Date   
Re: Harmonic performance - SSB vs CW

Warren Allgyer <allgyer@...>
 

BTW..... in re-reading this, unfortunately after it was posted, I note that my threshold line is set at -53 dBc rather than -43. In your imagination move the green line up one division. It does not change the outcome or the analysis.

WA8TOD

Re: Harmonic performance - SSB vs CW

Warren Allgyer <allgyer@...>
 

No one is going to want to hear this but the design of the PA output filter is probably fatally flawed and it is likely due to board layout issues.

I have been puzzled how the high order harmonics of 80 meters, for example, could possibly survive a 7th order filter which should have well over 50 dB of attenuation at the 5th harmonic. So today I set out to test the results with a 9th order filter, figuring more is better. The harmonics remained. But in troubleshooting that installation the source of the issue was revealed.

In the attached screenshot the purple trace is the 80 meter CW output with the harmonics clearly far in excess of the green -43 dBc legal threshold. The blue trace is the output with L20 removed which disables the 80 meter filter and blocks RF output from the finals from reaching the output connector. (Don't worry..... the tests were carried out with the drive reduced so the output was only one half watt. And I have a bag of spare IRF510s on hand......). The harmonics remain! How can that be?

Pic #2 shows the path 80 meter RF follows through all three switching relays in order to reach the filter. It is a very novel and inventive concept to use three relays to switch both ends of 4 filters. Most manufacturers would require 8 separate relays to do this job. And for a very good reason.

In order for a filter to provide the required 50+ dB of attenuation, the filter itself must have 60 dB or more of input-to-output isolation. If it does not then the unwanted products simply bypass the filter and go directly to the output. That appears to be exactly what is happening in the filter complex of this unit.

There is no easy fix for this. No amount of on board filtering and tweaking is going to improve harmonic suppression until the path around the filters is blocked. I suspect that path is via the relays themselves but board layout often is critical as well in such cases. My guess is the only solution would be either extensive external filtering or a carefully laid out daughter card to replace the existing filters and relays.

WA8TOD

Raduino Clone kit from W0EB-N5IB #ubitx

Jim Sheldon
 

Check my website, www.w0eb.com for details, but I now have a completely drop-in Raduino clone available in kit form for anyone needing a replacement for a damaged Raduino that they are otherwise unable to repair or just wanting to have a spare on hand.

It's being offered as a bare board, a complete kit of parts INCLUDING the NANO which will be pre-programmed with Ashhar Farhan's latest factory software from Github (Currently v4.3) or , for a slightly higher price, the kit version is being offered with the Si5351 already soldered in place and continuity checked to insure the connections are good and there are no shorts between the pins.
This card has some extra bypassing capacitors, the 4.7K CW pull up resistor can be directly mounted on the board (or if you are replacing an existing Raduino installation and have already wired it to your key jack you can leave it off the board).

The 7805 regulator has been mounted flat on the rear of the board with a heat sink and input dropping resistor so it runs much cooler.  The clone is just over a centimeter wider than an original but the display mounting holes have been kept to the exact same pattern so that a normal 16 X 2 parallel display will mount properly.  The display is not supplied with the kit to keep the cost lower as most users already have one or more on hand anyway,.

The pre-programmed NANO  will be supplied with the pins loose and not installed so the user can mount it either on the front (not recommended) or on the back of the card to keep it out of the way of the display in the manner of the current factory supplied Raduino cards.

Any software that currently runs on an original Raduino will run on this card including the KD8CEC versions.  (That includes CEC's Nextion enabled versions as well).

The construction manual, pictures of the board and ordering/availability information can be found on my website http://www.w0eb.com

Jim Sheldon, W0EB

Re: my mic

lkorahul
 


Hi!

Has anyone one tried MEMS microphone like these..


Replacement elements for mobile phones are available quite cheap. Some variants come with in built compressor and noise cancellation. Found a link with Youtube video looks pretty good...


Rahul VU3WJM



On Saturday, 4 August, 2018, 8:02:07 AM IST, Jack Purdum via Groups.Io <jjpurdum@...> wrote:


Al Peter, AC8GY, who has a lot more assembly skill than I do, made this mic for me using the stock element and switch:

Inline image

The case is one of those promo pens that had a small LED and battery in it. It really looks nice and is small enough to pack anywhere.

Jack, W8TEE


On Friday, August 3, 2018, 7:58:43 PM EDT, hirosmb <hirosmb@...> wrote:


I used the same stereo connector which is bundled with the uBitX kit, mic+ to pin #1 and switch to pin #2.

