Date   
Re: #ubitx Powering options? #ubitx

Jerry Gaffke
 

You're right, it's not a good idea to blindly parallel a bunch of batteries. 
But it can work just fine if they are of the same size and age and charge state.

If one has more internal resistance, that just means the other one will be doing more of the work.

However, if you connect them when not equally charged, one will charge the other.
In some cases the currents involved while the charge states equalize are excessive, far beyond
what either battery is rated for.  Could easily have an explosion.
Something to keep in mind, especially with Li-Ion batteries or large lead acid batteries.

Once the batteries in parallel reach the same charge state, there won't be any 
currents bouncing around. 
 
I have several of LED headlamps I bought on the web. 
Each has two 18650 Li-Ion batteries in parallel, they feed the LED through a resistor.
I doubt these particular 18650's have any kind of over-current protection, as the headlamps were quite cheap.
Use them all the time, work great.  And keep their charge just fine when sitting on the shelf.

We're off grid, I started out with  used golf cart batteries, wiring up multiple banks in parallel.
Around 10 KWH worth total, all having different histories and ages.
If anything, any extra internal resistance due to aging would have helped prevent excessive currents
if I had connected them in parallel without first bothering to check if the voltages were reasonably close.

Jerry, KE7ER


On Mon, Jan 15, 2018 at 04:14 pm, Michael Hagen wrote:
You do not want to parallel batteries, difference in internal resistance will cause one to try to charge another, and around we go, a circulating current between the batteries that will run them both down.  And we don't even get to use the power!

Re: Matched xtals #ubitx #bitx40

n2vdy
 

The documentation says 700 to 2500. It is a 4 pole filter at just under 9 MHz.

Re: Raduino v2.03 (BFO calibration for CW) released #bitx40

 

Steve : 

I will let Allard address the main points, in your posting but :

FWIW, I am also getting slightly lower output with VFO HIGH so currently I am using VFO LOW. 

The surging on the CW Sidetone is an undesired effect of where the sidetone is injected. What I have found is that it seems to
be less pronounced if you are using a higher impedance speaker/headphone. I normally use a Koss CS-100 electret computer 
headset (headphones are 32 ohms) and the sidetone surging is much less noticeable than with an 8 ohm speaker. 

Another good trick that you can use for adjusting the BFO is using a Broadband noise source along with an audio spectrum analyzer
program on a computer or tablet. This gives you a good idea of the filter response and it helps to visualize what you are hearing
as you adjust the BFO frequency.

Cheers

Michael VE3WMB 

Re: irf520 vs irf510

Gordon Gibby <ggibby@...>
 

​So Dr. Schmidt --- are you saying that the severe dropoff in power output from the ubitx / bitx40 would be ameliorated?


If so, I might be interested!    It would be quite nice to have a bit more power on 30 and 20 meters.....


comment?


gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of K9HZ <bill@...>
Sent: Monday, January 15, 2018 7:44 PM
To: BITX20@groups.io
Subject: Re: [BITX20] irf520 vs irf510
 
Of course the upside of using RD16HVF1 is that it is a real RF transistor... not a motor switch like the IRF510.  What you get for that is actually hidden in your comment about gain at high frequency. In fact, the gate capacitance with frequency is far better behaved with the RD device so complicated compensation networks to keep gain constant is not needed.  Hans Summers has a second set of pads on his 5 watt PA just for the use of these parts. 


