Date   
Re: Erratic tuning with my new uBitx

Ian Lee
 

Chris

"Enabled Adjust Frequency CW frequency" 
I thought that this feature was pretty good, so I set it the default use.
Perhaps this option will solve the problem you think.

I'll explain it briefly.
What you think is the right answer.
in LSB mode and USB mode, pressing the CW key will subtract or added the side tone value to frequency,.
The same is true for CWL and CWU modes.
(CWL and CWU are different only for BFO)

"Enabled Adjust Frequency CW frequency"   
When this option is checked, the actual transmission frequency will be displayed on the LCD window.

I found a bug that was not applied when I displayed this on the LCD window in RIT mode during this test. 
I will fix this bug in the next version.

I tried various tests before. 
and I'll post more details on the blog with the photos I just tested.

Ian KD8CEC


2018-04-11 0:31 GMT+09:00 Chris Clarke <csclarke@...>:

Hi Ian

I'm nearly there!

I've installed v1.061 firmware and uBITX Memory Managerv1.01 and unchecked the option to show frequency shift in CWL and CWU modes.

Can you tell me exactly what the option "Enabled Adjust Frequency CW frequency" does when ticked (which it is)?

After enabling RIT, now RitTX and RIT A both show identical values, whilst my actual TX frequency = RIT A - CW tone frequency (which I've just changed to match the 600Hz peak of my beloved W3NQN passive CW audio filter). RIT A changes as a I tune, as expected, and Rit TX is unchanged,as expected, and I suppose you could argue that Rit TX is the frequency to which I need to tune to get back whence I started, so is that the intention? But in my head I think I should be seeing the TX frequency!

I'm still clearly still misunderstanding something, but I'm definitely getting closer!

73 Chris
G3SQU



--
Best 73
KD8CEC / Ph.D ian lee
kd8cec@...
www.hamskey.com (my blog)

Re: uBitx just started transmitting a loud hum #ubitx-help

_Dave_ K0MBT
 

I had the bitx40 that quit transmitting. The electret mic failed. I didn't get the hum just silence. The replacement mic has given the radio increased power, about 10 watts. 

I wondered if humidity from my breath caused the failure. I like the idea of a voltage spike though. Seems more likely.  Am wondering if I should put a choke between voltage source and load resistor.
Dave
K0MBT

Re: VK4PLN's Radrino replacement boards

K9HZ <bill@...>
 

Nick, is there a schematic layout of the board posted somewhere?


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton - J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com


email:  bill@...

 


On Apr 10, 2018, at 10:07 PM, Nik VK4PLN <nickpullen@...> wrote:

Im glad you are happy with them, See my blog for a few photos, https://vk4pln.blogspot.com.au/
73 Nick

Re: #uBITX polyfuse? #ubitx

K9HZ <bill@...>
 

Depends upon the mode of failure i suppose.  My protection circuit posted on uBITx.net acts far quicker than a polyfuse could and is more certain to protect in any case.  


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton - J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com


email:  bill@...

 


On Apr 10, 2018, at 10:11 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

As a means of protecting the IRF510's, I think a polyswitch in the PA-PWR line should work great.
The IRF510's mostly fail due to overheating, a small polyswitch will have far less thermal mass
then the IRF510's plus heatsinks.

Often an LED and resistor in series are placed across the polyswitch,
such that when the polyswitch opens up the LED turns on.
That tells the operator to shut down power and let the polyswitch reset.

Would be interesting to experiment a bit, the IRF510's are cheap.
Turn up the gate bias pot till something gives.
My bets are on the polyswitch (rated for say 2 or 3A, will blow somewhat north of that).

I doubt you need a limiting resistor in this particular case. 

Jerry


On Tue, Apr 10, 2018 at 07:38 pm, lostfrogsrecords wrote:
They work slowly, need a current limiting resistor to allow the polyfuse to reach cutoff temperature before the protected device fails.  Again, slow...

