Date   

Re: SWR meter with second arduino

Gerard
 

Dennis,
Otherwise, I spent my afternoon watching videos on Kicad.
Well, I learned more. I hope to progress. LOL
cdt


Re: SWR meter with second arduino

Gerard
 

Dennis,

I only make hardware changes that exist. I have no control over the Arduino software at all. It’s a bit of a pile of things known to avoid having a spagetti type PCB  with all these additions.
If you manage to drive the equalizer with the 2nd arduino as a graphic menu, it would be interesting.
Watch this video
http://hamradiodesigns.com/index.php/ubitx-jackal/
this will give you ideas

cdt


Re: SWR meter with second arduino

Dennis C (WC8C)
 

On Fri, Nov 20, 2020 at 10:17 AM, Gerard wrote:
I was looking at this documentation for my information and I have a doubt about the connection.
http://www.hamskey.com/2019/04/installing-swr-and-rf-power-sensor-in.html
The wiring diagram looks incorrect to me.  I put the forward/reverse power to the second Arduino.  I seem to recall seeing an updated wiring diagram at one point, but I cant find it now.  The way the Hamskey site is organized is unfortunate - it makes it difficult to find the most up-to-date information.
 
--
Dennis WC8C


New PCB available for WA2EBY linear amp #linear-amp

Ken K0KV
 

After running my uBITX barefoot for the past 18 months (with 1700 FT8/FT4 contacts) I decided it was time to add a little more power.  The ever-popular WA2EBY linear amp seemed like a good route, except that nobody offered the circuit board anymore.  On a whim, I sent an email to amateurradiokits.in to see if they had even one board left over.  Sunil, VU3SUA responded that the old boards were gone, but they were just a few weeks away from releasing a totally new board for this design.   I asked to be their first customer, and very shortly had the new board in hand.  Here's my review (unsolicited, uncompensated): 

Having seen pictures of the earlier board in past construction articles, I can safely say the new board is a big improvement.   Cosmetically, it has all the professional elements that were previously missing: plated-thru holes and vias, solder masking and comprehensive silk-screening.   The size is a few tenths of an inch longer and narrower than the original, which turns out to be an excellent match for an inexpensive 150 x 60 x 25mm heatsink that is widely available on EBay as of this writing. 

Before you start building, you need to make two design choices.  First, your input attenuation – pads and traces are provided for a standard pi-network attenuator, but it’s up to you to choose the amount of attenuation needed for your setup and then compute the appropriate size/wattage resistors. Plenty of websites can help with these calculations.  Likewise, space is provided for a single band low-pass output filter, but the L and C values are up to you.  Again, no problem –  go to any WA2EBY article/website/blog published in the past 11 years and you’ll find them listed.


A few notes related to the photo:
  •  yes, there are still surface-mount capacitors – 10 of them.  And yes, mounting them seemed scary at first, but turned out to be much easier than I thought.  Plenty of YouTube videos are available to walk you through that process.     
  • the IRF510 pins need to be bent up 2-3 mm to allow the MOSFETS to mount flush to the heat sink while still maintaining adequate spacing for the board itself.  
  • the board has mounting holes for SMA connectors at the RF input and output.  I don’t generally use SMA’s on my projects, and the holes didn’t match up with the ones in my junk box, so I just soldered some mini-coax directly to the pads.
  • two other connection pads allow you to route the input signal to an external attenuator and back, if desired.  Otherwise, these points (J4 and J5) need to be jumpered. 
Because this is a mature design, you’ll find a wealth of published articles available to provide detailed advice on everything from component selection to toroid winding to expected performance.  It’s like having multiple assembly manuals to choose from.  Construction went smoothly, and the amp worked perfectly the first time I applied power.   As always with this design, tune-up consists of simply setting the bias current on the IRF510’s.   Stability is excellent, and very little drive is required to obtain full power out.  At some point I’ll do more comprehensive testing, but for now I’m having too much fun operating with it.
 

As a final note, the original QST articles (Mar, Apr 1999) provide an excellent analysis of the thermal challenges that come with running a pair of IRF510’s at 40+ watts.  Based on this, I've decided to run my amp at 30 watts output for the time being, until I have time to construct a better cooling system.  A couple of dB output power just seemed like a small price to pay to spend my time operating instead of replacing IRF510’s.

The WA2EBY PC Board can be ordered from amateurradiokits.in.  It is currently available as a bare board only, but will eventually be sold as a semi-kit as well.  Until it’s added to their website, you can email an inquiry to the address shown on their Contacts page, they’ll respond with the details.     


