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On Thu, Apr 12, 2018 at 2:48 PM, ajparent1 <kb1gmx@...> wrote: ARRL Single Sideband for the Radio Amateur 1970 p193 et seq.
"An Engineer's Ham-Band Receiver"
I've duplicated the PLL for another radio and copied ideas for radios I have built.
They worked very well.
Three reasons its not a fit for uBITx......
One: the MOSFets used disappeared in the late 70s.
Two: Its a narrow band front end using varicap tuning, usually called a preselector. Lots of band coils.
Three: is it would require much switching to take it out of the transmit path.
Allison
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On Thu, Apr 12, 2018 at 2:48 PM, ajparent1 <kb1gmx@...> wrote: ARRL Single Sideband for the Radio Amateur 1970 p193 et seq.
"An Engineer's Ham-Band Receiver"
I've duplicated the PLL for another radio and copied ideas for radios I have built.
They worked very well.
Three reasons its not a fit for uBITx......
One: the MOSFets used disappeared in the late 70s.
Two: Its a narrow band front end using varicap tuning, usually called a preselector. Lots of band coils.
Three: is it would require much switching to take it out of the transmit path.
Allison
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Ge evening Allison. I mentioned it because of the two fets used in cascade at the front end and the use of agc. It's design being nearly 50 years old is a totally different concept. As you said the semiconductors are obsolete but one could use modern ones if they want to do so. However, I have scanned the article which is hereto attached.
I scanned it at 600 dpi so I had to split it into three PDF files because of the 20 Mb attachment limit.? Regards to all. Lawrence
On Thu, Apr 12, 2018 at 2:48 PM, ajparent1 <kb1gmx@...> wrote: ARRL Single Sideband for the Radio Amateur 1970 p193 et seq.
"An Engineer's Ham-Band Receiver"
I've duplicated the PLL for another radio and copied ideas for radios I have built.
They worked very well.
Three reasons its not a fit for uBITx......
One: the MOSFets used disappeared in the late 70s.
Two: Its a narrow band front end using varicap tuning, usually called a preselector. Lots of band coils.
Three: is it would require much switching to take it out of the transmit path.
Allison
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Re: [qrp-tech] DC-DC converter experiment
It might be the DDS/VFO board we did for the QST article (March, 2015) on the Forty-9er. The only touchy thing about the buck converter was the Phillips head screw that adjusts the voltage which was easily torqued right off the board.
Jack, W8TEE
On Friday, April 13, 2018, 1:59:02 PM EDT, Nick Kennedy <kennnick@...> wrote:
I used one that looks a lot like that on a project with a DDS and Arduino
Nano. It was a hair smaller than a postage stamp. The input voltage came
from 6-NiMh cells and the output is steady at 5 V. Efficiency is high too.
From my notes:
I tested the little regulator, which is the size of a postage stamp. While
supplying 190 mA at 5 VDC with input voltage varying from 8.4 to 5.5 VDC
the efficiency was 87% to 93%.? Over the expected range of 8.4 V to 6.3 V,
it¡¯s 87% to 91%. It started to drop out at 5.4 volts input, but otherwise
the output was rock steady over the input voltage range. It¡¯s rated for 5.5
V to 12 V input and 3A output.
72-
Nick, WA5BDU
On Fri, Apr 13, 2018 at 12:14 PM, chuck adams < chuck.adams.k7qo@...> wrote: > Since I have to wait on the slow boat to test this, maybe one of you has > a similar item and can report to the group. > > Here is a DC-DC converter for down conversion and costs $0.79. > > > > I have no problem whatsoever with spending the $0.79 USD to try it > and I can, of course, find another use for the critter in powering 3.3V > DDS modules.? I just would have to wait 4 weeks for the critter to swim > across the Pacific ocean and maybe take a few days in KH6 land for DX. > > ?...? > > > Any one gone and played with one of these DC-DC converters in a > similar manner? > > chuck, k7qo > > >
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Re: Pressing 14 pin LCDs into I2C service
#parts
More than one way to skin a cat! tim ab0wr On Fri, 13 Apr 2018 08:05:31 -0700 "Kevin Luxford" <kbgluxford@...> wrote: I had in my bowerbird boxes some LCD displays purchased some years
ago.? Thinking that if an I2C controller backback were to be
attached, they would make handy displays for BITX or any other
project.? Only 4 wires to write and control is very attractive. So
some I2C backback controllers arrived from China via eBay, and it was
intended to attach the controller to the LCD display like the
prototype unit that was already working.? On unwrapping the LCDs from
their bubble wrap, I discovered, quelle horreur, that the LDCs had
only 14 pins.? Well 16 into 14 does not go, so to the LCD a 14 pin
female header was soldered, the controller plugged into the female
header leaving pins 15 and 16 dangling in the breeze.? Upon firing up
the test program in the Nano and rotating the contrast pot on the
controller, the contents of the text eventually appeared.? However,
no backlight on the LCD meaning that it had to be operated in
reasonably high ambient light.? Looking at the pinout diagram, a
possible hack was perceived. At the right hand end of the LCD were
two unused contacts, marked A and K.? Connecting A to Pin 2 (Vcc) and
K to Pin 1 (GND) resulted in a backlight appearing. Here are a couple
of pix showing the hack.? The first picture shows the two wires added
