|
Hi,
Re: the G6LBQ Bitx design. If you haven't found it (a link) already have a look here:
and here:
it seems some of the hams in YB land have taken an interest in the G6LBQ version of the Bitx.
Note: the gain distribution in the G6LBQ version is different to the standard Bitx design, it uses an MC1350 IF amp chip in the IF after the xtal filter, more gain (an extra 35 - 40dB) in the IF and an easy access to IF AGC using this chip. I guess the audio gain has been reduced to compensate for the extra gain in the IF.
I believe this version of the Bitx is no longer available but the circuit is still around on the net if you look for it.
Regards,
Pierre VK1XP
toggle quoted message
Show quoted text
On 28-10-2017 08:44, Smitty, KR6ZY wrote: Link?
On Oct 27, 2017, at 1:06 PM, alphaindia4oscartango via Groups.Io <alphaindia4oscartango@...> wrote:
What about the G6LBQ multiband bitx? That design looks pretty cool. The bandchanging looks really efficient.
73 de Chas ai4ot
Sent from my iPhone
|
Yes there are no boards available. Occasionally boards are mafe available if there a demand.
Last I heard, Andy was designing a new version.
73
Ken VA3ABN
On Oct 27, 2017 8:29 PM, < pierre@...> wrote: Hi,
Re: the G6LBQ Bitx design. If you haven't found it (a link) already have a look here:
and here:
it seems some of the hams in YB land have taken an interest in the G6LBQ version of the Bitx.
Note: the gain distribution in the G6LBQ version is different to the standard Bitx design, it uses an MC1350 IF amp chip in the IF after the xtal filter, more gain (an extra 35 - 40dB) in the IF and an easy access to IF AGC using this chip. I guess the audio gain has been reduced to compensate for the extra gain in the IF.
I believe this version of the Bitx is no longer available but the circuit is still around on the net if you look for it.
Regards,
Pierre VK1XP
On 28-10-2017 08:44, Smitty, KR6ZY wrote:
Link?
On Oct 27, 2017, at 1:06 PM, alphaindia4oscartango via Groups.Io <alphaindia4oscartango=yahoo.c[email protected]> wrote:
What about the G6LBQ multiband bitx?? That design looks pretty cool. The bandchanging looks really efficient.
73 de Chas ai4ot
Sent from my iPhone
|
and another link to a more original circuit:
Regards,
Pierre VK1XP
toggle quoted message
Show quoted text
On 28-10-2017 11:40, Ken wrote: Yes there are no boards available. Occasionally boards are mafe
available if there a demand.
Last I heard, Andy was designing a new version.
73
Ken VA3ABN
On Oct 27, 2017 8:29 PM, <pierre@...> wrote:
Hi,
Re: the G6LBQ Bitx design. If you haven't found it (a link) already
have a look here:
[1]
and here:
[2]
it seems some of the hams in YB land have taken an interest in the
G6LBQ version of the Bitx.
Note: the gain distribution in the G6LBQ version is different to the
standard Bitx design, it uses an MC1350 IF amp chip in the IF after
the xtal filter, more gain (an extra 35 - 40dB) in the IF and an
easy access to IF AGC using this chip. I guess the audio gain has
been reduced to compensate for the extra gain in the IF.
I believe this version of the Bitx is no longer available but the
circuit is still around on the net if you look for it.
Regards,
Pierre VK1XP
On 28-10-2017 08:44, Smitty, KR6ZY wrote:
Link?
On Oct 27, 2017, at 1:06 PM, alphaindia4oscartango via Groups.Io
<alphaindia4oscartango@...> wrote:
What about the G6LBQ multiband bitx? That design looks pretty cool.
The bandchanging looks really efficient.
73 de Chas ai4ot
Sent from my iPhone Links:
------
[1]
[2]
[3] /g/BITX20/message/33992
[4] /mt/6254077/236039
[5] /g/BITX20/post
[6] /g/BITX20/editsub/236039
[7] /g/BITX20
[8] /static/tos
[9] /g/BITX20/leave/defanged
|
There is also a groups.io group on the G6LBQ, although it's not very active.
