (open source) or offer their products at an enticing and fair price, or ask for voluntary pay from the consumer. There are already many people who take such attitude and being successful at dealing with reality.
  6. Student debt in the U.S.A is already $1.48 TRILLION. great part of that is attributed to the cost of books. Someone is getting rich in this system and typically it is not the authors.
 The world is constantly changing and sticking to old guns does not pay off. I suggest to stop whining and get on with your regularly scheduled programming...

--Ron   N7FTZ


On Thu, Aug 22, 2019 at 9:57 AM Jack Purdum via Groups.Io <jjpurdum=yahoo.com@groups.io> wrote:
This is an issue that hits home for me. One of my publishing companies has 3 people who's only job is to shut down torrent sites that allow free downloads of their books. Two years ago, they closed down over 2,000 sites that were downloading copyright material. They estimate that for every book I sell, three are downloaded illegally. We've even had universities point their students to these sites. It's impossible to stop them because the capital costs are little more than the cost of getting a domain name.

True, I'm out the royalties lost, but that's not the real cost of downloading/copying copyright material...regardless of the country's laws about it. The real cost are the books that don't come to the market because authors now know it's simply not worth the effort. If I were in it just for the money, I would have stopped writing around the turn of the century. We've even had readers on this site give the URL's of where my books can be downloaded free of charge. Since there is no way to stop them, my attitude now is: If you illegally download the book and read it, and decide it was worth it, then buy a copy of the book. I doubt there are many who follow this plan, but what else can an author do? It's a rock-hard-place situation.

Jack, W8TEE

On Thursday, August 22, 2019, 11:38:17 AM EDT, Arv Evans <arvid.evans@...> wrote:


The issue of posting something that might be under copyright does come up fairly frequently.
When this happens a lot of bandwidth is usually taken by those who charge in to protect the
copyright or patent, and not much ever comes of it.  Most do not know, or do not want to
admit, that for over half of the world copyrights and patents are irrelevant and are not enforced.
This makes it difficult or impossible to police violations in those countries.   Posting protected
material on a global forum like the BITX20 group seems to be a gray area because the person
posting the material may be in one of the unenforceable areas but the post can be read by
persons located in an enforceable area.  Best we can do is to ask that you do not post protected
material, and to remove those posts when it happens. 

Arv  K7HKL
_._


On Wed, Aug 21, 2019 at 11:00 PM kh6sky <kh6sky@...> wrote:
I have asked for permission from the ARRL to post an article from the early 60's and they refused to grant.  I am not optimistic about anything recent.  I have noted that QST authors sometimes post their articles on their own websites, for which I suppose they have permission, but don't know if it would be a work-around to go though the author and ask him to post it here.

Re: QST September 2019 pg42 to 47

pat griffin
 

Jack,
You have made this argument before and each time it is well put. I’m with you buddy.
73
Pat AA4PG


On Aug 22, 2019, at 11:57 AM, Jack Purdum via Groups.Io <jjpurdum@...> wrote:

This is an issue that hits home for me. One of my publishing companies has 3 people who's only job is to shut down torrent sites that allow free downloads of their books. Two years ago, they closed down over 2,000 sites that were downloading copyright material. They estimate that for every book I sell, three are downloaded illegally. We've even had universities point their students to these sites. It's impossible to stop them because the capital costs are little more than the cost of getting a domain name.

True, I'm out the royalties lost, but that's not the real cost of downloading/copying copyright material...regardless of the country's laws about it. The real cost are the books that don't come to the market because authors now know it's simply not worth the effort. If I were in it just for the money, I would have stopped writing around the turn of the century. We've even had readers on this site give the URL's of where my books can be downloaded free of charge. Since there is no way to stop them, my attitude now is: If you illegally download the book and read it, and decide it was worth it, then buy a copy of the book. I doubt there are many who follow this plan, but what else can an author do? It's a rock-hard-place situation.

Jack, W8TEE

On Thursday, August 22, 2019, 11:38:17 AM EDT, Arv Evans <arvid.evans@...> wrote:


The issue of posting something that might be under copyright does come up fairly frequently.
When this happens a lot of bandwidth is usually taken by those who charge in to protect the
copyright or patent, and not much ever comes of it.  Most do not know, or do not want to
admit, that for over half of the world copyrights and patents are irrelevant and are not enforced.
This makes it difficult or impossible to police violations in those countries.   Posting protected
material on a global forum like the BITX20 group seems to be a gray area because the person
posting the material may be in one of the unenforceable areas but the post can be read by
persons located in an enforceable area.  Best we can do is to ask that you do not post protected
material, and to remove those posts when it happens. 

