Re: Harmonics and Relay Replacement
Gilles, the only naive questions are the ones not asked .....or something like that ;o)
Arv, we (AQRP Wed lunch guys) were speculating that the Constant K filter design used on the uBITX was suspect in that it has terrible out of band matching and the resultant reflections due to poor VSWR might be the cause of the problem .....and that the AXICOM relays "happen to correct" some of that problem. One of the guys checked the Smith Chart results using the original uBITX relays against the AXICOM relays I had purchased for a given uBITX filter design. To his (and my) surprise they are nearly identical. Now, this is using a separate single LPF test fixture board with relays.
We're trying to find an industry standard test fixture for testing relay RF isolation.
73 Kees K5BCQ
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Ripley, stay mindful of the audio signal path through the K3 relay that also switches antenna for RX, TX.
This is a common reported / resolved audio problem.
Implemented in conjunction with the 'pop' fix, the audio is no longer routed to /switched using this relay.
Rgds,
Gary
AG5TX
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Re: Harmonics and Relay Replacement
Hello Kees, Arv
I am attentive to your discussions on relays. I am not a professional technician so I will definitely ask a silly question. But too bad I start.
Could the relays be replaced by other components (PIN diode, transistor, etc.)? Can current relays be replaced by AXICOM MT2 relays?
Again, my apologies for disturbing your conversations with naive questions.
73 QRO Gilles - F1BFU /FR
Kees
Some possible areas to look into: - Are there resonances in the relay activation path when (activated, or inactive)?
Thinking about permeability change in relay coils when current is flowing?
- What is the self-resonant frequency of the relay coils when activated and when
inactive?
- Is there any RF on the relay coils during transmit mode (RF Detector or O-scope)?
Seems there should be none...?
- How much RF, and at what frequency, is there on the toroids, other than the ones
that have been activated for a particular band?
- What happens to the harmonics and spurs when all but the active filter is removed
from the PCB?
- L-31 is very close to an RF PA heat sink.? Is it picking up unwanted RF?? Is it picking
up "unbalanced RF" because it is coupling to only one side of the RF PA output?
- Is imbalance between RF PA MOSFETs causing harmonic or spurious output?
- If input to the RF PA is clean, is it still clean if the RF PA output is terminated in a
purely resistive dummy load (without any LPFs connected)?
- If an LPF is connected by short jumpers instead of via the relay, is output clean
or unclean?? Is it clean if the relay activation lead is at ground instead of active?
- There are some who are building their own modular and non-modular versions
of the uBITX.? I wonder how they are doing with respect to harmonics and spurs?
Looking back over some of the suggested improvements it seems that there may have
been some eureka moments that might have been published before they were well
thought out.? Some of Allison's posts might indicate that we have been focusing on and
treating the symptoms instead of the source problem.?
It is probably unfair that I comment when I do not have the test equipment, skills, or
available time to perform in-depth tests.? But given the situation, talk is about all I
can do. ? ?? 8-(??
Arv _._
You may have seen all the discussion on using AXICOM relays. Until that is flattened and I understand the "why" I am refunding your money for the K5BCQ LPF board kits which were ordered as I continue to investigate further. Attached is a picture of the AXICOM?V23105-A5403-A201 relays just received from Mouser. You can see that there are some physical differences between them and the previous AXICOM relay pictures posted (coil spacing to contacts, and ?).? A good friend of mine, Glen, has donated an unmodified uBITX board for my future testing. Thank you Glen.  ?
73 Kees K5BCQ
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Re: Harmonics and Relay Replacement / Spurs.. ect.., an offer/request to other VKs
Nick, no replies posted so here goes... I don't have a "GOOD SA" but I have a good receiver and I would be keen to work on this with you. In particular if you get some boards made I would be happy to buy and test even if not proven.
Thanks for your Raduino boards.
73 Brian VK4BAP.
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Re: Front Panel for Nov, 2018 QST Dummy Load
It looks good, but I'm hoping that Al will find the print file in the next day or two. Let's wait until then to see if it shows up.
Jack, W8TEE
On Wednesday, October 17, 2018, 4:26:03 PM EDT, Doug W <dougwilner@...> wrote:
I think I am pretty close.? I do not have the OLED or enclosure to test so I would not be comfortable posting the file to the group not knowing if this even works.? Do you have access to a printer?? I could send you the file to test then if it works you can have the file to post anywhere and any way you want.? If it doesn't work, you can tell me where I am off and we can try again.? If you do not have access to a printer I could print one and send it to you.? If I knock down the height of the battery ledge it would fit in a regular envelope.? If you prefer to wait and see if Al finds his file you won't hurt my feelings either.? I'm still teaching myself to design things and this was good practice.
