This can't be good:-(
Joel
N6ALT
|
Re: RF power chain mods and improvements..
Arv:
I just got an explanation from Allison, which I will confirm
later. I measured the spurs in CW which I thought was a side tone,
but isn't. I need to retest with actual audio.
Howard
On 6/4/2018 12:21 PM, Arv Evans wrote:
toggle quoted message
Show quoted text
Howard
I'm
seeing about the same.
Arv
_._
On Mon, Jun 4, 2018 at 10:18 AM Howard Fidel < sonic1@...>
wrote:
Arv:
When properly driven, I see the spurs almost at -60dB.
Howard
On 6/4/2018 11:37 AM, Arv Evans wrote:
The
uBITX does actually work on 15M, 12M, and 10M (and yes
it does work on 11M as
evidenced
by the number of CB'ers who have purchased it).? Power
output is much lower
on
the higher bands, but is still enough to make QRP
contacts.? Just do not try to increase
power
output on upper bands by adding microphone gain.? Too
much microphone audio
will
cause spurs, distortion, and QRM.?
Arv?
K7HKL
_._
On Sun, Jun 3, 2018 at 9:01 PM Jerry
Gaffke via Groups.Io <jgaffke= [email protected]>
wrote:
To
keep the price down, I think hfsignals may as well
continue to use the 45mhz filter.
Perhaps claim 80m through 17m, beyond that is
experimental, disable 15m,12m, and 10m
in the stock firmware.? Different transistors for more
consistent gain should be considered.
However, if we can instrument drive level into the
mixers, sounds like we may be able to have
a clean signal on up to 30mhz.? ?Perhaps replace
transistors to get consistent gain through the 45mhz
IF
and the Q90 stage, then monitor the top of RV1 with a
diode RF probe into a Nano analog pin.
Better yet, add another 10dB of gain after the mixers
so the IRF510's show trouble (much more obvious)
long before the mixers do.? So maybe add an extra gain
stage between Q90 and RV1,
existing rigs could easily patch this in with an
MMIC.?
If we do decide to go to 70mhz and beyond for that
first IF, there are viable filters available.
In this post:??/g/BITX20/message/33203
Farhan explains that the 45mhz filter must be narrow
enough to reject signals 2 mhz away from center.
Here's the filters on Mouser that are between 70 and
90 mhz, and have a bandwidth of less than 4mhz:
? ??
The PX1002 from Murata looks good to me, center
frequency of 86.85mhz.
25khz wide, 3dB insertion loss, over 60dB of rejection
at 1mhz out,
datasheet shows how to use it in 50 ohm environment.
Not exactly cheap at $12 single unit, $6 if buying
hundreds from Mouser.
The similar PX1004 at 82.2mhz is harder to get,
especially in low quantities,
but might be preferred as it allows a lower vfo
frequency.?
To operate at 30mhz with an 86.85mhz first IF, the vfo
should be 86.85+30 = 116.85mhz.
The Si5351's internal vco is spec'd to a max of
900mhz, and our fractional output dividers can divide
down
to a minimum of 8.0, so 900/8=112.5mhz max using the
current si5351bx routines with the vco moved to
900mhz.
Hans, G0UPL, has found that the vco can be pressed to
go much higher, beyond 1100mhz,
so we could just cheat on that, perhaps 935mhz for the
vco giving 935/8 = 116.875mhz max.
I'd try that first.
The other possibility is to use the second Si5351
internal vco with fractional pll feedback and an
integer output divider on clk1, giving fine grained
frequency control up to 200mhz (290mhz, according to
Hans).
This second method would roughly double the size of
the si5351bx routines, but that's not a major hit.
The other two si5351 outputs would continue to use the
first vco, and be restricted to 112.5mhz max.
If using the equations of post?/g/BITX20/message/44278
the only needed change to the uBitx code outside the
Si5351bx routines would be to change this
uint32_t?
f45c? = 44995000;? ? ?// center of 45mhz filter
? to this:
uint32_t?
f45c? = 86850000;? ? ?// center of 87mhz filter
The filter and 50 ohm matching networks could
be on a very small PC board
glued to the back of the uBitx main board.
