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Re: uBITX - A reboot of the old BITX

 

Hi Ash has,?
First and foremost a super well done for you work. And secondly I too would be interested in a kit of parts. So if you decide to make a kit sign me in for one.?
Regards and 73's?
Mans 9h1gb?

On 6 Mar 2017 23:45, "Richard Spohn" <wb2gxm@...> wrote:
Ashhar, I for one (among many, I suspect) would jump at the chance to
purchase a uBitx kit from you / HFSigs.com.? Please, please develop
the uBitx into a kit!? Thanks again for the Bitx xcvrs! - Rich

On 3/3/17, Ashhar Farhan <farhanbox@...> wrote:
> It has been more than a decade since the BITX20 was first built. In these
> years, we have had many ideas knocking around. After looking hard at these,
> it became evident to me that a full reboot of the bitx series was needed to
> incorporate these.
>
> Raduino has been a game changer in many ways. It would have been
> unimaginable even a few years ago that for a dollar, you would be able to
> buy a single chip with three clock outputs for less than a dollar.
>
> Anyway, here is the new uBITX (I pronounce it as microBITX). I hope you all
> find it interesting. Unlike the Minima this is full tested and ready to be
> built.
>
> You can read about it on . It
> hasn't still made it to my home page. If you find any typos or anything
> that is not clear, push the reply button on this mail thread and I will fix
> it before it goes out to the world outside the
>
> There is no kit for it. As usual, the circuit is free for you to build,
> write about, forward and publish it wherever. However, commercial
> production of PCBs and kits is prohibited for now.
>
> Will HFsigs kit it? I am not sure. They are already swamped with a backlog
> of the bitx40 orders. I will have a conversation with the team and ask them
> about it.
>
> It goes without saying that without the help of so many of you this rig
> would never been possible. It is a joint effort of several people who have
> been helping along with things big and small.? Curiously, this rig derived
> much of its theory from an older text : Introduction to RF Design by
> Hayward. Hence, you will see it in the pictures of the rig too.
>
> - f
>
Re: uBITX - A reboot of the old BITX

 

I'm perhaps a little slow, but I'm trying to relate the ubitx with the HF-1. Can someone compare these two projects? I have something in the works right now, but I'm looking already for my next project, and until the ubitx came up, I was taking a serious look at the HF-1

But I'd hate to build the HF-1 if the ubitx is a superior design!

Can someone help an old fogie wrap his mind around these two projects?
A Band Scope for the BITX

 

Get a 13 dollar RTL-SDR Dongle and find a discarded Android phone.? Soon you can be watching the entire 40 meter band. Check out the article by Ken Marshall G4IIB:

The Bitx QSO Roundup

 

Y'know...with all these Bitx's out there...we could have our own
weekend QSO contest! I can hear it now! "See-Kew See-Kew Bit-Ex
See-Kew Bit-Ex..." -- contesters could exchange RST report, grid
square and their Bitx serial number to qualify! Of course after the
official exchange, the contest would probably go off the rails as
contesters continue to expound on all the mods they've completed in
their Bitx's...and after the weekend ends, find out after describing
all the add-ons to their radios that they've only completed five
qualifying exchanges. And then of course there's the contest subgroup
that would exchange Bitx QSOs via CW... Oh, BOY this would be a
glorious weekend, indeed!!!! -- Rich
Re: volume/tuning knob size. The outside diameter size, too

 

I am creating a Bitx40 design metal enclosure box. ?Would be nice in this thread if you share the outside diameter of the knobs you chose. Also the outside diameter of the tuning control and volume control from measurement or from a datasheet. ?I use this knowledge to verify clearance from other objects on the front panel and backside of front panel. ? Thank you for your small bit of help. ?A few comments will help. ?What color knobs do you prefer? ?You might snap a small qvga size photo 320x240 and attach here if there is space or use some photo bucket website. Fred. ? Http://kliktel.org/bitx40/omg. Photo of my metal case.
Re: Let the fun begin

 

Just got my BITX40, just checked the serial number and it reads
"O317". - Rich WB2GXM

On 3/8/17, Thomas Noel <tnoel@...> wrote:
Just a running total of how wildly successful this device has become.