to bring power to the backlight, while the second shows the female
header and the dangling Pins 15 and 16. 73 Kevin VK3DAP / ZL2DAP
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Re: uBITX SSB filter response question
#ubitx
Satish and Allison: I'm using chinesium SMD 1206 capacitors. Re: the questions about insertion loss, I realize now that I had not accounted for loss in my cables, and perhaps I'm not appreciating fully the implications of my test equipment. I'm a dopey artist, not an engineer! When shorted, the cables out-of and into the PHSNA present a 3.5 dBm loss. Each transformer adds 1.9 dBm loss, so double that and add the loss in the cables will represent a total loss of 7.3 dBm. When I bias the PHSNA for the 7.3 dBm loss and attach the filter (including the transformers on each end), I get this result, which puts me well inside the 4-7 dBm loss that you mention.  Would an ideal (but real-world) filter have a flatter top? Allison, you mention that doing a slow scan is better. I can only slow the baud rate from the PHSNA to the PC. The above graph is using a 56k baud rate, and the graph below slows down the baud rate to 9600. Not sure if this slows down things enough to give the detector enough time, but there it is. -Michael VE1LEB 
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Re: uBITX SSB filter response question
#ubitx
Michael,
Yes, that curve with the transformers looks much
better. I suspect mine does not look
that good. Have not swept it yet.
Please heed Allison's warning about sweep speed.
Rod
On 04/13/2018 09:05 AM, Michael LeBlanc
wrote:
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Thanks Rod. I'm
enjoying the journey and for the time being I can get on the air
any time with my appliance radio. ;-)
I was measuring it 'naked', without the transformers. Just before
reading your reply, though, I measured it again but through the
transformers, and the result is "softer":
I also was fastidious about recording the individual crystal
measurements, and (like you), put them in a spreadsheet and asked
it to re-order the crystals by centre frequency. Thanks also for
your thoughts on the filter's centre frequency. As long as I'm in
the ballpark, I'm happy.
-Michael VE1LEB
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Re: Dirt cheap uBitx case
#ubitx
Oh that is one sweet front panel!
Roy WA0YMH
I really like the idea of using the RJ45 jack for the mic.? I finally ended up making mine pretty traditional looking.? I'm still going to add the USB panel connection so I can hook it up to the computer without having to remove the cover.? I will also probably add an external IF connector now that Ian are experimenting with SDR hookups. - Dan, W2DLC
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Re: Dirt cheap uBitx case
#ubitx
I really like the idea of using the RJ45 jack for the mic.? I finally ended up making mine pretty traditional looking.? I'm still going to add the USB panel connection so I can hook it up to the computer without having to remove the cover.? I will also probably add an external IF connector now that Ian et.al are experimenting with SDR hookups. - Dan, W2DLC 
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Re: ubitx encoder hookup breadboard.
Dave
Understood.? My post was mostly to provide expanded info for general use.? Questions regarding rotary encoders tend to occur on a regular basis, mostly from new group members.??
Your method for enhancing robustness of the encoder connections is a good one.??
Thanks,
Arv _-_
Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message -------- From: davesters@... Date: 4/13/18 11:50 AM (GMT-07:00) Subject: Re: [BITX20] ubitx encoder hookup breadboard.
Hello ARV I didn't didn't like the way that wires were soldered in directly onto the tiny pins so I made a board which takes much of the strain off of the encoder contacts. You may use it freely. I am definitely a solution orientated person not a complainer.? I have a bitx40 with the variable pot. It does have decent sided solder terminals? twice a long twice as thick.? Not sure why the fonts on your post looked so large. Were you trying to emphasize something to me or just felt sorry for my old eyes :) 73 Dave K0MBT
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I built and audio cable that swaps the tip and ring so I can keep the original uBiTX mic wiring when plugging in a Baofeng mic.
Dan, W2DLC
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Re: ubitx encoder hookup breadboard.
Hello ARV
I didn't didn't like the way that wires were soldered in directly onto the tiny pins so I made a board which takes much of the strain off of the encoder contacts. You may use it freely. I am definitely a solution orientated person not a complainer.?
I have a bitx40 with the variable pot. It does have decent sided solder terminals? twice a long twice as thick.?
Not sure why the fonts on your post looked so large. Were you trying to emphasize something to me or just felt sorry for my old eyes :)
73
Dave
K0MBT
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Re: how to reach Farhan about a new radio board
I'd presume Farhan reads here form time to time.
The base design could with mods.
It needs an RF amp(LNA) for RX as on 2M SSB work weak signals are the rule.
This means getting the RX noise figure down and using monoband filters.? This
is more a matter of picking the right devices and board layout plus switching?
that amp out of the way for TX.