Arv  K7HKL
_._


On Wed, Aug 21, 2019 at 11:00 PM kh6sky <kh6sky@...> wrote:
I have asked for permission from the ARRL to post an article from the early 60's and they refused to grant.  I am not optimistic about anything recent.  I have noted that QST authors sometimes post their articles on their own websites, for which I suppose they have permission, but don't know if it would be a work-around to go though the author and ask him to post it here.

Re: Isolate any jacks/controls from metal chassis? #ubitx

Ian Reeve
 

We can buy this in the UK as a deterrent to slugs and snails guzzling our seedlings.I bought mine from a "*pound*" store in the gardening section


From: BITX20@groups.io <BITX20@groups.io> on behalf of jim via Groups.Io <ab7vf@...>
Sent: Thursday, August 22, 2019 6:08:28 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Isolate any jacks/controls from metal chassis? #ubitx
 
Got mine from a "stained glass shop" 30 or so years ago ...are any of those things still around?

Jim

On Thursday, August 22, 2019, 4:54:45 PM UTC, jhowell39 via Groups.Io <jhowell39@...> wrote:


Electric guitar body cavities (pickup mounts, etc) often use a conductive copper tape for shielding.  If anyone is having a shielding issue with 3D printed cases or wood cases, this might be a good solution.  Available here.
--
73! de KJ7EZN   Jim

Re: Isolate any jacks/controls from metal chassis? #ubitx

jim
 

Got mine from a "stained glass shop" 30 or so years ago ...are any of those things still around?

Jim

On Thursday, August 22, 2019, 4:54:45 PM UTC, jhowell39 via Groups.Io <jhowell39@...> wrote:


Electric guitar body cavities (pickup mounts, etc) often use a conductive copper tape for shielding.  If anyone is having a shielding issue with 3D printed cases or wood cases, this might be a good solution.  Available here.
--
73! de KJ7EZN   Jim

Re: QST September 2019 pg42 to 47

Jack Purdum
 

This is an issue that hits home for me. One of my publishing companies has 3 people who's only job is to shut down torrent sites that allow free downloads of their books. Two years ago, they closed down over 2,000 sites that were downloading copyright material. They estimate that for every book I sell, three are downloaded illegally. We've even had universities point their students to these sites. It's impossible to stop them because the capital costs are little more than the cost of getting a domain name.

True, I'm out the royalties lost, but that's not the real cost of downloading/copying copyright material...regardless of the country's laws about it. The real cost are the books that don't come to the market because authors now know it's simply not worth the effort. If I were in it just for the money, I would have stopped writing around the turn of the century. We've even had readers on this site give the URL's of where my books can be downloaded free of charge. Since there is no way to stop them, my attitude now is: If you illegally download the book and read it, and decide it was worth it, then buy a copy of the book. I doubt there are many who follow this plan, but what else can an author do? It's a rock-hard-place situation.

Jack, W8TEE

On Thursday, August 22, 2019, 11:38:17 AM EDT, Arv Evans <arvid.evans@...> wrote:


The issue of posting something that might be under copyright does come up fairly frequently.
When this happens a lot of bandwidth is usually taken by those who charge in to protect the
copyright or patent, and not much ever comes of it.  Most do not know, or do not want to
admit, that for over half of the world copyrights and patents are irrelevant and are not enforced.
This makes it difficult or impossible to police violations in those countries.   Posting protected
material on a global forum like the BITX20 group seems to be a gray area because the person
posting the material may be in one of the unenforceable areas but the post can be read by
persons located in an enforceable area.  Best we can do is to ask that you do not post protected
material, and to remove those posts when it happens. 

Arv  K7HKL
_._


On Wed, Aug 21, 2019 at 11:00 PM kh6sky <kh6sky@...> wrote:
I have asked for permission from the ARRL to post an article from the early 60's and they refused to grant.  I am not optimistic about anything recent.  I have noted that QST authors sometimes post their articles on their own websites, for which I suppose they have permission, but don't know if it would be a work-around to go though the author and ask him to post it here.

Re: Isolate any jacks/controls from metal chassis? #ubitx

jhowell39@...
 

Electric guitar body cavities (pickup mounts, etc) often use a conductive copper tape for shielding.  If anyone is having a shielding issue with 3D printed cases or wood cases, this might be a good solution.  Available here.
--
73! de KJ7EZN   Jim

Re: QST September 2019 pg42 to 47

Dave New
 

Thanks, Hans.