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 Jan 15, 2018, at 1:39 PM, Diver Martin <diver.martin@...> wrote:

I think I mentioned it before, but anyone seeking to drop in a Mitsubishi RDMos part should be aware that 

a) They're designed for 12V operation.  You won't want to run them at 18V/etc
b) They have a different pinout, you'll have to solder them in with the leads mangled/crossed.  IRF510/20/30's are Gate-Drain-Source.  The RDMos series are Gate-Source-Drain.  This is a mod I still intend to try at some point, but have other projects on the plate first.
c) They have a different bias voltage.  Turn down the bias voltage before you key up, and then re-bias appropriately. If your IRF510's are biased at something like 4V when the bias voltage for the RDmos's are 2V (I'm making total wild assumptions, it could be the other way around), you'll instantly turn the devices on full-current and potentially blow something up.  
d) The feedback network will want to be different.  These have much more gain at high frequencies.  You may need more negative feedback.
e) You can use an uninsulated grounded heatsink, as the tabs of the these devices is the source and not drain.

I'm looking forward to hearing from someone who's done the mod and tried it out.

On Mon, Jan 15, 2018 at 10:52 AM, Tim Gorman <tgorman2@...> wrote:
Dave,

Would this be a satisfactory drop-in replacement? I can't find any info
on input or output capacitance to compare it to an irf510.

From the Smith chart on the datasheet I'm guessing the input
capacitance is about 60pf (been a long time since I've used a Smith
Chart) at 30Mhz, much less than the irf510. Would that impact the
negative feedback used on the amp significantly (0.1uf in series with a
220ohm resistor)?

By the same token the output capacitance would appear to be much higher
than the irf510. I suspect that will impact the design of the bandpass
filters but I'm not sure by how much without doing a lot of
calculations.

I'm just looking for something that would provide more reliability
under adverse conditions (e.g. high swr) than the irf510. Don't really
care if it provides higher output or not - but that might come later
<grin>.



On Sun, 14 Jan 2018 22:51:06 -0800
"Dave Bottom" <ars.kd6az@...> wrote:

> Or the Mitsubishi RF RD16HHF1 MOSFET designed for 2-30MHz RF
> applications. Under $5 each.  Or the RD16HVF1 only pennies more and
> good through 2M.
>
> With a 12VDC to 24/28VDC DC to DC converters (about $4) and the Mitsu
> parts can be bolted directly to a big heatsink attached to the
> chassis, no insulator required.
> Probably good for 20W through 10M although run off batteries a bit
> shorter battery life.  At real 5W QRP they should be happy forever.
>
> Dave WI6R
>
> On Sun, Jan 14, 2018 at 4:33 PM, Tim Gorman <tgorman2@...> wrote:
>
> > All,
> >
> > Looking to order some spare output finals for the ubitx I have on
> > order.
> >
> > In looking around the IRF520 appears to have higher ratings than the
> > IRF510 with a lower Rds.
> >
> > The 510 does have much lower input and output capacitance.
> >
> > There is hardly any difference in price.
> >
> > Any recommendations on which to order?
> >
> > tim ab0wr
> >
> >
> >
> >
>
>







--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: Matched xtals #ubitx #bitx40

Michael Hagen
 

OH, that sounds neat!

Do they say Range .. From BW to BW?

Keep us informed,

Mike, WA6ISP



On 1/15/2018 4:58 PM, n2vdy via Groups.Io wrote:
I have a Russian radio kit I haven't put together yet called the Druzhba-M. It has a crystal filter with varactor diodes that it uses to vary the bandwidth of the filter.

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: irf520 vs irf510

Tim Gorman
 

Thanks, Diver.

I think I'll just stick with the irf510's for now. They are cheap if I
play too hard with them!

tim ab0wr

On Mon, 15 Jan 2018 11:39:36 -0800
"Diver Martin" <diver.martin@...> wrote:

I think I mentioned it before, but anyone seeking to drop in a
Mitsubishi RDMos part should be aware that

a) They're designed for 12V operation. You won't want to run them at
18V/etc
b) They have a different pinout, you'll have to solder them in with
the leads mangled/crossed. IRF510/20/30's are Gate-Drain-Source.
The RDMos series are Gate-Source-Drain. This is a mod I still intend
to try at some point, but have other projects on the plate first.
c) They have a different bias voltage. Turn down the bias voltage
before you key up, and then re-bias appropriately. If your IRF510's
are biased at something like 4V when the bias voltage for the RDmos's
are 2V (I'm making total wild assumptions, it could be the other way
around), you'll instantly turn the devices on full-current and
potentially blow something up. d) The feedback network will want to
be different. These have much more gain at high frequencies. You
may need more negative feedback. e) You can use an uninsulated
grounded heatsink, as the tabs of the these devices is the source and
not drain.

