Date   
JackAl Voltage Chart

Jack, W8TEE
 

All:

The voltage chart for the JackAl board is now posted on hamradiodesigns.com. The program source code will be available for download on Monday.

Jack, W8TEE
Al, AC8GY


Re: uBitX v4.3 calibration

_Dave_ K0MBT
 

Yeah Vic you want to calibrate the frequency display first. I didn't like using wwv for calibration of frequency. They have the intermittent carrier. I reloaded to a version 1.08 of kd8cec and tuned it to a Commercial AM station I figured a big station would have a much more accurate carrier than I would need. Once you do that then go back in and set the bfo to 11996500 or so and adjust it from there.

I tried the latest version of kd8cec, 1.1, but didn't find the option to run it on the 1602 display,

Vic see you down the log.
73
Dave
k0mbt

Re: Tracing receive signal for low signal

jim
 

Random cutting of traces is not "my" way of trouble finding ..tho at times I've  been tempted ..Amps at Q12 and Q32 would both need to be well terminated as they would be terminated into the crystal filters ..Both (any) crystal filter is highly reactive around the passband frequency and as such need to be well matched/terminated ..Easiest to add amp at antenna end 50 ohm in/out ..use relay or switch to control receive/transmit ..

That being said, I've dead-bugged a version of the Q30/31/32 amp ..replacing Q31 with a PNP (2n3906).. R31=10 k and R34 150 ohms.. collector of Q31 to R35 ,,,gives (at first glance) ~50 db gain ... Have yet to hack the microBitx to really try it tho

Expect it will be noisy and unstable , but ...maybe

Jim


On Saturday, January 12, 2019, 5:55:15 PM PST, Dave Space <davesspacebar@...> wrote:



So given there doesn't seem to be any significant loading there.  So don't think it makes sense to cut the trace to the mixer anymore right to test?

Evans board seems to match a lot of the voltage levels on parts so seems like something else is up perhaps.
It seems like we do know with enough power things will work... so potentially could just add amplifier stages after Q12 and after Q32 would likely workaround the rather anemic receive?  



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Re: Tracing receive signal for low signal

Dave Space
 

I had that pre-amp earlier in the receive line between K3 and K1 and what I noticed that amp vs the new pre-amp I put in at volume high  is the pre-amp between K3 and K1 just sounded like it amplified the noise as much as the signal making the noise as loud as the signal.  Where the amp at vol high seems to have done a better job picking up the signal and less noise (at least if I don't have the gain too high).
I think maybe because the low pass filter rejected a bunch of noise so the amplification stages amplified less of the noise (at least that's the best way I could describe it from a noise quality I can hear).  Thus why I was thinking it might be better to amplify after the low pass filters (it probably lost some signal there also anyway).

What I'm thinking is two transistor stages common emitter then emitter follower to get the low output impedance for following Q12 (so common emitter + emitter follower )and Q32 (common emitter + emitter follower)

The only other way I can think of to track down the board differences is buy a second uBitx board that hopefully works (though I'd be hosed if it didn't) and just analyze component by component all the way through until I find something with a meaningful difference.

Re: Tracing receive signal for low signal

Dave Space
 

Actually I think with the pre-amp I might have had a loose connection and had to adjust the gain.
It seems a lot better now.  I actually got around 130mv p-p at vol high with 100uV into the antenna.  I might have been getting inconsistent readings due to the breadboard loose connections or something.

Also often I would do some initial on air tests with a ham stick before switching over to my full 40m dipole.

I need to do more testing but the on air tests sound really good with this pre-amp in place now and connections good.

I might need to actually dead bug the pre-amp onto an actual board to keep the connections from being loose.

(at the moment I'm listening to a s7-s9 signal over the earbuds and I'm not wearing them they are on the other side of the room :) )

Re: Tracing receive signal for low signalou've

jim
 

If you've got it working to your satisfaction, thats probably a good place to stop ..

Jim


On Saturday, January 12, 2019, 9:43:00 PM PST, Dave Space <davesspacebar@...> wrote:


Actually I think with the pre-amp I might have had a loose connection and had to adjust the gain.
It seems a lot better now.  I actually got around 130mv p-p at vol high with 100uV into the antenna.  I might have been getting inconsistent readings due to the breadboard loose connections or something.

Also often I would do some initial on air tests with a ham stick before switching over to my full 40m dipole.

I need to do more testing but the on air tests sound really good with this pre-amp in place now and connections good.

I might need to actually dead bug the pre-amp onto an actual board to keep the connections from being loose.