This daughterboard could include a new BiDi amp with
appropriate transistors.
If the uBitx mixers are problematic at 86.85mhz, then
perhaps a couple ADE-1's also,
replacing everything from T2 to T4 inclusive.? Parts
cost of around $10 if building hundreds,
$15 bucks if adding the two ADE-1's.?
Then everybody will get fixated on making the uBitx
work on 6 meters
and we get to do this all over again.
Jerry, KE7ER
?
On Sun, Jun 3, 2018 at 03:44 pm, ajparent1/KB1GMX
wrote:
Its not a drop in.? The filter would
likely be hard to find and costly or for a one off
salvage from?
an old junker commercial radio.?
I think Kenwood radios used a 63mhz filter or maybe
ICOM.? so lets do a thought
experiment on what needs to be done.
The filter would need to be matched and like data
for it will require experimental testing.
The T30-2 toroids could be reused and rewould and
the cap for the L-networks changed
as needed.? The entire string of 3904s [all 6 of
them] in the 45mhz section would have
to be some thing like 2n2369, or better BFR106s.?
Then the firmware has to be revised as the first lo
needs to be higher to start maybe
65mhz and go up from there.??
So yes it can be done.? I don't have such a part so
thats ruled out.? So for a one off
maybe, doesn't help everyone though. and even if the
filter was not too expensive?
thats a lot of SMT and through hole work plus a new
firmware.? At the production
level it could add significant cost and interrupt
the product flow as you have all the
material in place and likely paid for.
Right now the most feasible option is bandpass
filters and switching.? Cost wise the
parts are cheap is SMT inductors are used.? The
trick there is drop in and play no
manufacturing tuning.
Allison
|
I struggled initially and was overwhelmed ?with one and almost gave up.
Yesterday I spent the whole day with it.
Rather than spill my findings and problems I would like to encourage "everyone" to have the patience and ambition to tackle it.
Google for youTubes, look at all of them. Some of them are lousy, some will be WAY over your head, but there are some gems out there.
There are several ways of programming and using them,fortunately.
Do like I found and use the P&M method (plagurize ? & modify) ?until you can do one from scratch. There are several from scratch demos.
Now to find another spare day to continue. Retirement is a full time job tho. ?73, Bo W4GHV since '54
|
Re: RF power chain mods and improvements..
A reminder:
* Generating CW
?* The CW is cleanly generated by unbalancing the front-end mixer
?* and putting the local oscillator directly at the CW transmit frequency.
?* The sidetone, generated by the Arduino is injected into the volume control
?*/
Straight from the source code.? CW TX is not prone to the SPUR issue as it is a clean
signal at the operating frequency with no mixing.? We still have to have low pass
filters to remove harmonics but thats easy and works.
SSB we involve two IFs two FIlters and three Mixers.? Much more going on and?
with far more complex interactions.
Allison
|
Re: The new uBITX boards are here
I ordered a kit a few weeks ago and think I will be receiving the board with the updated discreet audio amp.? Somewhere I thought I saw that a 32 ohm speaker would be the best fit for this amp, but can't find this post anymore.? What is the best impedance and what is the approximate power out??
I found a small mylar speaker at Mouser that is 150 - 20K, but only 1/5 of a watt, 32 ohms.? Another speaker I found is a bit larger at another vendor, but is 16 ohms.? it is? 2 inches, and handles 2 watts, 180-17K so should be a bit better if this power amp puts out a watt or so.?
I can't seem to find the speaker that looks best for this "on paper" yet, just wondering about the new audio amp's requirements.
|
Re: RF power chain mods and improvements..
Howard
I'm seeing about the same.
Arv
_._
On Mon, Jun 4, 2018 at 10:18 AM Howard Fidel < sonic1@...> wrote:
Arv:
When properly driven, I see the spurs almost at -60dB.
Howard
On 6/4/2018 11:37 AM, Arv Evans wrote:
The
uBITX does actually work on 15M, 12M, and 10M (and yes it does
work on 11M as
evidenced
by the number of CB'ers who have purchased it).? Power output
is much lower
on
the higher bands, but is still enough to make QRP contacts.?