Vince.
toggle quoted message
Show quoted text
On 10/27/2017 08:45 PM, pierre@... wrote: and another link to a more original circuit:
Regards,
Pierre VK1XP
On 28-10-2017 11:40, Ken wrote:
Yes there are no boards available. Occasionally boards are mafe
available if there a demand.
Last I heard, Andy was designing a new version.
73
Ken VA3ABN
On Oct 27, 2017 8:29 PM, <pierre@...> wrote:
Hi,
Re: the G6LBQ Bitx design. If you haven't found it (a link) already
have a look here:
[1]
and here:
[2]
it seems some of the hams in YB land have taken an interest in the
G6LBQ version of the Bitx.
Note: the gain distribution in the G6LBQ version is different to the
standard Bitx design, it uses an MC1350 IF amp chip in the IF after
the xtal filter, more gain (an extra 35 - 40dB) in the IF and an
easy access to IF AGC using this chip. I guess the audio gain has
been reduced to compensate for the extra gain in the IF.
I believe this version of the Bitx is no longer available but the
circuit is still around on the net if you look for it.
Regards,
Pierre VK1XP
On 28-10-2017 08:44, Smitty, KR6ZY wrote:
Link?
On Oct 27, 2017, at 1:06 PM, alphaindia4oscartango via Groups.Io
<alphaindia4oscartango@...> wrote:
What about the G6LBQ multiband bitx? That design looks pretty cool.
The bandchanging looks really efficient.
73 de Chas ai4ot
Sent from my iPhone
Links:
------
[1]
[2]
[3] /g/BITX20/message/33992
[4] /mt/6254077/236039
[5] /g/BITX20/post
[6] /g/BITX20/editsub/236039
[7] /g/BITX20
[8] /static/tos
[9] /g/BITX20/leave/defanged
--
Michigan VHF Corp.
|
The original files for the G6LBQ rig are in our files section.
Note that the original VFO used a Si570 chip, not a Si5351A.
john
AD5YE
|
What is it about the G6LBQ that makes it inherently more ¡°multiband¡± than the BitX-40 v3? Architecturally, it looks very similar, and has an opaque ¡°multi-band band pass filter¡± block on the diagram that really doesn¡¯t provide any insight.
My (naive?) thought to make my BitX multiband was to use QRP-Labs LPF and BPF modules, on two of the relay switching boards. Swap out the LPF and BPF, and signal to the Raduino somehow which band is selected to adjust the VFO accordingly.
Is there any more than that? My hope is to get 80, 40, and 20m out of it at least, maybe 15m or 10m if the circuit can handle a 33MHz or 40MHz VFO.
-Mark
toggle quoted message
Show quoted text
On Oct 27, 2017, at 5:29 PM, pierre@... wrote:
Hi,
Re: the G6LBQ Bitx design. If you haven't found it (a link) already have a look here:
and here:
it seems some of the hams in YB land have taken an interest in the G6LBQ version of the Bitx.
Note: the gain distribution in the G6LBQ version is different to the standard Bitx design, it uses an MC1350 IF amp chip in the IF after the xtal filter, more gain (an extra 35 - 40dB) in the IF and an easy access to IF AGC using this chip. I guess the audio gain has been reduced to compensate for the extra gain in the IF.
I believe this version of the Bitx is no longer available but the circuit is still around on the net if you look for it.
Regards,
Pierre VK1XP
On 28-10-2017 08:44, Smitty, KR6ZY wrote:
Link?
On Oct 27, 2017, at 1:06 PM, alphaindia4oscartango via Groups.Io <alphaindia4oscartango@...> wrote:
What about the G6LBQ multiband bitx? That design looks pretty cool. The bandchanging looks really efficient.
73 de Chas ai4ot
Sent from my iPhone
|
This is the bitx20 group for a reason, the original bitx was for 20m.
