Date   
Re: VK4PP uBitx LPF BANK add-on Board

Gordon Gibby <ggibby@...>
 

Two suggestions:

1. Looks pretty tight.   You might leave a bit more room for the hobbyist to reassemble the filters

2.  I don’t see RF bypassing on the coil wiring—so signal can bypass the filters on those wires.  Consider caps maybe even series inductors - I used smd 100 micro Henry




On Aug 31, 2018, at 03:29, Timothy Fidler <engstr@...> wrote:

Nick
1. Wired OR diodes used for Relays J1A B  great idea. and I can see you seem to have allowed for relay contacts being opposite sensed. Ie J1A B set is active when Energised and Energised is out of cct.
2 . you have three signals and because of the wired or you have effectively four states without using a decoder. So how is the R5 to be energised. ?? Is it there for case of special software mod plus I2C or ....?

3. You need to define the relay functions.  From a Sota point of view it makes sense that J1AB set is a 20/30m Filter. Ie NO relay energised when working 20m.
then J2 becomes 80 m. then J3 40m  and J4 becomes 15/17 and J5 becomes Ten m after some magic.
4. You have allowed  spike suppression diodes for all relays except first pair. Forgotten or  there is a reason. ? 
5. Kees Talen is also talking of a Five relay board design.  With Decoding to be done Off board somehow. Perhaps you need to check up his thoughts.
6. Given  5.  I would suggest that you allow sufficient pads for a  74HCT42 decoder and  a 78L05 to power it.  These pads could be on basis of wired chip mounted as SM (legs become feet at 2mm up from tips) so the cost of the holes is not there.  You will also need 4 off BS250 P Mosfets  (simplest solution and they are cheap) to activate the last four relays sets.  The points where the Wire goes off to the Wired OR should be  a through hole rondel.  All this could be squeezed in up T LHS of board as presented without much increase in board space.

The final wiring could be done with  Cat E wiring cores stripped out for those who wanted to go this way . I would suggest the following mapping  000 as input to decoder  means nothing.  Same for 001.  010 activates relay set 2 and also energises J1AB via wired OR  .  ...etc all the way to 101. If you use PNP transistors, you will be up for one extra current control resistor per bit.  BS250s are logic level Mosfets  RDS on approx 14R.  Futurlec.com have  them Rockby in Australia list them but have to order them in. 

The mappings and Relay usage have to be defined up front or  the software will be a schmozzle. 

Is the current voltage going to K1 coil 12V .. the schematic calls it Tx voltage. It appears likely to be 12VDC but without details of the guts of the Raduino I cannot be sure.


Re: VK4PP uBitx LPF BANK add-on Board

Timothy Fidler
 

Nick
1. Wired OR diodes used for Relays J1A B  great idea. and I can see you seem to have allowed for relay contacts being opposite sensed. Ie J1A B set is active when Energised and Energised is out of cct.
2 . you have three signals and because of the wired or you have effectively four states without using a decoder. So how is the R5 to be energised. ?? Is it there for case of special software mod plus I2C or ....?

3. You need to define the relay functions.  From a Sota point of view it makes sense that J1AB set is a 20/30m Filter. Ie NO relay energised when working 20m.
then J2 becomes 80 m. then J3 40m  and J4 becomes 15/17 and J5 becomes Ten m after some magic.
4. You have allowed  spike suppression diodes for all relays except first pair. Forgotten or  there is a reason. ? 
5. Kees Talen is also talking of a Five relay board design.  With Decoding to be done Off board somehow. Perhaps you need to check up his thoughts.
6. Given  5.  I would suggest that you allow sufficient pads for a  74HCT42 decoder and  a 78L05 to power it.  These pads could be on basis of wired chip mounted as SM (legs become feet at 2mm up from tips) so the cost of the holes is not there.  You will also need 4 off BS250 P Mosfets  (simplest solution and they are cheap) to activate the last four relays sets.  The points where the Wire goes off to the Wired OR should be  a through hole rondel.  All this could be squeezed in up T LHS of board as presented without much increase in board space.

The final wiring could be done with  Cat E wiring cores stripped out for those who wanted to go this way . I would suggest the following mapping  000 as input to decoder  means nothing.  Same for 001.  010 activates relay set 2 and also energises J1AB via wired OR  .  ...etc all the way to 101. If you use PNP transistors, you will be up for one extra current control resistor per bit.  BS250s are logic level Mosfets  RDS on approx 14R.  Futurlec.com have  them Rockby in Australia list them but have to order them in. 

The mappings and Relay usage have to be defined up front or  the software will be a schmozzle. 

Is the current voltage going to K1 coil 12V .. the schematic calls it Tx voltage. It appears likely to be 12VDC but without details of the guts of the Raduino I cannot be sure.