--
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Re: Harmonics and Relay Replacement
Kees
Some possible areas to look into: - Are there resonances in the relay activation path when (activated, or inactive)?
Thinking about permeability change in relay coils when current is flowing?
- What is the self-resonant frequency of the relay coils when activated and when
inactive?
- Is there any RF on the relay coils during transmit mode (RF Detector or O-scope)?
Seems there should be none...?
- How much RF, and at what frequency, is there on the toroids, other than the ones
that have been activated for a particular band?
- What happens to the harmonics and spurs when all but the active filter is removed
from the PCB?
- L-31 is very close to an RF PA heat sink.? Is it picking up unwanted RF?? Is it picking
up "unbalanced RF" because it is coupling to only one side of the RF PA output?
- Is imbalance between RF PA MOSFETs causing harmonic or spurious output?
- If input to the RF PA is clean, is it still clean if the RF PA output is terminated in a
purely resistive dummy load (without any LPFs connected)?
- If an LPF is connected by short jumpers instead of via the relay, is output clean
or unclean?? Is it clean if the relay activation lead is at ground instead of active?
- There are some who are building their own modular and non-modular versions
of the uBITX.? I wonder how they are doing with respect to harmonics and spurs?
Looking back over some of the suggested improvements it seems that there may have
been some eureka moments that might have been published before they were well
thought out.? Some of Allison's posts might indicate that we have been focusing on and
treating the symptoms instead of the source problem.?
It is probably unfair that I comment when I do not have the test equipment, skills, or
available time to perform in-depth tests.? But given the situation, talk is about all I
can do. ? ?? 8-(??
Arv _._
You may have seen all the discussion on using AXICOM relays. Until that is flattened and I understand the "why" I am refunding your money for the K5BCQ LPF board kits which were ordered as I continue to investigate further. Attached is a picture of the AXICOM?V23105-A5403-A201 relays just received from Mouser. You can see that there are some physical differences between them and the previous AXICOM relay pictures posted (coil spacing to contacts, and ?).? A good friend of mine, Glen, has donated an unmodified uBITX board for my future testing. Thank you Glen.  ?
73 Kees K5BCQ
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Re: Front Panel for Nov, 2018 QST Dummy Load
I think I am pretty close.? I do not have the OLED or enclosure to test so I would not be comfortable posting the file to the group not knowing if this even works.? Do you have access to a printer?? I could send you the file to test then if it works you can have the file to post anywhere and any way you want.? If it doesn't work, you can tell me where I am off and we can try again.? If you do not have access to a printer I could print one and send it to you.? If I knock down the height of the battery ledge it would fit in a regular envelope.? If you prefer to wait and see if Al finds his file you won't hurt my feelings either.? I'm still teaching myself to design things and this was good practice.
--
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Re: Harmonics and Relay Replacement
You may have seen all the discussion on using AXICOM relays. Until that is flattened and I understand the "why" I am refunding your money for the K5BCQ LPF board kits which were ordered as I continue to investigate further. Attached is a picture of the AXICOM?V23105-A5403-A201 relays just received from Mouser. You can see that there are some physical differences between them and the previous AXICOM relay pictures posted (coil spacing to contacts, and ?).? A good friend of mine, Glen, has donated an unmodified uBITX board for my future testing. Thank you Glen.  ?
73 Kees K5BCQ
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The ¡° I can hear myself in the speaker when I transmit¡± problem has nothing to do with 45 mhz crystal filter board that I installed for spurious signal suppression on the higher bands. I confirmed it by replacing the uBITX mother board from another kit that I have not yet built. Had the same problem with the unmodified board as well. ? I suspect that RF is getting into this little eBay audio amplifier that I added early on in the build to boost the audio output from V4 board in my kits. I noticed this problem about the same time that I replaced the stock microphone element in the kit with this one that I bought from Mouser. ? ? This element has much more gain then the stock one so now I need to find a way to add a mic gain control for the uBITX to bring the gain down a bit. ? Ripley ? Sent from for Windows 10 ?