I'm looking forward to hearing from someone who's done the mod and
tried it out.

On Mon, Jan 15, 2018 at 10:52 AM, Tim Gorman <tgorman2@...> wrote:

Dave,

Would this be a satisfactory drop-in replacement? I can't find any
info on input or output capacitance to compare it to an irf510.

From the Smith chart on the datasheet I'm guessing the input
capacitance is about 60pf (been a long time since I've used a Smith
Chart) at 30Mhz, much less than the irf510. Would that impact the
negative feedback used on the amp significantly (0.1uf in series
with a 220ohm resistor)?

By the same token the output capacitance would appear to be much
higher than the irf510. I suspect that will impact the design of
the bandpass filters but I'm not sure by how much without doing a
lot of calculations.

I'm just looking for something that would provide more reliability
under adverse conditions (e.g. high swr) than the irf510. Don't
really care if it provides higher output or not - but that might
come later <grin>.



On Sun, 14 Jan 2018 22:51:06 -0800
"Dave Bottom" <@WI6R> wrote:

Or the Mitsubishi RF RD16HHF1 MOSFET designed for 2-30MHz RF
applications. Under $5 each. Or the RD16HVF1 only pennies more
and good through 2M.

With a 12VDC to 24/28VDC DC to DC converters (about $4) and the
Mitsu parts can be bolted directly to a big heatsink attached to
the chassis, no insulator required.
Probably good for 20W through 10M although run off batteries a bit
shorter battery life. At real 5W QRP they should be happy
forever.

Dave WI6R

On Sun, Jan 14, 2018 at 4:33 PM, Tim Gorman <tgorman2@...>
wrote:
All,

Looking to order some spare output finals for the ubitx I have
on order.

In looking around the IRF520 appears to have higher ratings
than the IRF510 with a lower Rds.

The 510 does have much lower input and output capacitance.

There is hardly any difference in price.

Any recommendations on which to order?

tim ab0wr






Re: BITX QSO Afternoon/Night, Sunday, January 14, 3PM/7PM Local Time, 7277 kHz in North America, 7177 kHz elsewhere

Willy
 

Hi Michael,It is helpful to have adjustable BFO to tailor the BitX. I see elsewhere the suggestion to use this feature to tailor your XMIT audio let us know what tricks  you discover. Thanks to you and Allard for some good  work.
73 Willy 

On Mon, Jan 15, 2018 at 10:04 AM, Michael Babineau <mbabineau.ve3wmb@...> wrote:
I heard nothing on  7.277 Mhz from 7:00 pm onwards, here in Ottawa, so I gave up after about an hour. 
Tuning around the lower part of the band a could hear a few weak South American CW stations. 

I will try to remember to get on the air next Sunday at 3:00pm as I think that conditions will be more conducive to
making some SSB QSOs. 

Cheers 

Michael VE3WMB 

P.S. I am now running Allards V2.03 code and this makes is a massive improvement for those wanting to use there BITX40s on both CW and SSB.

With the BFO frequency controlled by the DDS chip it is now possible to easily change the BFO frequencies to shift the IF filter passband and improve
the SSB RX and TX audio while also effectively suppressing any residual carrier on SSB. Having separate BFO frequency settings for CWL and CWU
allows you to obtain full power out on CW with < 10mW of residual carrier when in TX (PTT closed) without the key down. 


Re: A little off Topic? SDR Program PC?

