Date   

hickmodawg@...
 

Why not use the online calculators to get an estimate of the number of turns we need, and then use an inexpensive meter to fine-tune the number and arrangement of windings before installing the toroid on the board?  I got a cheap LC100-A meter on EBay that measures inductance and I was a little shocked to see how the inductance values of my toroids changed just from moving the windings closer or farther apart, not just from adding or subtracting winds.  It seems to me, that the size and composition of the toroid, and the spacing of the windings may have an effect on the resulting inductance, not just the number of windings.  I’m really still quite new to this, but, I’m wondering, why not use a meter before installing our toroids onto the board?  Is it because these cheap meters are very inaccurate?
Martin, AJ6CL

Re: ubitx v5 receive problem

pd0zz@...
 

My 2 cents... Do you have a real strong MW radiostation near you? In that case it would be advisable to install a special filter onto the motherboard. Look at this small BCI-filter...
https://www.youtube.com/watch?v=fgQenFJOjr4

Furthermore a BFO tune-up as described by VK3YE is very advisable...
https://www.youtube.com/watch?v=sXJmAhpAjeI

Happy ubitx-ing!

Op 2-11-2019 om 15:40 schreef howard winwood:
just completed my ubitx v5 built into a ready made case, everything went together as expected, on switch on, nothing from speaker but headphones ok. found a short across the speaker terminals on the front panel circuit board (my fault!).
receive sounds very noisy, when a long wire is connected (not a proper antenna yet....) I get a massive increase in noise, very hard to distinguish stations even with volume control turned down. Also find it difficult to tune into a ssb contact.
I have an old home made tx/rx (about 40 years old) that picks up signals much better with almost no noise on same piece of wire than ubitx and tunes into ssb signal very easily on its analogue vfo, compared to ubitx.
is this normal for ubitx or do I have a problem?
Ubitx is supposed to have a sensitive receiver but due to the high noise level does not seem as sensitive as my old rig who's arial input goes straight into a diode ring mixer.
anyone have any ideas please?

Virusvrij. www.avast.com

Re: ubitx v5 receive problem

howard winwood G4GPF
 

Thanks for that Curt, sounds logical, why did I not think of that!!!!
I would have thought that bfo would be something they set at factory, but obviously not. Frequency set up was spot on so didn't think to check bfo settings. Will have a play when I get a minute.
Thanks once again
G4GPF

On Sat, 2 Nov 2019, 15:30 Curt via Groups.Io, <wb8yyy=yahoo.com@groups.io> wrote:
Howard

I don't have any v5 experience but sounds like your BFO calibration may be off. Note the positioning of this oscillator relative to the crystal filter determine what is heard, I imagine it is the issue. Instructions on bfo calibration are around, but use something provided for v5. It should sound nice when properly adjusted.

Your makeshift antenna should receive fine on lower bands, but may be insensitive on some higher bands.

Curt

Re: uBitx V3 low power continues

Ashhar Farhan
 

Ted,
The CW is generated independent of the IF and audio system. On the other hand the receiver is working, this rules out any problem in the RF mixer or the low pass filter. 
You must concentrate on the transmitter drivers and PA. The trouble is with those stages. Do you have access to an oscilloscope?

- f

On Sat 2 Nov, 2019, 6:44 PM Ted via Groups.Io, <k3rta=yahoo.com@groups.io> wrote:
Ashhar,

Yes, the receive is spectacular, with an added RFpreamp installed.  I can pick up whatever my Kenwood TS130S can hear. 

Please note the very low SSB modulation in comparison with a tune/CW note. I'd expect a fully-modulated "FIIIIIVVVE" to be aroud the same 'scope width as a CW note, give or take; my SSB is no more than about 25-30% of that with a compressor in line that had worked perfectly until I let the magic out somewhere along the way.

I was thinking "balanced mixer out of whack" or some such, though my theory isn't up to date.  Now, I asked about circuits prior to Q90 because this wide disparity between SSB peak envelope and CW occurs before that, hence my thought that the
problem could preceed this stage.

Thank you, sir, for any further thoughts on the subject.

Ted
K3RTA

Re: ubitx v5 receive problem

Curt
 

Howard

I don't have any v5 experience but sounds like your BFO calibration may be off. Note the positioning of this oscillator relative to the crystal filter determine what is heard, I imagine it is the issue. Instructions on bfo calibration are around, but use something provided for v5. It should sound nice when properly adjusted.

