Date   
Re: Simple spur fix

 

Lev, Any experiments on this ?


At 05/09/2018, you wrote:
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.

Usb lsb invertiti R3

negroniwalter@...
 

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.

Re: High Frequency Choke for Bitx40

David Wilcox
 

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

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.

http://www.learnabout-electronics.org/PSU/psu12.php

Re: Simpler spur fix

Matthias Zwoch
 

Am 14.10.2018 um 03:34 schrieb Joe Puma:
This popped up on Amazon when I searched for 1210 680nh
https://www.amazon.com/Fixed-Inductors-680nH-145mA-pieces
On Oct 12, 2018, at 11:27 PM, Raj vu2zap <@Raj> 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

Jim Sheldon
 

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" <@Raj>
To: BITX20@groups.io
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: Simpler spur fix

 

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

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
https://www.amazon.com/Fixed-Inductors-680nH-145mA-pieces
On Oct 12, 2018, at 11:27 PM, Raj vu2zap <@Raj> 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: Simpler spur fix

Alan G4NMA
 

The parts in the photo appear to be these parts:

https://www.budgetronics.eu/index.php?action=article&aid=13200&lang=EN

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.

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" <@Raj>
To: BITX20@groups.io
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

Don - KM4UDX
 

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 

Re: Harmonics and Relay Replacement

Lawrence Galea
 

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: BITX20@groups.io
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: µBITX v3 : TX OK but no audio on RX

F5PCX
 

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. 

Re: Fun with Pennsylvania QSO Party AA2MZ/QRP

_Dave_ K0MBT
 

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

Re: Something not right 24V PA BITX40

JolietTim
 

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.

Re: Fun with Pennsylvania QSO Party AA2MZ/QRP

Ed.T - aa2mz
 

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 

Re: Recommended fixes on ubitx.net

Jerry Gaffke
 

So what exactly are these seniors complaining about?

They heard you had a uBitx, and think you should not be using it at all?
They somehow checked your harmonics and out-of-band spurs that are 30dB or more down from 10 Watts?
They are hearing IMD and carrier leakage in your signal, well within an AM phone signal's bandwidth and thus quite legal?

I would not be above giving them seniors a little guff about dumping several hundred watts into the ether
just to talk to their buddies across town.  Especially if they are younger than I am.
Even if they are legal, their spurs and harmonics might well cause greater interference than your little uBitx.
To say nothing of their fundamental.

A stock uBitx generally sounds good enough on the air, assuming you don't have the mike gain artificially high
or RV1 cranked higher than it should be.  Bench testing with a spectrum analyzer shows a few issues that we should
all address.  Between Raj's move from toroids to surface mount inductors at  L5,7 (and perhaps L1,2,3,4 per post 60648)
and Mike Doty's use of Axicom relays suitable for use in a radio, we may soon have an easy recipe for a fully legal uBitx.
 
I encourage everyone with a uBitx to clean it up once these fixes have settled out.
And I encourage those QRO operators to turn it down a bit when appropriate.

Jerry, KE7ER



On Sun, Oct 14, 2018 at 06:25 AM, Don - KM4UDX wrote:
Senior folks in my club bash me 'bout my spurious emissions. They have strongly encouraged me to "work on that rig" as they say. 

Re: Harmonics and Relay Replacement

Jim Sheldon
 

Raj,

Rather than just using double shielded coax from the 2 pin RF plug on the uBITX to the BNC, I carefully installed gold plated female SMA connector and that should help some but I'm just using the SMA on my test rig. The other ones are faring well enough and legal so I'm leaving them as-is. I changed my mind on the machined pin sockets and modified some old Mica filled DIP sockets I had on hand from many years ago. I pulled the unused contacts out so have Mica dielectric between pins and these sit up about 2mm off the board. Should be interesting to see the results. Be Wednesday before all the parts get here so I'll report the results in a few days.