Michael Hagen
 

 I got one of those black boxes with a SDR inside.  It does not have the down converter as some, you change the parameters
in the program to get HF.   It has 2 SMAs,  HF, and then above.
 I got it to work with SDR Sharp (#) on my PC.  It is running W10.  I like it. Less than $30 for the Radio?  Still need some kind of outside antenna?

The website says SDR# does not work anymore for XP. 
My Old laptop is XP, anyone know which program with the least problems works for XP?
Any one with this experience?

73's
Mike, WA6ISP

Re: Microphone frequency response

bill richardson
 

I’m all set now.. found my problem.. I have been using the mic element that came with the 2 bitx40’s. The problem was the mic case I placed them in. I’m using two of the same mics that I got from eBay call Sundely I pulled the elements from the mics and used the elements that came with the bitx40’s. What I found out was on the back side of the PTT board was 3 SMD caps going to ground and they are in the audio path. I removed them and now my audio reports are much better.

Sent from my iPhone

On Jan 15, 2018, at 1:31 PM, Mvs Sarma <mvssarma@...> wrote:

 we can use Maxim MAX7400 to limit the Mic Bandwidth. It is good Chip , costly though.

regards
 sarma
 vu3zmv

Regards
MVS Sarma
 

On Mon, Jan 15, 2018 at 11:51 PM, bill richardson <ng1p.bill@...> wrote:
Thanks Allard.. I’ll try upgrading to v2. I have done all the mods in the v1 track so it’s worth a try. I did put a variable cap to manually adjust the BTO but my audio was still favoring the lows. 

Sent from my iPhone

On Jan 15, 2018, at 1:14 PM, Allard PE1NWL <pe1nwl@...> wrote:

On Mon, Jan 15, 2018 at 10:05 am, Arv Evans wrote:
I would first look at BFO versus filter passband as a possible
solution
With the arduino v2 software (https://github.com/amunters/bitx40-raduino-v2) you can easily correct the BFO frequency.
A minor modification (https://github.com/amunters/bitx40-raduino-v2/blob/master/digital%20BFO%20mod.png) is required for this software.

73 Allard PE1NWL


Re: Matched xtals #ubitx #bitx40

n2vdy
 

I have a Russian radio kit I haven't put together yet called the Druzhba-M. It has a crystal filter with varactor diodes that it uses to vary the bandwidth of the filter.

Re: Matched xtals #ubitx #bitx40

Arv Evans
 

John AD5YE

I have not had time to play with this but I wonder what would be the result if
a small amount of each interstitial capacitance in a ladder filter were made
variable.  Might there be any advantage from being able to tweak these values
by a few percentage points?

Arv  K7HKL
_._


On Mon, Jan 15, 2018 at 5:14 PM, John Backo <jabac@...> wrote:
Good show, Arv. Good information.

But for a xtal filter, usually of a ladder construction,
the more closely matched the xtals, the better.

The ladder filter is not quite the same as the Chebyshev.
Most of the RF manuals work with these and mention the
ladder filter sort of in passing.

Usually, a ladder filter uses closely matched xtals, and the
bandwidth is controlled by the capacitance. Hence, all the parts
should be pretty closely matched. I guess the major work with
ladder filters is that of G3UUR. He has been diligent in investigating
and cataloging their properties.

Most of the QRP rigs I have seen use a ladder filter. They seem to be
a bit simpler to work with. I myself would stick with +/- 50 Hz or so.
If one gets a large enough batch of GOOD xtals to begin with,
and matches them with a consistent oscillator, that goal is easily
achievable, and usually one can find several sets to +/- 10 Hz.

john
AD5YE




Re: #ubitx Powering options? #ubitx

Michael Hagen
 

Probably Ford?

The proper way is to have a 24V starter, and they are put in series for Start?  Then charged though isolation diodes?

I think GM did that for Mil Trucks?  Not sure though?

I bet you have to buy both NEW batteries of same make at same time?

You would not want an old one and new one paralled?