Re: uBitX: Ordered Feb 20, received ship notice today, Apr. 6 #ubitx

yachtdesign@...
 

ordered 5th of March, today (11.4.) I`ve got the paypal shipping notification. Will be interesting when it will arrive.

Re: VK4PLN's Radrino replacement boards

kevintg51@...
 

Hi Bill
Try this:- https://vk4pln.blogspot.com.au/  Nick did post it.
Cheers
Kevin VK2KTG

Re: uBitx just started transmitting a loud hum #ubitx-help

James
 

Raj, the receive is 100% fine. I only get the hum on transmit.

Re: W0EB/W2CTX Latest uBITX software release #ubitx

Jim Sheldon
 

OK Chris,
Yes over-use of the encoder/function button prompted a lot of our changes as you have to keep holding it longer and longer to get to certain functions and the human timer isn't the best at times - LOL.

Jim

------ Original Message ------
From: "Chris Clarke" <csclarke@...>
Sent: 4/11/2018 3:09:00 AM
Subject: Re: [BITX20] W0EB/W2CTX Latest uBITX software release #ubitx

Thanks Jim, I'll have a go at that wiring. I have tried implementing your firmware but my key didn't function as presently wired. I like the ideas in your menu implementation but I did find it difficult to remember how to proceed at certain points, in particular how to get straight back to the normal tuning function after selecting RIT ... kept finding I was doing the wrong thing!
73
Chris G3SQU

Re: Erratic tuning with my new uBitx

Chris Clarke G3SQU
 

Great, thanks very much Ian

Chris G3SQU

Re: VK4PLN's Radrino replacement boards

K9HZ <bill@...>
 

Thats just a picture of the board?


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

 

Owner – Operator

Villa Grand Piton - J68HZ

Soufriere, St. Lucia W.I.

Rent it: www.VillaGrandPiton.com


email:  bill@...

 


On Apr 11, 2018, at 7:48 AM, kevintg51@... wrote:

Hi Bill
Try this:- https://vk4pln.blogspot.com.au/  Nick did post it.
Cheers
Kevin VK2KTG

Re: uBitx just started transmitting a loud hum #ubitx-help

Skip Davis
 

Dave are you using shielded cable on your mic? It could be RF getting into the mic circuit. If you are using shielded cable try putting decoupling caps across the mic audio line. 

Skip Davis, NC9O

On Apr 11, 2018, at 06:02, davesters@... wrote:

I had the bitx40 that quit transmitting. The electret mic failed. I didn't get the hum just silence. The replacement mic has given the radio increased power, about 10 watts. 

I wondered if humidity from my breath caused the failure. I like the idea of a voltage spike though. Seems more likely.  Am wondering if I should put a choke between voltage source and load resistor.
Dave
K0MBT

Re: AGC circuit to try?

Dexter N Muir
 

Bill N2CQR ('Soldersmoke') has been using 2 FETs in 'series'/cascode as dual-gates. Jxxx numbers. Bog-standard, readily available. AFAIK good NF, gain-bandwidth etc...

73
Dex, ZL2DEX

Re: AGC Added to uBITx

K4LXY
 

Do you mean R253?
Howard 

Re: POP fix

ve7hcw@...
 

Re: AGC circuit to try?

Kees T
 

Wes Hayward, W7ZOI, also has an article on using dual J-FETs in cascode mode for AGC use.

73 Kees K5BCQ 

Audio pop on CW

K4LXY
 

I think I solved the audio pop problem on CW based on the VE1BWV muting circuit (see uBitx.net)

Earlier I tried this muting circuit, which mutes the audio during transmit, but it also muted the sidetone.

The solution was to use his muting circuit but insert the sidetone on the top side of the volume control, after the muting circuit, instead of earlier in the audio circuit as it was originally.
 
The idea was suggested earlier by Philip as part of his AGC solution (though he incorrectly identified the resistor involved as R235 rather than R253).
 
