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Hi everyone, I just completed some tests on a Bitx40 running in 20 meters band. I addes the 20 as secondary band activate when needed. I apply some mods to switch to secondary QRPLab BPF filter centered to 20 meters and removed the C91 and C92 caps to work in USB. I done some RX tests in the weekend of iaru hf contest to listen some stations Active.
Here the issues registered:
1) the 20 RX sensitivity was a bit weak compared to 40 meters. I need to increase volume. ( To receive the 20 meters the vfo run to 26 MHZ, mybe some stage suffers of poor performance in this High frequency?)
I also tryed to increase the vfo over maximum allowed by raduino, using external buffer, but no results.
Please read the issues as: work but could work better!
2) the RX was not very clean: voice acceptable, but RX of Digital mode not very stable ( probably the cause could be the vfo shift for poor tuning control. I need to add lock function in firmware ...) Or interferences for free wire of connection.
3) Sometimes when switch on or change vfo to other band or mode, the bf amplifier start a self oscillation ...Resulting in my wife's screaming (the tests were also performed during the night!)
No tests was performed at the moment in TX because i need to install the LPF for the new band.
The firmware to make the test was a modified version of 1.17.1, few temporary mods to preset the vfo b to 14 MHz USB and correct the freq. Display.
These my tests.
Giuseppe Callipo IK8YFW.
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Giuseppe:
I also have purchased QRPLabs ?20 M BPF and LPF in hopes of converting BITX40 to 20 M for JT65. ?Trying to decide if I want to make it dual band 40/20 or just dedicate it to 20 M service. Could you share the modified version of 1.17.1. ?sketch ? ? Thanks
Greg
KD4VV
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Giuseppe, I am delighted with point 3 of your test.HI .... 73 de YU1KM/QRP from Belgrade.
On Wed, Jul 12, 2017 at 1:21 PM, <greggaston@...> wrote: Giuseppe:
I also have purchased QRPLabs ?20 M BPF and LPF in hopes of converting BITX40 to 20 M for JT65.? Trying to decide if I want to make it dual band 40/20 or just dedicate it to 20 M service. Could you share the modified version of 1.17.1. ?sketch ? ? Thanks
Greg
KD4VV
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Yes, if the problem persist i need to add a muting function at mode or band change.?
The firmware must avoid not safe operations, as variables frequencies limit when select other band etc... At the moment the bitx40 firmware Is 40mt centric. ?We need to work hard on firmware.?
PS. Also to mitigate wife reaction HI ! ?
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Good morning Giuseppe
?
Thanks for sending me the ?your modified ?Raduino ?.INO file for 20 meters. ? I don't have the equipment to make elaborate tests but the operating results are good. ? ?I have been working 20 meters JT65 with good  success using your file and ?the BITX40 ?after replacing the BPF and LPF with QRPLabs 20m ?filters. ?On receive, it actually outperforms my ICOM 746PRO - just judging by operating both radios simultaneously ?and observing how many stations I copy on each. Usually log more on the BITX40
I added a VOX and 2 ?- 600/600 ohm audio transformers on the MIC and SPKR connections ?to make a better interface to the computer.
I limit the output to 2 W out of respect for the final PA - this is plenty for JT65.
So this little radio and a laptop make a great traveling pair.
?
Greg
KD4VV
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Hi dear Greg I'm glad to read your news !
If you need I make a new version of firmware with?
More effettive bande change.?
The firmware Is available here:?
It extend the latest version of firmware, and you do not need any external library.?
It is ready to compile and load.
A make a small function that work in Place of rit to allow change bands when push two times the function Button. In the next release a try to recovered the rit also, but i do not use in pratical operations.
Hope this is usefull for you.
Best 73 de IK8YFW.
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Hi,
I am in the process of adding 20 meter to the bitx40v3.
I built several filters (some qrplabs)
I can rx 20 quite well but when i transmit on 20 ?I show a high swr 5+ as soon as i go back to 40 all is well at 1.1.
I have tried several bandpass and lpf filters but no luck.
I was wondering if you had a picture of where you tapped into for the lpf and bandpass filters ?....Where did you cut?
Thanks
Any help would be appreciated
VE1BWV
Joe
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This might be a silly question, but are you using an antenna that is resonant on 20M?? Have you tested the output using a dummy load?
Just questions after reading your post.
Marco - KG5PRT?
On Sep 13, 2017 8:27 PM, "Joe" < joeman2116@...> wrote: Hi,
I am in the process of adding 20 meter to the bitx40v3.
