Re: reverse polarity protection (ubitx.net)
Bill Cromwell
Hi,
toggle quoted messageShow quoted text
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 --
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,
toggle quoted messageShow quoted text
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 --
bark less - wag more
|
|
Re: One question only...
Bill Cromwell
Hi Walt,
toggle quoted messageShow quoted text
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, --
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:
|
|
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:
|
|
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
iz oos.. re getting cores etc at a reas price 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.
|
|
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
|
|
Re: Harmonic performance - SSB vs CW
Check your SPAM folder and if they are there mark as not spam.
toggle quoted messageShow quoted text
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
|
|
Re: Nextion Editor for Linux Mint ??
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:
|
|
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:
|
|
Re: ND6T AGC and Click kit wiring notes
..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
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.
|
|