1. BITX20@groups.io
   Date   
Re: reverse polarity protection (ubitx.net)

Bill Cromwell
 

Hi,

I have been in and repaired radios (and other electronics) where that reverse diode has blown. The failure mode was dead short to ground so the rest of the gear was still protected.

When one of my daughters married Dr. Murphy I thought I would get a break from Murphy's Law. But instead I get extra!

73,

Bill KU8H

On 08/07/2018 09:34 AM, Mvs Sarma wrote:
the diode could be 1N540x a 3 amp device , as it is feared that diode
might blow faster than fuse (rule of MURPHY !!)
_._,_._,_
--
bark less - wag more
Re: One question only...

ajparent1/KB1GMX <kb1gmx@...>
 

Rigol is a satisfactory machine if used properly.  Its big advanatage is price, for what it is and can do its a deal
you can't even get the attention of Keysight (Hp ne Agilent now...) refurbished equipment for that kind of money.

That said..

I've seen people using HP do stupid things and claim but the machine said such and so.  I've done it the hard
way for decades and every time I get a piece of gear life gets easier and I had to learn to use it correctly.  Most
if not all of the measurements discussed are not hard to do and do not require exotic gear but will require patience
and knowing how to perform the measurement.

To that end a copy of EMRFD the section on tests and measurements is well worth it.

Allison
Re: Harmonic performance - SSB vs CW

Bill Cromwell
 

Hi,

Check to see if you (accidentally) banned him from your inbox. Our screens are busy places and it is easy enough to accidentally bump the wrong thing. Been there - done that.

Check your 'spam bin' and 'trash bin' or whatever your mail system calls it. You can correct it there if you find Glenn's posts.

73,

Bill KU8H

On 08/07/2018 04:03 AM, William R Maxwell wrote:
Can anybody explain why I am not receiving Glenn's posts on this subject
but I am receiving the responses he receives, such as this from Colin.
Yet, if I go to the group page to view Colin's reply, I can step back
to find Glenn's post. Why should they not be appearing as emails, as
they had previously, since we moved to groups.io

Bill, VK7MX
--
bark less - wag more
Re: One question only...

Bill Cromwell
 

Hi Walt,

I still believe the problems can and will be overcome. There should be a flurry of activity while all the Bitx machines get updated with the fixes. I am sure it won't be as simple as a patch made of old chewing gum and a rubber band but it won't be like giving up an arm and a leg, either. I could be wrong. I was wrong once. I thought I had made a mistake but I hadn't <evil grin>.

There ARE some things to say about people who 'buy a Rigol' and concluding their findings must be accurate. Some can use them and some can't. This is really not the place to be parading credentials. There are people who can get the results with or without a 'Rigol' and others who can't even if they are shown a screen print. Spending time on that won't really resolve anything and will just create hard feelings. We need everybody aboard to get this radio on course. We can be sure there are issues. Debates about who said what and when they said it will not correct the problems. Only create more problems and maybe doom the radio to the landfill.

I won't be putting mine on the air until I have some sturdy filters on the output muzzling the spew. I am expecting an eventual, practical resolution to the problems:) This how 'open source' works :)

73,

Bill KU8H

On 08/07/2018 12:29 AM, WaltR wrote:
Hello Bill,

Its very unfortunate that a well intended kit that was assembled with
questionable quality parts, circuit and several other anomalies beyond
my comprehension, is in its present quandary. The principals it appears,
had good intentions and are to be commended for that. However, they have
no authority in North America. In fact the Border agencies of both our
countries are probably raising their eyebrows over the entire fiasco,
If not they soon will be. As I said earlier in my position As XO on
board ship I can’t afford to run afoul of the authorities so my bitx 40
and ubitx have been destroyed. Sad really, I will be looking at the kits
from QRP LABS. Or maybe I should purchase a good used FT817.
As an aside I had SIGINT techs look at the harmonic signature on the
Harris, Wolfsburg and Bendix King gear and found them to exceed
requirements by 30%, but of course again I’m comparing caviar to
peanuts. My wife chastises me for my attitude ergo I’m at sea for 6
months of the year. I’m trying to do better hi hi. It’s no wonder I’m
not allowed in the house before dark.