Here is what I did
Removed R253.
To the end of R235 that was also connected to C252, I added in series a 1K resistor and .1 microfarad capacitor, then going to the yellow wire on the volume control (top).
 
There are two things about my setup that make it different than Philip’s but it should work as suggested above.
 
1) I have a Hi-Per-Mite SCAF after the volume control, and it may provide some amplification.
 
2) Earlier I had replaced R250 with a variable resistor so that I could control the sidetone volume, so I have the option of fine-tuning sidetone volume.
 
73 Howard K4LXY

Re: AGC circuit to try?

ajparent1 <kb1gmx@...>
 

It can be done with 2 Jfets, 2 bipolar if the lower input impedance is useful, or 1 of each (HyCas).
IF one wants to be retro a 12AT7!

They all work.  The two J-fets is really old and appear in ths Allied Radioshack AX-190 from
the early 70s.  Two transistors was over 10 years before.  Hycas actually was in the same
time frame.  HyCas was published as a complete IF with RF derived AGC and it works
very well.

I've used all the chips ua703, MC1550, CA3028 and their variants and follow ons
like the 1350/1590.    They work but require care or you get of what you asked for.
All of them where differential mode is used suffer an increase in noise as agc is
increased.  The exception is maybe the CA3028 as it can be used in cascade
mode as well and  will avoid that.  That noise increase degrades signal quality.

Designs like dual Jfet, Dual gate mosfets like the BFR998 tend to be quieter.
They are more difficult in incorporate in some topologies.  I think they are worth
it.  A high dynamic range receiver puts a very high requirement on succeeding
stages.

Like K9HZ I've built enough high performance radios for hobbe and some commercial
and I have one general comment.  AGC can be an aid to a smooth performing radio.
You can calculate and model it to death, then you build it, most importantly test it
and listen to it.  If it sounds good you done all to often it will not.   Many times its 
easier to do it empirically  cut, try and test.  Right wrong and what I want doesn't
matter if it meets your criteria.  

One thing, filter ripple is hard to hear for most people and unless its more than 6DB 
most will not.  Most commercial filters can easily have 3Db of ripple.  I doubt one
made form less than hand picked parts is much better than that.  I've never made
a satisfactory quality filter without hand picking the crystals for both frequency
and Q and same for the parallel caps.  Data can be picky and not like that but
our ears are not the same (we have different preferences) and we are building
to suit the ears.  


Allison

Re: AGC circuit to try?

Kees T
 

Since dual gate BF998 units are apparently older and either not stocked or obsolete, I would assume the BF2040 is acceptable to try (and inexpensive).

73 Kees K5BCQ 

Re: AGC circuit to try?

Lawrence Galea
 

Also used by DL6WD Rudolf Fischer.
See ARRL Single Sideband for the Radio Amateur 1970 p193 et seq.
"An Engineer's Ham-Band Receiver"
Used in the RF amplifier with 0-60dB manual RF gain control
Regards
Lawrence

On Wed, Apr 11, 2018 at 11:45 AM, Dexter N Muir <dexy@...> wrote:

Bill N2CQR ('Soldersmoke') has been using 2 FETs in 'series'/cascode as dual-gates. Jxxx numbers. Bog-standard, readily available. AFAIK good NF, gain-bandwidth etc...

73
Dex, ZL2DEX


Re: AGC circuit to try?

Jerry Gaffke
 

You can tell the BF998 is an older part because the datasheet identifies it as a "tetrode".
    https://www.mouser.com/datasheet/2/196/bf998series-59603.pdf
Would be very cool to be able to say I have a tetrode front end in my uBitx.


On Wed, Apr 11, 2018 at 12:27 pm, Sandy T wrote:
Since dual gate BF998 units are apparently older and either not stocked or obsolete, I would assume the BF2040 is acceptable to try (and inexpensive).