Date   

Re: Harmonics

Jerry Gaffke
 

Yes, I understand the cruft is unwanted mixer products, makes sense.
I'm hoping that limiting mike levels, reducing IF gain, and increasing LO injection levels
will take care of that cruft.

I'm bucking the complexity of all the added filters.
The uBitx has been popular because it is simple, would be nice to keep it so.

Jerry


On Tue, Aug 14, 2018 at 10:31 AM, ajparent1/KB1GMX wrote:
Now The cruft you see... look at that long explanation in #57038 about mixing and
making mush.  I only went the 4th harmonic.  The usual is not less than the 7th or 11th.


Re: Harmonics

Jerry Gaffke
 

Allison,

Hmm, post 57037
Guess you were talking to Kees then.   ;-)

Good summary of the pitfalls in single conversion.
My Swan 100MX has lots of band specific filters and lots of shielding to do what it does.
Not something I want to duplicate.
 
We're very close to usable, would be nice to build something bulletproof
with regard to compliance without adding additional band specific filters. 

I'm still favoring a bump up from 45mhz for first IF, there are zero additional parts involved. 
Reduce IF gain, increase LO power levels, standardize on mike construction,
all with the aim of getting a consistent and clean signal out of the first mixer into the 30mhz LPF.
Add one more stage to the power amp (ouch!) since levels going into Q90 will be reduced.
 
Separate board modules laid out as strips, 4 layer boards, copper tape shielding, semiconductors more exotic
than the 2n3904, those all seem preferable to the complexity of a half dozen new switchable filters. 
With low audio levels and proper transmit LPF's  we get RF to the antenna that is nearly compliant.
That suggests using a few of these alternative measures will be sufficient.

Jerry


On Tue, Aug 14, 2018 at 09:22 AM, ajparent1/KB1GMX wrote:
Jerry,
It referred to your post  #57037
Its the exercise of why DBMs look easy but make people unhappy.
Nowhere is ther e more than one conversion in that discussion or even a receiver.
its about what you get from mixers (some much worse than others) for two simple
signals.

Now to your topic:
>>>>Perhaps my vague suggestion of going back to a single conversion rig.
The thought being, if we are adding all these filters between the first mixer and the power amp,
could make them all bandpass and do away with the 45mhz IF.  <<<<

First be warned its long and goes round some covering a lot of ground for what and why.

Opening:
The problem with single conversion is the choice of IF.  Minima used 20Mhz and 15M was 
too close for simple low loss wide filters.  The Minima issues spawned HF1 which begat 
uBitx.  The underlying desire was for low cost continuous tuning from some low frequency 
to at least 30mhz.   That is its history and its important as it is why some paths and 
choices came to be.

Single conversion does work.  I have 14 radios that mange to do well on on or many
bands though 2m!.  A few are even multiband radios.

Those that come to mind are the Tempo-one (9mhz if) but 17M and 30M are near impossible.
WM20 has an 8mhz IF, which is too close to 40M to do that.

Two of my radios have nice commercial 8 pole filters at 7.8mhz which rule out 40M also too close.

The Atlas-210X a classic 80/40/20/15/10 radio uses a IF of 5.520mhz single conversion.
It might work on 30M (the 2if spur is 10.44mhz but can be trapped). All the other possible
bands are a go save for 60M (way to close to the IF to filter).

FYI the HW101 is dual conversion low IF at 3.395mhz and the second conversions is
hIghly pre-selected in the 8mhz range (tunable IF) to keep birdies down.  This was the
common technique for many radios and also KWM2, S51, HRO others many using
455khz filters in the last if.

There is a lot of history there for single and dual (even triple) conversion
and the key is those known to be great radios were big, well shielded and well 
filtered ( some with frightening mechanics to tune many stages).

