¿ªÔÆÌåÓý

Date

Re: The new uBITX boards are here

 

For use around the house, I plugged in a pair of old computer speakers I was not using.? While only one of them puts out sound as is (stereo speakers), it sounds very good.? The amp in the speaker helps boost the sound level.?



On Mon, Jun 4, 2018 at 5:04 PM, Arv Evans <arvid.evans@...> wrote:
Jamie

It depends...on how you will be using your BITX.? For CW only your speaker might be
good if its response peaks at around 700 Hz.? For SSB only you might like a speaker
that has a "communications passband" of between 200 and 3200 Hz.? Amateur radio
does not require full bandwidth high-fidelity sound.?

Almost any small speaker will work.? The acoustic characteristics of the speaker housing
is usually more important than the speaker specification.?

Audio amplifier IC's usually use some sort of push-pull or totem-pole output stage and
thus will match from 4 ohms upward to 100 ohms.? Audio output power is usually
dependent on speaker impedance.? Lower impedance works the audio amplifier harder
and delivers more audio output.? It helps to look up the datasheet specification for the
particular AF output device to see what it says is best for impedance match and for
maximum output at specific impedances.

Arv? K7HKL
_._


On Mon, Jun 4, 2018 at 10:24 AM Jamie Anderson <jamiea@...> wrote:
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..

 

The significant spur is generated in the last mixer where 45mhz IF on one port, 73mhz lo,
and the signal at 28mhz out plus 17mhz spur.? The spur at low levels tracks both the tuning?
and the drive level, no drive no significant signal (in the Spec-A? noise about -100DBM).

The other is a side result of 11.995(+-) leaking.? That guy is there but very weak
and well below the level of concern.

Allison


Re: Github's future?

Bo Barry
 

Google has or had something


Nextion NX3224K028 in TWO days! #ubitx #parts

Bo Barry
 

On eBay from Kansas.? It's the 2.8" enhanced model with RTC and GPIO
.
He has a direct sales site too. If you plan to order one before July 31st drop me an email and I'll give you the company link and code for a 5% discount!

73, Bo W4GHV since '54
my Gmail is the same as my Novice call in '54 WN4GHV? (to make it long enough for Gmail)


Re: Github's future?

 

There are several other on-line version-control systems.? Some are free and others
charge high prices for their use.? Some have potential for BITX code development
work, and some less appropriate.?
Those of us using Linux already have local RCS and VCS that was migrated from ancient
UNIX tools.? CVCS (Concurrent Version Control System) is also available on Linux systems.
Some of the readily available IDE packages also include either RCS or CVS tools.? Of course
these are local solutions, but they could be made accessible to others via a shared file
system on cloud-computing servers.

If the Microsoft purchase of GitHub does become a problem then we might want to look at
some of these alternatives.?

It might be interesting to approach the people who made and support to see if they
could include some sort of version control as an option for groups that are interesting in code
development..

Arv
_._


On Mon, Jun 4, 2018 at 10:34 AM Joel Caulkins <caulktel@...> wrote:
This can't be good:-(

Joel
N6ALT


Re: RF power chain mods and improvements..

 

>>For my tests I inserted 1KHz at variable levels and adjusted the audio level for?
cleanest RF on the oscilloscope.? Then I performed a frequency sweep to look for?
spurs.? As long as the microphone port audio input is below 45 millivolts the spurs seem?
to be down at least 50db, but can be pushed even further down by reducing the audio?
level to around 32 millivolts.? This seems to be where oscilloscope peak-to-peak RF level?
is about the same as when using CW mode.??<<<

What was the power out on 10M?

The actual input I was using was such that full up was 150mv P-P (about 100mV rms)
and usually lower at 70mvPP (50mVrms).

Adding a band pass filter for 10m helped.? at 80/40/20m there were no significant
spurs, save for harmonics about 50 db down.

Allison


Re: RF power chain mods and improvements..

 

Ralph,? What was the line up of mods.

The spur is not a linearity issue its just there.
I inserted a band pass filter haywired in at 28Mhz and though sloppy the spur was?
suppressed an additional 20DB (-73dbc).? That was with most of my mods at 8W
and the input level driven to 80M max levels.

Generally the amp has been reasonably linear, just hurting for gain from
about 8mhz to 28mhz.?

Allison


Re: RF power chain mods and improvements..