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From: RipleySent: Tuesday, October 16, 2018 10:41 PM To: [email protected]Subject: Re: [BITX20] Simple spur fix ? Hello Raj, ? I have ver 4 of the uBITX board. Adjusting the BFO frequency a bit brought the carrier down to below -40dBS so I am good to go there. However, I still have this semi-distorted whisper of my voice coming out of the speaker when I transmit. It happens on all bands but is most notable at 80 and 40 meters. A picture of the filter board as connected is attached. This issue doesn¡¯t appear to negatively effect the audio of my transmitted signal. I am getting good audio reports. ? Previous to this mod I had installed just the 45 mhz crystal filter ?to address the spurs issue and didn¡¯t notice any audio in the speaker when I was transmitting. ? Tomorrow I am going to pull the filter board and install just the crystal filter again to see what happens ? Ripley ? Sent from for Windows 10 ? ? A close up sharp photo will help to check. ? V3 or V4 ? ? Raj ? At 16/10/2018, you wrote: >Hello All, > >I just finished implementing the 45 Mhz crystal filter fix with the 7:2 impedance matching transformer on the output of the crystal. Now I am hearing myself in the speaker when I transmit and I am seeing the carrier wave on the SA when I push the PTT on the mic. > >I not sure why the crystal filter mod would be related to these two issues. Anyone experience anything similar? > >Ripley ? ? ? ?
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Re: Front Panel for Nov, 2018 QST Dummy Load
Metrics are for smart people. Note that the vertical separator is tangent to the OLED recess, which makes it perfect for wedging a 9V battery between the case and the separator. See below:
Jack, W8TEE
On Wednesday, October 17, 2018, 1:14:06 PM EDT, Doug W <dougwilner@...> wrote:
Jack, I haven't built your dummy load but figured I would take a shot at recreating the panel to help out those that need it. A few more dimensions would be very helpful.
- thickness of panel? 1/8"
- height, thickness and outside dimensions of reinforcing lip around perimeter of panel 3/16"
- diameter of corner screw holes 1/4" and distance between center of holes 2 3/8 , 2", both horizontal and vertical spacing 5/16" from outer edge to center
- diameter of switch opening 1/4"
- was this designed for a specific enclosure?? if I can find the enclosure dimensions online it would answer some of these questions.
I am not currently an ARRL member so I may be asking questions that you covered in the article. This is normally where I would go on a very long rant about imperial units but I'll skip it :) The picture is about as far as my skills take it without the other dimensions.? As I have stated many times I am far from a skilled designer so if anyone is following this that actually knows what they are doing I will happily send what I have so far and of course plan on sharing the final file if I get that far.  --
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A few years back I did a dummy load in much the same fashion Jack did, but using ten pieces, 510 ohm, 2 W resistors. Used flat copper flashing strips instead of wired to mount the resistors. Intended for QRP.
I used a 1/2 pint paint can from Ace Hardware. Poured the paint into an olive jar for later use and cleaned out the can.
Named it "Cantennino" - little cantenna ?? - as homage to Heathkit
For 10W and under, there was no need to use the oil fill.
Jack's detector and Arduino system should work just as nicely on the smaller load.
N5IB
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Re: Something not right 24V PA BITX40
Appreciate the input.
Similar output from the computer audio output compared to my microphone. Most of my contacts have been with FT8. Keep looking at it and can't figure out why 20V and 24v outputs are low.
I would love to have 20 watts out....
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
I have been a QRP OP since my Novice License. I don't call out QRP. What difference does it make? If another station hears you and begins conversation that is all that matters. when we exchange information name, QTH, how long been a ham, Rig and Antenna and power used to transmit is when I announce that I am QRP.
If you make contact it makes no difference whether you transmit QRO or QRP. In my Opinion. Terry - KB8AMZ Brimfield Twp, OH USA EN91hd Linux User# 412308, Ubuntu User# 34905,?PCARS#78, NAQCC#6668, QRP-ARCI#8855, SKCC#14195
Much slower this morning but made three more before breakfast. I'm just running of of 8 AA batteries so I think that folks with good antennas heard me and folks without or pointing the other way didn't.?
Next week is the New York QSO party so I'll try parking on frequency and calling and hopefully the other stations will do the hard work.
Look for me 10/20/18? on 7.230 (give or take) please!?
73, AA2MZ?
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Re: Front Panel for Nov, 2018 QST Dummy Load
Jack, I haven't built your dummy load but figured I would take a shot at recreating the panel to help out those that need it. A few more dimensions would be very helpful.