??
Note the date at the bottom of that page.
Several here have hacked their bitx40v3 for 80m or 20m.
qrpkits.com sells a 17m version.
Yup, just a matter of the LPF and BPF, plus some raduino programming.
Much easier now that we have parts like the dds chips, si570, and si5351.
Used to be a real chore to get a good stable vfo going for all those bands.
You could build one of those other kits, or buy all the parts for something like the G6LBQ.
But at $59, the bitx40v3 comes with parts gathered and soldered down to a board.
toggle quoted message
Show quoted text
On Fri, Oct 27, 2017 at 08:09 pm, Smitty, KR6ZY wrote:
Is there any more than that? My hope is to get 80, 40, and 20m out of it at least, maybe 15m or 10m
|
Smitty:
Yes; it can be done.
Check each and every band for birdies.
Check out the HRI DDS v.4 for a dual mcu DDS
that uses the second mcu to control bandswitching.
You will have to modify that for the Si5351 instead of the
AD9850 for the DDS. But you are not alone.
With the present BITX40 board configuration, it is unlikely
that the IRF510 will go very well above 17m or so.
Figure out a layout with a separate PA and relay controlled
LPFs. The BPF configuration is much simpler...probably
one or two circuits will do.
Check out the Minima and uBITX designs to see what problems
have already been run into...designing a multi-band superhet is
not exactly simple. There are a lot of variables.
But it can be done with a BITX40 board as the basis. Go for it.
Build and MEASURE; work with blocks that fit together for a whole.
The easiest thing to do is design everything with a 50 ohm in/out
impedance. Then everything matches.
john
AD5YE
|
Group,
I have my BitX-40 working on 160 ,80 ,40 ,20 with the. QRP LABS filters and relay board. I use a multi rotary switch to manually switch the bands. I do have a little weird problem on 160 and 20 where I get higher SWR when I used a tuner on these bands however if I use a resonate antenna it works fine. Output on 20 is about 2 Watts and I doubt that it would work beyond 17 meters. I would love to get it working at 15 meters but I believe the amps loose too much at the higher frequencies.
For what it's worth... I originally removed the band pass and low pass and installed header pins to swap out the filters by just plugging them in and out but I got tired of removing the lid.
73's
Mike WA3O
|
The IRF 510 works up to 10 m, but from 4 watts on 40 m goes down to 1 watt on 10 m, that is the cost of a simple solution, discovered while using a Genesis G-40, a kit made out of the YU1LM's AVALA. A flat, broadband amplifier would be better, but that is an more modified BitX.
Jose, CO2JA
toggle quoted message
Show quoted text
El 28-Oct-17 a las 06:28 AM, John Backo via Groups.Io escribi¨®: Smitty:
Yes; it can be done.
Check each and every band for birdies.
Check out the HRI DDS v.4 for a dual mcu DDS
that uses the second mcu to control bandswitching.
You will have to modify that for the Si5351 instead of the
AD9850 for the DDS. But you are not alone.
With the present BITX40 board configuration, it is unlikely
that the IRF510 will go very well above 17m or so.
Figure out a layout with a separate PA and relay controlled
LPFs. The BPF configuration is much simpler...probably
one or two circuits will do.
Check out the Minima and uBITX designs to see what problems
have already been run into...designing a multi-band superhet is
not exactly simple. There are a lot of variables.
But it can be done with a BITX40 board as the basis. Go for it.
Build and MEASURE; work with blocks that fit together for a whole.