 

Allison is correct that things are much cleaner when using CW.?

For my tests I inserted 1KHz at variable levels and adjusted the audio level for
cleanest RF on the oscilloscope.? Then I performed a frequency sweep to look for
spurs.? As long as the microphone port audio input is below 45 millivolts the spurs seem
to be down at least 50db, but can be pushed even further down by reducing the audio
level to around 32 millivolts.? This seems to be where oscilloscope peak-to-peak RF level
is about the same as when using CW mode.?

I could not duplicate this using an averaging type RF voltmeter as the signal level detector.

It is interesting to vary the microphone port input frequency and watch each spur to see
if it moves up or down.? This could be an aid in figuring out how each spur is being
generated.?

Arv
_._


Arv
_._


On Mon, Jun 4, 2018 at 10:32 AM Howard Fidel <sonic1@...> wrote:
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:
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




Re: Nextion Display

 

Bo ?
I know exactly what you are talking about but I now feel like I am making some progress. I hope Dr. Ian makes some of his work with the Nextion ?available to us soon.
I liked your last sentence, I sometimes feel like I had more free time before I retired than I do now.?
73's ?kn4ud ?
--
Allen ?Merrell


Re: The new uBITX boards are here

 

Jamie

It depends...on how you will be using your BITX.? For CW only your speaker might be
good if its response peaks at around 700 Hz.? For SSB only you might like a speaker
that has a "communications passband" of between 200 and 3200 Hz.? Amateur radio
does not require full bandwidth high-fidelity sound.?

Almost any small speaker will work.? The acoustic characteristics of the speaker housing
is usually more important than the speaker specification.?

Audio amplifier IC's usually use some sort of push-pull or totem-pole output stage and
thus will match from 4 ohms upward to 100 ohms.? Audio output power is usually
dependent on speaker impedance.? Lower impedance works the audio amplifier harder
and delivers more audio output.? It helps to look up the datasheet specification for the
particular AF output device to see what it says is best for impedance match and for
maximum output at specific impedances.

Arv? K7HKL
_._


On Mon, Jun 4, 2018 at 10:24 AM Jamie Anderson <jamiea@...> wrote:
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..

 

I don't recall the exact amount of power out but it was greater than 6 1/2 watts out.

My thinking is that if I put in a 1000 hz tone in the mic input and wound it up to the maximum and backed off a db or so?
whatever stage was saturating would come out of saturation and be more or less linear.

This was after being in the CW mode that I used the pot on the ubitx board to get the maximum out and backed it off some to where the power just started? to fall off.


On Mon, Jun 4, 2018 at 3:47 PM, Tim Gorman <tgorman2@...> wrote:
When the power starts to fall off you are still putting out 8 watts
with the 1000 hz tone?

tim ab0wr

On Mon, 4 Jun 2018 13:04:33 -0400
"Ralph Mowery" <rmowery42@...> wrote:

> Using a HP 8924c in the SA mode I do not seem to be seeing any of the
> spurs down to at least
> - 50 dbm.? That is by feeding in a 1000 hz tone to the mic input and
> adjusting the audio level to maximum output and cutting it back to
> where the power just falls off.
>
> However I do see the carrier (that is supposed to be suppressed) of
> about -5 to 0 dbm.? That is with the modifications and RD16HHF1
> outputs for a power of about 8 watts on 28 MHz.



Re: RF power chain mods and improvements..

 

When the power starts to fall off you are still putting out 8 watts
with the 1000 hz tone?

tim ab0wr

On Mon, 4 Jun 2018 13:04:33 -0400
"Ralph Mowery" <rmowery42@...> wrote:

Using a HP 8924c in the SA mode I do not seem to be seeing any of the
spurs down to at least
- 50 dbm. That is by feeding in a 1000 hz tone to the mic input and
adjusting the audio level to maximum output and cutting it back to
where the power just falls off.

However I do see the carrier (that is supposed to be suppressed) of
about -5 to 0 dbm. That is with the modifications and RD16HHF1
outputs for a power of about 8 watts on 28 MHz.


On Mon, Jun 4, 2018 at 11:37 AM, Arv Evans <arvid.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


------------------------------


Re: Building homebrew ubitx: Need pre-v3 schematic PDF. Also, source for 45M15 (45 MHz IF) filter?

