Hi,
Those toroids are said to be "self-shielding". It is difficult to get signals coupled into or out of them except by the windings that are actually on the core. But not impossible. Was it Raj who told us that he already tried shielding and it didn't make much difference. The fact it made a little difference (non zero) says that maybe the toroidal inductors are subjected to intense fields. The small inductors might be reducing the exposure and thus the bad consequences.
On my bench I have had to resort to placing a turn or two through a donut core to couple enough signal into test/measurement gear to get a reading. Sometimes holding a tertiary inductor in just the right position and angle worked - and sometimes not. So position might be important to this success. The self shielding feature of the toroids is a very large factor.
73,
Bill KU8H
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On 10/15/2018 06:45 PM, Sascha Bohnet | DL5SMB via Groups.Io wrote: Maybe this is a stupid question but wouldn't it be possible to just
shield the original toroids from electromagnetic influences?
I have a small copper cube made from plumbers Sheet copper in mind which
could be connected to the ground on the underside.
Or is this just a little bit na?ve?
I would actually give it a try myself - but as I do not have a spectrum
analyzer, I would not be able to find out if it did help or not.
Of course changing them to SMD inductors is easier - but this way the
high Q toroids could be preserved.
--
bark less - wag more
|
Re: I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD
Hi Dave,
OK, I'll email you via qrz and paypal you 14GBP - OK?
|
Raj, indeed I did not reply to anything. Acknowledged you have two boards with stock 560nH L5 and L7 and there was no significant change. I will see to find at a local store both values (560 and 680) in SMD format. According to the circuit description the filter is around 500 ohm
Il 16/ott/2018 13:10, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
>
> Oos,
>
> You replied to some other issues, so no idea what you replied to.
>
> L5 and & on two board stock values was around 560nH.. they needed two more turns and that did not
> help much. These filters are 650 Ohms IMHO.
>
> The sample book had no 720uH so the nearest I took 680nH. Make do!
>
> Still no enlightenment of why SMDs worked.. probably shielding and being close to the ground plane
> below.
>
> At 16/10/2018, you wrote:
>
>> Are the values of L5 and L7 well calculated? The stock are 720nH, the Raj's are 680nH, but I get on software something like 530nH if the network has a 50 ohm input and a 500 ohm output. Another question is whether or not a different topology of toroids would give better results.
>>
>> Il 16/ott/2018 05:59, "Raj vu2zap" < rajendrakumargg@...> ha scritto:
>> 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
>
|
Oos,
You replied to some other issues, so no idea what you replied
to.
L5 and & on two board stock values was around 560nH.. they needed two
more turns and that did not
help much. These filters are 650 Ohms IMHO.
The sample book had no 720uH so the nearest I took 680nH. Make
do!
Still no enlightenment of why SMDs worked.. probably shielding and being
close to the ground plane
below.
At 16/10/2018, you wrote:
toggle quoted message
Show quoted text
Are the values of L5 and L7 well
calculated? The stock are 720nH, the Raj's are 680nH, but I get on
software something like 530nH if the network has a 50 ohm input and a 500
ohm output. Another question is whether or not a different topology of
toroids would give better results.
Il 16/ott/2018 05:59, "Raj vu2zap"
<
rajendrakumargg@...> ha scritto:
- 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
|
Are the values of L5 and L7 well calculated? The stock are 720nH, the Raj's are 680nH, but I get on software something like 530nH if the network has a 50 ohm input and a 500 ohm output. Another question is whether or not a different topology of toroids would give better results.
Il 16/ott/2018 05:59, "Raj vu2zap" < rajendrakumargg@...> ha scritto: 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
|
Re: I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD
Hello Art Boelke, ???????????????? Thanks for your offer,the amount is okay for the agc board plus all componants and cicuit diagram I will weigh the jiffy bag and get back to you with a complete price.Regards Dave G0 AYD YOU CAN VIEW MY QRZ PAGE.
I will buy the AGC board with components.? $15.00 ?
On Mon, Oct 15, 2018 at 2:30 PM Dave Dixon < wylyeguy2@...> wrote: the AGC & POP fix boards are by N6 DT..