I just thought about when I changed my battery in my F150 4WD a year ago.

I could not properly lift it UP over the Fender (lifted 4WD).   I have to use a blanket not to scrape the paint!

They are sooo Heavy!

Glad I only have one at $150 ea!

Mike



On 1/15/2018 4:30 PM, Vince Vielhaber wrote:
My diesel truck has paralleled batteries.  They go dead from time to time but it's from other things dragging them down before doing it to each other.

Vince.

On 01/15/2018 07:14 PM, Michael Hagen wrote:
You do not want to parallel batteries, difference in internal resistance
will cause one to try to charge another, and around we go, a circulating
current between the batteries that will run them both down.  And we
don't even get to use the power!

I think they did this on some vehicles like diesel trucks, I would think
you would want to disconnect them when not being charged?

I am not an expert on this, just seems bad?

73's

Mike, WA6ISP


On 1/15/2018 3:57 PM, Simon Rumble wrote:
Thanks Jerry that's exactly the flaw in my thinking right there! It
did seem a bit good to be true. So series wiring increases voltage but
not capacity. Makes sense.

Amending my spreadsheet, two lantern batteries (6V, 26 Ah) might be
the best option. Alternatively I'll have a look at some rechargeable
options but I'm not sure I'll be able to sort that by the end of the week.

On Tue, 16 Jan 2018 at 10:22 Jerry Gaffke via Groups.Io
<jgaffke@... <mailto:yahoo.com@groups.io>> wrote:

    Simon,

    If you stack eight  1.8AH  at 1.5V batteries in series, you get
    12V at 1.8AH.
    They would have to be in parallel to get 14.4AH, but then you only
    have 1.5V.

    Also, those AH ratings are typically for 20 hour discharge rates,
    if you are sucking a couple amps they will fold up in minutes.
    And battery current will get worse if you bump up power by using a
    boost converter
    to power the IRF510.

    I'd recommend jacking into the cigarette lighter for 12v if you
    are driving, bring a long cord.
    If a short hike and a long operating session, maybe get a $20 lead
    acid riding lawnmower battery.
    Or use the Li-Ion battery pack from a drill motor or impact driver.

    Avoid feeding your rig much more than 12v.

    Jerry, KE7ER



    On Mon, Jan 15, 2018 at 03:01 pm, Simon Rumble wrote:

        So my question is about off-grid power. Can I get away with 8x
        AA batteries in series or should I use a step up converter to
        keep the voltage up? Looking at amp hours on paper I'd get
        around 33 hours of operating (calculations here
        <https://docs.google.com/spreadsheets/d/1iMoxFaz4LxE1N9BUUOBxKgtoME8QLftqJYUnBnnUv7s/edit?usp=sharing>)
        though I imagine there'd be quite a voltage drop by the end of
        that, but even half that operating time would be pretty good.

        Thoughts? I don't have time to set up a rechargeable option
        really.



--
--
Simon Rumble <simon@... <mailto:simon@...>>
www.simonrumble.com <http://www.simonrumble.com>
VK2VSR

--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...




-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: irf520 vs irf510

K9HZ <bill@...>
 

Of course the upside of using RD16HVF1 is that it is a real RF transistor... not a motor switch like the IRF510.  What you get for that is actually hidden in your comment about gain at high frequency. In fact, the gate capacitance with frequency is far better behaved with the RD device so complicated compensation networks to keep gain constant is not needed.  Hans Summers has a second set of pads on his 5 watt PA just for the use of these parts. 