Thomas W Noel
KF7RSF

On Mar 8, 2017, at 9:57 AM, Daniel Acevedo <dan.ace86@...> wrote:

Just curious, what does the serial number tell you?
Re: Let the fun begin

 

The number is like this :
AB-xyz
The xyz is the serial number within the batch B. A is not a number, it is the initial of the tester. 'F' is for farhan, 'U' is Uma, etc.?
- f
-?

On 9 Mar 2017 10:01 a.m., "AndyH" <ahecker@...> wrote:

Hi Randy,

Here's a bit more data for your list

73, Andy

KG5RKP ?869 ?11/19/2016 ?11/22/2016 ?12/19/2016
Re: Let the fun begin

 

Hi Randy,

Here's a bit more data for your list

73, Andy

KG5RKP ?869 ?11/19/2016 ?11/22/2016 ?12/19/2016
Re: Wiki Fu

 

Kind of like Kung Fu. ?Except this is used to do battle with Wiki's, not Kung's.


On Wed, Mar 8, 2017 at 04:50 pm, College Professor Simon Thompson wrote:

What’s Wiki Fu?
. . .

?
Re: Wiki Fu

[email protected]
 

An ancient Polynesian boat building technique as in Kon Wiki....

J/K, it's is a play on Google Fu which is a measure of a person's ability to find things on Google.

James
Re: Finding an AGC circuit with fast/slow attack

 

Found this on?eBay item number:?271695585529

  • GEC-PLESSEY-SL611C-RF-IF-Amplifier-Wide-AGC-Range-50dB
  • GEC-PLESSEY-SL611C-RF-IF-Amplifier-Wide-AGC-Range-50dB
10 available from Isreal-free shipping
Hope this helps
73 WA9DOH

GEC PLESSEY SL611C, RF/IF Amplifier, Wide AGC Range: 50dB


On Wed, Mar 8, 2017 at 3:25 PM, Henning Weddig via Groups.Io <hweddig@...> wrote:

Folks,

I made simulations on a "discrete version" of the SL611 (component values from the Plessey 1975 data book) using LTSPICE and then upon success with teh simulaiton I also made a pcb layout. There is also a discrete version of the SL621 as a layout (I am using EASY PC). For unknown reasons I can not upload the pdf files into my folder (DK5LVs stuff)

Can somebody advise how to upload?

Henning

DK5LV



Am 08.03.2017 um 21:33 schrieb William Kimber:


Somewhen in the past there was a version of the SL621 AGC circuit made with individual transistors.? Try searching the RSGB handbook or tech topics.

Cheers,

William


On 03/09/2017 08:38 AM, Doug - via Groups.Io wrote:

Chuck,

? I am very interested in an AGC circuit for the BITX40. I have already installed a new audio output amp - LM386 - that works substantially better but on strong signals and a good antenna there is distortion from some point onboard. Having to ride the volume is a pain in the you know what. I was looking at my radio-engineer handbook and one of the AGC circuits they show uses the Plessy Sl621 AGC chip. I doubt it is still available but if it was it would make things very simple. Google it, the PDF data is still out there. This uses audio to establish AGC that could be applied in some way to probably Q1 on the BITX board.






Re: Finding an AGC circuit with fast/slow attack

 

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or you could do worse than check out the IF AGC (and S Meter) approach used by Eamon Skelton EI9GQ in his various rig designs. A google seatrch will find them. I intend to use one of his designs, which are all generally similar and also echo the "epitome" IF AGC design that Ashar champions.


Bill, VK7MX


On 9/03/2017 7:33 AM, William Kimber wrote:


Somewhen in the past there was a version of the SL621 AGC circuit made with individual transistors.? Try searching the RSGB handbook or tech topics.