At least two of the commercial radios I have Argo505 and the Triton have a 9mhz IF but are
from the 80/40/20/15/10 only era.  So bands like 17M are plagued with 2if (~18mhz) spurs, 
30M requires really good filters to keep 9mhz out of the air.  For those radios 60, 12M
are easy though. 

The only radio I have that has 500khz to 30mhz (+6M) tuning and a 9mhz HF First IF
is the Tentec Eagle first IF is 9mhz but the level of filtering is intense. You cannot tune
close to 9mhz without hearing negative effects.

So a single conversion can work but you have to jump a few hurdles.
IF it were easy everyone would have done it already.

If one is willing to dismiss with all that Phasing radios using digital IFs
are doable now with inexpensive processors and fairly simple RF to
base band conversion. That is other wise known as image rejecting
DC RX/TX where the image is the other sideband!

Allison


Re: Harmonics

ajparent1/KB1GMX <kb1gmx@...>
 

Jerry,
>>>Warren's Spectrum Analyzer screenshot of 2W out on 15m shows the 23mhz spur to be 50dB down,
which is fully compliant.       https://groups.io/g/BITX20/photo/65861/2?p=Name,,,20,1,0,0<<<

When you get the amp flattened out so it has gain that pops up.  Note, he is normalized to 2W.
Who's going to use 2W?  Who will push the mic?  

Now The cruft you see... look at that long explanation in #57038 about mixing and
making mush.  I only went the 4th harmonic.  The usual is not less than the 7th or 11th.

There is a detailed explanation and calculator for this at:
https://www.microwaves101.com/encyclopedias/spur-search

Its why its called mixer products not plain old signals.

Allison


Re: Harmonics

Arv Evans
 

Allison

Interesting thought...I wonder if anybody has tried using the "sub-harmonic mixer" idea in
a transceiver design?  Having the LO at half the mixer frequency might make things better
From limited reading it seems that there are both benefits and problems associated with
implementation. 

Arv
_._


On Tue, Aug 14, 2018 at 10:22 AM ajparent1/KB1GMX <kb1gmx@...> wrote:
Jerry,
It referred to your post  #57037
Its the exercise of why DBMs look easy but make people unhappy.
Nowhere is ther e more than one conversion in that discussion or even a receiver.
its about what you get from mixers (some much worse than others) for two simple
signals.

Now to your topic:
>>>>Perhaps my vague suggestion of going back to a single conversion rig.
The thought being, if we are adding all these filters between the first mixer and the power amp,
could make them all bandpass and do away with the 45mhz IF.  <<<<

First be warned its long and goes round some covering a lot of ground for what and why.

Opening:
The problem with single conversion is the choice of IF.  Minima used 20Mhz and 15M was 
too close for simple low loss wide filters.  The Minima issues spawned HF1 which begat 
uBitx.  The underlying desire was for low cost continuous tuning from some low frequency 
to at least 30mhz.   That is its history and its important as it is why some paths and 
choices came to be.

Single conversion does work.  I have 14 radios that mange to do well on on or many
bands though 2m!.  A few are even multiband radios.

Those that come to mind are the Tempo-one (9mhz if) but 17M and 30M are near impossible.
WM20 has an 8mhz IF, which is too close to 40M to do that.

Two of my radios have nice commercial 8 pole filters at 7.8mhz which rule out 40M also too close.

The Atlas-210X a classic 80/40/20/15/10 radio uses a IF of 5.520mhz single conversion.
It might work on 30M (the 2if spur is 10.44mhz but can be trapped). All the other possible
bands are a go save for 60M (way to close to the IF to filter).

FYI the HW101 is dual conversion low IF at 3.395mhz and the second conversions is
hIghly pre-selected in the 8mhz range (tunable IF) to keep birdies down.  This was the
common technique for many radios and also KWM2, S51, HRO others many using
455khz filters in the last if.

There is a lot of history there for single and dual (even triple) conversion
and the key is those known to be great radios were big, well shielded and well 
filtered ( some with frightening mechanics to tune many stages).

