Re: Something not right 24V PA BITX40
Power does not decrease when on 12V for the PA only on 24V.
Using a 3 amp supply for the 12V both main board and the PA (when it is on 12V). When I switch the PA to 24V, I use a set of LIPO batteries from my kids RC plane. Power source has not changed from before to after boxing. I added a switch and an external jack so I don't have to unplug or open the case to change sources.
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Re: Fun with Pennsylvania QSO Party AA2MZ/QRP
Nice! I made a contact to a PA QSO party with my bitx40 too. NY3B 7.191. Tried some others but got frustrated and turned on my Kenwood 430.??
73
Dave
k0mbt
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Re: ?BITX v3 : TX OK but no audio on RX
After a lot of investigations (HI !) I found that there is a contact beetween pins 3 and 5? (K3) but there is not any continuity beetween pin 3 and M1 and beetween pin 5 and M2. But continuity is 0K beetween M1, 2 ,3 and 4 which is logical.
I discovered also that Q70 was fried although I changed it recently...
73 - Jean F5PCX.?
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Re: Harmonics and Relay Replacement
Jim I agree with you regarding the lowest number of turns.
My theory is that the relay contacts are acting as the primary of a current transformer inducing the RF current flowing in the contacts into the great number of turns of the relay coil which would explain the RF voltage found and posted by someone on the relay supply lines. It's like a normal current transformer but with the primary on the outside of the coils with the strong RF field inducing the voltage in the relay coli. Apart from the possible blowby from the contacts to the other contacts due to the strong RF field, the RF voltage on the relay coil would also induce a current in the other contacts reducing the isolation. It is true that one can say that the current in the relay contacts would cancel each other as one is going in one direction and the other in the opposite direction, but the intense RF field and the small spacing could lead to unexpected results. It could also be considered that the contacts are acting like a small loop inducing a current in the relay coil. Remember that a transmitting loop has a very strong field in its vicinity. This is why I asked earlier on whether someone had or intend to check whether the results are the same with the different relay coil inductance. The lower inductance ones would have a lower voltage induced in the relay coil due to the smaller number of turns which can be checked by the RF voltage on the relay supply lines and also leading to better isolation. This is just my theory. Regards
Lawrence
On Sun, Oct 14, 2018 at 1:39 PM Jim Sheldon < w0eb@...> wrote: Raj,
I thought the same thing, but maybe, even using sockets, just for the
experiment, I could get some relative comparisons between the types to
see if any were better than others.? I suspect the 500mw version, Arrow
part# V23105A5503A201 will be the best because they have the lowest coil
resistance, fewest turns on the coil.? The only thing that worries me
using that relay is it's current draw - I'm hoping it won't be too much
for the switching transistors in the uBITX.? ?The 400mW relays are
working and switching OK but the additional current from the lower coil
resistance may become a problem and I'm not sure yet.
I don't want to risk ruining the board by soldering and unsoldering the
relays several times so planned on using sockets but ONLY on the one
board I'm planning on setting up as a test station.? I'll build it up on
a board but use double shielded Teflon insulated COAX from the uBITX
boards 2 pin connector to the BNC output and make all digital and audio
wires twisted pair to the front panel jacks, encoder and switch.? The
construction will be open, no case but the uBITX board will be mounted
on a 16 gauge aluminum plate to give a good underside ground plane and
good low Z grounds for all connections.
I have some good, gold plated machined pin socket strips that are very
low profile and will use those to create the sockets.? Again, for these
tests I will only look for which of the 4 relay types gives the best
harmonic attenuation between types and then I will solder that set into
a uBITX for the final results.? Only way I know to test all 4 types
without possibly ruining a good board from too much
soldering/de-soldering of relays.? A repaired trace would negate the
original test results as it's characteristics would be different.
Hope people can understand what I'm trying to say here.
Jim
------ Original Message ------
From: "Raj vu2zap" <rajendrakumargg@...>
To: [email protected]
Sent: 10/14/2018 1:06:47 AM
Subject: Re: [BITX20] 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
>
>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
>
>
>
>
|
Re: Recommended fixes on ubitx.net
Tom - great link, thank you. Do you recommend I wait a while, or is this part good to go?
Senior folks in my club bash me 'bout my spurious emissions. They have strongly encouraged me to "work on that rig" as they say.?
Thanks again!
Don
Km4udx?