The easiest thing to do is design everything with a 50 ohm in/out
impedance. Then everything matches.
john
AD5YE
|
to what do you attribute the reduction in output power? Is it gate capacitance acting like a low pass input filter to the IRF510, or is it drain capacitance, or something else? would be appreciative of better understanding....] gordon ________________________________________ From: [email protected] < [email protected]> on behalf of Jose Amador <jose.co2ja@...> Sent: Saturday, October 28, 2017 7:32 AM To: [email protected]Subject: Re: [BITX20] Multiband bitx G6LBQ links The IRF 510 works up to 10 m, but from 4 watts on 40 m goes down to 1 watt on 10 m, that is the cost of a simple solution, discovered while using a Genesis G-40, a kit made out of the YU1LM's AVALA. A flat, broadband amplifier would be better, but that is an more modified BitX. Jose, CO2JA El 28-Oct-17 a las 06:28 AM, John Backo via Groups.Io escribi¨®: Smitty:
Yes; it can be done.
Check each and every band for birdies.
Check out the HRI DDS v.4 for a dual mcu DDS
that uses the second mcu to control bandswitching.
You will have to modify that for the Si5351 instead of the
AD9850 for the DDS. But you are not alone.
With the present BITX40 board configuration, it is unlikely
that the IRF510 will go very well above 17m or so.
Figure out a layout with a separate PA and relay controlled
LPFs. The BPF configuration is much simpler...probably
one or two circuits will do.
Check out the Minima and uBITX designs to see what problems
have already been run into...designing a multi-band superhet is
not exactly simple. There are a lot of variables.
But it can be done with a BITX40 board as the basis. Go for it.
Build and MEASURE; work with blocks that fit together for a whole.
The easiest thing to do is design everything with a 50 ohm in/out
impedance. Then everything matches.
john
AD5YE
|
And then it pops up to 225w on 6m: ? /g/BITX20/message/22597There are lots of things that can limit an amp from performing well as frequencies go up. Don't be too quick to blame the device. Jerry, KE7ER
On Sat, Oct 28, 2017 at 04:32 am, Jose Amador wrote:
The IRF 510 works up to 10 m, but from 4 watts on 40 m goes down to 1 watt on 10 m
|
Is there a way of using the QRPlabs filter pcb and switching bands that way. I fancy building a tri bander 80, 40 & 20mtrs and having other bands as a listen on option, or just building one up as a multi band RX.
Any thoughts on this. Although I still have to get my Bitx40 master piece finished and on the air properly. First and only contact was 9A2L not bad for a 1st contact.
Phil - G7BZD?
On Sat, Oct 28, 2017 at 2:25 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote: And then it pops up to 225w on 6m: ?/g/BITX20/message/22597
There are lots of things that can limit an amp from performing well as frequencies go up.
Don't be too quick to blame the device.
Jerry, KE7ER
On Sat, Oct 28, 2017 at 04:32 am, Jose Amador wrote:
The IRF 510 works up to 10 m, but from 4 watts on 40 m goes down to 1 watt on 10 m
|
Yeah, that¡¯s exactly what I¡¯m intending to do. :-)
-Mark
toggle quoted message
Show quoted text
On Oct 28, 2017, at 6:53 AM, philip yates < phil@...> wrote: Is there a way of using the QRPlabs filter pcb and switching bands that way. I fancy building a tri bander 80, 40 & 20mtrs and having other bands as a listen on option, or just building one up as a multi band RX.
Any thoughts on this. Although I still have to get my Bitx40 master piece finished and on the air properly. First and only contact was 9A2L not bad for a 1st contact.
Phil - G7BZD?
|
All,
I got the unpoulated G6LBQ pcb from another ebayer. I have assembeld this board but found out, that it does not work correctly.
One big problem is the spurious oscillation of the MC1350 at full gain. This is due to the fact that the "source" impedance shown to the MC1350 is high, as the load at the output of the IC. According to an application note for the MC1590 (the samce chip but in a TO99 case and wider temperature range) there are restrictions concerning the allowable soruce and load impedances for stable operation of this chip.
In addition I suspect that the "load" of the xtal filter i.e. the high input impedance of the MC1350 will give a correct load of then filter and therefore result in a reasonable ripple of the filter.
Andy originally used a monoltihc filter which has a much higher termination impedance than the ladder filters used by Ashar Farhan.