At least two of the commercial radios I have Argo505 and the Triton have a 9mhz IF but are
from the 80/40/20/15/10 only era.  So bands like 17M are plagued with 2if (~18mhz) spurs, 
30M requires really good filters to keep 9mhz out of the air.  For those radios 60, 12M
are easy though. 

The only radio I have that has 500khz to 30mhz (+6M) tuning and a 9mhz HF First IF
is the Tentec Eagle first IF is 9mhz but the level of filtering is intense. You cannot tune
close to 9mhz without hearing negative effects.

So a single conversion can work but you have to jump a few hurdles.
IF it were easy everyone would have done it already.

If one is willing to dismiss with all that Phasing radios using digital IFs
are doable now with inexpensive processors and fairly simple RF to
base band conversion. That is other wise known as image rejecting
DC RX/TX where the image is the other sideband!

Allison








Re: Harmonics

Kees T
 

 Jerry Gaffke
Aug 13   

Warren's Spectrum Analyzer screenshot of 2W out on 15m shows the 23mhz spur to be 50dB down,
which is fully compliant.       https://groups.io/g/BITX20/photo/65861/2?p=Name,,,20,1,0,0
Of course, shouting into the mike to get a bit more power out will make it worse.
And there is some worrying cruft below 15m, I have no idea where that's coming from.

Jerry
==============================================

So what is the problem again on 15m ?

73 Kees K5BCQ


Re: Harmonics

ajparent1/KB1GMX <kb1gmx@...>
 

Of course none of that helps the current uBITX owners but shows that in the last
4 years technology things hinted at then the current way.

And in there why it came to be this way.

Allison


Re: Harmonics

ajparent1/KB1GMX <kb1gmx@...>
 

Jerry,
It referred to your post  #57037
Its the exercise of why DBMs look easy but make people unhappy.
Nowhere is ther e more than one conversion in that discussion or even a receiver.
its about what you get from mixers (some much worse than others) for two simple
signals.

Now to your topic:
>>>>Perhaps my vague suggestion of going back to a single conversion rig.
The thought being, if we are adding all these filters between the first mixer and the power amp,
could make them all bandpass and do away with the 45mhz IF.  <<<<

First be warned its long and goes round some covering a lot of ground for what and why.

Opening:
The problem with single conversion is the choice of IF.  Minima used 20Mhz and 15M was 
too close for simple low loss wide filters.  The Minima issues spawned HF1 which begat 
uBitx.  The underlying desire was for low cost continuous tuning from some low frequency 
to at least 30mhz.   That is its history and its important as it is why some paths and 
choices came to be.

Single conversion does work.  I have 14 radios that mange to do well on on or many
bands though 2m!.  A few are even multiband radios.

Those that come to mind are the Tempo-one (9mhz if) but 17M and 30M are near impossible.
WM20 has an 8mhz IF, which is too close to 40M to do that.

Two of my radios have nice commercial 8 pole filters at 7.8mhz which rule out 40M also too close.

The Atlas-210X a classic 80/40/20/15/10 radio uses a IF of 5.520mhz single conversion.
It might work on 30M (the 2if spur is 10.44mhz but can be trapped). All the other possible
bands are a go save for 60M (way to close to the IF to filter).

FYI the HW101 is dual conversion low IF at 3.395mhz and the second conversions is
hIghly pre-selected in the 8mhz range (tunable IF) to keep birdies down.  This was the
common technique for many radios and also KWM2, S51, HRO others many using
455khz filters in the last if.

There is a lot of history there for single and dual (even triple) conversion
and the key is those known to be great radios were big, well shielded and well 
filtered ( some with frightening mechanics to tune many stages).

At least two of the commercial radios I have Argo505 and the Triton have a 9mhz IF but are
from the 80/40/20/15/10 only era.  So bands like 17M are plagued with 2if (~18mhz) spurs, 
30M requires really good filters to keep 9mhz out of the air.  For those radios 60, 12M
are easy though. 