Just do not try to increase
power
output on upper bands by adding microphone gain.? Too much
microphone audio
will
cause spurs, distortion, and QRM.?
Arv?
K7HKL
_._
On Sun, Jun 3, 2018 at 9:01 PM Jerry Gaffke via
Groups.Io <jgaffke= [email protected]> wrote:
To keep the
price down, I think hfsignals may as well continue to use the
45mhz filter.
Perhaps claim 80m through 17m, beyond that is experimental,
disable 15m,12m, and 10m
in the stock firmware.? Different transistors for more
consistent gain should be considered.
However, if we can instrument drive level into the mixers,
sounds like we may be able to have
a clean signal on up to 30mhz.? ?Perhaps replace transistors
to get consistent gain through the 45mhz IF
and the Q90 stage, then monitor the top of RV1 with a diode RF
probe into a Nano analog pin.
Better yet, add another 10dB of gain after the mixers so the
IRF510's show trouble (much more obvious)
long before the mixers do.? So maybe add an extra gain stage
between Q90 and RV1,
existing rigs could easily patch this in with an MMIC.?
If we do decide to go to 70mhz and beyond for that first IF,
there are viable filters available.
In this post:??/g/BITX20/message/33203
Farhan explains that the 45mhz filter must be narrow enough to
reject signals 2 mhz away from center.
Here's the filters on Mouser that are between 70 and 90 mhz,
and have a bandwidth of less than 4mhz:
? ??
The PX1002 from Murata looks good to me, center frequency of
86.85mhz.
25khz wide, 3dB insertion loss, over 60dB of rejection at 1mhz
out,
datasheet shows how to use it in 50 ohm environment.
Not exactly cheap at $12 single unit, $6 if buying hundreds
from Mouser.
The similar PX1004 at 82.2mhz is harder to get, especially in
low quantities,
but might be preferred as it allows a lower vfo frequency.?
To operate at 30mhz with an 86.85mhz first IF, the vfo should
be 86.85+30 = 116.85mhz.
The Si5351's internal vco is spec'd to a max of 900mhz, and
our fractional output dividers can divide down
to a minimum of 8.0, so 900/8=112.5mhz max using the current
si5351bx routines with the vco moved to 900mhz.
Hans, G0UPL, has found that the vco can be pressed to go much
higher, beyond 1100mhz,
so we could just cheat on that, perhaps 935mhz for the vco
giving 935/8 = 116.875mhz max.
I'd try that first.
The other possibility is to use the second Si5351 internal vco
with fractional pll feedback and an
integer output divider on clk1, giving fine grained frequency
control up to 200mhz (290mhz, according to Hans).
This second method would roughly double the size of the
si5351bx routines, but that's not a major hit.
The other two si5351 outputs would continue to use the first
vco, and be restricted to 112.5mhz max.
If using the equations of post?/g/BITX20/message/44278
the only needed change to the uBitx code outside the Si5351bx
routines would be to change this
uint32_t?
f45c? = 44995000;? ? ?// center of 45mhz filter
? to this:
uint32_t?
f45c? = 86850000;? ? ?// center of 87mhz filter
The filter and 50 ohm matching networks could be on a
very small PC board
glued to the back of the uBitx main board.
This daughterboard could include a new BiDi amp with
appropriate transistors.
If the uBitx mixers are problematic at 86.85mhz, then perhaps
a couple ADE-1's also,
replacing everything from T2 to T4 inclusive.? Parts cost of
around $10 if building hundreds,
$15 bucks if adding the two ADE-1's.?
Then everybody will get fixated on making the uBitx work on 6
meters
and we get to do this all over again.
Jerry, KE7ER
?
On Sun, Jun 3, 2018 at 03:44 pm, ajparent1/KB1GMX wrote:
Its not a drop in.? The filter would likely be
hard to find and costly or for a one off salvage from?
an old junker commercial radio.?
I think Kenwood radios used a 63mhz filter or maybe ICOM.?
so lets do a thought
experiment on what needs to be done.
The filter would need to be matched and like data for it
will require experimental testing.
The T30-2 toroids could be reused and rewould and the cap
for the L-networks changed
as needed.? The entire string of 3904s [all 6 of them] in
the 45mhz section would have
to be some thing like 2n2369, or better BFR106s.?