Re: SWR meter with second arduino

Dennis C (WC8C)
 

With all this, I think what I did will be a better base for the second Arduino code as Dr. Lee's version has very little available memory left.  You could also look at some thing more powerful that an Arduino to give you more room for additions.  If you do this, I suggest something with at least 2 uarts so you can eliminate the need for software serial.
--
Dennis WC8C


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

Jerry Gaffke
 

Jack,

The IRF520 has double the gate charge, so needs more drive.
It is not trivial to build a good wideband driver, and more power can mean an extra stage.
If all you want is 10W in a linear amp, two IRF510's is a good choice.

I'll have to look at that QST article.
I doubt it's a linear amp, and thus not suitable for SSB.
I doubt it has flat gain from 2 to 30mhz like the QSX amp.
I doubt it gets 50W when running on 12vdc.
It probably needs a signal source with way more power than the QSX amp,
as the QSX amp includes a suitable driver stage.

Hans also has a 50W kit for a class C amp (non linear) at $29.50:
    https://www.qrp-labs.com/50wpa.html
Includes a PIN diode TR switch, which is very cool.
Uses two IRF510's.

Jerry, KE7ER



On Sun, Nov 22, 2020 at 09:13 AM, Jack, W8TEE wrote:
I was just reading an article by David Cripe (QST, Oct., 2010) which won the QST Challenge that year. He designed a 50W amp based in the IRF520. His amp cost $32 to build and the power transistors are dirt cheap. Is there a reason why they are not more widely used?
 
Jack, W8TEE


Re: Email still coming in no email button selected

Reed N
 

Stab in the dark: is it possible that you signed up twice with different emails, and you're getting the emails forwarded by your client, rather than directly to the account?


Reed


Re: S-Meter Nextion, ask

Dennis C (WC8C)
 

I have not use a LM358 so I cant say what the advantages are.  I just Used what I had on-hand.  A quick peek at the data sheet and it seems like it should work as a replacement.  I think the key feature you want is that the op amp output can swing to ground.

With the circuit you linked, there is rectification/smoothing in the Op Amp output.  I think this should should work for the SMeter, but I think the FFT/CW Decode features will not work properly as it expects the full signal (preferably centered at 2.5V)

Other than that, be sure that the signal into the Arduino doesn't exceed 5 volts.

If you get the LM358 to work, please let me know so I can update the page with the alternative.
--
Dennis WC8C


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

Mick
 

I’ve been wondering about swapping the 510 with 2 520’s. I’m not going to do it I have a nice little 70w amp ( it uses irf540’s) But in these swap discussions I’ve not seen the irf520 option brought up.
--
 

73
Mick VA3EPM 


Re: SWR meter with second arduino

Gerard
 

Dennis,
Here’s what I’m thinking about.
First of all, I made a Ubitx house from A to Z and I only use the reception part for now. See my different posts.
I want to improve what exists, and for that I read everything that was written on the HFsignal website.
What I would like to add (list not completed)
A separate power supply for the Nextions(s) (Bridge,self and regulator separately)
Internal box regulation (fan trip)
Installation of a removable SSB filter (Small plug-in pcb). This to change the frequency easily.
Taking into account changes seen on power stage (2n2222 + modified transformers)
Establishment of a AGC
Setting up an equalizer
Setting up preconnexions for HF power amplifier (relays?)
Encoder changes (Added resistances to suppress noise)
Added components for SWR meter (Your circuit or KD8CEC (lm358))
Addition 2nd arduino
Addition of additional control transistors on free legs of the 2nd Arduino for future controls (ex of relays)
Addition 2nd Nextion
All these modifications exist, they must be implemented on a circuit.
I’m not a Kicad specialist, I spend a little time at night on it. It took me 4 days to make a small circuit. That’s unfortunate, because you actually have to do all the operations by hand.
I thought that after I made the schematic and the choice of prints, that he was going to generate a circuit. A priori no, there too it is manual...unless I do not master the tool. Connexions must be do manually!! (Only "Cheveulu" to help.
it's just a project.

NB: I also just saw that we can also put another Arduino. The V3 should work I think. Attention, on A.... o, we sell V3, but it looks like a Nano. The cabling is not the same. I think the programs should work on the V3.

So some work this winter....
cdt


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

Jack, W8TEE
 

Hi Jerry:

I was just reading an article by David Cripe (QST, Oct., 2010) which won the QST Challenge that year. He designed a 50W amp based in the IRF520. His amp cost $32 to build and the power transistors are dirt cheap. Is there a reason why they are not more widely used?