The only radio I have that has 500khz to 30mhz (+6M) tuning and a 9mhz HF First IF
is the Tentec Eagle first IF is 9mhz but the level of filtering is intense. You cannot tune
close to 9mhz without hearing negative effects.

So a single conversion can work but you have to jump a few hurdles.
IF it were easy everyone would have done it already.

If one is willing to dismiss with all that Phasing radios using digital IFs
are doable now with inexpensive processors and fairly simple RF to
base band conversion. That is other wise known as image rejecting
DC RX/TX where the image is the other sideband!

Allison








Re: Does anyone have an AGC/Click kit to sell?

Ion Petroianu, VA3NOI
 

Sorry, the postage was $8.50, total cost was $11.50
--
Ion

VA3NOI


Re: Does anyone have an AGC/Click kit to sell?

Ion Petroianu, VA3NOI
 

I made some AGC boards for myself. Both TH and SMT. They use Don's schematic but a different layout than Kees used to offer.
They come in panels of 10 TH and 12 SMT. One panel is $3 plus postage.
Postage is expensive and slow from Canada. Bob Lebund got a panel from me and it was $11.50 to mail that one panel.
If you need some I still have 7 SMT panels and 10 TH panels.
You will have to supply the components.
Files showing the PCB and schematic and BOM for TH are here:
https://app.box.com/s/qf4jubi8942dhwdc8lhivctycnue4f12
--
Ion

VA3NOI


Re: Harmonics

Kees T
 

Nick, 'if" you are looking for more .............these are just suggestions.

This is how my board is wired, except that it uses plug-in LPFs. 

Shorter paths are always good.
Your relays may be different from mine but it looks like the N/C contact is connected to the LPFs. I would use the Armature
     for the LPFs so the N/C is ground and the N/O is the RF buss.
Traces should be ~60mil with no flood fill over a solid ground plane (better impedance control)
Double up on the capacitor footprints (for trimming caps)
Turn the middle inductor 90 degrees (to reduce coupling)
Place the diode and cap closer to the relay coil
Run the relay control/power wiring through the gap under the coils
+V goes to the "1" pin .....I've found relays that don't like to have the power reversed

73 Kees K5BCQ


Re: Chassis Wiring Twisted/Braided?

Clark Martin
 

Yes, definitely twist related wires together. For example, all three wires of the volume pot (3 wires), the speaker output (2), key (2), power (2 or 3), encoder (4), mic(3).  By twisting, what gets induced in one twist tends to get canceled out in the next.  And vice versa with regards to a cable emitting a signal.  But don’t twist together unrelated wires, those which you wouldn’t want crosstalk on.

As a side note, in Ethernet (and other) cables, not only is each pair twisted, the rate of twist (twists per inch) is different to avoid coupling from one pair to another.  If each pair had the same twist rate they would tend to couple as well as if there were no twists.

Clark Martin
KK6ISP

On Aug 14, 2018, at 7:55 AM, WD0AKZ <pasek001@...> wrote:

Over the years I have seen radio and computer chassis/board-to-board wiring as singles, twisted, or braided.  On all that I have built I generally twist the wires from board to board or to chassis components (always coax for RF & Mic) mainly because it gives a cleaner look and is easier to route.  I have heard some say that this is good or bad depending on what signals the particular wires are carrying.  So, in regards to the uBITX any suggested Do’s/Don’t other than keep the wiring as short as is practical or keep what away from what?




Re: Spurs - BPF fix? #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

Arv,

Interesting filter.  However how effect is it  at 23.8mhz (dial frequency of 21.2)?
Looks to be maybe 18db loss at that frequency.  It may be enough.


Allison


Re: uBITX and nulling the carrier #ubitx-help

ajparent1/KB1GMX <kb1gmx@...>
 

Madam George,  :)    HInt: MR Parent was my father, i am his daughter.