On Mon, 15 Oct 2018 at 16:58, John Lauber < jlauber@...> wrote: Will you take $10?? I¡¯ll pay with PayPal. John WI6P ? From: [email protected] <[email protected]> On Behalf Of Dave Dixon
Sent: Monday, October 15, 2018 08:03
To: [email protected]
Subject: [BITX20] I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD ?
|
Re: I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD
Hello Nigel, ???????????????? I still have one for sale at ?11.00 plus post ive been inundated with offers so seems ?11.00 is the going rate.You can contact me via G0 AYD paypal is dixontribe@... post will be say ?3.00 first class post.Let me know asap please.Regards Dave G0 AYD.
I will buy the AGC board with components.? $15.00 ?
On Mon, Oct 15, 2018 at 2:30 PM Dave Dixon < wylyeguy2@...> wrote: the AGC & POP fix boards are by N6 DT..
On Mon, 15 Oct 2018 at 16:58, John Lauber < jlauber@...> wrote: Will you take $10?? I¡¯ll pay with PayPal. John WI6P ? From: [email protected] <[email protected]> On Behalf Of Dave Dixon
Sent: Monday, October 15, 2018 08:03
To: [email protected]
Subject: [BITX20] I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD ?
|
Re: uBITX default frequency
All you have to do is tune to the frequency that you want to boot to and the switch between VFO A and B
This saves the new freq into A. Switch back to VFA A.. next power up your VFO A choice will be default.
Raj
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At 16/10/2018, you wrote: As you can tell, I still haven't got my uBITX thrown together yet! A friend has one with the stock firmware from when the uBITX was first released. He commented that when powered on, it always comes up on a frequency on the 40M band. Is it a simple matter of editing a newer version of the software and uploading it to the Raduino to get it to boot up on some other frequency? I'm sure the original firmware "works" but I have been encouraging him to upgrade.
--
73 Keith VE7GDH
|
As you can tell, I still haven't got my uBITX thrown together yet! A friend has one with the stock firmware from when the uBITX was first released. He commented that when powered on, it always comes up on a frequency on the 40M band. Is it a simple matter of editing a newer version of the software and uploading it to the Raduino to get it to boot up on some other frequency? I'm sure the original firmware "works" but I have been encouraging him to upgrade.
--
73 Keith VE7GDH
|
A close up sharp photo will help to check.
V3 or V4 ?
Raj
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Show quoted text
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
|
One of the first thing I tried was shielding. The PA, 30MHz LPF and 45MHz filter and even the
first BiDi amp. The whole effort made a little improvement but I was not satisfied.
I even tried soldering old IF transformer cans that I have a lot of...
Raj
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At 16/10/2018, you wrote: Maybe this is a stupid question but wouldn't it be possible to just shield the original toroids from electromagnetic influences?
I have a small copper cube made from plumbers Sheet copper in mind which could be connected to the ground on the underside.
Or is this just a little bit na?ve?
I would actually give it a try myself - but as I do not have a spectrum analyzer, I would not be able to find out if it did help or not.
Of course changing them to SMD inductors is easier - but this way the high Q toroids could be preserved.
|
I have a factory stock Raduino for sale. It has the KD8CEC software now but came with the factory software installed. Only used a couple of hours until I got my original board fixed and calibrated. Excess to my needs at present.
$35 total shipped to Continental US and PayPal preferred.?
Other shipping, please ask..?
--
72 and God bless
KD4EPG
|
|
|
Mad,
Going to Axicom relays looks like it pretty much cleans up our issues with harmonics.
But this thread is about spurs, not harmonics.
Raj has found that replacing the toroids at L5,L7 around Y1
and also L1,L2,L3,L4 on the 30mhz LPF with SMD inductors will clean up the spurs.
With both spurs and harmonics cleaned up, the rig can met regs.
Yes, the board layout is not ideal.
Board layout is why we have coupling from the power amp into Raj's L5 and L7.
But looks like replacing some relays and inductors is all we need do
to clean up the spurs and harmonics well enough to meet regs.