Jack, W8TEE

On Sunday, November 22, 2020, 11:46:49 AM EST, Jerry Gaffke via groups.io <jgaffke@...> wrote:


If you want a clean linear HF amp of about 10W when running on 12v,
the QSX amp is nice cheap option:
    https://www.qrp-labs.com/linear.html
Gain is flat over frequency.
IMD is way down, very well behaved.
Can run forever at 10W out without overheating.
Current price for the kit is $26 + shipping.
 
It uses 2 IRF510's.
 
There is zero advantage to using an expensive RD* device instead, given proper design.
One issue is that the tab of the IRF510 is at 12v, so proper design involves making sure
that tab is electrically insulated from the heatsink.  Another issue is the poor heat conduction
from the IRF510 die to the tab, so, proper design means a really good heat sink.
Gate is considerably more capacitive, so proper design means giving it sufficient drive.
The QSX amp covers all these bases.
 
Input impedance varies some over frequency, probably best to feed it with
a 50 ohm source, have a 75 ohm resistor to ground in parallel with the new amp.
I believe you would want a driver capable of round 20dBm into 50 ohms, or 2.24vrms.
Should be adjustable by a few dB, as not all these amps will have exactly the same gain.
 
If hacking this amp into the uBitx, you might try to retain the pre-driver stages
at Q90 and Q911,Q912, using the pot at RV1 to adjust the power level into the new amp.
However, you may need better than 2n3904's at Q90,911,912 if you want gain
to stay flat over all of HF.  Or perhaps reduce the gain in those two stages
so they can handle 30mhz well, and add a third 2n3904 stage.
 
If HFSignals were to create a v7 uBitx, could do worse than borrow that QSX amp.
Contribute occasionally to Hans' beer money fund if feeling particularly guilty about it.
 
Jerry, KE7ER
 

--
Jack, W8TEE


Re: Email still coming in no email button selected

jaytee1@...
 

Admins....any suggestions.
I blocked this group on email and its still coming through. Now I am really confused. Endstate, I may have to unsubscribe and only subscribe when I have a question the un-subscribe....Not efficient at all.....lol


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

Jerry Gaffke
 

If you want a clean linear HF amp of about 10W when running on 12v,
the QSX amp is nice cheap option:
    https://www.qrp-labs.com/linear.html
Gain is flat over frequency.
IMD is way down, very well behaved.
Can run forever at 10W out without overheating.
Current price for the kit is $26 + shipping.
 
It uses 2 IRF510's.
 
There is zero advantage to using an expensive RD* device instead, given proper design.
One issue is that the tab of the IRF510 is at 12v, so proper design involves making sure
that tab is electrically insulated from the heatsink.  Another issue is the poor heat conduction
from the IRF510 die to the tab, so, proper design means a really good heat sink.
Gate is considerably more capacitive, so proper design means giving it sufficient drive.
The QSX amp covers all these bases.
 
Input impedance varies some over frequency, probably best to feed it with
a 50 ohm source, have a 75 ohm resistor to ground in parallel with the new amp.
I believe you would want a driver capable of round 20dBm into 50 ohms, or 2.24vrms.
Should be adjustable by a few dB, as not all these amps will have exactly the same gain.
 
If hacking this amp into the uBitx, you might try to retain the pre-driver stages
at Q90 and Q911,Q912, using the pot at RV1 to adjust the power level into the new amp.
However, you may need better than 2n3904's at Q90,911,912 if you want gain
to stay flat over all of HF.  Or perhaps reduce the gain in those two stages
so they can handle 30mhz well, and add a third 2n3904 stage.
 
If HFSignals were to create a v7 uBitx, could do worse than borrow that QSX amp.
Contribute occasionally to Hans' beer money fund if feeling particularly guilty about it.
 
Jerry, KE7ER
 


Re: SWR meter with second arduino

Dennis C (WC8C)
 

The audio equalizer sounds really interesting.  If you pursue it I'd really like to follow what you do.  One of reasons I revamped the Smeter firmware was to make room in the program for additional features like this, so this is perfect.  One of the things that will need to be dealt with is that the standalone Smeter currently only intercepts data from the Raduino to the Nextion, but not from Nextion to Raduino.  It would not be difficult to add this feature - the wiring would have to change, of course.  This would open up many more possibilities as well.

