[ARC5] Drift in BC-453 - more

Bill Cromwell wrcromwell at gmail.com
Sun Dec 17 14:23:23 EST 2017 

Hi Bob,

Thanks for the info about various flavors of WSPR. I interpreted that 
(regarding my own use) as bad and worse. I'm a 'forty meter ham' so the 
X flavor is right out. Since I am most always interested in what other 
hams are doing - what is the X version of WSPR for? Microwaves or...?

Sometimes I can pass along information that gives or leads others toward 
a solution or resolves a piece of the puzzle. So now I know much more 
about WSPR than I ever wanted to know - just like you said:)

73,

Bill  KU8H



On 12/17/2017 12:36 PM, Bob kb8tq wrote:
> Hi
>
> Ok, so just to try to get this back to some sort of solid base:
>
> There are many different things all called WSPR. You have 2.0, 2.1 and
> X. They
> share some things in common. They each have very different requirements for
> stability. In addition software *can* do interesting frequency tracking
> things with
> some other modes, but not so much with WSPR.
>
> If you go to Mr Google, he can tell you far more about each type of WSPR
> than
> you would ever want to know. There’s also way more about various PSK modes
> than you would ever need to dig into, unless you are about to take a nap
> :) ….
>
> So, back to the start of this:
>
> Which WSPR are we talking about? If it’s the 15 minutes  < 0.1 Hz stuff
> …. not going to
> happen with a non-crystal based tube set. It also isn’t going to work at
> normal HF frequencies
> no matter what the radio (straight off the official web site ….).
>
> So no, this is not some sort of failing of this or that radio. It’s also
> not anything
> that changing out a cap or two will fix. The X mode stuff simply is not
> designed
> to work with this sort of gear. The other modes …. probably fine.
>
> Bob
>
>> On Dec 17, 2017, at 12:17 PM, J Mcvey via ARC5 <arc5 at mailman.qth.net
>> <mailto:arc5 at mailman.qth.net>> wrote:
>>
>> It's good to know that you got a narrow digital signal to work on a
>> command set.
>> At least I now know it's not a total fools errand on my part...
>> thanks!
>>
>>
>> On Saturday, December 16, 2017 10:23 PM, Bill Cromwell
>> <wrcromwell at gmail.com <mailto:wrcromwell at gmail.com>> wrote:
>>
>>
>> Hi,
>>
>> If it matters..I have used a command receiver for PSK-31. After a warmup
>> I was able to just sit and copy the mail. I have let my 80 meter command
>> receiver go but that is the one that I used. I didn't mention it since
>> the question is about the BC-453. Mine is much more stable and I don't
>> have to let it run for hours before I can use it. Waterfalls produce
>> straight lines and most transmitters stay on the same displayed
>> frequency for hours.
>>
>> Ken said he would try his on WSPR. I would just because I am curious now
>> but I have abandoned WSPR. I also have too many other things to do. I
>> would like to know if it can do WSPR and if not, why not.
>>
>> I don't notice any issues with soundcards. I assume whatever bad habits
>> those xtals in the sound cards may have it doesn't interfere with my
>> uses. I have read reports from some hams about how they modify the sound
>> card to stabilize it with rubidium or caesium or gps. I don't recall
>> them claiming it solved a problem. Just that they wanted to do it. Maybe
>> Beethoven sounds more mellow or something <evil grin>.
>>
>> 73,
>>
>> Bill  KU8H
>>
>> On 12/16/2017 09:09 PM, Bob kb8tq wrote:
>> > Hi
>> >
>> > You *will* notice 5 Hz a minute on SSB. Most people will notice 5 Hz /
>> > 10 minutes if the QSO goes on for a while. You also will get a bit
>> > bothered by it on 170 Hz shift RTTY if pictures or something similar is
>> > being sent. Net operation is yet another place you will notice it. PSK
>> > modes tend to be bothered by a few Hz of shift, simply because of the
>> > narrow bandwidth. That puts pretty much all of them in the category
>> as well.
>> >