I made some mods to my built but have not completed it...
Henning Weddig
DK5LV
Am 28.10.2017 um 02:29 schrieb pierre@...:
toggle quoted message
Show quoted text
Hi,
Re: the G6LBQ Bitx design. If you haven't found it (a link) already have a look here:
and here:
it seems some of the hams in YB land have taken an interest in the G6LBQ version of the Bitx.
Note: the gain distribution in the G6LBQ version is different to the standard Bitx design, it uses an MC1350 IF amp chip in the IF after the xtal filter, more gain (an extra 35 - 40dB) in the IF and an easy access to IF AGC using this chip. I guess the audio gain has been reduced to compensate for the extra gain in the IF.
I believe this version of the Bitx is no longer available but the circuit is still around on the net if you look for it.
Regards,
Pierre VK1XP
On 28-10-2017 08:44, Smitty, KR6ZY wrote:
Link?
On Oct 27, 2017, at 1:06 PM, alphaindia4oscartango via Groups.Io <alphaindia4oscartango@...> wrote:
What about the G6LBQ multiband bitx?? That design looks pretty cool. The bandchanging looks really efficient.
73 de Chas ai4ot
Sent from my iPhone
|
A simple substitute of the RD15HVF1 for the IRF510 (different pin-out!) makes the rf amp capable of at least 30 MHz. ?The IRF510 becomes very inefficient over about 20 MHz.?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ ? Owner - Operator Big Signal Ranch ¨C K9ZC Staunton, Illinois ? Owner ¨C Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it:
email:??bill@... ?
toggle quoted message
Show quoted text
On Oct 28, 2017, at 12:28 AM, John Backo via Groups.Io < iam74@...> wrote: Smitty:
Yes; it can be done.
Check each and every band for birdies.
Check out the HRI DDS v.4 for a dual mcu DDS
that uses the second mcu to control bandswitching.
You will have to modify that for the Si5351 instead of the
AD9850 for the DDS. But you are not alone.
With the present BITX40 board configuration, it is unlikely
that the IRF510 will go very well above 17m or so.
Figure out a layout with a separate PA and relay controlled
LPFs. The BPF configuration is much simpler...probably
one or two circuits will do.
Check out the Minima and uBITX designs to see what problems
have already been run into...designing a multi-band superhet is
not exactly simple. There are a lot of variables.
But it can be done with a BITX40 board as the basis. Go for it.
Build and MEASURE; work with blocks that fit together for a whole.
The easiest thing to do is design everything with a 50 ohm in/out
impedance. Then everything matches.
john
AD5YE
|
I believe that is plain normal gain loss as frequency rises, it is a
cheap switching mosfet, not an HF rated device. I just used two amps
after it to some 400 on 40, and 100 w on 10 m.
toggle quoted message
Show quoted text
On 10/28/17, Gordon Gibby <ggibby@...> wrote: to what do you attribute the reduction in output power?
Is it gate capacitance acting like a low pass input filter to the IRF510,
or is it drain capacitance, or something else?
would be appreciative of better understanding....]
gordon
________________________________________
From: [email protected] <[email protected]> on behalf of Jose Amador
<jose.co2ja@...>
Sent: Saturday, October 28, 2017 7:32 AM
To: [email protected]
Subject: Re: [BITX20] Multiband bitx G6LBQ links
The IRF 510 works up to 10 m, but from 4 watts on 40 m goes down to 1
watt on 10 m, that is the cost of a simple solution, discovered while
using a Genesis G-40, a kit made out of the YU1LM's AVALA. A flat,
broadband amplifier would be better, but that is an more modified BitX.
Jose, CO2JA
El 28-Oct-17 a las 06:28 AM, John Backo via Groups.Io escribi¨®:
Smitty:
Yes; it can be done.
Check each and every band for birdies.
Check out the HRI DDS v.4 for a dual mcu DDS
that uses the second mcu to control bandswitching.