Cheers,

William


On 03/09/2017 08:38 AM, Doug - via Groups.Io wrote:

Chuck,

? I am very interested in an AGC circuit for the BITX40. I have already installed a new audio output amp - LM386 - that works substantially better but on strong signals and a good antenna there is distortion from some point onboard. Having to ride the volume is a pain in the you know what. I was looking at my radio-engineer handbook and one of the AGC circuits they show uses the Plessy Sl621 AGC chip. I doubt it is still available but if it was it would make things very simple. Google it, the PDF data is still out there. This uses audio to establish AGC that could be applied in some way to probably Q1 on the BITX board.





Re: Wiki Fu

College Professor Simon Thompson
 

开云体育

What’s Wiki Fu?

On Mar 8, 2017, at 12:33 PM, jmlynesjr@... wrote:

Added a Wiki Cheat Sheet to help anyone that may want to contribute to the Wiki. Bottom topic on the first page.

James
Re: Let the fun begin

 

Hi

Not really sure. These are the numbers that I have collected.

Randy, K7AGE

BITX40 Deliveries – Randy, K7AGE 3/8/17





SN Ordered Shipped Arrived Num of Days
VE3MIC 412 10/24/16
11/17/16 24
K7AGE 02-139 12/23/16 12/29/16 1/9/17 17
4X4LF 02-213 12/12/16
1/23/17 42
K4RJJ 234



KE0OG 02-607 1/11/17
2/7/17 27
DM1VA 02-734 1/13/17
2/6/17 24
KF4FGI 02-782

2/3/17
AndyH 02-869



W7DKO 02-925 About two weeks
02/22/22
KI6SSI 2-929 02/03/17
02/21/17 18
Richard 02-945

2/13/17
AG7CT 02-953 1/22/17


K3RLL 02-970 1/26/17
2/9/17 14
Bill Uebele F3-1718 2/8/17
3/4/17 24
KM4WII 43-228 2/12/17
3/7/17 23

On Wed, Mar 8, 2017 at 10:40 AM, Thomas Noel <tnoel@...> wrote:
Just a running total of how wildly successful this device has become.

Thomas W Noel
KF7RSF

On Mar 8, 2017, at 9:57 AM, Daniel Acevedo <dan.ace86@...> wrote:

Just curious, what does the serial number tell you?

Re: Finding an AGC circuit with fast/slow attack

 

The audio amp with AGC as seen in the uBitx could be a good addition to the Bitx40. ?That amp will have less distortion than the LM386. ?

If you want to know what's involved for really good AGC, follow the link in this post: ?/g/BITX20/message/22670??
Re: Finding an AGC circuit with fast/slow attack

William Kimber
 

开云体育


hi all,


The SL621 works from the audio but controls the RF/IF. It has fast attack, to reduce the signal, a longish hang time to cope with inter-word/sentence gaps and then rapid decay to rapidly bring gain back up to full.

Personally I would prefer to control IF and/or RF rather than detected audio.? Controlling AF creates risk of overload in IF/detector.?

Cheers,

Will?


On 03/09/2017 11:21 AM, John Baggott wrote:

Hi,

On most discreet AGC circuits tis a Diode that feeds a resistor capacitor pair, it is the time constant (t = R * C ) that determines how fast or slow the AGC will work, it would be easy to replace the fixed resistor with a pot and experiment , if you can not get it slow enough increase teh capacitor value.

Cheers

On Wed, Mar 8, 2017 at 5:02 PM Marc Jones via Groups.Io <gw0wvl=[email protected]> wrote:
Why not use a NE570 compressor as a AGC ..??

Regards?

Marc 'Gw0wvl'..


On Wed, 8 Mar 2017 at 21:34, Doug - via Groups.Io
<dsc3507=[email protected]> wrote:

I found the following most interesting articles in a Google search -

I did not see anything about the discrete equiv. for the SL621.

