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And what "unit" pray tell are we talking about here?
Roy WA0YMH
On Thu, May 16, 2019, 9:12 PM David Wilcox via Groups.Io <Djwilcox01= [email protected]> wrote: Farhan,
I heard your lecture at FDIM and purchased one of the units but need instruction in how to use it.? Github only has the upgraded code files.? Please advise.
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And what "unit" pray tell are we talking about here?
Roy WA0YMH
On Thu, May 16, 2019, 9:12 PM David Wilcox via Groups.Io <Djwilcox01= [email protected]> wrote: Farhan,
I heard your lecture at FDIM and purchased one of the units but need instruction in how to use it.? Github only has the upgraded code files.? Please advise.
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Re: Low power output on ubitx
I have check all again, and the rv1 at 2/3 was best modulation but the output doesn't get higher than 4-5W on 80m an 3W on 40M.. the other Bands still get 1-2 on 15M or 10M
THIS CAN NOT BE THE UBITX OUTPUT THAT SHOULD BE THE RIGHT ONE , WHAT CAN I CHECK IF Q90 IS NOT SHORTET I REALLY GONE CRAZY..
sorry this makes real bad vibrations everytime i get outdoor for testing on lagre antenna in the nature and everytime there is no way, or even when have luck it really strong to get qso with this.. and this issue should be able to find but i'm doesn't find till now?
Hope for any idea
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Nice
Hmmm - could I buy enough stuff that the discounts could greatly supplement the travel cost?? LOL with that but nice of those merchants to make the gesture.?
selling kits at FDIM implies that the hardware design is complete!? adding a larger display and updating firmware code can be down-loadable.? one can imagine more will come for sale at HFSignals to help fund his long trip to Dayton!? (ditto with QSX for another VIP who was at FDIM).
It takes some time to supply and kit things - nice that some folk at FDIM have first fruit.? They owe use reports after building and using them!?
73 Curt
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Farhan sold some last night at FDIM (and yes, I have one ;) ). The sign he had implied that there is a ¡®normal¡¯ price of $100, and he sold them at a discount, so I would assume that you will eventually be able to order them.?
--
Karl Heinz - K5KHK
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Re: setup for analysis of before/after measurements of v4 spectrum purity
Robert and Evan, ?thank you for sharing! I have some heavy duty hp variable attenuators that I can front to the fixed ones when they arrive. But the 50db tap looks easy to make and probably can put it together before the fixed set arrives from China.?
Did either of you use the two tone window sound generator? ?How did you set the input volume?
73
Mark
AJ6CU
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Re: setup for analysis of before/after measurements of v4 spectrum purity
I have used the SDRPlay as a SA, and had some challenges.
1 - First of all, the frequency span was not big enough to measure the harmonics on 40 meters in one test.? You need to change the center frequency to do the test in two separate measurements.? I was not sure that the gain stayed the same, so I my experience, the harmonics test was inconclusive.
2 - It was not clear how the gain controls operated in the SA software.? I still am not sure, so maybe someone can be specific on how to defeat the AGC and adjust the gain for a good capture.
3 - I built the following 50 ohm "tap":
I still needed a step antenuator feeding the SDRPlay from the tap.
uBitx = TAP = Watt meter = Dummy Load
? ? ? ? ? ? ? ?|
? ? ? ? ? ? ? ?L= Step Antenuator = SDRPlay
It has been awhile, but I believe I had to adjust the step antenuator and gain to insure that when I added or removed 10 db, the SA software reported the same amount of change (this was how I overcame the AGC issues)
4 - The SDRPlay SA software will warn when you are getting close to overload.? Even if you stay below the warning message, there is signal compression even without the AGC engaged (reason for the set testing)?
My experience was it was good for close in purity testing, not so good for the harmonics
Above is my experience, things may have changed, or there may be better ways to accomplish the task.? Yours may vary.
73
Evan
AC9TU
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Re: setup for analysis of before/after measurements of v4 spectrum purity
I'd start with 60db at the least, and go up from there.? 60db is
1000x voltage (loss or gain).? Those SDR dongles are quite
sensitive (mine is down in the microvolts, maybe fractional
microvolt range), and if the Bitx puts out 7 watts, that's roughly
53 v p-p in a 50 ohm setup.??