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 Jan 15, 2018, at 1:39 PM, Diver Martin <diver.martin@...> wrote:

I think I mentioned it before, but anyone seeking to drop in a Mitsubishi RDMos part should be aware that 

a) They're designed for 12V operation.  You won't want to run them at 18V/etc
b) They have a different pinout, you'll have to solder them in with the leads mangled/crossed.  IRF510/20/30's are Gate-Drain-Source.  The RDMos series are Gate-Source-Drain.  This is a mod I still intend to try at some point, but have other projects on the plate first.
c) They have a different bias voltage.  Turn down the bias voltage before you key up, and then re-bias appropriately. If your IRF510's are biased at something like 4V when the bias voltage for the RDmos's are 2V (I'm making total wild assumptions, it could be the other way around), you'll instantly turn the devices on full-current and potentially blow something up.  
d) The feedback network will want to be different.  These have much more gain at high frequencies.  You may need more negative feedback.
e) You can use an uninsulated grounded heatsink, as the tabs of the these devices is the source and not drain.

I'm looking forward to hearing from someone who's done the mod and tried it out.

On Mon, Jan 15, 2018 at 10:52 AM, Tim Gorman <tgorman2@...> wrote:
Dave,

Would this be a satisfactory drop-in replacement? I can't find any info
on input or output capacitance to compare it to an irf510.

From the Smith chart on the datasheet I'm guessing the input
capacitance is about 60pf (been a long time since I've used a Smith
Chart) at 30Mhz, much less than the irf510. Would that impact the
negative feedback used on the amp significantly (0.1uf in series with a
220ohm resistor)?

By the same token the output capacitance would appear to be much higher
than the irf510. I suspect that will impact the design of the bandpass
filters but I'm not sure by how much without doing a lot of
calculations.

I'm just looking for something that would provide more reliability
under adverse conditions (e.g. high swr) than the irf510. Don't really
care if it provides higher output or not - but that might come later
<grin>.



On Sun, 14 Jan 2018 22:51:06 -0800
"Dave Bottom" <ars.kd6az@...> wrote:

> Or the Mitsubishi RF RD16HHF1 MOSFET designed for 2-30MHz RF
> applications. Under $5 each.  Or the RD16HVF1 only pennies more and
> good through 2M.
>
> With a 12VDC to 24/28VDC DC to DC converters (about $4) and the Mitsu
> parts can be bolted directly to a big heatsink attached to the
> chassis, no insulator required.
> Probably good for 20W through 10M although run off batteries a bit
> shorter battery life.  At real 5W QRP they should be happy forever.
>
> Dave WI6R
>
> On Sun, Jan 14, 2018 at 4:33 PM, Tim Gorman <tgorman2@...> wrote:
>
> > All,
> >
> > Looking to order some spare output finals for the ubitx I have on
> > order.
> >
> > In looking around the IRF520 appears to have higher ratings than the
> > IRF510 with a lower Rds.
> >
> > The 510 does have much lower input and output capacitance.
> >
> > There is hardly any difference in price.
> >
> > Any recommendations on which to order?
> >
> > tim ab0wr
> >
> >
> >
> >
>
>







--
Martin Held - AE7EU
http://ae7eu.com/
-------------------------------------------------------------------------------
If there aren't any questions, then what is there to learn?

Re: #ubitx Powering options? #ubitx

Vince Vielhaber
 

My diesel truck has paralleled batteries. They go dead from time to time but it's from other things dragging them down before doing it to each other.

Vince.

On 01/15/2018 07:14 PM, Michael Hagen wrote:
You do not want to parallel batteries, difference in internal resistance
will cause one to try to charge another, and around we go, a circulating
current between the batteries that will run them both down. And we
don't even get to use the power!

I think they did this on some vehicles like diesel trucks, I would think
you would want to disconnect them when not being charged?

I am not an expert on this, just seems bad?

73's

Mike, WA6ISP


On 1/15/2018 3:57 PM, Simon Rumble wrote:
Thanks Jerry that's exactly the flaw in my thinking right there! It
did seem a bit good to be true. So series wiring increases voltage but
not capacity. Makes sense.

Amending my spreadsheet, two lantern batteries (6V, 26 Ah) might be
the best option. Alternatively I'll have a look at some rechargeable
options but I'm not sure I'll be able to sort that by the end of the week.