- thickness of panel
- height, thickness and outside dimensions of reinforcing lip around perimeter of panel
- diameter of corner screw holes and distance between center of holes, both horizontal and vertical spacing
- diameter of switch opening
- was this designed for a specific enclosure?? if I can find the enclosure dimensions online it would answer some of these questions.
I am not currently an ARRL member so I may be asking questions that you covered in the article. This is normally where I would go on a very long rant about imperial units but I'll skip it :) The picture is about as far as my skills take it without the other dimensions.? As I have stated many times I am far from a skilled designer so if anyone is following this that actually knows what they are doing I will happily send what I have so far and of course plan on sharing the final file if I get that far.  --
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Front Panel for Nov, 2018 QST Dummy Load
All: A number of you have written for the 3D printing file for the dummy load that is featured in the Nov issue of QST. Al designed it and it was not sent to QST, but should have been. Al had a system crash last week and cannot find the STL file for the case...yet. He's pretty sure he has it backed up, but has not found it. In the interim, for those who have some 3D design talent, this might help:  A -- panel width 3" B -- panel height 2.5" C -- distance between vertical support for 9V battery, between lip and support? 5/8" D -- recess for OLED display: 1 3/16" E -- distance between bottom of OLED opening and recess edge 3/8" F -- opening for OLED display 15/16 x 5/8" G -- recess width 1 1/8" H -- outter panel edge to recess? edge 1" ?I -- switch opening approx 5/16" from left edge, 1 3/16" from top edge (depends on switch used) We will post the file when we find it. If anyone does create a new file, please share it here with everyone else and send us a copy. We will post it on our site (hamradiodesigns.com) if we can locate the original. Jack, W8TEE
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Re: Harmonics and Relay Replacement
Received the AXICOM?V23105-A5403-A201 relays from mouser this morning and tested them. The results were NOT as expected (not low enough). Dissected one to make sure it had the AXICOM internal structure .....it does.
What would you consider the proper way of testing the relay for coupling ? I connected the two relay N/C contacts (which are also connected to the relay armature) ....one side to the TG and one side to the SA with/without a 50 ohm resistor across the TG output at the relay. Also attached a small wire from Ground to Ground. Then I added 47nF caps to ground at the coil leads to see the effect. The AXICOM relay had a 4dB reduction, the uBITX relay had a 9dB reduction indicating to me more had signal coupled to that coil.?
73 Kees K5BCQ
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It's a quart paint can that I bought at Lowes. I bought the mineral oil at Walgreens, but I'm sure any drug store would carry it. As far as I know, the type of mineral oil doesn't matter. I simply bought the cheapest I could find.
Jack, W8TEE
On Wednesday, October 17, 2018, 1:31:40 AM EDT, Donald <donwestpwl@...> wrote:
I would like to ask the size of the can (I assume it is a quart),
the brand of mineral oil you used, and sources for both. I did not
see that information in the article/webpage. I haven't had any
dealings with mineral oil and would appreciate knowing of some
good for 100 Watts of RF.
I agree, build-it projects are good! The more, the better!
73, Donald, KB5PWL
On 10/16/2018 10:32 PM, Jack Purdum via
Groups.Io wrote:
Thanks, Guy, you note is appreciated. We plan to keep
badgering editors to have more construction projects, as we
think there are a fairly significant number of us out here who
really do enjoy building "stuff"!
Again, thanks!
Jack, W8TEE
?
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I bought a life membership back in 1972! Best investment I ever made!
Jack, W8TEE
On Wednesday, October 17, 2018, 9:18:11 AM EDT, James Lynes <jmlynesjr@...> wrote:
Jack: Good luck!
The dirth of technical articles makes the annual decision to renew QST very difficult.
James
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On Sun, Oct 14, 2018 at 09:12 PM, Ashhar Farhan wrote:
can you forward me the email that you wrote to hfsiganls? i will follow it up with them
?
- f
Good morning Farnham
I sent you a private message!
The text of the email I sent to Hfsignals is this:
Good evening
This year I bought a BITX40 kit and accidentally burned the board with arduino!??
It is only possible to buy the Raduino board with Si5351, Arduino Nano with loaded code. Fully tested?
When does it cost shipping to Italy?
?
Thank you
good job
Sergio?
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Re: Radrino for the bitx40 - Spare needed
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Ripley
Terry Morris