I think the difference here is that QRP Labs are advertisers in QST, where I don't think that HFSignals has ever placed an ad there.

I notice from time to time that when a particular manufacturer's rig is reviewed that sometimes an ad is placed directly within the review or at least on a facing page at the start or end.  Seems like QST gives an opportunity to the manufacturer of favored placement of an ad, if they so desire (and are willing to pay, I'm sure).

Asher, did you get an opportunity to place an ad in that one QST, and ended up turning it down?

I could see where manufacturers that typically don't advertise in QST might like to take advantage of a one-time ad placement, not only for marketing purposes, but also to qualify for the ability to place the review on their web site, as a qualifying advertiser.

73,

-- Dave, N8SBE

-------- Original Message --------
Subject: Re: [BITX20] QST September 2019 pg42 to 47
From: "Hans Summers" <hans.summers@...>
Date: Thu, August 22, 2019 9:16 am
To: "BITX20@groups.io" <BITX20@groups.io>

FYI - 

I emailed ARRL for permission to reproduce the reviews of the QCX 5W CW transceiver kit and the QLG1 GPS Receiver kit and Dummy Load kits from the August and September 2019 QST editions. I received permission around 8 hours later. I have added these reviews to the relevant pages of the QRP Labs site e.g. http://qrp-labs.com/qcx

Farhan, you could ask about the BITX review too. 

73 Hans G0UPL

Re: Audio pre-amplifier for microphone?

Ian Reeve
 

Hi Arv,

 

Thankyou for your advice. As it stands using the stock electret element wired as shown in the instructions produces a very poor ssb output. The equivalent output on cw is around 10 watts depending on the band, so I know the mic amp and modulator are being well under-driven.

I will experiment and use the information you have kindly supplied to achieve a workable solution. Ideally I would like a solution where normal speech levels produce a ssb power of over 80% of available rf output as compared to cw on the same rig,same band.

 

My Kenwood TS590SG effortlessly achieves that,so that will be my aim!

 

Best 73

 

Ian M0IDR

 

Sent from Mail for Windows 10

 


From: BITX20@groups.io <BITX20@groups.io> on behalf of Arv Evans <arvid.evans@...>
Sent: Thursday, August 22, 2019 4:47:35 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
Ian

The microphone operating voltage can be isolated from the transistor input with a suitable
value capacitor (observe polarity if using an electrolytic cap).  The output of your transistor
amp can be isolated from the input to a following stage by also using an isolating capacitor.
That said, it might not be a good idea to add additional amplification to the microphone input
because that could over-drive the existing microphone amplifier and following modulator
circuit.  It really depends on your microphone, speech level, and room acoustics. 

Arv  K7HKL
_._


On Thu, Aug 22, 2019 at 2:15 AM Ian Reeve <ian.radioworkshop@...> wrote:
The uBITX as it stands sends a positive voltage to the unit that sends the mic signal,how do you arrange a one transistor amplifier to work without a separate supply.I have tried and failed.Any help or a schematic would be great. Thx. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Wednesday, August 21, 2019 10:26:40 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
A simple one transistor preamp makes a huge improvement, but don’t overdrive the amplifier!


On Aug 21, 2019, at 16:52, Neil Tolman via Groups.Io <k1nbt@...> wrote:

Has anyone used a mono pre-amp for the mic on the v5 uBITX?
Any thoughts or references would be helpful.
Thank you and 73,
Neil K1NBT

Re: Audio pre-amplifier for microphone?

Arv Evans
 

Ian

The microphone operating voltage can be isolated from the transistor input with a suitable
value capacitor (observe polarity if using an electrolytic cap).  The output of your transistor
amp can be isolated from the input to a following stage by also using an isolating capacitor.
That said, it might not be a good idea to add additional amplification to the microphone input
because that could over-drive the existing microphone amplifier and following modulator
circuit.  It really depends on your microphone, speech level, and room acoustics. 

Arv  K7HKL
_._


On Thu, Aug 22, 2019 at 2:15 AM Ian Reeve <ian.radioworkshop@...> wrote:
The uBITX as it stands sends a positive voltage to the unit that sends the mic signal,how do you arrange a one transistor amplifier to work without a separate supply.I have tried and failed.Any help or a schematic would be great. Thx. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Wednesday, August 21, 2019 10:26:40 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
A simple one transistor preamp makes a huge improvement, but don’t overdrive the amplifier!