I will add the SMA inductors in place of L5 and L7 though and found the Murata 1206 ones at Mouser. 10 on order and that will cover the 5 rigs I have.

Jim - W0EB

------ Original Message ------
From: "Raj vu2zap" <@Raj>
To: BITX20@groups.io
Sent: 10/14/2018 7:57:58 AM
Subject: Re: [BITX20] 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" <@Raj>
To: BITX20@groups.io
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


Simpler spur fix

Gary Hanson
 

Here is a part number for 680 nh smd inductor from Arrow electronics.  Data sheet available on product page.  Looks like the size is a 1212.  I have not tried it yet, but specs look about right

ASPI-M3015-R68M-T 
NEW!
Inductor Surface Mount

Abracon ASPI-M3015-R68M-T Inductor Surface Mount

MANUFACTURER

Abracon 

PRODUCT CATEGORY

Inductor Surface Mount

DESCRIPTION

Inductor Power Wirewound 680nH 20% 100KHz 4.1A 35mOhm DCR 1212

Product Technical Specifications

EU RoHSSupplier Unconfirmed 
ECCN (US)EAR99
TypePower
TechnologyWirewound
Inductance (H)680n
Tolerance20%
Inductance Test Frequency (Hz)100K
Maximum DC Current (A)4.1
Maximum Saturation Current (A)8
Maximum DC Resistance (Ohm)35m
Number of Terminals2
Case Size1212
Minimum Operating Temperature (°C)-40
Maximum Operating Temperature (°C)125
MountingSurface Mount
Product Length (mm)3.2
Product Depth (mm)3.2
Product Height (mm)1.5

Gary, KJ5VW

Re: Simpler spur fix

Henning Weddig
 

due to the high current capability i assume that this choke is to be used in DC DC converters and not at RF i.e. 45 MHz!

Am 14.10.2018 um 18:36 schrieb Gary Hanson:

Here is a part number for 680 nh smd inductor from Arrow electronics.  Data sheet available on product page.  Looks like the size is a 1212.  I have not tried it yet, but specs look about right

ASPI-M3015-R68M-T 
NEW!
Inductor Surface Mount

Abracon ASPI-M3015-R68M-T Inductor Surface
                      Mount

MANUFACTURER

Abracon 

PRODUCT CATEGORY

Inductor Surface Mount

DESCRIPTION

Inductor Power Wirewound 680nH 20% 100KHz 4.1A 35mOhm DCR 1212

Product Technical Specifications

EU RoHS Supplier Unconfirmed 
ECCN (US) EAR99
Type Power
Technology Wirewound
Inductance (H) 680n
Tolerance 20%
Inductance Test Frequency (Hz) 100K
Maximum DC Current (A) 4.1
Maximum Saturation Current (A) 8
Maximum DC Resistance (Ohm) 35m
Number of Terminals 2
Case Size 1212
Minimum Operating Temperature (°C) -40
Maximum Operating Temperature (°C) 125
Mounting Surface Mount
Product Length (mm) 3.2
Product Depth (mm) 3.2
Product Height (mm) 1.5

Gary, KJ5VW

Re: Simpler spur fix

Jerry Gaffke
 

That Abracon ASPI-M3015-R68M-T is good for 4 Amps.
Some dinky little inductor in an 0805 package would probably do fine at L5,7
A shielded inductor of some sort could be a plus.

Jerry


On Sun, Oct 14, 2018 at 09:48 AM, Gary Hanson wrote:
Here is a part number for 680 nh smd inductor from Arrow electronics.  Data sheet available on product page.  Looks like the size is a 1212.  I have not tried it yet, but specs look about right

Re: Harmonics and Relay Replacement

Kees T
 

i agree with Raj and that an excellent "standard" test configuration, for all to use, would be to look at the coupling between the N/C contacts on both sides which would include the relay armature length and compare the 2. Axicom relays are "in the mail".

73 Kees K5BCQ