--
Dennis WC8C


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

ohwenzelph
 

I think that, if it’s like Spanish,  voi is probably more like our southern y’all, “you all”, distinguishing you singular from you plural. In English “you” works for both. In high school I had to take a year of Latin.  (was supposed to take 2 but they could see that was pointless) and there declensions and I was like “what the ???”


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

MadRadioModder
 

This is a fair assessment. There are more limitations in the pre-driver stages at higher frequencies that would limit any gains made with the RD devices.  Its better to start at Q90 and work towards the final amplifiers. 


MRM

 


On Nov 22, 2020, at 8:54 AM, Evan Hand <elhandjr@...> wrote:

Bob,
The IRF510 and RD15HVF1 can both be used in this design, but are not really electrically equal, nor are they near the same cost (if you can find the RD15HVF1 part).  For this transmitter, the RD15HVF1 would be a better part to keep the output more consistent across the bands.  

The IRF510 was designed as a high-speed high power switch.  The RD15HVF1 was designed to be used as a VHF power amp. 
The IRF510 has a higher voltage capability.
The RD15HVF1 has better gain at higher frequencies.

The BIG difference is in the price.  Doing a quick search on the internet gave an eBay price of $6.00 for the RD15HVF1 vs a Mouser price for the IRF510 of $0.98 for quantity one.

Since there are other parts of the uBITX that limit the power output at 10meters, the advantage of the higher frequency of the RD15HVF1 is negated to a large extent.  You could spend the $12+ shipping to experiment, but not really worth it to me.  It will not solve any of the earlier boards (v3, v4) purity issues so you are spending money for, at best,  a few watts at the higher end of the range.  You can get some of the frequency advantages by increasing the voltage to the finals in the uBITX with the IRF510s, the design for the RD15HVF1 is 12.5volts.  The side effect of increasing the voltage using the IRF510s is that the power goes up across all of the bands, not just the higher ones (for some this is a good thing).

Above are my interpretations of the datasheets I found and could be in error.  I just wanted to point out that they are not truly the same, just that both will work in the uBITX as designed.
As always I am happy to get any feedback or corrections so that I can continue to learn about this hobby.
73
Evan
AC9TU

--

…_. _._


Easy Bitx Kit #bitx20 #bitx40

Sunil Lakhani
 

It's been few months we launched are Easy Bitx Kit .
The kit has some new features that eleminate the earlier drawbacks of bitx kits .
The manual with complete details can be found on our website .
Easy Bitx has fifteen individual packets which help building in step by step.Just like the old days .
The kit is also available on our website .
The kit can be build for any one band .
80mt 40mt or 20mt .
The website has 20mt kit by default .if you wish a 40mt kit then include a note in purchase .
80mt one we will start soon .
Those who want the kit without enclosure can email us vu3sua@...

https://amateurradiokits.in

Best of 73s 
Sunil 


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

Todd Carney
 

The difference between "formal" pronouns and "familiar" ones is an ordinary feature of many languages: Italian is one of many including Spanish and French. Most school children in the English-speaking world are at least exposed to it.


On Sun, Nov 22, 2020, 1:08 AM IW4AJR Loris <lorisbollina@...> wrote:
Hello Todd

It is extremely difficult to translate Italian into English ...
Italian is a complex and unique language in concepts and definitions, English is too simplistic a language to express certain concepts ... 
Do you want an example: 

tu sei -> you are 
voi siete -> you are 
tu hai -> you have 
voi avete -> you have 

it is enough for you ? .... Loris


Re: uBitX v.6 schematic / driver and finals transistor symbols / #ubitxv6 #v6

Todd Carney
 

Good background. Regarding Farhan's language, he has a better command of English than at least half the American population. All his documentation is in perfect English.


On Sun, Nov 22, 2020, 5:09 AM Curt via groups.io <wb8yyy=yahoo.com@groups.io> wrote:
You guys pretty much solved it. A little more backgound.
When the designer layed out the board he wanted both PA options to be supported on it. So to get both on the board he had to out both on the schematic.
When ubitx was updated, likely no changes were made to the PA.
Perhaps a note on schematic would have clarified this, but maybe a note in the designers language may not have helped many of us.

Curt


Re: Email still coming in no email button selected

jaytee1@...
 

Okay for the Admin.
I have blocked this contact in my email and will see if that worked. 
Great try and suggestions but its strange that it cant be stopped with the “No Email” selection. If a solution is found for that then I will be able to get emails only on the threads I’m following as opposed to all.
Once again thanks all for the help.

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