Re: calibration question #ubitx-help

iz oos
 

Just to exclude you weren't listening the WWV. You also can use the other references at 5 and 15Mhz. Usually when I calibrate something as a double check I use these references too and a shortwave broadcast using ssb


Il 31/ago/2018 00:24, "Mike KK7ER" <groupio@...> ha scritto:
Thanks, Iz Oos!  Just to be sure I'm not missing something subtle, why not just use WWV?  It is AM, isn't it?  And I know for sure that it is on 10.000000 MHz which is more than I can say for AM shortwave broadcasts chosen at random.

--Mike

Re: CW PTT attack time to slow #ubitx

Joop Stakenborg <joop.stakenborg@...>
 

ajparent1/KB1GMX schreef op 2018-08-30 20:55:
Another user installed the KD8CEC software and found it to be an
improvement.
Changing the pull up will not help the issue. The factory code is
slow in
recognizing keying.
Okay!
Yes, I bet it takes a while for the code to recognize if we have a keyer input and then switch from USB to CW... Maybe I should hack the code a bit since I want to stick to the stock firmware for a while.

Another approach I see is changing the hardware input. I will investigate both and get back on this topic.

Allison
Regards,
Joop PG4I

Re: CW PTT attack time to slow #ubitx

Joop Stakenborg <joop.stakenborg@...>
 

Ben Holmes schreef op 2018-08-30 20:17:
This might be a possible fix:
https://qrpguys.com/ubitx-cw-conditioning-adapter
_._,_._,_

Thanks Ben,

will have a look.

Regards,
Joop PG4I

Re: UBITX V3 TX GAIN VARIATIONS

MadRadioModder
 

All of my modelling says it should.  There have been many posts on this subject months ago…  about 400pf is a good start.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Kees T
Sent: Thursday, August 30, 2018 4:57 PM
To: BITX20@groups.io
Subject: Re: [BITX20] UBITX V3 TX GAIN VARIATIONS

 

Allison,

All of the WA2EBY derived dual MOSFET Amp designs I've seen (IRF510, RD16HHF1, RD15HHF1) have a "compensation capacitor" across the output transformer primary.  Used to balance the 3-30MHz range gain. I used one on my 20W Amp kit (and the feedback loop if needed).

The uBITX PA does not have such a capacitor on the schematic .....why ?

73 Kees K5BCQ


Virus-free. www.avg.com

--

…_. _._

Re: VK4PP uBitx LPF BANK add-on Board

Nick VK4PP
 

Probably just the boards, You need to re-use the LPF from the existing board.
Option to add a Firth filter is you want.

Relays are Omron g6s-2 12v

73 Nick VK4PP

Re: VK4PP uBitx LPF BANK add-on Board

ARNAB SEN VU2CMV
 

Dear OM,
               Will you make it available as a kit ? DIY or Assembled ?
73s

ARNAB SEN ( VU2CMV )
6/35 JM SENGUPTA ROAD.
B-ZONE.
DURGAPUR-713205.
MOB:9434833047


On Fri 31 Aug, 2018, 09:10 Nick VK4PP, <nickpullen@...> wrote:
More:

Re: VK4PP uBitx LPF BANK add-on Board

Nick VK4PP
 

More:

Re: UBITX V3 TX GAIN VARIATIONS

MadRadioModder
 

Actually I’ve been doing a lot of experimentation on flattening/ linearizing the transmit chain.  The parts I’ve fallen on are the NE46134’s.  They have plenty of gain, Ft of 5 GHz, and with the proper inter stage transformer design… An almost flat (-0/+0.6 dB) frequency profile swept from 0.5-60 MHz is possible.  I suppose prototyped, it isn’t much of a uBITx though.

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Kees T
Sent: Thursday, August 30, 2018 10:46 AM
To: BITX20@groups.io
Subject: Re: [BITX20] UBITX V3 TX GAIN VARIATIONS

 

On Tue, Aug 28, 2018 at 04:25 PM, Rod Davis wrote:

WARNING: q911,q912,q92,q93,q96,q97 all dissipate at least 296 mW. That
means 250 mW transistors are not acceptable.

So, in searching for a better Ft device for the TX chain:
the BFR106 has the dissipation, but the 3.5 to 5GHz Ft invites instability
the MMBT10     lists dissipation at 225 mW, so it may not be a good candidate
the MMBT2369 lists dissipation at 225 mW, so it may not be a good candidate
the DTX2222A has the dissipation, but the Ft is not better than 2n3904, and
the footprint is not compatible with the board.

I was wondering about the reasoning behind using several parallel 2N3904 transistors in the uBITX circuit.....they are inexpensive, but why not just use a single 2N2222 ?

73 Kees K5BCQ


Virus-free. www.avg.com

--

…_. _._

VK4PP uBitx LPF BANK add-on Board

Nick VK4PP
 

Hi All.
Hows this look:


73 Nick VK4PP

Re: UBITX V3 TX GAIN VARIATIONS

jim
 


On Thursday, August 30, 2018, 7:46:10 PM PDT, ajparent1/KB1GMX <kb1gmx@...> wrote:


On Thu, Aug 30, 2018 at 02:56 PM, Kees T wrote:
All of the WA2EBY derived dual MOSFET Amp designs I've seen (IRF510, RD16HHF1, RD15HHF1) have a "compensation capacitor" across the output transformer primary.  Used to balance the 3-30MHz range gain. I used one on my 20W Amp kit (and the feedback loop if needed).