I built several filters (some qrplabs)
I can rx 20 quite well but when i transmit on 20 ?I show a high swr 5+ as soon as i go back to 40 all is well at 1.1.
I have tried several bandpass and lpf filters but no luck.
I was wondering if you had a picture of where you tapped into for the lpf and bandpass filters ?....Where did you cut?
Thanks
Any help would be appreciated
VE1BWV
Joe
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Yes , same results into my dummy load But also tried with auto tuner.
Joe
On Sep 14, 2017 12:32 AM, "M Garza" < mgarza896@...> wrote: This might be a silly question, but are you using an antenna that is resonant on 20M?? Have you tested the output using a dummy load?
Just questions after reading your post.
Marco - KG5PRT?
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Did you use an antenna tuner!
Sent from my iPhone
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Not a real HFer, but some auto-tuners will automatically switch to another antenna for another band. Are you sure yours is not switching to an unconnected outlet?
73...
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Ok, Just to make sure we understand the setup: Bitx40 with 20M filter fitted to board, coax to auto tuner w/ power meter, coax to dummyload. Does that sound correct?? Forgive me if I am asking questions again, I have not read all of this thread. Is the 20M filter a separate filter, or are you modifying the existing 40M filter to be resonant in the 20M band? It kind of sounds like your filter is not presenting a 50 ohm load.? Check the values in the filter.? I fixed an amp that had a built in low pass filter.? The filter's first capacitor was bad and was causing the output to be attenuated and caused the amp to get very hot. If you have access to an antenna analyzer, take the 20M filter off, put some connectors on it and test it with a dummyload.? It should show good swr response in the 20M band.? If it doesnt, there is your issue.? If it does work, check your connections on the board and make sure you do not have any connections to the 40M filter (except ground). If you have a stand alone watt meter, test the output with a dummyload.? This is just to make sure the tuner is not causing the issue.
Hope these ideas help.
Marco - KG5PRT?
On Sep 14, 2017 7:52 PM, "Dexter N Muir" < dexy@...> wrote: Not a real HFer, but some auto-tuners will automatically switch to another antenna for another band. Are you sure yours is not switching to an unconnected outlet?
73...
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Thanks for the inputs.
Yes the cabling is as you indicated.
I have a inductor/ capacitor testor and varified each component.
My setup is a new 20 mtr lpf and new 20 band pass filter.
I have 2 of each for testing.
Qrplabs and 2 others based on similar design aleardy in the bitx.
I do have a antenna analyzer, i will try your suggestion.
Thanks
Joe
VE1BWV
Ok, Just to make sure we understand the setup: Bitx40 with 20M filter fitted to board, coax to auto tuner w/ power meter, coax to dummyload. Does that sound correct?? Forgive me if I am asking questions again, I have not read all of this thread. Is the 20M filter a separate filter, or are you modifying the existing 40M filter to be resonant in the 20M band? It kind of sounds like your filter is not presenting a 50 ohm load.? Check the values in the filter.? I fixed an amp that had a built in low pass filter.? The filter's first capacitor was bad and was causing the output to be attenuated and caused the amp to get very hot. If you have access to an antenna analyzer, take the 20M filter off, put some connectors on it and test it with a dummyload.? It should show good swr response in the 20M band.? If it doesnt, there is your issue.? If it does work, check your connections on the board and make sure you do not have any connections to the 40M filter (except ground). If you have a stand alone watt meter, test the output with a dummyload.? This is just to make sure the tuner is not causing the issue.
Hope these ideas help.
Marco - KG5PRT?
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I just started a builder's club (Greater Cincinnati Builders Group) and we have several members who are new hams and have never built a circuit or a kit. Most are terrified of making a mistake. What Joe touches on below is also a very common fear for new builders: Using the wrong part (axial inductor vs resistor) or value. Remember the guy who wrote the Lord's Prayer on a pinhead? Well, he's the same guy who writes the capacitor numbers on caps...another source of confusion for new builders. We've helped reduce the fear and confusion with this:
 You plug the part in before you use it and it tells you the value of: resistors, capacitors, inductors, diodes, transistors, etc. Cost: $20. (ebay: 142169115833) If you know someone who has the same issues, you might tell them about this device.
Jack, W8TEE
From: Joe <joeman2116@...>
To: [email protected]
Sent: Friday, September 15, 2017 8:37 AM
Subject: Re: [BITX20] [Bitx40] tests on 20 meters rx
Thanks for the inputs.
Yes the cabling is as you indicated.
I have a inductor/ capacitor testor and varified each component.
My setup is a new 20 mtr lpf and new 20 band pass filter.
I have 2 of each for testing.