Then the firmware has to be revised as the first lo needs to
be higher to start maybe
65mhz and go up from there.??
So yes it can be done.? I don't have such a part so thats
ruled out.? So for a one off
maybe, doesn't help everyone though. and even if the filter
was not too expensive?
thats a lot of SMT and through hole work plus a new
firmware.? At the production
level it could add significant cost and interrupt the
product flow as you have all the
material in place and likely paid for.
Right now the most feasible option is bandpass filters and
switching.? Cost wise the
parts are cheap is SMT inductors are used.? The trick there
is drop in and play no
manufacturing tuning.
Allison
|
What range did you use on your meter?
The ones in the transmit chain are working so when in transmit,
you should have 0.6V there.
Howard
On 6/4/2018 12:03 PM, hakan.sjostrom@... wrote:
toggle quoted message
Show quoted text
To check if the
trifilars are shorted I have to unsolder them, so I wait a little
with that.
But I measured the 3904:s. All of them had zero volts between base
and emitter.
I also measured the voltage between each leg and earth. The
highest voltage was around 0.005 volt. Looks strange to me..
And I must tell it was 30 years since I was an active ham, I am 70
now so I'm a little rusty on the electronic skills? ;-)
H?kan
|
Re: RF power chain mods and improvements..
Arv:
When properly driven, I see the spurs almost at -60dB.
Howard
On 6/4/2018 11:37 AM, Arv Evans wrote:
toggle quoted message
Show quoted text
The
uBITX does actually work on 15M, 12M, and 10M (and yes it does
work on 11M as
evidenced
by the number of CB'ers who have purchased it).? Power output
is much lower
on
the higher bands, but is still enough to make QRP contacts.?
Just do not try to increase
power
output on upper bands by adding microphone gain.? Too much
microphone audio
will
cause spurs, distortion, and QRM.?
Arv?
K7HKL
_._
On Sun, Jun 3, 2018 at 9:01 PM Jerry Gaffke via
Groups.Io <jgaffke= [email protected]> wrote:
To keep the
price down, I think hfsignals may as well continue to use the
45mhz filter.
Perhaps claim 80m through 17m, beyond that is experimental,
disable 15m,12m, and 10m
in the stock firmware.? Different transistors for more
consistent gain should be considered.
However, if we can instrument drive level into the mixers,
sounds like we may be able to have
a clean signal on up to 30mhz.? ?Perhaps replace transistors
to get consistent gain through the 45mhz IF
and the Q90 stage, then monitor the top of RV1 with a diode RF
probe into a Nano analog pin.
Better yet, add another 10dB of gain after the mixers so the
IRF510's show trouble (much more obvious)
long before the mixers do.? So maybe add an extra gain stage
between Q90 and RV1,
existing rigs could easily patch this in with an MMIC.?
If we do decide to go to 70mhz and beyond for that first IF,
there are viable filters available.
In this post:??/g/BITX20/message/33203
Farhan explains that the 45mhz filter must be narrow enough to
reject signals 2 mhz away from center.
Here's the filters on Mouser that are between 70 and 90 mhz,
and have a bandwidth of less than 4mhz:
? ??
The PX1002 from Murata looks good to me, center frequency of
86.85mhz.
25khz wide, 3dB insertion loss, over 60dB of rejection at 1mhz
out,
datasheet shows how to use it in 50 ohm environment.
Not exactly cheap at $12 single unit, $6 if buying hundreds
from Mouser.
The similar PX1004 at 82.2mhz is harder to get, especially in
low quantities,
but might be preferred as it allows a lower vfo frequency.?
To operate at 30mhz with an 86.85mhz first IF, the vfo should
be 86.85+30 = 116.85mhz.
The Si5351's internal vco is spec'd to a max of 900mhz, and
our fractional output dividers can divide down
to a minimum of 8.0, so 900/8=112.5mhz max using the current
si5351bx routines with the vco moved to 900mhz.
Hans, G0UPL, has found that the vco can be pressed to go much
higher, beyond 1100mhz,
so we could just cheat on that, perhaps 935mhz for the vco
giving 935/8 = 116.875mhz max.