Just finished (phase 1) of modifying to the WA2EBY topology ....Success is assured ...removes a metric B**t-ton of spurs and cruft ..Only getting 1 watt at 80 meters (100 mW on 10) but things are looking MUCH better

Jim

Re: UBITX V3 TX GAIN VARIATIONS

ajparent1/kb1gmx
 

Those points need series inductive(lossy ferrite) and/or resitive isolation as the
caps have ESR and however low if you present RF from the power supply side
its not sufficiently effective.

Of course if the ground via adds resitance it may not help.

Allison

Re: UBITX V3 TX GAIN VARIATIONS

ajparent1/kb1gmx
 

On Thu, Aug 30, 2018 at 02:56 PM, Kees T wrote:
All of the WA2EBY derived dual MOSFET Amp designs I've seen (IRF510, RD16HHF1, RD15HHF1) have a "compensation capacitor" across the output transformer primary.  Used to balance the 3-30MHz range gain. I used one on my 20W Amp kit (and the feedback loop if needed).

I'm familiar with your 20W amp.  Nice work.

The uBITX PA does not have such a capacitor on the schematic .....why ?

Actually the cap does several things but it may or maynot be there.  Most cases its to 
counteract remnant or leakage reactance from the transformer that occurs due to leads
and also coupling less that 1.   

In the case of the uBitx the existing transformer is well coupled but has far to much
inductance and any capacitance tended to make it worse at higher frequencies.
the winding is also high resistance.  Add to that the leas are long (full length) and
there are long and many tracks due to layout that are built of narrow traces. With
the circulating currents of @a or more would you use traces that narrow?

The feedback is not RLC but RC and should be RLC to compensate for the reactive
input of all mosfets.

That said if you delivered at least 500mW of power to the gates you get 10W out.
The drivers however do not deliver this above 9-10mhz.  So you get deceasing
output to 10M.  For mine at 10M it was 1.8W out but the drive was a mere .075mW.
Yet we blame the IRF510, looks to me 13db or more gain is not so bad.

The cap does not need to be a 500V part even at 28V as the mosfets will self destruct
at 100V, so a 100V cap is fine so long as it can handle high RF current.

Allison

Re: Raduino Pill

W3JDR
 

Today I got the Si5351 running, so all the subsystems (LCD, encoder, Si5351) are now operational. Next step is to try to build stock uBitX code on the new platform.

Re: Personal Best Distance, SSB Phone #ubitx

Ken
 

Nice one Joel!

73 Ken
VA3ABN

On Thu, Aug 30, 2018 at 6:26 PM, Joel Caulkins <caulktel@...> wrote:
I worked a station in Antartica from my QTH in Oregon, a distance of 10,455 miles, on a Bitx17A running 8 watts into a EFHW antenna. I have the QSL card to prove it!

Joel
N6ALT


Re: Personal Best Distance, SSB Phone #ubitx

Timothy Fidler
 

JC  Keep that Bitx17A .. it seems there will not be many more kits made.

BTW if you can get the 9 turn fine tuning air variable  out of an old UHF TV receiver ( typically can be made to tune 3-30pf  and less over the full 9 turns by cutting comps out and wiring the plates in parallel) you may be able to produce a non thermally moving VFO for that beast.  Australia killed off the Analogue network a while back and I had the opp. to examine the internals of some of these. 

 

Timothy E. Fidler : Engineer BE Mech(1) Auckland , NDT specialist AINDT UT /RT3 , MT2 CB #2885, 
Telephone Whangarei   022  691 8405
e: Engstr@...



----- Original Message -----
From:
BITX20@groups.io

To:
<BITX20@groups.io>
Cc:

Sent:
Thu, 30 Aug 2018 15:26:36 -0700
Subject:
Re: [BITX20] Personal Best Distance, SSB Phone #ubitx


I worked a station in Antartica from my QTH in Oregon, a distance of 10,455 miles, on a Bitx17A running 8 watts into a EFHW antenna. I have the QSL card to prove it!

Joel
N6ALT

Re: UBITX V3 TX GAIN VARIATIONS

Kees T
 

......and the "compensation capacitor", since it's across RF voltages, should be a 500V Mica in the 47pF to 150pF range.

73 Kees K5BCQ 

Re: Personal Best Distance, SSB Phone #ubitx

 

I worked a station in Antartica from my QTH in Oregon, a distance of 10,455 miles, on a Bitx17A running 8 watts into a EFHW antenna. I have the QSL card to prove it!

Joel
N6ALT

Re: calibration question #ubitx-help

Mike KK7ER
 

Thanks, Iz Oos!  Just to be sure I'm not missing something subtle, why not just use WWV?  It is AM, isn't it?  And I know for sure that it is on 10.000000 MHz which is more than I can say for AM shortwave broadcasts chosen at random.

--Mike