Fun with Pennsylvania QSO Party AA2MZ/QRP
I've only recently got my bitx40 working after replacing a bad Arduino board and an end fed antenna with a good Nano and a sloping dipole.Plenty of ears but zero contacts until this weekend. I'm in western NY so most contacts to Pennsylvania were a few hundred miles or less. I didn't stand out in the pileups but with patience I made contact with all but two stations I tried. In a contest, I think calling QRP helps even if the receiving station doesn't get bonus for it. QSO Party Contest continues Sunday so if you want to check out how your "couple of watts" does to Pennsylvania, today is the day!
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Re: Harmonics and Relay Replacement
Jim,
My take on this relay business is that both contacts are being inductively coupled.
Imagine the NC contacts on one side - it is a loop and will be inductive. The same goes
for the other pair on the other side..
By adding a socket we may not get the best rejection from Axicom relays. I have also
socketed KT1/2/3 .. the relays have arrived and I am at the farm.. so a week more
of suspense.
If someone with a SA like 815 can feed in the tracking gen through a 47 ohm resistor
to one NC contacts in/out and take the Analyser input from the other NC contact set
and then sweep say up to 100MHz, we get some enlightenment. I am eagerly waiting
to try for myself.
Raj
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At 13/10/2018, you wrote: Looking at the differences between the original Hongfa relays -S (for sensitive) version in my uBITX boards and the Axicom relays Mike Doty and I installed in place of them, the Axicom had lower coil resistance in the 400 mW coils vs the 200 mW coils fot the Hongfa relays. That means fewer turns of wire in the Axicoms and subsequently less inductance. That may be a huge factor in the isolation between the two types. The coil resistance for the Axicom that matches the Hongfa in DC spec aldo has the exact same listed coil resistance.
I'm going to order 5 each of the 150mW, 200 mW and 500 mW versions, put sockets on my 3rd V4 board and see how much difference there is between the 3 other types relative to the already installed 400 mw version. Hopefully that will give us some definitive answers. Be Monday before I can order them so it will be a few days before any testing can be done.
Jim Sheldon, W0EB
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Re: Recommended fixes on ubitx.net
Tom,
What I bought from the Bay stated as Murata does not seem to be right.
The inductor has S.M printed on it.
I say try one that has the right value and SHIELDED. That should keep it
from picking up RF.
Raj
At 14/10/2018, you wrote:
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Don,
The closest to a recommendation of an actual part is this:
From following the thread, the identified part resolving the issue is
680 nH, reportedly Murata branded, about size 1210, and shielded.
I am waiting for but haven't seen confirmation of a fix so far.
Tom - KF5NWC
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Re: Harmonics and Relay Replacement
Since it has been proven that there is coupling between the relay solenoid coil and the long relay armature (apparently a lot more on the non Axicom relays) .....what can be done with the original relays since internal surgery is out. I have been focused on adding series inductance to the relay solenoid coil. Results in previous posts. Well, there is also less coupling on the original relays if you reduce the RF on the solenoid coil by bypassing both coil ends with short leads to ground at the relay. I'm using 47nF capacitors and see a 3dB reduction.? ? and that's at Rigol power levels.
73 Kees K5BCQ
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Re: Something not right 24V PA BITX40
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Check Arrow.com.? a lot cheaper. I bought 10ea "1276AS-H-R68M=P2" 680nh smd inductors for?$3.41.? I also bought 5ea of the "V23105A5403A201" relays for $11.57.? With tax and FREE overnight shipping, i paid $16.22....
Marco - KG5PRT
On Sat, Oct 13, 2018, 8:34 PM Joe Puma < kd2nfc@...> wrote: This popped up on Amazon when I searched for 1210 680nh?
I ordered a sample book from China.. good for experiments.RajAt 13/10/2018, you wrote:Been looking around for the 1210 680nh inductors and cannot find a source yet. I noticed some suppliers only sell in very large quantities like 2000. So has anyone found a source yet or if so would be willing to sell a few to us who want them. Just putting it out there for consideration. Please pm me to make arrangements. 73 n7hwr
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This popped up on Amazon when I searched for 1210 680nh?
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On Oct 12, 2018, at 11:27 PM, Raj vu2zap < rajendrakumargg@...> wrote: I ordered a sample book from China.. good for experiments.RajAt 13/10/2018, you wrote:Been looking around for the 1210 680nh inductors and cannot find a source yet. I noticed some suppliers only sell in very large quantities like 2000. So has anyone found a source yet or if so would be willing to sell a few to us who want them. Just putting it out there for consideration. Please pm me to make arrangements. 73 n7hwr
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Re: High Frequency Choke for Bitx40
Wow...I just read my description above and it's pretty bad!? ?But the link is really good :)
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Re: High Frequency Choke for Bitx40
Here's my obligatory "I'm no expert, but.." statement.? ?I'm no expert but I bet what's being done here is an "LC" filter or "Inductance / Capacitance" filter.? Or perhaps an enhancement of the existing one.? This circuit is commonly used to smooth out ripples and other such nasties in A/C or varying D/C current.? The choke filters out higher frequencies above some certain value, and the capacitor allows lower frequencies that you want thru and smooths them out.