The sheer number of builders, the responses in this group, would suggest
that there is a strong need for a simple affordable all band QRP rig,
that is a fact, It will be interesting to see what happens in the next
while.

In the research I have done there are some kits available from China,
Russia and also Malaysia , they may be more in cost but perhaps ???


On a final observation you can buy all kinds of brands of test gear but
there are only certain brands that are deemed to be certification
instruments when operated by a certified knowledgeable technician, just
because you go out and buy a Rigol
doesnt mean that now you are instantly an industry expert.

Early day tomorrow, anchors aweigh at 0400

cheers and 73
WRS
--
bark less - wag more
Eprom erased

m5fra2@...
 

I have accidently erased the eprom on my uBITX. How can it be restored?

 

Colin – M5FRA

 

 
Re: reverse polarity protection (ubitx.net)

MVS Sarma
 

the diode could be 1N540x a 3 amp device , as it is feared that diode might blow faster than fuse (rule of MURPHY  !!)
Re: Ubitx will be here tomorrow. Any suggestions for a Bitx newbie #ubitx

f1mqj
 

What's new Marty ?
Remi - F1MQJ
Re: reverse polarity protection (ubitx.net)

MVS Sarma
 

Sarma surely responds.
 The reverse protection diode has been shown in the ubitx sch , both v3 and v4 perhaps.
 I would only suggest that let us have a fuse in series to dc of say 5 amps. the reverse diode would sit after the fuse to ground.
 Any accidental reverse connection , the fuse would blow and reverse voltage would not continue to the actual circuit, once fuse blows.


Regards
MVS Sarma
 

On Tue, Aug 7, 2018 at 1:56 PM, Mike Woods <mhwoods@...> wrote:
Jonathan

I will add PH2LB's reverse voltage protection solution to that page at your suggestion.  I hadn't noticed that idea previously, but did recognise the distinctive build so I guess it is on ubitx.net somewhere.

I am not sure about the diagram from MVS Sarma.  Let's wait and see whether he responds?   He may care to redraw the diagram if he agrees!  Everybody seems to draw those sockets differently ...

73

Mike ZL1AXG ubitx.net


On 7/08/18 2:58 AM, Jonathan Washington wrote:
Hi there,

In wiring my µBITX based on the guides and notes available at hfsignals.com, ubitx.net, this group's wiki, and the like, I noticed a discrepancy related to reverse polarity protection.

I believe the diagram with included fuse by MVS Sarma at https://ubitx.net/ubitx-fix-reverse-polarity-protection/ has the jack wired in reverse (- tip, + sleeve) of the standard (+ tip, - sleeve).  I suppose wiring it this way could be a good way to test if the fuse will do its job!

I should note that this solution seems preferable to the solution(s) provided in W4RJP's wire-up diagram (v1.9) posted at https://groups.io/g/BITX20/wiki/UBITX-Assembly , where it looks like the fuse and the diode would both blow in the case of reverse voltage, and the reverse voltage would still flow through the µBITX.  In MVS Sarma's solution, my understanding is that only the fuse would blow, and the µBITX wouldn't be exposed to any reverse voltage.

Also, I wonder if Mike might consider adding to the reverse polarity page PH2LB's reverse polarity protection solution from here:

I haven't tried it yet, but it seems ridiculously simple, and reasonably effective.  I'd probably still want to add a fuse with that solution, though, to protect against accidental shorts.


Jonathan, KD5CFX


--
Mike Woods
mhwoods@...


PDF
reverse diode with Fuse.pdf

Re: Harmonic performance - SSB vs CW

Gordon Gibby <ggibby@...>
 

"Without adding other relays like omrI on g5 g6 and alike, maybe some might prefer just connect the outputs of the four filters to separate antenna outputs, one for each filter. Isn't more simple? Would it solve the harmonics issue?"


A simple-minded solution that will likely work for the one or more that I'll be using "manually" will be a SPDT switch on the outside end of each filter.   Cut the loooong return traces, rewire existing relays as needed, tiny little perfboard off to the side to hold 3 or 4 switches (depending on how many bands I really care about) and wire the outputs with some coax back into the circuit.   Rewrite software if needed to activate desired relays after a bit of rewiring.   Done   



A slightly more exotic solution would be small printed circuit board off to the side instead of the switches;  wire the output of each filter to another (cheap) relay there;   perhaps add one additional 2n3904 to drive those relays, so the existing 2n3904 isn't overtaxed---but now only 2 relays in filter needed at any time....   Can even put in inductors to the coils or in the power line to prevent signal escaping that way.   Might even add an LED so i can see which filter is in use.   