I have not had a chance to go through them yet. I also need to look at my many ARRL handbooks. There are discrete AGC circuits defined. The circuit is not as much the problem as how to apply the AGC to the BITX. For ease of use I would use audio AGC so two connections to the existing board would be all that is needed.? Not looking for perfect just a lot better than it is now.

I also don't want to reinvent the wheel. If this has already been done or anyone has any ideas please pass it on.

I emailed a ham who apparently used the Plessy SL621 in a recent homebrew receiver design. I suspect he had it in his junkbox but if this is still an available chip somewhere it would make things a lot easier.


--
Cheers

John Baggott
My BitX40 build

 

Here is a link to my recent Bitx40 build -


http://crompton.com/hamradio/bitx40/
Re: Finding an AGC circuit with fast/slow attack

 

Hi,

On most discreet AGC circuits tis a Diode that feeds a resistor capacitor pair, it is the time constant (t = R * C ) that determines how fast or slow the AGC will work, it would be easy to replace the fixed resistor with a pot and experiment , if you can not get it slow enough increase teh capacitor value.

Cheers

On Wed, Mar 8, 2017 at 5:02 PM Marc Jones via Groups.Io <gw0wvl=[email protected]> wrote:
Why not use a NE570 compressor as a AGC ..??

Regards?

Marc 'Gw0wvl'..


On Wed, 8 Mar 2017 at 21:34, Doug - via Groups.Io
<dsc3507=[email protected]> wrote:

I found the following most interesting articles in a Google search -

I did not see anything about the discrete equiv. for the SL621.

I have not had a chance to go through them yet. I also need to look at my many ARRL handbooks. There are discrete AGC circuits defined. The circuit is not as much the problem as how to apply the AGC to the BITX. For ease of use I would use audio AGC so two connections to the existing board would be all that is needed.? Not looking for perfect just a lot better than it is now.

I also don't want to reinvent the wheel. If this has already been done or anyone has any ideas please pass it on.

I emailed a ham who apparently used the Plessy SL621 in a recent homebrew receiver design. I suspect he had it in his junkbox but if this is still an available chip somewhere it would make things a lot easier.


--
Cheers

John Baggott
Re: Finding an AGC circuit with fast/slow attack

 

Why not use a NE570 compressor as a AGC ..??

Regards?

Marc 'Gw0wvl'..


On Wed, 8 Mar 2017 at 21:34, Doug - via Groups.Io
<dsc3507@...> wrote:

I found the following most interesting articles in a Google search -

I did not see anything about the discrete equiv. for the SL621.

I have not had a chance to go through them yet. I also need to look at my many ARRL handbooks. There are discrete AGC circuits defined. The circuit is not as much the problem as how to apply the AGC to the BITX. For ease of use I would use audio AGC so two connections to the existing board would be all that is needed.? Not looking for perfect just a lot better than it is now.

I also don't want to reinvent the wheel. If this has already been done or anyone has any ideas please pass it on.

I emailed a ham who apparently used the Plessy SL621 in a recent homebrew receiver design. I suspect he had it in his junkbox but if this is still an available chip somewhere it would make things a lot easier.
Re: Surprised

 

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Probably W1AW code practice. Mine did the same!

73, Bob KI0G?

On Mar 8, 2017, at 3:51 PM, Daniel Acevedo <dan.ace86@...> wrote:

Nice. I just heard today that these little boars are antennas themselves! How was the audio with an antenna?

On Mar 8, 2017 1:47 PM, "Steve Black via Groups.Io" <kb1chu=[email protected]> wrote:

I took my new Bitx40 out of my shack to show my wife right after it was finished. As soon as I hooked it up to a 12 volt battery it came to life and I heard real slow morse. So slow I could follow it. The funny part is that no antenna was connected. As soon as it appeared it was gone. I got a tiny bit of the conversation but no calls. Steve KB1CHU?
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