(at the moment I'm listening to a s7-s9 signal over the earbuds and I'm not wearing them they are on the other side of the room :) )

Re: Mini PA für my uBITX #ubitx

Timothy Fidler
 

https://www.ebay.com/itm/90W-HF-Power-Amplifier-For-FT-817-IC-703-SUNSDR2-PRO-KX3-QRP-Ham-Radio/182056979298?hash=item2a63710b62:g:d~UAAOSwP~tW6cCQ:rk:13:pf:0

this vendor is top-cc* in Shanghai - never used him  - this is simply answering the question.

There is probably only one mafr down in a tin shack somewhere in PRC and these legions of resellers.  He quotes it as  90 w Module which is bollocks. 

NB no LPF with this incarnation. some other vendors of the same basic  PCB have an LPF but it is the single relay for both in and out type - as per what the MX-P50 uses.

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.

File: uBitx4 voltages.xlsx

Uploaded By: Rajendra Kumar G G

Description:
DC voltages TX/RX uBitxv4

You can access this file at the URL:
https://groups.io/g/BITX20/files/VU2ZAP/uBitx4%20voltages.xlsx

Cheers,
The Groups.io Team

Re: uBitx V4 test point measurement chart #ubitx #ubitx-help

 

Ted,

Just uploaded into files section RC RX/TX voltages without modulation. See files \ VU2ZAP folder.

Power supply adjusted to 12.0V during RX and TX.

Hope it helps!

Cheers
Raj

Re: New file uploaded to BITX20@groups.io

 

There is also an older format XLS file in the folder if required.

https://groups.io/g/BITX20/files/VU2ZAP/uBitx4%20voltages.xls


On Sun, Jan 13, 2019 at 12:31 PM, "BITX20@groups.io Notification" <BITX20+notification@groups.io> wrote:

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.

File: uBitx4 voltages.xlsx

Uploaded By: Rajendra Kumar G G <rajendrakumargg@...>

Description:
DC voltages TX/RX uBitxv4

You can access this file at the URL:
https://groups.io/g/BITX20/files/VU2ZAP/uBitx4%20voltages.xlsx

Cheers,
The Groups.io Team

Re: Mini PA für my uBITX #ubitx

DC3MS
 



Right, the module seems to be sold by many different sellers in asia. Dont expect to get documentation or service, they just sell it.

The boards are named "XF-P100" and "XF-LPF-HF".  

I am not promoting these modules as the amp can be changed to whatever you like, i just wanted to control it via i2c using Arduino.


@Timothy : I have tried to run in on 24V and my Zetagi HP500 showed  90W output with 5W drive. Given the MRF186s specs, wheres the catch ?

 

 

 

Re: Mini PA für my uBITX #ubitx

DC3MS
 

Thank you Timothy.

Heres a link : https://www.ebay.com/itm/Assembled-LPF-low-pass-filter-90W-SSB-CW-AM-RF-HF-power-amplifier-HAM-RADIO/121965988356?hash=item1c65bd4a04:g:2kgAAOSwFxBXHHYO:rk:3:pf:0

 

Re: Mini PA für my uBITX #ubitx

Timothy Fidler
 

Reply : Some of the photos I have seen have marginal looking  OPTs on them as in things that look like longitudinally split core coaxial cores.

2.  THe fully assembled versions will have a heat sink based on something like 30 W dissip most likely.  When you look at the MRF 186 specs it is rather in efficient so 
heat,  when it is run at 90 W out continuously could be a real problem.  A modern mosfet RF Amp will be nominally 60 percent eff in class B but NOT this one.

3. Some of the units have a power supply capacitor that is marginal at 24 V supply. - It can be changed out - in fact the Ozzie Wordpress article may have mentioned that.

apart from that , no issues !  PS it would be fascinating to find out how so many of these VHF gemini pairs got left in a sack in PRC prior  to their being repurposed for current use  - I guess they were intended for some military project that was canned or a better device (higher efficiency) was found and these ones went begging.??

Re: Mini PA für my uBITX #ubitx

Bob Lunsford <nocrud222@...>
 

Got more options with an eBay search...
https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=HF+Power+Amplifier+For+FT-817+IC-703+SUNSDR2+PRO+KX3+QRP+Ham+Radio&_sacat=0

Bob — KK5R

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

On Sun, 1/13/19, Timothy Fidler <engstr@...> wrote:

Subject: Re: [BITX20] Mini PA für my uBITX #ubitx
To: BITX20@groups.io
Date: Sunday, January 13, 2019, 12:56 AM

https://www.ebay.com/itm/90W-HF-Power-Amplifier-For-FT-817-IC-703-SUNSDR2-PRO-KX3-QRP-Ham-Radio/182056979298?hash=item2a63710b62:g:d~UAAOSwP~tW6cCQ:rk:13:pf:0

this vendor is top-cc* in
Shanghai - never used him  - this is simply answering the
question.

