Re: ?BITX as a Tool for Recruiting New Hams
put on your dark glasses, pull out an led pointer and ask everyone to look at it.
On 16 Dec 2017 12:14 am, "Jack Purdum via Groups.Io" <jjpurdum= [email protected]> wrote: If you want to attract a crowd (including the police!) go to a park, put up a portable antenna (mag loop, Buddipole, even a Hamstick), set up your radio with a battery or small (10W) solar panel, and start calling CQ. People are naturally curious when they see this. If you want a larger crowd, tell them you work for the gov't but can't tell them any more than that or you'd have to kill them.
Jack, W8TEE
From: Ashhar Farhan <farhanbox@...>
To: [email protected]
Sent: Friday, December 15, 2017 1:33 PM
Subject: Re: [BITX20] ?BITX as a Tool for Recruiting New Hams
Given the shrinking urban spaces, we need to take the sota movement, combining radio and outdoors. weekend radio meets in parks, fox hunts and pedestrian contests are the way to go me thinks. - f
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Ordered mine on the 9th as well.? Just turned the computer on (5:15 a.m.? Central US time) and have a notification from PayPal that HF Signals had updated the shipping info with a DHL tracking#.? No email received from HF Signals, but according to the DHL tracking site it left Hyderabad, India at 22:50 Hyderabad time on Thursday the 14th and is now on it's way.? Current location shown on the tracking site is Departed East Midlands, UK at 0802 a.m.. UK Time for delivery to Park City, KS by end of day Monday the 18th.? That's pretty good DHL service once it got moving.? Looks like I'll get it in time for Christmas.
W0EB
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With a Raduino/BITX configuration (specifically), it is unlikely that any harm would occur were one to connect USB and radio power at the same time.? Power from the radio to the Raduinopasses through the 5V regulator on the Raduino and is fed into the Nano via the +5V (Pin 12 unregulated input).? Power from the USB port passes through the on board regulator of the Nano.? The +5V pin is effectively bi-directional in that the Nano and other connected devices (LCD display) can obtain their power froma regulated +5V source.? If there are few and/or low current devices running on this power there is (usuallly) no issue if you plug in the USB and again, in the case of a BITX/Raduino (specifically) power at the same time.
The real danger of destroying a Nano is when it is not when external +5V on Nano pin12 and USB are connected at the samei time. The real danger is in a (hardware) configuration where it is powered by +5V (pin 12) and is sharing power with a number of other devices.
If the Nano +5V (pin 12) is not disconnected from the other circuitry/devices on that common +5V bus, connecting the USB power (to program the Nano or to make use of serial print 'debug'), can blow the Nano on board regulator if the other devices on the +5V bus draw excessive current from the Nano on board regulator.
Again, in the 'stock configuration' of a BITX/Raduino combination, this should not be a problem.
That said, if there is ANY doubt/concern, it is as suggested, best to disconnect from any external power before plugging in the USB power.
The electrical schmaticfor the NANO can be found at:
73, Robin
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Re: Holy fast delivery Batman!
?Ordered I think later in the day on Dec 9th....just got a paypal tracking number for DHL and apparently I might see this on Monday.? ?Very happy --- demonstrated a couple of different mountings of bitx40 to the local ARES group at a meeting last Wednesday
and also demo'd the computer/digitally controlled vacuum tube Heathkit SB-100 as a result of the Raduino -- fascinating capabilities brought within the grasp of a huge number of hams by Ashhar's work!? ?
I sympathize with those still waiting.? ?I remember when I first built my Heathkit Hw-16 and it didn't work properly and I couldn't figure it out and had to ship it back to Benton Harbor waiting weeks to months to ever see it again --? there was no such
thing as "overnight" in those days.? ?And I couldn't have afforded it anyway.? ?Took several tweaks by both the factory AND me before I got the key clicks out of that transmitter under control, and I was using crystals I believe in the beginning before I built
the companion VFO.? ??
This bitx stuff is highly reminiscent of those days.??
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Mine arrived today too.? I haven't even thought about a case!
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Re: #uBITX Front end overload protection
#ubitx
Ray --
I was quite aware that Ashhar had stated
"the front end diodes in the mixer will clamp any signal higher than half a volt. this should take care of the very powerful signals.
adding diodes at the open front end can lead to a very large number of spurs in ubitx. unfortunately, unlike the bitx40, ubitx does not have the luxury of a narrow, triple tunec circuit.
- f"
However, I didn't understand how a diode ring mixer, on the other side of a transformer, and further on the other side of a low pass filter, could protect Q90.....
which is precisely? why I wrote
"I'm not smart enough to know exactly how the ring modulator would guarantee to protect from this..."
and also why I theorized the actual mode of destruction of Q90 as follows:
"presumably what blows the transistor isn't Forward bse emitter current, but instead a reverse voltage that destroys the junction.??"
and as Ashhar had not commented on the existence ALREADY of ONE DIODE i the front end, namely, the base-emitter junction of Q90, I wrote the following:
"the base-emitter junction of this transistor already puts one diode effectively in the input of the rig.
not exactly sure how putting one more would raise the level of spurs tremendously?"