// hiro, JJ1FXF

image1.jpeg


2018/08/04 8:11、Eddie Esserman <ee@...>のメール:

Very nice.  Any hint on the connector wiring, please, Vves?

Thanks.

Eddie WA4JXL

sorry for all these posts and questions.

None supprest carrier in TX

George
 

Hi all. I don't know how to suppres great carrier in TX mode.

Re: 12MHz xtals and QER Filter

Rahul Srivastava
 

Allison,

Here paralleling of cap arose  due to sheer unavailability of good quality caps in pF range in local mkt. I wanted to optimise the filters to best possible extent on local components so that people assembling uBitx in future can do so with whatever in hand or in junk box. It is very helpful to know the impact of such substitutions on filter response.

I did try out some 8 and 10MHz filters based on half bridge lattice following the work of DL6ZB , OM Rolf here:



I found them relatively easy to make, matching non critical and impedance's  easily manageable. 

Also found some HC49U 4.43MHz xtals in my old component bin they must be at least 25+ years old from Philips from my post student and struggle days, matched them now  a lot of about 25 xtals and all within 80Hz,  Talk about Quality..!! I made one QER SSB filter its plot is attached. Planning to give a try to some QER filters on 4.915MHz saw a picture on net for an add on board for K2 based on this topology, but I too would prefer xtals in 8-9MHz range with former being more common value.  

As you recommended to avoid ringing sweep rate is kept very slow by keeping the sample rate high on SNA at 1000 samples it sweeps at about 20KHz per minute. 

More as experimentation goes on ...

TNX and 73

Rahul VU3WJM





Re: Front Panel Stereo Socket Board Wiring Layout

Ian Reeve
 

Hi Eddie,  wiring for 4 pin :  pin 1. Mic input,  pin2 PTT,pin3 is put ground and pin 4 is mic ground. So link 3and 4 to earth and pin one is mic and pin 2 is ptt makes sense to keep connections short and screen the mic lead.Hope this helps. Ian M0IDR


From: BITX20@groups.io <BITX20@groups.io> on behalf of Mvs Sarma <mvssarma@...>
Sent: Saturday, August 4, 2018 4:19:27 AM
To: BITX20@groups.io
Subject: Re: [BITX20] Front Panel Stereo Socket Board Wiring Layout
 
If one has working MICs meant for other rigs that he uses, we can by a similar connector and wire accordingly . It helps sharing the  same mic for ubitx.
regards
sarma
vu3zmv


On Sat, Aug 4, 2018 at 8:08 AM, R. E. Klaus via Groups.Io <reklaus@...> wrote:
There really is no "standard" for wiring mic connectors. Each brand seems to have their own scheme. Unless you are trying to match a mic from an existing radio, just wire it so it makes sense to you.


Re: End Fed antennas w/ uBITX #ubitx

iz oos
 

Hi Allison, these 1:49 transformers are just conventional transformers. Would you think that a 1:4 and a 1:9 current (not the voltage ones) transmission line transformers in series to get a ratio 1:36 would be too lossy as I think or may be used? In that case the transmission line of the 1:9 transformer is just 150 ohm which is theoretically too low.


Il 04/ago/2018 00:54, "ajparent1/KB1GMX" <kb1gmx@...> ha scritto:
The feature that is desired of ferrties and iron power for transformers is coupling as
close as possible to 1.  Very hard to get that with air cores.

However by building them as transmission line transformers (Guanella)
its possible to do that with excellent coupling factors.

Allison

Re: any tips for debugging RFI issue? #ubitx-help

Mike KK7ER
 

Again, thanks for the explanation.  After adding the air choke and counterpoise (17.5ft -- I'll trim it back tomorrow), the uBITX now behaves properly when keying the mic and transmitting CW!!!

The SWR is a bit higher, though.

Also, it has moved a bit toward the Frankenstein's monster end of the aesthetic spectrum.


73 Mike KK7ER

Re: New antennas group.

Vince Vielhaber
 

No it wasn't. Arv just created the antenna group today. The loop group you're talking about is different.

Vince.

On 08/03/2018 11:34 PM, Mvs Sarma wrote:
formerly it was
https://groups.yahoo.com/neo/groups/loopantennas/info

Regards
MVS Sarma
vu3zmv

On Sat, Aug 4, 2018 at 8:56 AM, Vince Vielhaber <vev@...
<mailto:vev@...>> wrote:

antennas

https://groups.io/g/antennas

Vince.