>>The skert or shape of 12 MHz filter is too great as you mentioned. Thus mooving BFO higher will give you not only carrier .<<

First moving it up applied to mine please read.  Also If I put it there I had the classic
tinny audio.  Any audio below 900hz would be at least 15db down or more, again for
my filter. The spectrum analyzer was used to measure and confirmation. I have both Rigol
and HP8568B as part of the instruments needed in my work.

I agree 2.5:1 (6:60db) shape factor is poor.  Part of it is the layout and grounding.
Actually carrier suppression is not a factor of the filter as it only adds to it.  The
assumption is balanced modulator works properly and is not compromised
by RF leakage paths.

I'm glad you did the work for yours.  You made a better filter.   I could easily built a
better filter using those 8 crystals as I was quite disappointed.  That was not the point. 
I repeat it was to measure and characterize the existing filter on the board.

I have better 45 mhz 4 pole filters as well for my parts bin.  I did also redesign
and correct the matching network to get the filter back on frequency as it
was also asymmetric and off frequency.

Many problems and many  small fixes.

Allison


Chassis Wiring Twisted/Braided?

WD0AKZ
 

Over the years I have seen radio and computer chassis/board-to-board wiring as singles, twisted, or braided.  On all that I have built I generally twist the wires from board to board or to chassis components (always coax for RF & Mic) mainly because it gives a cleaner look and is easier to route.  I have heard some say that this is good or bad depending on what signals the particular wires are carrying.  So, in regards to the uBITX any suggested Do’s/Don’t other than keep the wiring as short as is practical or keep what away from what?

Tnx

de George
WD0AKZ

Dit - dit


Re: FYI - a DIY source of some nice stuff.. #calibration #filters #parts

Jerry Gaffke
 

He's got some unique, properly designed, well documented stuff there.
Jerry


On Tue, Aug 14, 2018 at 07:11 AM, Lawrence Macionski wrote:
I received an email from Makis Katsouris, SV1AFN in Greece. He offers for sale a few nice items relevant to the BITX series of Transceivers. His latest addition is a GPS disiplined oscillator 1Khz to 1028 Mhz. If you want or need accurate, this is it!
He has a 1.8Mhz High pass filter to elimate BCB interference, and a 160-10 M Ham Band  pre-selector. Plus many other interesting items.

I have purchase from him and shipping from Greece to Kansas USA occurred within a week.
You can surf his offerings at:
https://www.sv1afn.com/

Larry W8LM


FYI - a DIY source of some nice stuff.. #calibration #filters #parts

Lawrence Macionski <am_fm_radio@...>
 

I received an email from Makis Katsouris, SV1AFN in Greece. He offers for sale a few nice items relevant to the BITX series of Transceivers. His latest addition is a GPS disiplined oscillator 1Khz to 1028 Mhz. If you want or need accurate, this is it!
He has a 1.8Mhz High pass filter to elimate BCB interference, and a 160-10 M Ham Band  pre-selector. Plus many other interesting items.

I have purchase from him and shipping from Greece to Kansas USA occurred within a week.
You can surf his offerings at:
https://www.sv1afn.com/

Larry W8LM



Re: Does anyone have an AGC/Click kit to sell?

N5KBP
 

I need one as well if there is anyone else out there with an extra one.

--
N5KBP


Re: Does anyone have an AGC/Click kit to sell?

 

Hi Chuck,

I have a set of each I'll sell you, please contact me at my email address.

Joel
N6ALT


Does anyone have an AGC/Click kit to sell?

Chuck K5IJD
 

Kees says he is out of stock.

If you have an extra, let me know & I will contact you to work out the details. 

Thanks,
--
73's DE Chuck K5IJD


New file uploaded to BITX20@groups.io

BITX20@groups.io Notification <BITX20+notification@...>
 

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the BITX20@groups.io group.

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Description:
Document with all the explanations of how to create this modification, including photos of traces to cut.

You can access this file at the URL:
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