 

I believe this is the original uBitx schematic:? ?

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.
I believe he is using the 45m15a, which is probably 15 khz wide with two poles.
But most anything 45mhz with 2 or 4 poles will work.
Bandwidth of available filters varies from 7.5 khz to 30khz, this shouldn't matter much either.?

A search for "45 mhz crystal filter two pole" finds this throughole part, in stock at Mouser:
? ??ECS ECS-45K20A
I'd guess that will work fine.

Most such crystal filters are now surface mount.
Those would work too, but may be harder to hack into an existing PC board.
I don't think I would bother with creating a new board.
? ??

Perhaps a more serious issue for you is that the old uBitx schematic only shows
two low pass filters after the IRF510's.? These did not sufficiently attenuate the second harmonic.
The current design has four low pass filters there.??
If all you have is two LPF's, I suggest you stuff them for your favorite two bands.
Lower bands could be supported by adding an appropriate LPF stolen from the current uBitx design
in line with your antenna coax.? Of course, whichever of the two LPF's inside the rig that you select,
nothing higher than that will get out to the antenna port.? ?
I suggest stuffing LPF's for 20 and 40 meters (also covering 17m and 30m, respectively),
use an external LPF for 80m.

Give anything above 17m a pass for now, as those bands are a bit problematic.
Power out can be down under a watt on those high bands, and we can have an out of band spur
when transmitting.? Those issues are still being resolved.

Jerry, KE7ER



?

On Mon, Jun 4, 2018 at 11:32 am, David Feldman wrote:
This posting contains two questions:

I am building a homebrew version of ubitx (on PCB layout I created myself). PCB was manufactured a year ago, but did not start bringing up circuit at that time.

Since about 2 weeks ago, I have been bringing up the receive path first (along with necessary microcontroller and synthesizer stages), one stage at a time, beginning with the loudspeaker, and so far having good results and fun experience.

I realize now (that I am at the 45 MHz IF filter, heading towards the first mixer) that I did not save schematic I used to create PCB, and v3 schematic (more recent) includes a part (the 45 MHz crystal filter) I did not find in the version I based my PCB layout on. I understand the benefit of the filter, however, I wish to continue progress on my PCB based on older design, as I will gather changes (including use of the newer IF filter design) for a future PCB rev.

My PCB layout assumed multi-pole LC filter from the schematic I had available at the time (original or maybe v2, but not v3 or later). In this version, the 45M15(A? B? F?) filter was not included, and it is not present on my PCB layout.

So, I have two questions:

1. What is URL or other way to find version of ubitx based on LC filter in 45 MHz path?

2. Where is current source for the 45M15 (A? B? F?) filter used in V3 and later designs? I did not find it in search on US distributors nor on ebay; I understand these should be low cost part with good availability, so I think I am not looking in right place?

Thank you, and this is very enjoyable project!

73 Dave WB0GAZ wb0gaz@...


Re: Correct levels from computer to uBitx in digimodes

 

I used my DS202 pocket scope, $99 Amazon, to read the output from the stock mic into the radio while saying aaahhhh at a normal volume. Then installed a SSM2167 board with a 10k potentiometer on the output and adjusted it for about 125% of the previous reading.? That little scope works great for audio levels.? It's cute too.
--
Lee - N9LO? "I Void Warranties"

?


Re: Github's future?

 

Microshaft, more control for them less choice for us just what they say we can have. Monopoly !!
--
Allen ?Merrell


Re: Building homebrew ubitx: Need pre-v3 schematic PDF. Also, source for 45M15 (45 MHz IF) filter?

 

The same schematic works for both. I will send you the LC filter details if you need them. The 45 mhz filters are regularly available on ebay.
- f

On 5 Jun 2018 12:02 am, "David Feldman via Groups.Io" <wb0gaz=[email protected]> wrote:
This posting contains two questions:

I am building a homebrew version of ubitx (on PCB layout I created myself). PCB was manufactured a year ago, but did not start bringing up circuit at that time.

Since about 2 weeks ago, I have been bringing up the receive path first (along with necessary microcontroller and synthesizer stages), one stage at a time, beginning with the loudspeaker, and so far having good results and fun experience.