On 08/03/2018 10:59 PM, allen west wrote:

What is the exact name of the new antennas group that has been
mentioned here?

Al,

KB4RA




--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com




Re: New antennas group.

MVS Sarma
 

formerly it was

Regards
MVS Sarma
 vu3zmv

On Sat, Aug 4, 2018 at 8:56 AM, Vince Vielhaber <vev@...> wrote:
antennas

https://groups.io/g/antennas

Vince.



On 08/03/2018 10:59 PM, allen west wrote:
What is the exact name of the new antennas group that has been mentioned here?

Al,

KB4RA




--
  Michigan VHF Corp.   http://www.nobucks.net/   http://www.CDupe.com/
                          http://www.metalworkingfun.com




Re: New antennas group.

Vince Vielhaber
 

On 08/03/2018 10:59 PM, allen west wrote:
What is the exact name of the new antennas group that has been mentioned here?

Al,

KB4RA

Re: New antennas group.

MVS Sarma
 

Yahoo group "loop antennas" moved here


Regards
MVS Sarma
 

On Sat, Aug 4, 2018 at 8:29 AM, allen west <kb4ra67@...> wrote:
What is the exact name of the new antennas group that has been mentioned here?

Al,

KB4RA




Re: Front Panel Stereo Socket Board Wiring Layout

MVS Sarma
 

If one has working MICs meant for other rigs that he uses, we can by a similar connector and wire accordingly . It helps sharing the  same mic for ubitx.
regards
sarma
vu3zmv


On Sat, Aug 4, 2018 at 8:08 AM, R. E. Klaus via Groups.Io <reklaus@...> wrote:
There really is no "standard" for wiring mic connectors. Each brand seems to have their own scheme. Unless you are trying to match a mic from an existing radio, just wire it so it makes sense to you.


New antennas group.

allen west
 

What is the exact name of the new antennas group that has been mentioned here?

Al,

KB4RA

Re: Front Panel Stereo Socket Board Wiring Layout

R. E. Klaus
 

There really is no "standard" for wiring mic connectors. Each brand seems to have their own scheme. Unless you are trying to match a mic from an existing radio, just wire it so it makes sense to you.

Re: my mic

Jack, W8TEE
 

Al Peter, AC8GY, who has a lot more assembly skill than I do, made this mic for me using the stock element and switch:

Inline image

The case is one of those promo pens that had a small LED and battery in it. It really looks nice and is small enough to pack anywhere.

Jack, W8TEE


On Friday, August 3, 2018, 7:58:43 PM EDT, hirosmb <hirosmb@...> wrote:


I used the same stereo connector which is bundled with the uBitX kit, mic+ to pin #1 and switch to pin #2.

// hiro, JJ1FXF

image1.jpeg


2018/08/04 8:11、Eddie Esserman <ee@...>のメール:

Very nice.  Any hint on the connector wiring, please, Vves?

Thanks.

Eddie WA4JXL

sorry for all these posts and questions.

Re: Managed to pull foil trace off Pop Fix Board (R5)-both sides, K5BCQ kits, Any tricks to get R5 back in place? #parts #ubitx-help

Dexter N Muir
 

First SMD project? OK, then note: to remove a resistor, heat both ends (blob the whole item!) and swipe away from pads to open area (works for smd caps, diodes, transistors too, so long as you don't keep the heat on longer than necessary. ICs really need heat-gun tools.). Repair your faux-pas by finding where those missing pads' traces lead - and to other component pads - and drape an ordinary resistor between. It won't be the prettiest, but it'll work. The component may even stick to the iron tip - if removed from there quickly it most likely will still be OK - a tissue for the job will help you keep track of it.
73,
Dex ZL2DEX

Re: 12MHz xtals and QER Filter

ajparent1/kb1gmx
 

Rahul,

Parallel caps also offer lower ESR best is the values are near the same but
it helps.

The biggest is crystals ground for series resonance vs parallel.  IT seems to get me a
lower ESR and Lm.

When I'm doing a lattice or half lattice filter I look for both parallel and series as the 
mode difference for a given frequency tends to work in favor for that.

My preferred frequency for filters are under 10mhz with 9.6, 9 and 8 being most common
but other like 5, 5.0688 have been done.  There is less drift with temperature.
I know that from doing a wider than SSB roofing filter at 36mhz,  it had to be or heated!

Allison

Re: New "ANTENNAS" group has been formed.

ajparent1/kb1gmx
 

I have not found one.

However:

Antennas  on groups IO is officially open.

Allison