On Aug 21, 2019, at 16:52, Neil Tolman via Groups.Io <k1nbt@...> wrote:

Has anyone used a mono pre-amp for the mic on the v5 uBITX?
Any thoughts or references would be helpful.
Thank you and 73,
Neil K1NBT

Re: raduino crystal question

Jerry Gaffke
 

To calibrate the si5351, just repeatedly adjust the value of the calibration variable si5351bx_vcoa,
until the uBitx is operating at the correct frequency (or you measure one of the three output clocks to be correct).
You must call si5351bx_setfreq() to update the output so the new si5351bx_vcoa value can take effect.

The above method says how to calibrate iteratively, without any math.
Alternately you can calculate the correct value for si5351bx_vcoa.
That variable is nominally 875000000, which is the frequency of the internal oscillator, 875.0 mhz.
All output frequencies (and the operating frequency of the uBitx) are strict ratios of that internal oscillator.

Example: 
Assume you are just starting out, and si5351_vcoa is at the nominal value of 875000000
You tell clk2 to be at 30mhz with     si5351bx_setfreq(2, 30000000);
But your frequency counter says clk2 is at   30.001000mhz
That means that the internal oscillator is actually    875mhz * 30.001/30.000 = 875.029167mhz
Adjust the si5351bx_vcoa value to be 875029167, and the next call to si5351bx_setfreq() should be dead accurate.

In my own Raduino code I adjust si5351bx_vcoa directly, and save it to EEPROM when happy with the calibration.
Farhan added a level of indirection to this, his routine si5351_setcalibration() adds an offset to the nominal 875000000 value,
and stores that offset to EEPROM.

There have been lots and lots of posts in this forum about trouble getting the si5351 calibrated.
Which suggests to me that all available firmware out there is doing this wrong.
See posts 35235, 54501 44278, 44515

Regarding the crystal loading capacitance:
The crystals are manufactured to have a parallel resonant frequency that is on target
when there is a specific capacitance (perhaps 20pf) across that crystal due to 
traces and other parts connected to the crystal (parts such as the si5351).
The Raduino apparently has significantly less to 20pf,
so the outputs of the si5351 are consistently too high in frequency by a few hundred ppm.
See posts  35275, 61287.

Jerry, KE7ER
 


On Wed, Aug 21, 2019 at 10:45 PM, <ashok.das81@...> wrote:
Thanks KE7ER, thats enough for me to start building.  May I ask for some insight into calibration process ?

Re: Audio pre-amplifier for microphone?

Ian Reeve
 

Gordon,

 

Thx so much for the advice. I would rather use the existing”phantom” supply as I have fitted a miniature 3 pin mic socket. I will try both methods, I already have a switched dec supply on tx from the relay.

I have now three solutions and would thank you all for helping me out on this low audio problem on SSB.

 

I will use my oscilloscope to monitor the output direct from the mic and compare it to the level at the input to the uBITX to get a gain comparison between the different suggestions

 

Having fun with uBITX!

 

73

 

Ian M0IDR

 

Sent from Mail for Windows 10

 


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Thursday, August 22, 2019 3:02:22 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
This is actually easier than it looks. Awful lot of microphones work exactly this way.    

 Life is easier for you if you simply bring out a dc positive voltage from the Radio as a separate work, but if you don’t want to do that, you can use a diode to rectify the microphone line, then run it into a big capacitor and bingo you have DC.   Used at DC to provide power for the electric through a resistor, about 2000 ohms.  Use a capacitor, about 10 µF, to take the output from the electric, to the base of a transistor.   The two N3904 would work fine.  Connect the emitter to ground.  Use simple biasing with a 470,000 ohm resistor from the base to the collector of the transistor.   Connect the collector directly to that DC biased microphone wire from the radio.   

Done.   

I’m in a car, so I can’t draw it for you.




On Aug 22, 2019, at 04:15, Ian Reeve <ian.radioworkshop@...> wrote:

The uBITX as it stands sends a positive voltage to the unit that sends the mic signal,how do you arrange a one transistor amplifier to work without a separate supply.I have tried and failed.Any help or a schematic would be great. Thx. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Wednesday, August 21, 2019 10:26:40 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
A simple one transistor preamp makes a huge improvement, but don’t overdrive the amplifier!


On Aug 21, 2019, at 16:52, Neil Tolman via Groups.Io <k1nbt@...> wrote:

Has anyone used a mono pre-amp for the mic on the v5 uBITX?
Any thoughts or references would be helpful.
Thank you and 73,
Neil K1NBT

Re: Audio pre-amplifier for microphone?