There is probably
only one mafr down in a tin shack somewhere in PRC and these
legions of resellers.  He quotes it as  90 w Module which
is bollocks. 

NB no LPF
with this incarnation. some other vendors of the same
basic  PCB have an LPF but it is the single relay for both
in and out type - as per what the MX-P50 uses.

Re: Mini PA für my uBITX #ubitx

Bob Lunsford <nocrud222@...>
 

A consideration here is to wonder if any spurs, etc., get
amplified with the amp. May need more LPF's to keep it
within FCC specifications. Just a thought.

Bob — KK5R

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

On Sun, 1/13/19, DC3MS <mark.schraven@...> wrote:

Subject: Re: [BITX20] Mini PA für my uBITX #ubitx
To: BITX20@groups.io
Date: Sunday, January 13, 2019, 2:58 AM



Right, the module seems to be sold by many
different sellers in asia. Dont expect to get documentation
or service, they just sell it.
The boards are named "XF-P100" and
"XF-LPF-HF".  
I
am not promoting these modules as the amp can be changed to
whatever you like, i just wanted to control it via i2c using
Arduino.


@Timothy : I have tried to run in on 24V and my
Zetagi HP500 showed  90W output with 5W drive. Given the
MRF186s specs, wheres the catch ?

Re: uBitX v4.3 calibration

Vic WA4THR
 

Playing more with the uBitX, currently “breadborded” (wired up with alligator clip jumpers) on the desk. I found that it is going into transmit during the calibration phase, and that appears to be intentional. In other modes the PTT switch acts normally. I tuned my main rig to 10mHz and, watching the pan adaptor screen, I moved the apparent uBitX carrier up to zero beat the frequency, alternating listening on USB and LSB, and now it seems right on frequency. Then I played a little with the BFO and it is sounding better. They really should change the instructions on the website as I have never heard that this is the way it is supposed to be done and that seems odd for a new or impoverished ham who would not likely have another rig with SSB capability to listen to.

I plan to play around in this temporary hookup and probably load the CEC sketch and see about converting the display. Then the big question of whether I start modifying the rig for spurs and harmonics or wait for the v.5 board.

=Vic=

Re: Bitx40 #bitx40help #bitx40

Vic WA4THR
 

With the Raduino otherwise disconnected, can you plug its USB port into a USB line from your computer or a cell charger? That will power it up on 5v and you can see if it is displaying and acting normally to see if it has any issues from being misswired.

=Vic=

Re: uBitX v4.3 calibration

EI4GNB
 

I was baffled by this too. All a bit strange.

For uBitx V 4.3 calibration Here's what i did:

Change band to 20m, attach a dummyload, or a decent antenna for 20m, with a low SWR. Use Your frequency counter, then start the calibration routine - the radio will key up , then adjust so Your frequency counter reads bang on 20mhz.

After You do this, Things will be fall into place i suspect, including the BFO problems i bet You are having.

Yes, i know. This sounds wrong, but i could NOT get my uBitx to behave predictably until i did this. I actually thought i had fried it it was so unstable and off-frequency, then i did the calibration thing, but with the radio on 20m, and it all fell into place.

Re: Mini PA für my uBITX #ubitx

DC3MS
 

The heat dissipation on 24V really is high - i stick to 13.8V and 30W on the meter.

The PA is still to be analyzed regarding spurs - this is going to be done in the near future.

 

uBix - transmit clicking when Mic inserted

Jim Miller
 

Hello everyone,

I've sent several messages in the past asking about why my uBitx clicks (relay) as if it's trying to transmit when I connect a mic to the jack.  I've even sent some images of how I have it wired up and as best as I can tell I have it wired up correctly (search for previous posts).  I've also tried using the little button mic that comes with the kit and have the same issue.  

At this point, I don't know what else to do so I'm going to ask if there's an Elmer out there who'd be willing to be a 2nd pair of eyes and confirm that either there's an issue or I'm an idiot (the latter is more likely).  I'd be glad to pay shipping back and fourth (I'm in St.Louis, MO).

Thank you,
Jim Miller
AE0BZ