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Re: Harmonics and Relay Replacement
GM Jim, At 14/10/2018, you wrote: Raj,
I thought the same thing, but maybe, even using sockets, just for the experiment, I could get some relative comparisons between the types to see if any were better than others. I suspect the 500mw version, Arrow part# V23105A5503A201 will be the best because they have the lowest coil resistance, fewest turns on the coil. The only thing that worries me using that relay is it's current draw - I'm hoping it won't be too much for the switching transistors in the uBITX. The 400mW relays are working and switching OK but the additional current from the lower coil resistance may become a problem and I'm not sure yet. 400mW is 33mA that should be OK for the transistors. I will try lower current one when I find a cheaper source or a vendor who will send me by USPS. I don't want to risk ruining the board by soldering and unsoldering the relays several times so planned on using sockets but ONLY on the one board I'm planning on setting up as a test station. I'll build it up on a board but use double shielded Teflon insulated COAX from the uBITX boards 2 pin connector to the BNC output and make all digital and audio wires twisted pair to the front panel jacks, encoder and switch. The construction will be open, no case but the uBITX board will be mounted on a 16 gauge aluminum plate to give a good underside ground plane and good low Z grounds for all connections. Thats sensible, I put in sockets for the same reason. That board with L5/7 changed had spurs below -50dbm and its put to rest. I was thrilled with Mike Doty's find (Remember Roy Doty ? - PopSci). I ordered the same 400mW relays as I thought that lower power ones MAY be a little different in construction. Just KT1,2,3 change should do the trick. The other two don't play much of a part in harmonics leaking through. I tried a lot of mods, most gave a few dbs of improvement while others made things worse. The fix that makes dramatic improvement is the root of the problem. For spurs the TX signal leaking into the first mixer was cured with TX losses with a 45MHz filter.. further thinking led me to L5 and its position made a difference but not a fix.. the SMD for L5 made a big difference. Sort of a eureka moment! High Q inductor in this board layout is not in best interest of impedance matching.. we are only stepping up 50 to 650 Ohms and back. I need to experiment with a tapped toroid 2:7 without the caps and see - that might also fix the spurs issue. I wish someone would try that and report - I am at my farm. I have some good, gold plated machined pin socket strips that are very low profile and will use those to create the sockets. Again, for these tests I will only look for which of the 4 relay types gives the best harmonic attenuation between types and then I will solder that set into a uBITX for the final results. Only way I know to test all 4 types without possibly ruining a good board from too much soldering/de-soldering of relays. A repaired trace would negate the original test results as it's characteristics would be different.
Hope people can understand what I'm trying to say here. I read you! I added the same pins. With a collaboration like this group we will make a great and simple exciter / QRP rig! Jim Raj ------ Original Message ------
From: "Raj vu2zap" <rajendrakumargg@...>
To: [email protected]
Sent: 10/14/2018 1:06:47 AM
Subject: Re: [BITX20] 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
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
|
The parts in the photo appear to be these parts:
Not sure they are Murata parts.
I would concur that a part marked ¡®681k¡¯ is normally 680uH, but these seem not to follow that convention.
|
That is 680nH or 68 followed by one 0 - uH would have been 684 marking IMHO - like resistors.
I measured them and they were exact 680nH.
In some places the discussion relating to 680uH is about relays.
While people are buying 680nH, please also buy 331 = 330nH (10 Nos) for replacing the 30MHz LP filter
which also helped. L1 is very sensitive to surroundings causes ringing when touched.
Raj
toggle quoted message
Show quoted text
At 14/10/2018, you wrote: Am 14.10.2018 um 03:34 schrieb Joe Puma:
This popped up on Amazon when I searched for 1210 680nh
On Oct 12, 2018, at 11:27 PM, Raj vu2zap <rajendrakumargg@...> wrote:
Been looking around for the 1210 680nh inductors and cannot find a source yet. In some postings are mentioned 680uH inductors in some 680nH. uH or nH?? I had a look at the picture in Raj's posting #60465 and read there 681K. This would mean 680uH 10%. Inductor values in nH should be marked with N according to standart.
73 Matthias, DD7NT
|
Re: Harmonics and Relay Replacement
Raj,
I thought the same thing, but maybe, even using sockets, just for the experiment, I could get some relative comparisons between the types to see if any were better than others. I suspect the 500mw version, Arrow part# V23105A5503A201 will be the best because they have the lowest coil resistance, fewest turns on the coil. The only thing that worries me using that relay is it's current draw - I'm hoping it won't be too much for the switching transistors in the uBITX. The 400mW relays are working and switching OK but the additional current from the lower coil resistance may become a problem and I'm not sure yet.