Gordon Gibby
 

If the gain is too high for your taste, simply stick a 1000 to 10,000 a resistor in the emitter wire of the transistor

Instant negative feedback

On Aug 22, 2019, at 08:50, Ian Reeve <ian.radioworkshop@...> wrote:

Thx Nikos, I will take a look at the specifications of this, I tried one similar a while ago and found the gain far too much.Anything is worth a try,the modulation level on Ssb is far too low only producing around ,2 watts output on speech peaks.  Cheers. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of SV9CVJ Nikos <sv9cvj@...>
Sent: Thursday, August 22, 2019 12:28:08 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 

Re: Audio pre-amplifier for microphone?

Gordon Gibby
 

This is actually easier than it looks. Awful lot of microphones work exactly this way.    

 Life is easier for you if you simply bring out a dc positive voltage from the Radio as a separate work, but if you don’t want to do that, you can use a diode to rectify the microphone line, then run it into a big capacitor and bingo you have DC.   Used at DC to provide power for the electric through a resistor, about 2000 ohms.  Use a capacitor, about 10 µF, to take the output from the electric, to the base of a transistor.   The two N3904 would work fine.  Connect the emitter to ground.  Use simple biasing with a 470,000 ohm resistor from the base to the collector of the transistor.   Connect the collector directly to that DC biased microphone wire from the radio.   

Done.   

I’m in a car, so I can’t draw it for you.




On Aug 22, 2019, at 04:15, Ian Reeve <ian.radioworkshop@...> wrote:

The uBITX as it stands sends a positive voltage to the unit that sends the mic signal,how do you arrange a one transistor amplifier to work without a separate supply.I have tried and failed.Any help or a schematic would be great. Thx. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of Gordon Gibby <ggibby@...>
Sent: Wednesday, August 21, 2019 10:26:40 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
A simple one transistor preamp makes a huge improvement, but don’t overdrive the amplifier!


On Aug 21, 2019, at 16:52, Neil Tolman via Groups.Io <k1nbt@...> wrote:

Has anyone used a mono pre-amp for the mic on the v5 uBITX?
Any thoughts or references would be helpful.
Thank you and 73,
Neil K1NBT

Re: WSPR and APRS mobile

Ted
 

QRP Labs has some nice and very innovative stuff though I'm not shopping for new hardware, necessarily.  This  was arguably a question better suited for an APRS or WSPR forum, maybe even an EMCOMM group though I figured someone else in the uBitx world might have dabbled with low-power positioning and traffic data already & who might have chosen a format or software package based upon this radio specifically.  

I'm soon to be taken out of circulation due to surgery and figured I'll have time to do some bench trials with a netbook, radio, and simulated "mobile" (read: tuned whip) aerial.  I guess when the time comes, l'll plod along and see where it goes.

Re: Audio pre-amplifier for microphone?

Ian Reeve
 

Thx Nikos, I will take a look at the specifications of this, I tried one similar a while ago and found the gain far too much.Anything is worth a try,the modulation level on Ssb is far too low only producing around ,2 watts output on speech peaks.  Cheers. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of SV9CVJ Nikos <sv9cvj@...>
Sent: Thursday, August 22, 2019 12:28:08 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 

Re: Audio pre-amplifier for microphone?

SV9CVJ Nikos
 

Re: Audio pre-amplifier for microphone?

Ian Reeve
 

Hi Tom,

 

Thankyou very much for pointing me towards this neat little circuit.

 

I have a dynamic mic insert so I will give it a go later today

 

Thx and 73

 

Ian M0IDR

 

Sent from Mail for Windows 10

 


From: BITX20@groups.io <BITX20@groups.io> on behalf of Tom, wb6b <wb6b@...>
Sent: Thursday, August 22, 2019 10:54:28 AM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Audio pre-amplifier for microphone?
 
On Thu, Aug 22, 2019 at 01:15 AM, Ian Reeve wrote:
how do you arrange a one transistor amplifier to work
Here is a possibility that was posted some time ago.
http://ubitx.net/2018/12/05/dynamic-mic-preamp-runs-off-phantom-power-from-ubitx/

Tom, wb6b

Re: WSPR and APRS mobile

Curt
 

Ted

Check qrp-labs website. Some folk are launching expendable balloon payloads that go around the world. They offer a wonderful transmitter that does wspr called U3S. Even with 200 mW mine has reached VK, ZL and Antarctica.

Your ubitx should be a great wspr receiver. And psk31 etc. SSB voice will do better in the fall.

Curt