You will have to modify that for the Si5351 instead of the
AD9850 for the DDS. But you are not alone.
With the present BITX40 board configuration, it is unlikely
that the IRF510 will go very well above 17m or so.
Figure out a layout with a separate PA and relay controlled
LPFs. The BPF configuration is much simpler...probably
one or two circuits will do.
Check out the Minima and uBITX designs to see what problems
have already been run into...designing a multi-band superhet is
not exactly simple. There are a lot of variables.
But it can be done with a BITX40 board as the basis. Go for it.
Build and MEASURE; work with blocks that fit together for a whole.
The easiest thing to do is design everything with a 50 ohm in/out
impedance. Then everything matches.
john
AD5YE
|
You guys dissing the IRF510 should take another look at the link in this post: ? /g/BITX20/message/34004Allison truly knows what she is talking about, in spite of the occasional auto-correction error. The primary disadvantages are poor heat transfer and a tab that is connected to the drain instead of the source. It's fine with a 24v supply, those 5w CB finals like the RD's are not. Jerry
|
Jerry:
I wouldn't be so quick to defend the IRFxxx series.
Remember, these were designed to be switching
transistors working at about 500 KHz.
Yes, they can be adapted to RF with great success, but,
as Allison, Motorola, and WA2EBY discovered, layout is
critical as well as heat dispersion.
Most of the higher output amps involve more than one
device with large compensation for the input capacitance,
and a heavy heat sink.
Incidentally, the IRF610 gives much the same performance
as the IRF510, but it is rated to 100v instead of 70v. It is
an easy fix for more power.
john
AD5YE
|
Something purpose built for use at RF is better in several ways, but the irf510 works and it's cheap. ?I'm happy to defend it. Especially for use on a $59 ssb transceiver. Many early attempts at using the switching fets fell short above 7mhz, but the wa2eby amp gives a recipe for something that works to 30mhz. Allison's 4x4 push pull using 8 irf510's for 225 watts on 50 mhz shows that if you know what you are doing you can push it even further. Yes, you need to account for the irf510's lousy heat transfer characteristics.? The bond wires to the die add inductance that limit the max usable frequency. The relatively high input capacitance (for an RF FET) means the driver stage has to be very low impedance and give a fair bit of power as he frequency goes up. The Vgs vs Id curves don't look terribly linear compared to a good RF FET. RF amplifiers can be puzzling beasts even with the best of devices. But there's many examples of good irf510 amps out there to copy from. Be sure to look hard at the physical design too (short leads, ground planes, heat sinks, input separated from output) if you expect similar results. ? The pcb layout of the bitx40v3 probably won't work well?on the higher bands. ? A push-pull amp has cleaner output and lower bias currents than the ?single irf510 of the bitx40, but a well adjusted bitx40 works surprisingly well. The irf610 is very interesting, spec shows about the same gate charge as the irf510. Curious that few if any amateur linears are are using it. Here's a few links that might be of interest:
https://ludens.cl/Electron/mosfetamps/amps.html
http://m0rzf.co.uk/20W_Amplifier/index.html
http://www.w6pql.com/1_kw_sspa_for_1_8-54_mhz.htm
http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart1.pdf
http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart2.pdf
http://www.arrl.org/files/file/QST%20Binaries/kossor.pdf
http://www.g0kla.com/scpa/SimpleCheapPA.php
Jerry, KE7ER
Jerry:
I wouldn't be so quick to defend the IRFxxx series.
Remember, these were designed to be switching
transistors working at about 500 KHz.
Yes, they can be adapted to RF with great success, but,
as Allison, Motorola, and WA2EBY discovered, layout is
critical as well as heat dispersion.
Most of the higher output amps involve more than one
device with large compensation for the input capacitance,
and a heavy heat sink.
Incidentally, the IRF610 gives much the same performance
as the IRF510, but it is rated to 100v instead of 70v. It is
an easy fix for more power.
john
AD5YE
|
Smitty, N6MTS
Jose Amador
K9HZ