In both cases, ground the unused filter output when not used.   


Full blown solution is new filter assembly completely, but the above solutions will probably handle my existing boards....  When I had heathkits there were ALWAYS modifications being developed to fix this or that problem with the units.   I have a few DOCUMENTS full of them to refer to when refurbishing those units.



In the long run, likely the bandpass filters (at least a stage or so) prior to power amplifier is probaby a good idea and then a redesign of the output filtering --- a version 5 of this wonderful kit transceiver!



Someone criticized the bitx40 filter or something as "not being enough" -- remember, that if the harmonic is already down 15 dB.....that is 15 dB less filtering required.   Same thing as with desense isolation required for duplexers---cleaner transmitter and hardier receivers require less of the duplexer filters!   


Got to get me a step-attenuator box.....or an HF spectrum analyzer....just got a simpleton VHF/UHF analyzer for $110 and able to see duplexer performance for the first time.    


Cheers,

gordon





From: BITX20@groups.io <BITX20@groups.io> on behalf of iz oos <and2oosiz2@...>
Sent: Tuesday, August 7, 2018 3:25 AM
To: BITX20@...
Subject: Re: [BITX20] Harmonic performance - SSB vs CW
 

Without adding other relays like omron g5 g6 and alike, maybe some might prefer just connect the outputs of the four filters to separate antenna outputs, one for each filter. Isn't more simple? Would it solve the harmonics issue?


Il 07/ago/2018 08:56, "m5fra2 via Groups.Io" <m5fra2=btinternet.com@groups.io> ha scritto:

That is excellent Glenn, I never ceased to be amazed by this group.

 

Colin – M5FRA

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Glenn
Sent: 06 August 2018 23:42
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonic performance - SSB vs CW

 

More to see if it's possible rather than anything else, I was working on a PCB that would fit in same space as the original LPF area, but switching on both ends of each filter. (ie 3 more relays)  I didn't alter the actual switching sequence just added the extra relays controlled in the same manner as the original ones. Picture is of the PCB. No switching transistors are on the PCB, yet.  You can see space either side though.

This is not all routed as you can see, just the RF paths in and out of the relays. (The inductors are shown with 4 holes, just because i  had that part in my LIB.) Orientations may change.

glenn vk3pe
Re: Harmonic performance - SSB vs CW

Warren Allgyer <allgyer@...>
 

The filter components as designed are perfectly adequate once the relay and layout problems are addressed. Yes, there are likely improvements that can be made with optimization but they are fine as is. 

I have removed the filter components from the uBitx and laid them out in a straight line on perf board. It is not pretty but that was not my intent..... I wanted to see how they perform. They perform superbly in this layout.

Photos of the board and the filter profiles are attached.

WA8TOD
Re: reverse polarity protection (ubitx.net)

w4rjp
 

Unfortunately, I did not make it clear about the DC power source fusing on the early wire-up version I gave Patrick for his stock Wiki. My assumption was that DC power source fusing would be ahead of the uBitx power jack and the reverse polarity protector. 

The fast blow fuses shown on the wire-up diagram were me being overly cautious about the possibility of excessive current draw, mostly from the PA and had nothing to do with reverse polarity.  In addition to the DC power source fusing I use Anderson Power Poles to insure the correct DC polarity. MVS Sarma fusing/reverse polarity is a better approach than what is recommended by HF Signals. Keep in mind a silicon diode is just a starting point for reverse polarity protection. 

Anyone acquiring, wiring, and using one of Farhan's great low cost radios should realize they are meant for experimenters and tinkers.
Re: End Fed antennas w/ uBITX #ubitx

Timothy Fidler
 

iz oos.. re getting cores etc at a reas price 
 an inspiration that might benefit me as I get to find out of this Indian is reliable.