Qrplabs and 2 others based on similar design aleardy in the bitx.
I do have a antenna analyzer, i will try your suggestion.
Thanks
Joe
VE1BWV
Ok, Just to make sure we understand the setup: Bitx40 with 20M filter fitted to board, coax to auto tuner w/ power meter, coax to dummyload. Does that sound correct?? Forgive me if I am asking questions again, I have not read all of this thread. Is the 20M filter a separate filter, or are you modifying the existing 40M filter to be resonant in the 20M band? It kind of sounds like your filter is not presenting a 50 ohm load.? Check the values in the filter.? I fixed an amp that had a built in low pass filter.? The filter's first capacitor was bad and was causing the output to be attenuated and caused the amp to get very hot. If you have access to an antenna analyzer, take the 20M filter off, put some connectors on it and test it with a dummyload.? It should show good swr response in the 20M band.? If it doesnt, there is your issue.? If it does work, check your connections on the board and make sure you do not have any connections to the 40M filter (except ground). If you have a stand alone watt meter, test the output with a dummyload.? This is just to make sure the tuner is not causing the issue.
Hope these ideas help.
Marco - KG5PRT?
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That's a great tool to have, even if you know what you are doing, but your eyes are getting a bit older, and you've postponed that trip to the eye doctor a few times :) Also, if you don't need that case around the component tester, you can get just?the guts for about a third of that price (it's about $30 with shipping):? - under $10, including shipping.
On Fri, Sep 15, 2017 at 8:58 AM, Jack Purdum via Groups.Io <econjack@...> wrote: I just started a builder's club (Greater Cincinnati Builders Group) and we have several members who are new hams and have never built a circuit or a kit. Most are terrified of making a mistake. What Joe touches on below is also a very common fear for new builders: Using the wrong part (axial inductor vs resistor) or value. Remember the guy who wrote the Lord's Prayer on a pinhead? Well, he's the same guy who writes the capacitor numbers on caps...another source of confusion for new builders. We've helped reduce the fear and confusion with this:
 You plug the part in before you use it and it tells you the value of: resistors, capacitors, inductors, diodes, transistors, etc. Cost: $20. (ebay: 142169115833) If you know someone who has the same issues, you might tell them about this device.
Jack, W8TEE
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?under $10, including shipping
Oops, I just noticed that the price is now $10.95
|
I sell the same thing without the case for $12.50 shipped to the conus.
Vince.
toggle quoted message
Show quoted text
I just started a builder's club (Greater Cincinnati Builders Group) and we
have several members who are new hams and have never built a circuit or a
kit. Most are terrified of making a mistake. What Joe touches on below is
also a very common fear for new builders: Using the wrong part (axial
inductor vs resistor) or value. Remember the guy who wrote the Lord's
Prayer on a pinhead? Well, he's the same guy who writes the capacitor
numbers on caps...another source of confusion for new builders. We've
helped reduce the fear and confusion with this:
You plug the part in before you use it and it tells you the value of:
resistors, capacitors, inductors, diodes, transistors, etc. Cost: $20.
(ebay: 142169115833) If you know someone who has the same issues, you
might tell them about this device.
Jack, W8TEE
From: Joe <joeman2116@...>
To: [email protected]
Sent: Friday, September 15, 2017 8:37 AM
Subject: Re: [BITX20] [Bitx40] tests on 20 meters rx
Thanks for the inputs.
Yes the cabling is as you indicated.
I have a inductor/ capacitor testor and varified each component.
My setup is a new 20 mtr lpf and new 20 band pass filter.
I have 2 of each for testing.
Qrplabs and 2 others based on similar design aleardy in the bitx.I do have
a antenna analyzer, i will try your suggestion. ThanksJoe
VE1BWV
On Fri, Sep 15, 2017, 1:18 AM M Garza <mgarza896@...> wrote:
Ok,Just to make sure we understand the setup:Bitx40 with 20M filter fitted
to board, coax to auto tuner w/ power meter, coax to dummyload.Does that
sound correct??? Forgive me if I am asking questions again, I have not
read all of this thread.Is the 20M filter a separate filter, or are you
modifying the existing 40M filter to be resonant in the 20M band?It kind
of sounds like your filter is not presenting a 50 ohm load.?? Check the
values in the filter.?? I fixed an amp that had a built in low pass
filter.?? The filter's first capacitor was bad and was causing the output
to be attenuated and caused the amp to get very hot.If you have access to
an antenna analyzer, take the 20M filter off, put some connectors on it
and test it with a dummyload.?? It should show good swr response in the
20M band.?? If it doesnt, there is your issue.?? If it does work, check
your connections on the board and make sure you do not have any
connections to the 40M filter (except ground).If you have a stand alone
watt meter, test the output with a dummyload.?? This is just to make sure
the tuner is not causing the issue.