I realize now (that I am at the 45 MHz IF filter, heading towards the first mixer) that I did not save schematic I used to create PCB, and v3 schematic (more recent) includes a part (the 45 MHz crystal filter) I did not find in the version I based my PCB layout on. I understand the benefit of the filter, however, I wish to continue progress on my PCB based on older design, as I will gather changes (including use of the newer IF filter design) for a future PCB rev.

My PCB layout assumed multi-pole LC filter from the schematic I had available at the time (original or maybe v2, but not v3 or later). In this version, the 45M15(A? B? F?) filter was not included, and it is not present on my PCB layout.

So, I have two questions:

1. What is URL or other way to find version of ubitx based on LC filter in 45 MHz path?

2. Where is current source for the 45M15 (A? B? F?) filter used in V3 and later designs? I did not find it in search on US distributors nor on ebay; I understand these should be low cost part with good availability, so I think I am not looking in right place?

Thank you, and this is very enjoyable project!

73 Dave WB0GAZ wb0gaz@...





Building homebrew ubitx: Need pre-v3 schematic PDF. Also, source for 45M15 (45 MHz IF) filter?

 

This posting contains two questions:

I am building a homebrew version of ubitx (on PCB layout I created myself). PCB was manufactured a year ago, but did not start bringing up circuit at that time.

Since about 2 weeks ago, I have been bringing up the receive path first (along with necessary microcontroller and synthesizer stages), one stage at a time, beginning with the loudspeaker, and so far having good results and fun experience.

I realize now (that I am at the 45 MHz IF filter, heading towards the first mixer) that I did not save schematic I used to create PCB, and v3 schematic (more recent) includes a part (the 45 MHz crystal filter) I did not find in the version I based my PCB layout on. I understand the benefit of the filter, however, I wish to continue progress on my PCB based on older design, as I will gather changes (including use of the newer IF filter design) for a future PCB rev.

My PCB layout assumed multi-pole LC filter from the schematic I had available at the time (original or maybe v2, but not v3 or later). In this version, the 45M15(A? B? F?) filter was not included, and it is not present on my PCB layout.

So, I have two questions:

1. What is URL or other way to find version of ubitx based on LC filter in 45 MHz path?

2. Where is current source for the 45M15 (A? B? F?) filter used in V3 and later designs? I did not find it in search on US distributors nor on ebay; I understand these should be low cost part with good availability, so I think I am not looking in right place?

Thank you, and this is very enjoyable project!

73 Dave WB0GAZ wb0gaz@...


Re: Correct levels from computer to uBitx in digimodes

Joe Puma
 

¿ªÔÆÌåÓý

When I hooked my bitx40 to my computer I adjusted audio coming out of the computer ?using the volume in computer mixer and monitoring on another radio. For wsjtx I used the waterfall as a visual aid and the radios volume knob to adjust audio into computer.?

This worked well. There is room to play but looking how other applications join a radio with a computer like when making a AllStar node and wiring up speaker and Mic to a computer people put resistors in place to bring the levels down. Like 68k ohms on the radio audio out. Taken before the volume pot so the pot is not controlling the volume. And 10k ohms on the Mic in on radio.?

Here¡¯s the example I am talking about.?

image1.jpeg

What I found that might be more useful instead of worrying about signal levels is hooking the radio up so it¡¯s not electrically connected by using some 1:1 transformers. I found that with using my 100w radio and long audio wires your setup might be susceptible to RF getting in the wires. ?I have an issue on 40 meters with RF getting in my audio if I use my powered mic or long extension wires on my Mic cable. Ferrite beads don¡¯t seem to solve the problems.?

Joe
Kd2nfc?



On Jun 4, 2018, at 10:02 AM, Jan Brink <janbrink@...> wrote:

How does one determine the correct output level from computer to mic in on the uBitx for digimodes like FT8 JT65 PSK etc.? On my FT817 / 897 I watch ALC level. How to do this on the uBitx? ?

Jan
PD0JBZ


Re: Github's future?

 

Agreed, not good.? Anyone aware of an alternate platform for sharing code?


Re: Nextion Display

 

Jack
Thanks for the reply, LOL, I have the book and I need to dig it out and get back into it again. The work you and AL did is fantastic. I just hope to get a similar result with less options on a smaller display. The filter part I am just not going to try programming that I am going to cheat and use a Sotabeam adjustable that I have this will cure filter and audio amp all in one package but just won't ?be on the screen.
73's ?kn4ud ?
--
Allen ?Merrell