The TX power chain line up would have to be radically different.? Between MMIC
devices and the absolute need for decent filtering the low level (ato about 10 to
50mW) part is fairly straight forward.? Once there two more stages should do it
using LDMOS devices (RF06VHF and RD15VHF) using stipline broad band
layout.? This is one case where getting the layout right or even going multi-layer
board can make it an less an iterative process.? ?A larger board can make it easier.
The si5351? goes high enough for VHF work.
VHF is pickier of things like tuned circuit design and also layout is everything.
There is a need for a good monoband 2M SSB/CW radio not only for QRP ops but also for use as 2M IF behind higher frequency transverters.
Allison
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Re: uBITX SSB filter response question
#ubitx
One warning when measuring narrow filter use a very slow sweep.? At narrow resolutions if
the sweep is too fast the curve will not match the actual.? It is as much detector response
time as its filter delays.? When too fast the it will appear tilted, and when you slow down
you will see more accurate result.
The filter insertion loss in the 4 to 7 db? range sounds correct.? Though I might be better if
higher Q capacitors are used we are not talking a 3DB difference.? Also dId you calibrate
out the transformers first?? That can add a DB of loss sometimes more.
Allison
Allison
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Bill which chips were you using??
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On Apr 13, 2018, at 10:37 AM, Bill KC5SB < blmerideth@...> wrote: I have toasted 2 of them so far.? I installed a socket after the first one died and bought several more for spares.? So far no problems after the second one was installed - crossed fingers.? Hope I don't jinx myself on Friday the 13th.
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Re: BITX QSO Afternoon/Evening, Sunday, April 15, 3PM & 7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere.
We do it every week! Welcome to the club!?
--
John - WA2FZW
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Re: uBITX SSB filter response question
#ubitx
In both the curves without and with transformer your filters loss appears to be around -7 db's
In my opinion this is bit too high -3db is just right up to -5db is acceptable according to the experts, what type of capacitors are used in this filter? The multi layer ceramic capacitors are really of lo loss. If you use the modern SMD ones in my opinion that will reduce the loss in the filter? ?
On Fri, Apr 13, 2018 at 9:35 PM, Michael LeBlanc <michaelleblanc1@...> wrote: Thanks Rod. I'm enjoying the journey and for the time being I can get on the air any time with my appliance radio. ;-)
I was measuring it 'naked', without the transformers. Just before reading your reply, though, I measured it again but through the transformers, and the result is "softer":
I also was fastidious about recording the individual crystal measurements, and (like you), put them in a spreadsheet and asked it to re-order the crystals by centre frequency. Thanks also for your thoughts on the filter's centre frequency. As long as I'm in the ballpark, I'm happy.
-Michael VE1LEB
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Re: Ian Lee KD8CEC integration of SDR demo
#ubitx
If you are a Linux user, take a look at Gqrx(). It's based on gnu radio and has a distribution for the Raspberry Pi.
Gqrx has a TCP/IP remote control interface and command API. I have written several wrappers in Perl and wxPerl to implement additional functionality such as scanning. James
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Re: uBITX SSB filter response question
#ubitx
Thanks Rod. I'm enjoying the journey and for the time being I can get on the air any time with my appliance radio. ;-) I was measuring it 'naked', without the transformers. Just before reading your reply, though, I measured it again but through the transformers, and the result is "softer":  I also was fastidious about recording the individual crystal measurements, and (like you), put them in a spreadsheet and asked it to re-order the crystals by centre frequency. Thanks also for your thoughts on the filter's centre frequency. As long as I'm in the ballpark, I'm happy. -Michael VE1LEB
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Re: uBITX SSB filter response question
#ubitx
Michael,
Not sure where I saw it, either here or on emrfd
email group: the quality of the capacitors
used in a crystal filter are quite important. Using NPO or C0G
is highly recommended.
Other ceramics have a piezo-electric feature that
is not desirable.
Also, grounding the crystal cases is of paramount
importance.
Rod KM6SN
On 04/13/2018 08:22 AM, Michael LeBlanc
wrote:
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Friends:
I'm scratch-building a uBITX, and completely new to building
crystal filters. Attached is the response curve of the 12MHz SSB
filter using my PHSNA.?
Does this look like it will work satisfactorily in the
radio? To select the crystals, I used the K8IQY crystal test
fixture and chose the closest ones to 12MHz from a bag of 50
inexpensive computer crystals.
I don't know if my PHSNA is accurately calibrated, so although it
looks like the filter passes between 11997 and 12000, I'm not sure
how much error there is in the frequency readings. But I'm pretty
sure that the -20dBm passband is less than 2.5khz. If the passband
is slightly to one side of 12MHz, does that matter?
I've received a new bag of 100 crystals, and I'm wondering if I
should take the time to characterize all of them and replace the 8
that are currently on the board with ones that have a closer
match. Any thoughts?
-Michael VE1LEB
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Michael LeBlanc
_Dave_ AD0B
Satish Chandorkar