Hope these ideas help.
Marco - KG5PRT??
On Sep 14, 2017 7:52 PM, "Dexter N Muir" <dexy@...> wrote:
Not a real HFer, but some auto-tuners will automatically switch to another
antenna for another band. Are you sure yours is not switching to an
unconnected outlet?
73...
| | Virus-free. www.avast.com |
--
Michigan VHF Corp.
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And here that same LCR tester at $8.86.
Place your bets.
I've been using a $10 UT10A DVM for the last 6 or 7 years, has an autoranging capacitance meter useful to maybe 10pf
if you are careful with the leads and subtract the self capacitance.
Happy enough with it, though had to take it apart after a few years to free up the selector wheel,
which wore out from use. ?Seldom run into a need to measure inductance.
Have a K5BCQ Vector Impedance Analyzer when things get serious, nicely characterizes caps and coils and resistors
and antennas over frequency with a complex impedance or SWR graph, showing points of self-resonance and such.
Under $100: ? ?http://www.qsl.net/k5bcq/Kits/Kits.html
Here's a nice stunt for measuring capacitance, should work on the Raduino with little more than a firmware change:
??
Probably ways to measure inductance as well if we were to scratch our heads some.
Maybe this winter if things slow down here I'll write up some alternate Raduino code to give
basic bitx40v3 functionality plus some debug tools using an extra $1 or so in parts. ?
So load Allard's stuff for normal use, this code when debugging:
? ? dvm
? ? capacitance meter
? ? rf and af probes
? ? characterize the crystal filter and bpf and lpf
? ? find 25mhz reference correction factor using wwv as per post 32365
? ? audio signal generator
? ? rf signal generator
? ? appropriate attenuators
?? ?complete debug instructions for the bitx40
If the uBitx gets off the ground, I'd like to see pads on the board for an optional AD8307/AD8310
after the crystal filter for use as an S-Meter, and allows us to use the uBitx as a low end spectrum analyzer.
Jerry
toggle quoted message
Show quoted text
On Fri, Sep 15, 2017 at 06:11 am, Karl Heinz Kremer wrote:
Oops, I just noticed that the price is now $10.95
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Hi,
I tested the 20 mtr filters with the ant analyser
The bandpass is peaking at around 13.55 with 1.4 swr and 55ohms
If i squeeze the toroids it moves the bandpass over to 14.05. So it looks like need some turns on the coils.
With the 20 mtr lpf it also needs more turns.
Next i will put the ant testor on the lpf and bandpass that are currently currently on the bitx40 v3.
Since i have them isolated it should provide a good look at what is actually working.
Thanks for the inputs
Progress is good.
Joe
VE1BWV
On Fri, Sep 15, 2017, 12:55 PM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: And here that same LCR tester at $8.86.
Place your bets.
I've been using a $10 UT10A DVM for the last 6 or 7 years, has an autoranging capacitance meter useful to maybe 10pf
if you are careful with the leads and subtract the self capacitance.
Happy enough with it, though had to take it apart after a few years to free up the selector wheel,
which wore out from use.? Seldom run into a need to measure inductance.
Have a K5BCQ Vector Impedance Analyzer when things get serious, nicely characterizes caps and coils and resistors
and antennas over frequency with a complex impedance or SWR graph, showing points of self-resonance and such.
Under $100: ? ?
Here's a nice stunt for measuring capacitance, should work on the Raduino with little more than a firmware change:
??
Probably ways to measure inductance as well if we were to scratch our heads some.
Maybe this winter if things slow down here I'll write up some alternate Raduino code to give
basic bitx40v3 functionality plus some debug tools using an extra $1 or so in parts. ?
So load Allard's stuff for normal use, this code when debugging:
? ? dvm
? ? capacitance meter
? ? rf and af probes
? ? characterize the crystal filter and bpf and lpf
? ? find 25mhz reference correction factor using wwv as per post 32365
? ? audio signal generator
? ? rf signal generator
? ? appropriate attenuators
?? ?complete debug instructions for the bitx40
If the uBitx gets off the ground, I'd like to see pads on the board for an optional AD8307/AD8310
after the crystal filter for use as an S-Meter, and allows us to use the uBitx as a low end spectrum analyzer.
Jerry
On Fri, Sep 15, 2017 at 06:11 am, Karl Heinz Kremer wrote:
Oops, I just noticed that the price is now $10.95
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