Therefore,??based on the above points, I suggested simply adding a REVERSE diode directly across base-emitter of Q90, designed to protect that transistor from being destroyed by a high REVERSE voltage (negative on base) as C80 becomes charged up by the half-wave
rectification caused by the base-emitter junction of Q90 in response to a large input RF waveform.....? [Q90 essentially performing half-wave rectification and charging up C80.]
The base-emitter of Q90 will conduct when the input waveform is POSITIVE, charging C80 in such a direction that when the input waveform goes NEGATIVE, C80 will add to the voltage and contribute to destroying the base emitter junction of Q90 --- adding a reverse
diode across the base-emitter junction would prevent that, and presumably do little to add any additional spurs, if spurs are indeed created by the existence of the base emitter junction of Q90 on the other side of C80 already.
Albert opined:
"I may be wrong, but Q90 is a transmit stage and is isolated from the rx path by C80.
?The ring diode mixer (D1 & D2) essentially are reverse diode pair acrosd the input to T2 secondary offering a limiting factor for Q22 in the rx stage. ?Actually those diodes are the first stage device (mixer) in the rx."
And agreed Q90 is a transmit stage, but the concern is that just as the corresponding transistor in the BITX40 version, it will NOT be protected by the series capacitor C80, but rather destroyed by it, due to the half wave rectification resulting from Q90's
base-emitter junction in the face of a strong incoming waveform.? ?Agreed that the diode ring mixer are a reverse diode pair across the a transformer secondary, but it is not clear (to me at least) how they offer protection to Q90 which receives PRE Low Pass
Filter radio frequency signals.? ?
Jerry's suggestion for a test,?
"Would be interesting to remove C80 (to avoid blowing?Q90)
and measure the AC voltages into L1
when driving the antenna port with various signals."
implicitly contains the assumption that Q90 is? **NOT** protected in the situation of high AC voltage applied the incoming antenna port, which was the impetus for my suggesting an alternate solution to the perceived problem.
Hope all that verbiage addresses the issues raised,
73,
Gordon Gibby
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Directly from the man, himself.? Message #3 in this thread:
"the front end diodes in the mixer will clamp any signal higher than half a volt. this should take care of the very powerful signals.
adding diodes at the open front end can lead to a very large number of spurs in ubitx. unfortunately, unlike the bitx40, ubitx does not have the luxury of a narrow, triple tunec circuit.
- f"
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Re: Programing Help for updating Bitx40
I think we all do......? Good stuff.? I just need to read it!
On Fri, Dec 15, 2017 at 11:35 PM, Raj vu2zap <rajendrakumargg@...> wrote:
ROTFL! Doc Jack you are a gem, I have your book too!
Raj, vu2zap
At 16/12/2017, you wrote:
Totally biased, but there a book
titled Beginning C for Arduino, 2nd Ed. by a guy named Purdum and
the first two chapters contain exactly what you're looking for. Go to
Amazon, read the reviews and see if it might fit your needs.
Jack, W8TEE
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Re: #uBITX Front end overload protection
#ubitx
Directly from the man, himself.? Message #3 in this thread: "the front end diodes in the mixer will clamp any signal higher than half a volt. this should take care of the very powerful signals. adding diodes at the open front end can lead to a very large number of spurs in ubitx. unfortunately, unlike the bitx40, ubitx does not have the luxury of a narrow, triple tunec circuit. - f"
On Fri, Dec 15, 2017 at 11:39 PM, Raj vu2zap <rajendrakumargg@...> wrote: At K1 pin 12 add two diodes parallel but opposite polarity to ground.
You can do that at K3 pin 14 alternatively.
Raj
At 16/12/2017, you wrote:
>So, regarding Q90 and protecting it from strong signals.....
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Re: BITX40 - frequency spectrum - Raduino irradiation - intermodulation products -
#bitx40help
Yes Frank,
See if the spurs change with bias, be gentle with the adjustment and keep watching the ammeter!
Raj
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At 15/12/2017, you wrote: Hi Raj,
thank you for your answer :-)
Is this only possible by RV1 / RV136?
Frank
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Re: #uBITX Front end overload protection
#ubitx
At K1 pin 12 add two diodes parallel but opposite polarity to ground.
You can do that at K3 pin 14 alternatively.
Raj
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At 16/12/2017, you wrote: So, regarding Q90 and protecting it from strong signals.....
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Re: Programing Help for updating Bitx40
ROTFL! Doc Jack you are a gem, I have your book too!
Raj, vu2zap
At 16/12/2017, you wrote:
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Totally biased, but there a book
titled Beginning C for Arduino, 2nd Ed. by a guy named Purdum and
the first two chapters contain exactly what you're looking for. Go to
Amazon, read the reviews and see if it might fit your needs.
Jack, W8TEE
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It should work, I have not tried it.. sitting on the farm with some coffee buyers from Holy Island in UK..