80 to 100 db would be better IMO.? That would help to not
overload the dongle... and should get the signal level down to the
point where you wouldn't be encountering any limiting in the
signal.?? Put a t fitting on your dummy load - one side goes to
the radio, the other to your attenuator.
If you have access to a step attenuator, even better.? That's the
way I'd do it (I've got one 120db to 0).? Start with 120 and
reduce the attenuation until you have enough signal to measure - I
think the specs call for better than 40 or 45db down for unwanted
signals, so you'd want your carrier to be higher than that.
I've done the "coax into dummy load, and then used a dongle to
measure near the coax" method.? That also worked well enough for
what I was doing.? It's a quick way to do it... without all of the
extra components.? You just start moving the dongle closer and
closer until you get enough signal.
Bob
N4FBZ
On 5/17/19 10:15 AM, Mark Hatch wrote:
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Hi,
Have all the "recommended" parts (inductors + relays) that is
supposed to make a "typical" v4 either FCC compliant or very
close. But before I did the surgery, wanted to do a before/after
measurement.
I am going to try to use the sdrplay sa software. I have seen
where several people have used it to at least get a ranging shot
on the spectrum. Will also send in a two tone signal thru
microphone port using a windows soundboard app that was suggested
on these forums.
So I do know I need to send the ubitx into a dummy load.... duh
And that I want to put lots of attenuation in front of the sdrplay
(people seem to be typically using 40db, but I will put more than
that to start until I figure it out.)
But nobody seems to mention how the sdrplay will pick up the
signal? I am guessing that I don't use *any* antenna and just let
the attenuators sit open. ?Can someone validate this? Also, any
experience in using the sdrplay SA software will be appreciated.
Would prefer not to blow it up if possible. :-)
73
Mark
AJ6CU
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setup for analysis of before/after measurements of v4 spectrum purity
Hi,
Have all the "recommended" parts (inductors + relays) that is supposed to make a "typical" v4 either FCC compliant or very close. But before I did the surgery, wanted to do a before/after measurement.
I am going to try to use the sdrplay sa software. I have seen where several people have used it to at least get a ranging shot on the spectrum. Will also send in a two tone signal thru microphone port using a windows soundboard app that was suggested on these forums.
So I do know I need to send the ubitx into a dummy load.... duh
And that I want to put lots of attenuation in front of the sdrplay (people seem to be typically using 40db, but I will put more than that to start until I figure it out.)
But nobody seems to mention how the sdrplay will pick up the signal? I am guessing that I don't use *any* antenna and just let the attenuators sit open. ?Can someone validate this? Also, any experience in using the sdrplay SA software will be appreciated. Would prefer not to blow it up if possible. :-)
73
Mark
AJ6CU
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Re: Original Bitx20 design
Hi N7QL,
The original Bitx20 is a single band design, thus one would generally just be concerned with harmonics generated by the PA.? These should have been taken care of by the low pass filter in the design.? However, for higher output probably another pole on the filter would be advised.? Of course overdriving the mic amp circuit can cause IMD too if one decides to change that part of the circuit.
The original design was fine, although there were many improvement to the design done by builders over the years.? It's biggest issue was no AGC and a loud burst of audio noise on PTT engagement and disengagement.
73,
Mark.
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I'm just discovering the Antuino and reading a bit about it. Is there a source for a kit or, at minimum, the pc board?
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Re: Inexpensive eBay Amplifier Kits
Jack,
Doesn't appear to be certified, so use at your own risk, however it seems like the same board and components used in the kits.
Jay
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Farhan,
I heard your lecture at FDIM and purchased one of the units but need instruction in how to use it. ?Github only has the upgraded code files. ?Please advise.
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Hello Sascha,
Great detective work in pinpointing the problem.
Your mod should work as in non-AM mode you revert to the standard CW timeout logic.
It is easy to verify but trying to send in CW.?
The timeout you are seeing is the one set as the CW delay to return to Rx which can be changed in the menu.
If the key has not been pressed for that delay value, the rig returns to Rx, and since we are never closing the key (Arduino input A6) in that AM mode it simply returned to Rx automatically.