(We might need to clean up a trace around the 40mhz transmit LPF, I'm not sure.)
Regarding Sascha's question:?
? ?"wouldn't it be possible to just shield the original toroids from electromagnetic influences?"
I think it very well could work, worth trying if you have shielding on hand but not the SMD inductors.
Copper blocks electric fields (and electromagnetic waves) quite well.
Though if it's stray magnetic fields that's causing trouble, maybe not.
Replacing the toroids with surface mount inductors seems easier to me
than adding well grounded copper cages around the toroids.
Jerry, KE7ER
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On Mon, Oct 15, 2018 at 05:52 PM, MadRadioModder wrote:
It¡¯s the PCB tracks/ /layout and relays that are the problem¡ not the toroids/ toroid layout.
?
|
Maybe a shield between the PA / LPF section and Mixer sections. Aand changing the relays. and maybe a few SMD inductors in the power feed to the RX section....
73 Nick VK4PP
|
It¡¯s the PCB tracks/ /layout and relays that are the problem¡ not the toroids/ toroid layout. ? ? MRM ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Sascha Bohnet | DL5SMB via Groups.Io
Sent: Monday, October 15, 2018 5:45 PM
To: [email protected]
Subject: Re: [BITX20] Simpler spur fix ? Maybe this is a stupid question but wouldn't it be possible to just shield the original toroids from electromagnetic influences?
I have a small copper cube made from plumbers Sheet copper in mind which could be connected to the ground on the underside.
Or is this just a little bit na?ve?
I would actually give it a try myself - but as I do not have a spectrum analyzer, I would not be able to find out if it did help or not.
Of course changing them to SMD inductors is easier - but this way the high Q toroids could be preserved. -- ¡_. _._
|
Re: Harmonics and Relay Replacement
I plan on doing the same. I already safely removed the 8 pin Op amp very clean too. So I shouldn¡¯t have any issue with the relays, hopefully. Waiting to order mine.
Joe
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On Oct 15, 2018, at 4:24 AM, Matthias Zwoch <zwoch@...> wrote:
Am 14.10.2018 um 23:57 schrieb Joe Puma:
Yea but changing the relays looks like the real winner here. Hello Joe,
It is not a big problem to get the HFD27 desoldered. A good desolder litz (I used 2,5mm from Felder) and a bit judding and pulling an they will come out without any damages at the PCB and the relais. Desoldered all 5. They will go in the scrapbox and this evenig the AXICOMs will take their places.
73, Matthias DD7NT
|
Maybe this is a stupid question but wouldn't it be possible to just shield the original toroids from electromagnetic influences?
I have a small copper cube made from plumbers Sheet copper in mind which could be connected to the ground on the underside.
Or is this just a little bit na?ve?
I would actually give it a try myself - but as I do not have a spectrum analyzer, I would not be able to find out if it did help or not.
Of course changing them to SMD inductors is easier - but this way the high Q toroids could be preserved.
|
Just assembled mine, had a faulty joint on encoder. Check it as I suspect it is associated with no tuning. Display is sign much is working. Once tuning is working, the work the audio. Rig does not have lots of excessive gain, so do advance the volume control. On my board the bfo was way off, so search for tune up instructions.
Curt
|
Re: I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD
I will buy the AGC board with components.? $15.00 ?
On Mon, Oct 15, 2018 at 2:30 PM Dave Dixon < wylyeguy2@...> wrote: the AGC & POP fix boards are by N6 DT..
On Mon, 15 Oct 2018 at 16:58, John Lauber < jlauber@...> wrote: Will you take $10?? I¡¯ll pay with PayPal. John WI6P ? From: [email protected] <[email protected]> On Behalf Of Dave Dixon
Sent: Monday, October 15, 2018 08:03
To: [email protected]
Subject: [BITX20] I HAVE 2 AGC AND POP FIX BOARDS COMPLETE WITH DIAGRAMS FOR SALE.MAKE ME AN OFFER DAVE G0AYD ?
|
Raj vu2zap
Nick VK4PP
MadRadioModder