Farhan has made provision for separate supply for the final.
Raj
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At 15/12/2017, you wrote: Ashhar, Sarma, Raj, other? Is it feasible to drive the uBitX PAs at 24V, or is that asking for trouble? Apologies if this has already been covered; please point me to the thread. Thanks, Craig w9ctw
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Re: Programing Help for updating Bitx40
Jeff, Doug is probably correct.? There is no real programming needed.? You will just be uploading a new program ("Sketch") into the NANO.?? The real programming has already been done.? ?This is about the same level of difficulty as updating firmware on a piece of hardware, in my opinion.
There has been some discussion as to whether you can have the radio powered up and the USB cable connected to your computer at the same time.?? To be safe, make sure your radio is not connected to any power.? The NANO will be powered via the USB connection from the computer.
I hope this clears up any confusion that might have existed.
Marco - KG5PRT
On Fri, Dec 15, 2017 at 9:39 PM, Doug W <KD9CYF@...> wrote: Jeffrey,
When you use the word programming do you mean writing and or modifying code or are you using the word programming to mean loading a sketch onto the arduino?
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Re: BITX QSO Night, Sunday, December 17, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
As long as the RFI from the guy around the block is off I will be on this weekend. Always up for a QSO during the week as well.
?
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Re: BITX QSO Night, Sunday, December 17, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Several folks have joined the Discord chat . Perhaps we can use this for time and frequency coordination for the QSO night?
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Not sure if I'll be able to get on at 3PM EST (2000UTC) this week, bit I'll try.
--
John - WA2FZW
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Re: BITX QSO Night, Sunday, December 17, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Not sure if I'll be able to get on at 3PM EST (2000UTC) this week, bit I'll try.
--
John - WA2FZW
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BITX QSO Night, Sunday, December 17, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
BITX QSO Night, Sunday, December 17, 7pm Local Time, 7277 kHz in North America, 7177 kHz elsewhere
Join us as we make contacts from BITX40 to BITX40 on 7.277 MHz in 40 meters!
This is a worldwide event for BITX40 stations starting at 7pm in each time zone. To participate, call CQ BITX on Sunday, starting at 7pm your local time. The BITX QSO Night continues through the evening and conditions usually improve after sunset, so it is worthwhile to participate later in the evening.
Suggested Best Operating Practices:
Work at QRP power levels unless conditions require more power.
Call and listen for CQ BITX on the hour and every quarter hour.
It is helpful if you call CQ BITX with your callsign, name and location.?
Repeat your callsign a number of times during your CQ BITX and during QSO's.
Start a QSO by confirming the callsign, location, name and signal report of the other operator.
Say the callsign, name and location of the other operator so others can hear.
If the frequency is busy, avoid long conversations.
After your initial QSO is complete, ask if there are any other stations who would like to contact.
Report your QSO's, discuss propagation, noise, signal reports, audio reports, antenna type, etc. in this thread.
This is an undirected, scheduled event.? The BITX QSO Night relies on you to call CQ BITX to initiate contacts with other stations, so warm up that final and transmit a few calls on Sunday evening.? Talk to you then!
--
John - WA2FZW
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Re: Programing Help for updating Bitx40
Jeffrey,
When you use the word programming do you mean writing and or modifying code or are you using the word programming to mean loading a sketch onto the arduino?
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Re: Programing Help for updating Bitx40
Thank You Marco,
I will read the Wiki tomorrow morning.? My old eyes are getting tired tonight.? I appreciate your suggestions and guidance on programing.? Lots to learn!
73 de Jeff K9JP
On Fri, Dec 15, 2017 at 10:06 PM, M Garza <mgarza896@...> wrote: You can also find a wealth of info in the WIKI:
There is a topic on installing the IDE and the libraries.
Good luck,
Marco - KG5PRT
-- Not all of me will die - - - The good I do will live forever.? <><
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Re: #uBITX Front end overload protection
#ubitx
I may be wrong, but Q90 is a transmit stage and is isolated from the rx path by C80. ?The ring diode mixer (D1 & D2) essentially are reverse diode pair acrosd the input to T2 secondary offering a limiting factor for Q22 in the rx stage. ?Actually those diodes are the first stage device (mixer) in the rx.
Again , I may be incorrect as that is how I interperste that portion.
73 WB8FEQ
Sent from my Verizon, Samsung Galaxy smartphone
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Re: Programing Help for updating Bitx40
You can also find a wealth of info in the WIKI:
There is a topic on installing the IDE and the libraries.
Good luck,
Marco - KG5PRT
On Fri, Dec 15, 2017 at 8:59 PM, M Garza <mgarza896@...> wrote: Hello Jeff, All the information you need is located here:?? Read the Readme file and look at the documentation.? If you still have questions, just ask. The hardest part is getting your nano to be seen by your computer in the IDE.
Hope this helps,
Marco - KG5PRT
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Jim Sheldon
Raj vu2zap
N8DAH
Albert Morris