First go to http://homebrewcorner.blogspot.com/p/page-update-642015-gek-baluns-1.html and see if that balun core is interesting to you. then  find Sunil who sells the Ubitx cases on this site  and get the proper email address for this Ganevashan or whatever he is called. Now the price he is asking converts to $21 USD. which is not a bad price if you had to go and order all the bits separately from all over  . Make sure you get the NON inline one which I would guess would be useless to you. Then see if he will sell you  spare core for research .   I would say you would get the whole lot landed in Italia  for $35 USD or so.  Then you can unsolder and retain the current Balun and do all your experiments with the extra core.  You have to get  a working email addr from Sunil because this coot does not answer to the one on the blogspot site.   if it all works I am most interested as I do have some cores but getting a ready to go core in box with fittings at this price  also sounds good.. if you get service from this coot  is of great interest to me. (It could  be everyone in India in RF knows his real email address  but it is all a bit rum to me.)  TEF 
Re: Harmonic performance - SSB vs CW

William R Maxwell
 

Thanks Raj but no, Glenn is not in the Spam folder.

Bill, VK7MX


On 7/08/2018 6:33 PM, Raj vu2zap wrote:
Check your SPAM folder and if they are there mark as not spam.

I use a prefilter called Mailwasher and I have groups.io domain to friends list.

At 07-08-18, you wrote:

Can anybody explain why I am not receiving Glenn's posts on this subject but I am receiving the responses he receives, such as this from Colin. Yet, if  I go to the group page to view Colin's reply, I can step back to find Glenn's post. Why should they not be appearing as emails, as they had previously, since we moved to groups.io

Bill, VK7MX
Re: End Fed antennas w/ uBITX #ubitx

iz oos
 

Thanks Allison for the feedback. The core I have used must be lossy for conventional transformers. I have just wired a 1:49 transformer using a small binocular core with 8uH at the input and 380uH at the output like the previous lossy transformer and wired in the way and this new one show not measurable SWR without any load which is a good thing. Of course using such small core I can't use it for TX probably even at qrp level. I have not the right cores in my drawer, so I will experiment with iron powder large cores (white, grey etc) maybe increasing the number of turns. Two turns with low permeability toroids at the primary seem to me too little especially below 10mhz.


Il 05/ago/2018 22:26, "ajparent1/KB1GMX" <kb1gmx@...> ha scritto:
Pretty good sign the core loss  is very high.  Its likely it does not match well at ~2500 ohms

I have never measured any for inductance as its like measuring it with a DC ohmeter,
not very informative.

Those I have tend be very high SWR no load high is greater than 20:1 at the low end
and at least 10:1 at the high end for a low power unit near me.  The problem is that's a
marginally informative as the loss can still be high or the ability to match is poor.

I can build a monoband L network in minutes and be far more sure it will be low
loss. 

Allison

Re: Harmonic performance - SSB vs CW

Raj vu2zap
 

Check your SPAM folder and if they are there mark as not spam.

I use a prefilter called Mailwasher and I have groups.io domain to friends list.


At 07-08-18, you wrote:

Can anybody explain why I am not receiving Glenn's posts on this subject but I am receiving the responses he receives, such as this from Colin. Yet, if  I go to the group page to view Colin's reply, I can step back to find Glenn's post. Why should they not be appearing as emails, as they had previously, since we moved to groups.io

Bill, VK7MX
Re: Nextion Editor for Linux Mint ??

SV9CVJ Nikos
 

Hi Tom ,

The uBITX_Manager is OK on my Linux Mint with Mono. I sent a message to Nextion and they answered .....


Posted on: 07-08-2018, 03:35 by Nikos

I would like to ask you how I can install Nextion Editor on Linux Mint. I try with Wine and Mono But I can't.

Posted on: 07-08-2018, 03:54 by Patrick

How to use operating system is beyond Nextion support.

Wine indeed works (other users have done)
- ensure Microsoft .NET 3.5 is installed.

............... but I did not find a solution.
Re: reverse polarity protection (ubitx.net)

Mike Woods
 

Jonathan

I will add PH2LB's reverse voltage protection solution to that page at your suggestion.  I hadn't noticed that idea previously, but did recognise the distinctive build so I guess it is on ubitx.net somewhere.

I am not sure about the diagram from MVS Sarma.  Let's wait and see whether he responds?   He may care to redraw the diagram if he agrees!  Everybody seems to draw those sockets differently ...