Your makeshift antenna should receive fine on lower bands, but may be insensitive on some higher bands.

Curt

ubitx v5 receive problem

howard winwood G4GPF
 

just completed my ubitx v5 built into a ready made case, everything went together as expected, on switch on, nothing from speaker but headphones ok. found a short across the speaker terminals on the front panel circuit board (my fault!).
receive sounds very noisy, when a long wire is connected (not a proper antenna yet....) I get a massive increase in noise, very hard to distinguish stations even with volume control turned down. Also find it difficult to tune into a ssb contact.
I have an old home made tx/rx (about 40 years old) that picks up signals much better with almost no noise on same piece of wire than ubitx and tunes into ssb signal very easily on its analogue vfo, compared to ubitx.
is this normal for ubitx or do I have a problem?
Ubitx is supposed to have a sensitive receiver but due to the high noise level does not seem as sensitive as my old rig who's arial input goes straight into a diode ring mixer.
anyone have any ideas please?

Re: uBitx V3 low power continues

Ted
 

Ashhar,

Yes, the receive is spectacular, with an added RFpreamp installed.  I can pick up whatever my Kenwood TS130S can hear. 

Please note the very low SSB modulation in comparison with a tune/CW note. I'd expect a fully-modulated "FIIIIIVVVE" to be aroud the same 'scope width as a CW note, give or take; my SSB is no more than about 25-30% of that with a compressor in line that had worked perfectly until I let the magic out somewhere along the way.

I was thinking "balanced mixer out of whack" or some such, though my theory isn't up to date.  Now, I asked about circuits prior to Q90 because this wide disparity between SSB peak envelope and CW occurs before that, hence my thought that the
problem could preceed this stage.

Thank you, sir, for any further thoughts on the subject.

Ted
K3RTA

Dave Dixon
 

hi curt,
            G3PCJ Walford electronics here in the uk has  produced a linear,mine and a friends use a 5 watt qcx to drive it up to 45 watts on 40 using a pair of irf 510s.but can be made for any band..regards Dave.


On Sat, 2 Nov 2019 at 03:15, Curt via Groups.Io <wb8yyy=yahoo.com@groups.io> wrote:
Thanks Allison for clariying. Based upon the message title, I am thinking the application here is a homebrew project. As for the exact number of watts, well enough is involved that I imagine merely a good irf510 amplifier is being sought. I think I recommended the best one around that uses a printed board.

73 curt

Re: Downloading firmware

Mike Kilpatrick <mike.kilpatrick@...>
 

Give me a few hours to put something together as well as deal with family matters and I’ll get back to you.

 

Mike

VK2DJP

 

M & J Kilpatrick
8 Chablis Drive
Cessnock
NSW 2325

Phone: +61 411 153 548

 

From: mgassman@...
Sent: Saturday, November 2, 2019 12:21
To: BITX20@groups.io
Subject: Re: [BITX20] Downloading firmware

 

Mike,

I’m just about to start my build.  If you send an email with the instructions, would you mind copying me too please?

Thanks,

Mike
WA0YCN

 

MVS Sarma
 

Even by using T30-6 , we get near by value  not exact value. balance is by adjusting the turn locations  etc and Farhan calls it tweaking.


On Sat, Nov 2, 2019 at 2:44 AM Woody <woody@...> wrote:
On 11/1/2019 19:12, circular.simetry@... wrote:
Hello everybody, i have build a homebrew ubitx and i am working now on the LPF the original uses T30-6 toroids i have available only T37-6 does anybody know how many turns i have to wind?

This might help...  Go to   https://toroids.info/
Enter  T30-6 toroid and the number of turns
Get the inductance
Enter T37-6 toroid and the inductance
Get the number of turns.
Caveat - Due to the difference in core sizes, it might not be possible to obtain an exact inductance match.

Woody, KZ4AK
KZ4AK.com
--

Curt
 

Thanks Allison for clariying. Based upon the message title, I am thinking the application here is a homebrew project. As for the exact number of watts, well enough is involved that I imagine merely a good irf510 amplifier is being sought. I think I recommended the best one around that uses a printed board.

73 curt

Re: uBitx V3 low power continues

Ashhar Farhan
 

Does the receiver work well? Are stations clear?