>> > Indeed a straight tube radio with no crystals involved will require some
>> > tuning to stay “on channel” for SSB. How much depends on 80M (not a
>> > whole lot) vs 10M (quite a bit). Both are normal HF bands that people
>> > run SSB on.
>> >
>> > Back in the day, the BC-453 was commonly used by a lot of us as a tack
>> > on “super IF” for various radios. I don’t ever remember it being an
>> > issue for drift compared to the radio that was feeding it. Simply put,
>> > the drift came from the 4 MHz -> 455 KHz process, not from the 455 -> 85
>> > KHz conversion.
>> >
>> > The debate seems to be 5 Hz per minute vs 5 uHz (or 5 mHz … ) per minute
>> > as the requirement for HF WSPR.
>> >
>> > Bob
>> >
>> >
>> >> On Dec 16, 2017, at 6:24 PM, J Mcvey via ARC5 <arc5 at mailman.qth.net
>> <mailto:arc5 at mailman.qth.net>
>> >> <mailto:arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>>> wrote:
>> >>
>> >> Neil,
>> >>
>> >> Yup!
>> >> I did mention 5Hz/minute.
>> >> The radio works fine for CW because the drift is almost imperceptible
>> >> to the human ear , but WSPR notices!
>> >>
>> >> I guess you haven't worked with waterfalls and these digital modes?
>> >> The issue is obvious.
>> >> This stuff requires a whole other level of timing and stability.
>> >> I also said that I will do a an actual analysis when time permits...
>> >>
>> >> My hope was that someone other than myself is attempting to get a
>> >> command set to receive  WSPR and JTXX modes.
>> >> Anybody?
>> >>
>> >>
>> >>
>> >>
>> >> On Saturday, December 16, 2017 5:53 PM, AKLDGUY .
>> <neilb0627 at gmail.com <mailto:neilb0627 at gmail.com>
>> >> <mailto:neilb0627 at gmail.com <mailto:neilb0627 at gmail.com>>> wrote:
>> >>
>> >>
>> >> The thread has meandered around because we haven't been given anything
>> >> to go on.
>> >> You have blamed the BFO but haven't mentioned any stability figure.
>> >>
>> >> Is the B+ feed to the BFO tube original? Are the resistors good? Have
>> >> they been
>> >> replaced by significantly different values? Is the decoupling to it
>> >> still present? Are the
>> >> caps bad?
>> >>
>> >> Sounds silly, but has a 6SR7 been fitted yet the heater line been
>> >> rewired for 12V? Are
>> >> you running 25V on the heater line and a wiring mistake has resulted
>> >> in 25V on the
>> >> 12SR7?
>> >>
>> >> I hope you've eliminated the painfully obvious.
>> >>
>> >> Neil ZL1ANM
>> >>
>> >>
>> >> On Sun, Dec 17, 2017 at 3:50 AM, J Mcvey via ARC5
>> >> <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>
>> <mailto:arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>>> wrote:
>> >>
>> >>    This thread has taken many meandering twists and turns.
>> >>    It all started when I suggested that BFO stability may be the
>> >>    reason that WSPR cannot be decoded with a commend reciever.
>> >>    Yes, it is a "hobby thing" where I aspire to make a complete 630
>> >>    meter station from command components.
>> >>    One of the "Ham-mered' transmitters can be re purposed as the
>> >>    transmitter and the BC-453 as the receiver.
>> >>    The transmitter will be controlled by XCO or VCO with PLL.
>> >>
>> >>    The computer systems drift ARE NOT the issue with WSPR. It works
>> >>    fine with other rigs.
>> >>    The BC453 LO "seems" to be stable if I leave it on a weak beacon
>> >>    station for a period of time.
>> >>
>> >>    I built a 85 Khz fet Colpitts oscillator from some junk box
>> >>    components. I hope it will be more stable than the command set
>> >>    BFO, but
>> >>    it may have more phase jitter than I want.  We'll see...
>> >>    It will be used to drive the grid of the existing BFO oscillator
>> >>    disconnected from the set's BFO can. The plate circuit will remain
>> >>    intact .
>> >>
>> >>    I haven't had time to do  the drift measurements on the BFO and LO
>> >>    yet, but I will get there eventually. Stay tuned...
>> >>
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