Here's a pretty well written overview.
http://www.learnabout-electronics.org/PSU/psu12.php
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Re: Recommended fixes on ubitx.net
Don,
The closest to a recommendation of an actual part is this:
From following the thread, the identified part resolving the issue is?680 nH, reportedly?Murata?branded, about size?1210, and shielded.
I am waiting for but haven't seen confirmation of a fix so far.
Tom - KF5NWC
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Re: Recommended fixes on ubitx.net
Folks, is there a recommended source for the 680uh inductors?? I've looked over the thread, and don't see any references. But I may have missed it??
If this were added to the wiki, it would be fantastic. I know source links aren't reliable over time, but it would give us start??
Thank you for any help!
Don
km4udx
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Re: High Frequency Choke for Bitx40
Just a hobbyist here so keep that in mind. The link I sent previously is to what could be similar to the toroid in question, no guarentees. The link has the application notes for that toroid which lists:
RFI Suppression 5 - 500 MHz
That should be its application as a choke. If you look at the other items on that page you will see different applications noted for each with its performance characteristics in that role.
Tom
KF5NWC
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Thanks Raj Good night from here and good morning to you in India Lawrence
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Re: Harmonics and Relay Replacement
I've looked over that 181 page AXICOM spec sheet and there are 2 things that set them apart from the herd.
Common with the herd: they are "Signal Relays", 2pF between contacts, 4pF to the coil, have gold plated contacts, etc ....all good but not unique to Axicom).
1. The solenoid relay coil is located over the top of the relay armature which will reduce the coupling between the two, especially since the armature is shorter and not routed over the end of the solenoid relay coil.
2. The solenoid relay coil on the particular Axicom relay ordered?.......was? ??V23105A5403A201??the "403" means the option for a 400mW coil.? Now that is a difference because the "typical" relays have the 200mW coil option. More power means more current and probably fewer turns in the coil and potentially less coupling between the solenoid relay coil and the armature.?
Both #1 and #2 are not possible to fix outside the relay, may reduce coupling some between relays by adding series inductors. Capacitors across the relay coils have no effect. Capacitors to ground ? TBD
73 Kees K5BCQ
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Re: Recommended fixes on ubitx.net
Mike, let me add my thanks as well. ?Your detailed, concise info is exactly what I needed. ?Warmest 73, ?Chuck N1KGY
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Re: High Frequency Choke for Bitx40
Thank you for the links to the calculators.? The part I don't understand is what frequency range I'm trying to filter.? The choke that Akira JJ1EPE calls for goes in the power supply line for the Raduino.? What frequencies or type of interference is it meant to block???
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Re: Harmonics and Relay Replacement
Looking at the differences between the original Hongfa relays -S (for sensitive) version in my uBITX boards and the Axicom relays Mike Doty and I installed in place of them, the Axicom had lower coil resistance in the 400 mW coils vs the 200 mW coils fot the Hongfa relays. ?That means fewer turns of wire in the Axicoms and subsequently less inductance. ?That may be a huge factor in the isolation between the two types. ?The coil resistance for the Axicom that matches the Hongfa in DC spec aldo has the exact same listed coil resistance. ?
I'm going to order 5 each of the 150mW, 200 mW and 500 mW versions, put sockets on my 3rd V4 board and see how much difference there is between the 3 other types relative to the already installed 400 mw version. ?Hopefully that will give us some definitive answers. ?Be Monday before I can order them so it will be a few days before any testing can be done.
Jim Sheldon, W0EB
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Re: Recommended fixes on ubitx.net
Yes I agree. Thanks Mike. Between your site and the wiki I was able to get a wealth of information and perform the mods without having to be a rocket scientist level electrical engineer. Kudos to ?
Joe
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On Oct 13, 2018, at 4:45 AM, F1BFU - Fr - 79 < gilles.f1bfu@...> wrote: Hello Mike
Thank you very much for the work you do for . This site is really a mine of information for all those who have embarked on the adventure ubitx.
Gilles - F1BFU /FR Le?sam. 13 oct. 2018 ¨¤?00:39, Mike Woods < mhwoods@...> a ¨¦crit?: With two simple new fixes available to address the spectral purity
issues associated with the uBITx, I have been busy updating the
website this morning.? This includes an update to the the
warning message on the front page, clarifying the fact that simple
solutions exist to spectral issues on? the strengths and weaknesses
page, and the addition of a new "fix" page located here:
I have also updated the recommended fixes and mods page
located here:
Hopefully this will encourage more people to get into the wonderful
world of the uBITx, and keep the factory in peak production!
Mike ZL1AXG
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good evening
I have a problem with a BITX40 that never worked! I replaced the motherboard because I thought the problem was there. It is not so! Only the raduino remains! I wrote an email to HF-signals to find out how much the raduino costs, but they did not even answer me! Now I'm going to buy the kit on qrp-labs but I have a doubt! I had a raduino checked by a technician and a test with oscilloscope actually comes out the frequency of 5 mhz as it should be! Only when I connect it to the motherboard it totally changes the result!
?
Is this correct or does it have problems?
?
How can I test the radio with the old tuning system without the raduino?
What changes do I have to make?
?
Thanks Sergio
?
Sorry for my English!
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Re: Harmonics and Relay Replacement
Mike,
Now THAT spec from Farnell was what I was looking for.? The 151 pages have a lot of good RF information not found elsewhere.....but will take a little time to digest.
73 Kees K5BCQ??
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Raj vu2zap
Jim Sheldon