Thanks for keeping us informed.
73, John
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Re: Original Bitx20 design
I guess I need to rephrase the question. I think the original design could be a great place for me to start from because then I could try different mods and see the difference. I just was wondering if spurious emissions would be to too strong with the original design. I am excited that I will finally get to build this soon whether the original or the 3b. Thank you.
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Okay, I changed the condition to
if ((0 < cwTimeout && cwTimeout < millis())&&(isAM==0)
and was astonished, that this seems to do the trick.
However I do not know if this is recommendable or if this way any other problems will occur.
I will test it with the loop controller tomorrow, but I hope this works out.
I still don't know what the cause of the problem was, though I suppose now that it could be that the cwKeydown() function was started out of the cwKeyer function().
This could mean the cwTimeout never gets assigned the current time.....
Sascha
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So, I really start to close in on the problem:
In the ubitx.keyer file in? the cwKeyer function is in line 251? a "stopTX()".
If I do comment this out, in my fake AM mode TX is not stopped again after being triggered,
and I can still switch back to RX via cat (in fake AM and the usual CW).
If I uncomment it again, transmitting immediately stops in AM I I had triggered TX by CAT.? If I switch to the usual CW mode and trigger TX by CAT? it remains transmitting.
So now I need to find out, why I don't get pushed out of AM in the normal CW mode and why this happens in AM mode.....
So somehow in AM mode the condition
if (0 < cwTimeout && cwTimeout < millis()){
????????? cwTimeout = 0;
????????? keyDown = 0;
???????? stopTx(); // this causes the problem
is met while not being fulfilled in the normal CW mode.
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Re: Inexpensive eBay Amplifier Kits
Welp., I managed to fry mine. No power, seems like a DC short on the power wire. I was trying different coax cables making sure I had the best cable, then auto tuning ?and it just died. Fan stopped moving. Is it the mosfets?
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On May 16, 2019, at 3:50 PM, Joe Puma via Groups.Io < kd2nfc@...> wrote:
Thanks Curt. I was just reading some other posts where someone mentioned that the harmonica on the other frequencies will be seen as a high swr on the meter. Sounds good to me, I¡¯ll wait for the filters. The transformers were put together nicely. Wires not shorted to tube or anything. I made a PTT from the uBitx buy using a octocoupler and wired it to the T/R on the raduino. ? <image1.jpeg>On May 16, 2019, at 2:43 PM, Curt M. < Kc3hjp@...> wrote: Hi Joe, I would wait until you get the filters and then see what your SWR is. ?It's been a while since I've had mine on the Bird 43 looking at forward and reflected power. ?It was OK from what I remember. ?Be sure that you solder those tubes for the transformers into the supports and thatcher's the tubes are not loose. ?That make help you also if you did not already do that.
I tested the filter set on the analyzer and it looked pretty good in it's respective bands. ?I've see better and I've definitely seen worse but they are more than usable. ?I use them with the Bitx40 and uBitx without the amp.
Curt
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Re: Inexpensive eBay Amplifier Kits
Thanks Curt. I was just reading some other posts where someone mentioned that the harmonica on the other frequencies will be seen as a high swr on the meter. Sounds good to me, I¡¯ll wait for the filters. The transformers were put together nicely. Wires not shorted to tube or anything. I made a PTT from the uBitx buy using a octocoupler and wired it to the T/R on the raduino. ? 
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On May 16, 2019, at 2:43 PM, Curt M. < Kc3hjp@...> wrote: Hi Joe, I would wait until you get the filters and then see what your SWR is. ?It's been a while since I've had mine on the Bird 43 looking at forward and reflected power. ?It was OK from what I remember. ?Be sure that you solder those tubes for the transformers into the supports and thatcher's the tubes are not loose. ?That make help you also if you did not already do that.
I tested the filter set on the analyzer and it looked pretty good in it's respective bands. ?I've see better and I've definitely seen worse but they are more than usable. ?I use them with the Bitx40 and uBitx without the amp.
Curt
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Would you consider a write-up or a youtube video on the process?
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sdr freak
Jay - WS4JM
David Wilcox K8WPE