73

Mike ZL1AXG ubitx.net


On 7/08/18 2:58 AM, Jonathan Washington wrote:
Hi there,

In wiring my µBITX based on the guides and notes available at hfsignals.com, ubitx.net, this group's wiki, and the like, I noticed a discrepancy related to reverse polarity protection.

I believe the diagram with included fuse by MVS Sarma at https://ubitx.net/ubitx-fix-reverse-polarity-protection/ has the jack wired in reverse (- tip, + sleeve) of the standard (+ tip, - sleeve).  I suppose wiring it this way could be a good way to test if the fuse will do its job!

I should note that this solution seems preferable to the solution(s) provided in W4RJP's wire-up diagram (v1.9) posted at https://groups.io/g/BITX20/wiki/UBITX-Assembly , where it looks like the fuse and the diode would both blow in the case of reverse voltage, and the reverse voltage would still flow through the µBITX.  In MVS Sarma's solution, my understanding is that only the fuse would blow, and the µBITX wouldn't be exposed to any reverse voltage.

Also, I wonder if Mike might consider adding to the reverse polarity page PH2LB's reverse polarity protection solution from here:

I haven't tried it yet, but it seems ridiculously simple, and reasonably effective.  I'd probably still want to add a fuse with that solution, though, to protect against accidental shorts.


Jonathan, KD5CFX


--
Mike Woods
mhwoods@...
Re: Harmonic performance - SSB vs CW

William R Maxwell
 

Can anybody explain why I am not receiving Glenn's posts on this subject but I am receiving the responses he receives, such as this from Colin. Yet, if  I go to the group page to view Colin's reply, I can step back to find Glenn's post. Why should they not be appearing as emails, as they had previously, since we moved to groups.io

Bill, VK7MX


On 7/08/2018 4:56 PM, m5fra2 via Groups.Io wrote:

That is excellent Glenn, I never ceased to be amazed by this group.

 

Colin – M5FRA

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Glenn
Sent: 06 August 2018 23:42
To: BITX20@groups.io
Subject: Re: [BITX20] Harmonic performance - SSB vs CW

 

More to see if it's possible rather than anything else, I was working on a PCB that would fit in same space as the original LPF area, but switching on both ends of each filter. (ie 3 more relays)  I didn't alter the actual switching sequence just added the extra relays controlled in the same manner as the original ones. Picture is of the PCB. No switching transistors are on the PCB, yet.  You can see space either side though.

This is not all routed as you can see, just the RF paths in and out of the relays. (The inductors are shown with 4 holes, just because i  had that part in my LIB.) Orientations may change.

glenn vk3pe
Re: ND6T AGC and Click kit wiring notes

Timothy Fidler
 

..WARNING WArning.re chip subs for audio ref Eddie E - the TDA 7052AT is what Leon used. the  A and non A suffix versions are different in volume control area. Stick with Leon's AGC concept  if you go this way.                  https://www.nxp.com/docs/en/data-sheet/TDA7052A_AT.pdf
Re: ND6T AGC and Click kit wiring notes

Timothy Fidler
 

Eddie E Lucky day with the socket  the TDA7052 is your friend AGC is built in . I believe Futurlec.com  may still sell it if so it will be just pennies and F does not have any MOQ as far as I know. Never buy just one. Perhaps Leon as per below might do you a deal on two chips (but if he has inventory problems he won't . Don't muck him around. I need him.). May not be pin compat (you work it out ). well you can use a machined pin IC socket to bring out the existing socket to a piece of Veroboard and wing it.  Now look up Ozqrp.com  Find your way to the MST 3 schema via the documents section.   Look at audio section of the schematic . AGC Is is all there. Leon in NSWales . He is owner of Ozqrp has been doing AGC as std on his monobanders for  6 years and he only lives at the bottom of the world !!! .

Notice the L08 reggy driving the TDA... that is because Leon is a Pro. and checks this stuff out.  he has an interesting reversed voltage protection on his PCB too.  No fuse , no crowbar and essentially no voltage drop. 
28821 - 28840 of 84596  
More
Home Messages Hashtags Wiki About Features Pricing Updates Terms Help Twitter