On Sat 2 Nov, 2019, 7:51 AM ajparent1/KB1GMX, <kb1gmx@...> wrote:
If the problem is 20M only its either a filter issue or a relay issue for 20M only.

Not a lot of parts but I've seen the same complaint for 40M several times in V3 boards.
Problem wrong number of turns on the filter coils.

Allison

Re: uBitx V3 low power continues

ajparent1/kb1gmx
 

If the problem is 20M only its either a filter issue or a relay issue for 20M only.

Not a lot of parts but I've seen the same complaint for 40M several times in V3 boards.
Problem wrong number of turns on the filter coils.

Allison

Re: uBitx V3 low power continues

ajparent1/kb1gmx
 


A Scope is nice if your understand what your looking at.

The easy way is the amp has an output line that goes to the
relays and filters.  break that line and measure power there.

There is nothing that dies prior to Q90 that is in the Power amp.

However there are two IF amps that can be all sorts of wrong
and the alignment of the oscillators as well.

However CW is generated differently than SSB and for CW TX
none  of the IF stages are used.

So the only things that can be broke is the 33mhz LPF alone
the edge or the power amp.

Allison

ajparent1/kb1gmx
 

The general answer no one has.

The amp mentioned is a considerable improvement but it was designed
for a trx that provides the needed 25 milliwatts drive.   The predriver and
driver in the ubitx is still needed and they have issues as well.  That and
grafting it to the ubitx would be a challenge for the non RF experienced.

No one I know of has done a single board replacement amp that
can do 10W from the output of the low pass filter.   Its a difficult
design to get that much gain on one board without VHF layout
the level of ground plane needed for stability.

Allison

Re: Downloading firmware

Mike WA0YCN
 

Mike,

I’m just about to start my build.  If you send an email with the instructions, would you mind copying me too please?

Thanks,

Mike
WA0YCN

Re: uBitx V3 low power continues

 

Hi Ted,

I hope you are recovering well from you surgery and infection.  That's tough breaks for sure.

I think from your former post, you said you have an oscilloscope?  If this was my board, I would start going through it using the 'scope.  For example, rather than just assuming the PA chain works OK because it gets warm, put the rig on 80m and follow the CW signal through.  Check the gain on each stage and make sure it all looks good that way.

For SSB, put a tone out of your cell phone (lots of aps for that) onto the mic and follow that signal.  You should be able to see the audio signal right at the mic and then see gain in each stage up to the mixer.  Then you should see the signal at RF and keep following it.

While not exactly the same rig, this site http://golddredgervideo.com/kc0wox/bitx20a.htm will show you how signals look as you follow them through the rig.  Signal tracing on the TX side is not too bad since the signals are all reletively large.

73,


Mark

Re: Downloading firmware

Mike Kilpatrick <mike.kilpatrick@...>
 

I know exactly how you feel!

When I first started with the ubitx earlier this year I was totally confused being a newbie to Arduino etc.

 

I would be happy to send you step by step details of how I managed to get mine up and running using CEC firmware.

 

We can do it here or you can email me at mike.kilpatrick@...

 

Mike

VK2DJP

 

 

 

M & J Kilpatrick
8 Chablis Drive
Cessnock
NSW 2325

Phone: +61 411 153 548

 

From: yrralguthri@...
Sent: Saturday, November 2, 2019 09:42
To: BITX20@groups.io
Subject: [BITX20] Downloading firmware

 

Are there files I can simply copy to a thumb drive and connect this thumb drive to the ubitx and allow it to update?

I'm not understanding the procedures I see on the ubitx sites on how to update the firmware.  I've just bought and wired a ubitx, it works, but I would like to update it to the KD8CEC firmware that works with the standard two-line display.  

 

Downloading firmware

yrralguthri@...
 

Are there files I can simply copy to a thumb drive and connect this thumb drive to the ubitx and allow it to update?

I'm not understanding the procedures I see on the ubitx sites on how to update the firmware.  I've just bought and wired a ubitx, it works, but I would like to update it to the KD8CEC firmware that works with the standard two-line display.  

Curt
 

The PC board layout is a bit sensitive to HF signals. Why not purchase the similar PA from qrp-labs, certainly less expensive than doing your own board. Also Hans and Allison did lots of work to improve its performance.

Curt