I'd try that first.
The other possibility is to use the second Si5351 internal vco
with fractional pll feedback and an
integer output divider on clk1, giving fine grained frequency
control up to 200mhz (290mhz, according to Hans).
This second method would roughly double the size of the
si5351bx routines, but that's not a major hit.
The other two si5351 outputs would continue to use the first
vco, and be restricted to 112.5mhz max.
If using the equations of post?/g/BITX20/message/44278
the only needed change to the uBitx code outside the Si5351bx
routines would be to change this
uint32_t?
f45c? = 44995000;? ? ?// center of 45mhz filter
? to this:
uint32_t?
f45c? = 86850000;? ? ?// center of 87mhz filter
The filter and 50 ohm matching networks could be on a
very small PC board
glued to the back of the uBitx main board.
This daughterboard could include a new BiDi amp with
appropriate transistors.
If the uBitx mixers are problematic at 86.85mhz, then perhaps
a couple ADE-1's also,
replacing everything from T2 to T4 inclusive.? Parts cost of
around $10 if building hundreds,
$15 bucks if adding the two ADE-1's.?
Then everybody will get fixated on making the uBitx work on 6
meters
and we get to do this all over again.
Jerry, KE7ER
?
On Sun, Jun 3, 2018 at 03:44 pm, ajparent1/KB1GMX wrote:
Its not a drop in.? The filter would likely be
hard to find and costly or for a one off salvage from?
an old junker commercial radio.?
I think Kenwood radios used a 63mhz filter or maybe ICOM.?
so lets do a thought
experiment on what needs to be done.
The filter would need to be matched and like data for it
will require experimental testing.
The T30-2 toroids could be reused and rewould and the cap
for the L-networks changed
as needed.? The entire string of 3904s [all 6 of them] in
the 45mhz section would have
to be some thing like 2n2369, or better BFR106s.?
Then the firmware has to be revised as the first lo needs to
be higher to start maybe
65mhz and go up from there.??
So yes it can be done.? I don't have such a part so thats
ruled out.? So for a one off
maybe, doesn't help everyone though. and even if the filter
was not too expensive?
thats a lot of SMT and through hole work plus a new
firmware.? At the production
level it could add significant cost and interrupt the
product flow as you have all the
material in place and likely paid for.
Right now the most feasible option is bandpass filters and
switching.? Cost wise the
parts are cheap is SMT inductors are used.? The trick there
is drop in and play no
manufacturing tuning.
Allison
|
Re: RF power chain mods and improvements..
Arv,
You're right, it works at 15,12,10m.
And while I don't have a spectrum analyzer to verify this,?
my impression is that with mike gain sufficiently down the signal is legal.
Unfortunately, if only getting 0.5w on 10m, it will be human nature to shout louder
or add an external mike amp to get that power up.
It won't be obvious where the line is between an appropriate mike level?
and too high of level where it is transmitting a second signal at 45mhz-30mhz = 15mhz.
This spur needs to be addressed somehow, though not necessarily a complete redesign.
My favorite thus far, if it works, is to add another 10dB or so of gain between Q90 and RV1.
with an MMIC on a little daughterboard.? Too much mike gain is now obvious, because
the power amp will be non-linear.? Monitoring the operating frequency will show obvious
distortion and splatter, unlike the rather subtle spur that develops when overdriving the mixers.
I think.
Jerry, KE7ER
?
|
Re: Correct levels from computer to uBitx in digimodes
A VERY IMPORTANT point!
I'm fortunate to have an Icom7300 with a visible spectrum ?display.
I ordered a handy smeter kit and am going to put it on the ubitx Mike input line to set the level correctly.
Now I adjust it based upon the icom display and until the power starts to drop on the wattmeter.
Too much definitely puts you on the ham bands at MORE THAN ONE frequency!
Wish I had a small low level measuring instrument handy.
Wondering if those little $90 "digital scopes" work?
73, Bo W4GHV since '54
|
To check if the trifilars are shorted I have to unsolder them, so I wait a little with that.
But I measured the 3904:s. All of them had zero volts between base and emitter.
