Date   
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: 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: 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: 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@...


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
 

the diode could be 1N540x a 3 amp device , as it is feared that diode might blow faster than fuse (rule of MURPHY  !!)

Eprom erased

m5fra2@...
 

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

 

Colin – M5FRA

 

 

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

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...

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: 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: Instruction Manual needs revision #ubitx

N5KBP
 

Had the same thing here with version 4.3. as soon as I tell it to calibrate the vfo goes to 10 mhz and goes into transmit. I put my frequency counter on the output and adjusted the output to exactly 10.000.000 mhz from about 185 hz high. It took a count of 16 on the calibration screen. The only issue was that the sidetone would not cut off without power cycling the board.
--
N5KBP

Eprom

m5fra2@...
 

Forget last message fixed it!

 

Colin – M5FRA

Re: Harmonic performance - SSB vs CW

 

Put a 2pf cap from in to out and compare. I curious!!

Raj

At 07-08-18, you wrote:
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: Harmonic performance - SSB vs CW

iz oos
 

Warren, this proves the women that wounded the toroids made an excellent job. I had no doubt about that!


Il 07/ago/2018 14:22, "Warren Allgyer" <allgyer@...> ha scritto:
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)

Jerry Gaffke
 

My preferred solution:
    https://groups.io/g/BITX20/message/52904

The instructions for reverse polarity protecton on the uBitx WireUp page would be acceptable  
if they also showed a 3 Amp fuse in line with the +12v lead from the power supply.
A large Schottky would be preferable to a 1n4007 if using a shunt diode like that,
a 1n4007 at significant currents might have a forward voltage of a volt or more.

The drawing at the top of the polarity protection page on ubitx.net is wrong and best ignored:
    https://ubitx.net/ubitx-fix-reverse-polarity-protection/
I see two issues with that drawing:
1)  Jack has  +12v going through the barrel of the connector, that's not typical.
2)  If black is truly ground (as it should be on the provided wiring harness) then the shunt diode is reversed in the drawing
 
For a shunt diode scheme like that, be sure to have a fuse in the +12v lead.

A few people recommend a fuse in the ground lead too, but equipment grounding (3 wire plugs, RF ground rods, etc)
can give a path around that ground lead fuse.  I never bother.
 
Jerry

uBITX portable build #ubitx

Daniel Conklin
 

I have been fascinated with the popular paratrooper style transceiver kits.  When I saw the K7XPO build in the small Apache case it got my creative juices flowing.  I cut a piece of aluminum and formed it to hold the uBITX mainboard upside down in the case and at a slight angle.  There were a few logistical issues, but I managed to make it work. The center knob is currently RF attenuation and will hook up to the AGC miniboard once I get it finished.  The red momentary switch next to the middle plug on the right is a tune/spot switch.  The others will be function switches once I figure out the problem I'm having with pull-up resistors.  It's mounted by four small bolts and lock washers and nuts and sits in the box very solidly. The spaces on each side accommodate a 18650 battery pack and the microphone with the lid closed. I've already made some contacts with it, but I still have a couple of mods I want to complete, so It will be coming out of the box again for those soon.
73, Dan - W2DLC

Re: reverse polarity protection (ubitx.net)

Jerry Gaffke
 

The hfsignals WireUp instructions for power into the rig at the top of   http://www.hfsignals.com/index.php/ubitx-wire-up/
have a symbol that looks like headphones.
Some have mistaken it for a fuse, that's definitely the wrong position for a fuse.
The label on that symbol says "On/Off", so we can assume it's a power switch.

Here's an old post showing how I wired mine up:
    https://groups.io/g/BITX20/message/53016




On Tue, Aug 7, 2018 at 07:31 AM, Jerry Gaffke wrote:
My preferred solution:
    https://groups.io/g/BITX20/message/52904

The instructions for reverse polarity protecton on the uBitx WireUp page would be acceptable  
if they also showed a 3 Amp fuse in line with the +12v lead from the power supply.

Re: Harmonic performance - SSB vs CW

Kees T
 

Excellent job Warren and some nice pictures to boot.

Since you used the existing uBITX components, would your suggested next step be to provide a new LPF only board with relays or a manual switch ?  ....to be mounted on the uBITX board ?

On one of my earlier manually switched LPF designs, realizing that not just any DPDT switch would work, I ordered some "bandswitch rotary switches .....6 position x2 " from Mouser. They worked quite well. 

Which of the 4 filters are used for each band ?  

73 Kees K5BCQ 

Re: Harmonic performance - SSB vs CW

Jerry Gaffke
 

Like I said earlier, I'd be fine with plug in LPF's on a rig in this price class.

Those that want relay switching of the LPF's can buy an optional daughterboard to stuff into 
that same plug in socket.
Though relatively expensive, there are some nice small surface mount latching relays
if you want small and power efficient on that daughterboard.

My hack to the v3 that I have will be four straps, one at the output of each LFP into the antenna jack.
Rewire K3 as follows:
    K3-12 goes to K1-12
    K3-14 goes to T11-2
    K3-16 goes to ground

Remove the extra traces around the filters to avoid blow-by.

Insert one of the four straps as appropriate when switching bands.

The stock rig has all three relays powered down during receive, selecting the 30mhz LPF.
We could adjust the firmware to make use of KT1,2,3 for the input side of the LPF's,
this would also require powering KT1,2,3 and Q17,18,19 from the 12v rail instead of the TX rail.

I will instead simply remove the three relays, and put a second set of four straps there as well.

Jerry, KE7ER
 


On Tue, Aug 7, 2018 at 05:32 AM, Gordon Gibby wrote:

 

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