I don't want to risk ruining the board by soldering and unsoldering the relays several times so planned on using sockets but ONLY on the one board I'm planning on setting up as a test station. I'll build it up on a board but use double shielded Teflon insulated COAX from the uBITX boards 2 pin connector to the BNC output and make all digital and audio wires twisted pair to the front panel jacks, encoder and switch. The construction will be open, no case but the uBITX board will be mounted on a 16 gauge aluminum plate to give a good underside ground plane and good low Z grounds for all connections.
I have some good, gold plated machined pin socket strips that are very low profile and will use those to create the sockets. Again, for these tests I will only look for which of the 4 relay types gives the best harmonic attenuation between types and then I will solder that set into a uBITX for the final results. Only way I know to test all 4 types without possibly ruining a good board from too much soldering/de-soldering of relays. A repaired trace would negate the original test results as it's characteristics would be different.
Hope people can understand what I'm trying to say here.
Jim
toggle quoted message
Show quoted text
------ Original Message ------ From: "Raj vu2zap" <rajendrakumargg@...> To: [email protected]Sent: 10/14/2018 1:06:47 AM Subject: Re: [BITX20] 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
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
|
Am 14.10.2018 um 03:34 schrieb Joe Puma: This popped up on Amazon when I searched for 1210 680nh
On Oct 12, 2018, at 11:27 PM, Raj vu2zap <rajendrakumargg@...> wrote:
Been looking around for the 1210 680nh inductors and cannot find a source yet. In some postings are mentioned 680uH inductors in some 680nH. uH or nH?? I had a look at the picture in Raj's posting #60465 and read there 681K. This would mean 680uH 10%. Inductor values in nH should be marked with N according to standart. 73 Matthias, DD7NT
|
Re: High Frequency Choke for Bitx40
The learning module referenced is an excellent source for ALL electronics theory. ?Add it to your home page. ?This winter when it is too nasty to go outside and you are tired of making contacts you can sit by the fire and update your electronics knowledge.?
Thanks to DaveT.
Dave K8WPE
toggle quoted message
Show quoted text
On Oct 13, 2018, at 7:11 PM, davedt1e@... wrote: 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.
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In ricezione: su 40mt con impostazione di default Lsb non si riesce a rendere intelligibile la conversazione, impostando Usb tutto bene. Sui 20 mt il contrario.
In reception: on 40mt with default setting Lsb you can not make the conversation intelligible, setting Usb all right. On 20 meters the opposite.
|
Lev, Any experiments on this ?
At 05/09/2018, you wrote:
toggle quoted message
Show quoted text
Would that be a good solution to
make the IF amplifier tuned? Like this? Also, change the transistors to
BFS17P, this is more suited to RF.
73s de HA5OGL
On Wed, Sep 5, 2018 at 10:46 AM Raj vu2zap
<
rajendrakumargg@...> wrote:
- This fix reduced the spurs by up to 10 db?? and requires ONLY
ONE part to be added.
- There is big change above 10MHz in the board. There is some
improvement below also.
|
Re: Something not right 24V PA BITX40
Tim,
Looks like you 12V is not OK. Increase to 15V and see. I have run my boards on 15V with much better output.
If the power goes up and then settles back down, I suspect your 12V not sustaining current. I am not sure
how you are supplying power before and after boxing.. that should give you a clue.
Raj
toggle quoted message
Show quoted text
At 11/10/2018, you wrote: I have my BITX40 up and running. Just got on the air for the first time a month ago. Lots of FT8 contacts and a few other digital contacts. I just put it in a case with a switch for the PA power section.
I can run the PA with the 12 volts or switch to an external source. Before boxing it I was able 13 Watts on 24.5volts. Currently I only get 7 Watts on 24.5 volts.
On 12 volts I get 5.5 Watts with 1.2 amps draw with a loud hello and 97 mA idle
On 24.5 volts I get 7 Watts with 1.5 amp draw with a loud hello and 103 mA idle.
Did I break something or am I doing something wrong? Using Lipo batteries for the PA and they sit idle at 24.5 volts and drop to 24.1 during the transmit. I tried increasing the drive on RV136. Seems I might get more output momentary then it settles back down to 7 Watts.
Any thoughts are appreciated.
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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
toggle quoted message
Show quoted text
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
|
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:
toggle quoted message
Show quoted text
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
|
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
|
Re: Something not right 24V PA BITX40
|
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
|
_Dave_ AD0B
Raj vu2zap
Jim Sheldon
David Wilcox K8WPE