I also measured the voltage between each leg and earth. The highest voltage was around 0.005 volt. Looks strange to me..
And I must tell it was 30 years since I was an active ham, I am 70 now so I'm a little rusty on the electronic skills? ;-)
H?kan
|
Ouch! Then they can snatch GOOD programs to use and sell for free? Except for their buying price??
|
Microsoft¡¯s Open Source Coup: It¡¯s Buying GitHub for $7.5 Billion
Vince - K8ZW.
--
Michigan VHF Corp.
|
Re: RF power chain mods and improvements..
The uBITX does actually work on 15M, 12M, and 10M (and yes it does work on 11M as
evidenced by the number of CB'ers who have purchased it).? Power output is much lower
on the higher bands, but is still enough to make QRP contacts.? Just do not try to increase
power output on upper bands by adding microphone gain.? Too much microphone audio
will cause spurs, distortion, and QRM.?
Arv? K7HKL
_._
On Sun, Jun 3, 2018 at 9:01 PM Jerry Gaffke via Groups.Io <jgaffke= [email protected]> wrote: To keep the price down, I think hfsignals may as well continue to use the 45mhz filter.
Perhaps claim 80m through 17m, beyond that is experimental, disable 15m,12m, and 10m
in the stock firmware.? Different transistors for more consistent gain should be considered.
However, if we can instrument drive level into the mixers, sounds like we may be able to have
a clean signal on up to 30mhz.? ?Perhaps replace transistors to get consistent gain through the 45mhz IF
and the Q90 stage, then monitor the top of RV1 with a diode RF probe into a Nano analog pin.
Better yet, add another 10dB of gain after the mixers so the IRF510's show trouble (much more obvious)
long before the mixers do.? So maybe add an extra gain stage between Q90 and RV1,
existing rigs could easily patch this in with an MMIC.?
If we do decide to go to 70mhz and beyond for that first IF, there are viable filters available.
In this post:??/g/BITX20/message/33203
Farhan explains that the 45mhz filter must be narrow enough to reject signals 2 mhz away from center.
Here's the filters on Mouser that are between 70 and 90 mhz, and have a bandwidth of less than 4mhz:
? ??
The PX1002 from Murata looks good to me, center frequency of 86.85mhz.
25khz wide, 3dB insertion loss, over 60dB of rejection at 1mhz out,
datasheet shows how to use it in 50 ohm environment.
Not exactly cheap at $12 single unit, $6 if buying hundreds from Mouser.
The similar PX1004 at 82.2mhz is harder to get, especially in low quantities,
but might be preferred as it allows a lower vfo frequency.?
To operate at 30mhz with an 86.85mhz first IF, the vfo should be 86.85+30 = 116.85mhz.
The Si5351's internal vco is spec'd to a max of 900mhz, and our fractional output dividers can divide down
to a minimum of 8.0, so 900/8=112.5mhz max using the current si5351bx routines with the vco moved to 900mhz.
Hans, G0UPL, has found that the vco can be pressed to go much higher, beyond 1100mhz,
so we could just cheat on that, perhaps 935mhz for the vco giving 935/8 = 116.875mhz max.
I'd try that first.
The other possibility is to use the second Si5351 internal vco with fractional pll feedback and an
integer output divider on clk1, giving fine grained frequency control up to 200mhz (290mhz, according to Hans).
This second method would roughly double the size of the si5351bx routines, but that's not a major hit.
The other two si5351 outputs would continue to use the first vco, and be restricted to 112.5mhz max.
If using the equations of post?/g/BITX20/message/44278
the only needed change to the uBitx code outside the Si5351bx routines would be to change this
uint32_t? f45c? = 44995000;? ? ?// center of 45mhz filter
? to this:
uint32_t? f45c? = 86850000;? ? ?// center of 87mhz filter
The filter and 50 ohm matching networks could be on a very small PC board
glued to the back of the uBitx main board.
This daughterboard could include a new BiDi amp with appropriate transistors.
If the uBitx mixers are problematic at 86.85mhz, then perhaps a couple ADE-1's also,
replacing everything from T2 to T4 inclusive.? Parts cost of around $10 if building hundreds,
$15 bucks if adding the two ADE-1's.?
Then everybody will get fixated on making the uBitx work on 6 meters
and we get to do this all over again.
Jerry, KE7ER
?
On Sun, Jun 3, 2018 at 03:44 pm, ajparent1/KB1GMX wrote:
Its not a drop in.? The filter would likely be hard to find and costly or for a one off salvage from?
an old junker commercial radio.?
I think Kenwood radios used a 63mhz filter or maybe ICOM.? so lets do a thought
experiment on what needs to be done.
The filter would need to be matched and like data for it will require experimental testing.
The T30-2 toroids could be reused and rewould and the cap for the L-networks changed
as needed.? The entire string of 3904s [all 6 of them] in the 45mhz section would have
to be some thing like 2n2369, or better BFR106s.?
Then the firmware has to be revised as the first lo needs to be higher to start maybe
65mhz and go up from there.??
So yes it can be done.? I don't have such a part so thats ruled out.? So for a one off
maybe, doesn't help everyone though. and even if the filter was not too expensive?
thats a lot of SMT and through hole work plus a new firmware.? At the production
level it could add significant cost and interrupt the product flow as you have all the
material in place and likely paid for.
Right now the most feasible option is bandpass filters and switching.? Cost wise the
parts are cheap is SMT inductors are used.? The trick there is drop in and play no
manufacturing tuning.
Allison
|
Re: KD8CEC uBITX firmware 1.071
#ubitx
The advice given at this thread works well to get you back on track if your calibration gets knocked out of wack: /g/BITX20/message/47750Dan, W2DLC
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Re: Correct levels from computer to uBitx in digimodes
inline wattmeter? set as needed to keep from overheating.? PSK31 about 1/3 to 1/4 power.
It will be different for different modes and bands.
Many of my radios don't have ALC to watch so you need to know whats going out.
Allison
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Re: RF power chain mods and improvements..
With the 86mhz filter you need 98mhz and 74mhz for downconversion to 12mhz.
Thn you need LO to signal, with 86mhz filter maybe (have to run a spur table)
83 down to 55mhz? (LO below IF) will work.? Could work on first glance.
Or very simple three filters for 15/12/10 and switching to insert them in before?
the power amp, it can be done with diode as the levels are well below -10dbm
at that point.? ?Add a 10-12db mmic after that with max power out of 10dbm
and push for lower gain in the whole strip.? ?To select the filters we can use?
existing lines TXB and TXC mean thing until TXA is switched as there are
unused states there.?
For band pass selection we have the existing Low pass filter selectors.
TXA? ? TXB? ? TXC
---------------------------------------
0? ? ? ? ? 0? ? ? ? ? ?0? ? ? 30mhz LPF
1? ? ? ? ? 0? ? ? ? ? ?0? ? ?20-17m LPF
1? ? ? ? ? 1? ? ? ? ? ?0? ? ?40-30M LPF
1? ? ? ? ? 1? ? ? ? ? ?1? ? ?80-60M LPF
?Unused states 011 and 001
For for over 21mhz we have two control lines to select filters with TXB and TXC.
TXA =0 means the 20-30mhz selection TXA=1 means below 20mhz selection
or no additional band pass filters required.
So we can select up to 4 filters(two lines encoded) as needed with just a bit
more program logic.? Using the two lines raw then? and two of three (15, 12
and 10) can be selected.
And 6M, sure redesign the entire power chain everything, except for the irf510.
What is it about stuffing 7 pounds in a 5 pound box???
Allison
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Congratulations Michael.
Is a DRA-ITX or a BIT-KE rsrsrs?
Nicely done.
73 Saulo PY7EG
Here's a couple pics of my just finished Ubitx project...I call it my Drake TR8 QRP? built in a Drake MS7 speaker cabinet...Mike W4ZGI
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Ubitx factory firmware support CAT control?
#ubitx
Sorry for my question if answered already.
I want to know whether ubitx factory firmware support cat control or i need to install others.
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Re: BITX QSO Afternoon/Evening, Sunday, June 3, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
Howard,? I called CQ a couple of times after I talked to Stan, then went to bed.?
Dan, W2DLC
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Joel Caulkins/N6ALT