On Tue, 16 Jan 2018 at 10:22 Jerry Gaffke via Groups.Io
<jgaffke=yahoo.com@groups.io <mailto:yahoo.com@groups.io>> wrote:

Simon,

If you stack eight 1.8AH at 1.5V batteries in series, you get
12V at 1.8AH.
They would have to be in parallel to get 14.4AH, but then you only
have 1.5V.

Also, those AH ratings are typically for 20 hour discharge rates,
if you are sucking a couple amps they will fold up in minutes.
And battery current will get worse if you bump up power by using a
boost converter
to power the IRF510.

I'd recommend jacking into the cigarette lighter for 12v if you
are driving, bring a long cord.
If a short hike and a long operating session, maybe get a $20 lead
acid riding lawnmower battery.
Or use the Li-Ion battery pack from a drill motor or impact driver.

Avoid feeding your rig much more than 12v.

Jerry, KE7ER



On Mon, Jan 15, 2018 at 03:01 pm, Simon Rumble wrote:

So my question is about off-grid power. Can I get away with 8x
AA batteries in series or should I use a step up converter to
keep the voltage up? Looking at amp hours on paper I'd get
around 33 hours of operating (calculations here
<https://docs.google.com/spreadsheets/d/1iMoxFaz4LxE1N9BUUOBxKgtoME8QLftqJYUnBnnUv7s/edit?usp=sharing>)
though I imagine there'd be quite a voltage drop by the end of
that, but even half that operating time would be pretty good.

Thoughts? I don't have time to set up a rechargeable option
really.



--
--
Simon Rumble <simon@... <mailto:simon@...>>
www.simonrumble.com <http://www.simonrumble.com>
VK2VSR
--
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID "MotDog@..."
Mike@...

Re: Matched xtals #ubitx #bitx40

John Backo
 

Good show, Arv. Good information.

But for a xtal filter, usually of a ladder construction,
the more closely matched the xtals, the better.

The ladder filter is not quite the same as the Chebyshev.
Most of the RF manuals work with these and mention the
ladder filter sort of in passing.

Usually, a ladder filter uses closely matched xtals, and the
bandwidth is controlled by the capacitance. Hence, all the parts
should be pretty closely matched. I guess the major work with
ladder filters is that of G3UUR. He has been diligent in investigating
and cataloging their properties.

Most of the QRP rigs I have seen use a ladder filter. They seem to be
a bit simpler to work with. I myself would stick with +/- 50 Hz or so.
If one gets a large enough batch of GOOD xtals to begin with,
and matches them with a consistent oscillator, that goal is easily
achievable, and usually one can find several sets to +/- 10 Hz.

john
AD5YE

Re: #ubitx Powering options? #ubitx

Michael Hagen
 

You do not want to parallel batteries, difference in internal resistance will cause one to try to charge another, and around we go, a circulating current between the batteries that will run them both down.  And we don't even get to use the power!

I think they did this on some vehicles like diesel trucks, I would think you would want to disconnect them when not being charged?

I am not an expert on this, just seems bad?

73's

Mike, WA6ISP


On 1/15/2018 3:57 PM, Simon Rumble wrote:
Thanks Jerry that's exactly the flaw in my thinking right there! It did seem a bit good to be true. So series wiring increases voltage but not capacity. Makes sense.

Amending my spreadsheet, two lantern batteries (6V, 26 Ah) might be the best option. Alternatively I'll have a look at some rechargeable options but I'm not sure I'll be able to sort that by the end of the week.

On Tue, 16 Jan 2018 at 10:22 Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
Simon,

If you stack eight  1.8AH  at 1.5V batteries in series, you get 12V at 1.8AH.
They would have to be in parallel to get 14.4AH, but then you only have 1.5V.

Also, those AH ratings are typically for 20 hour discharge rates,
if you are sucking a couple amps they will fold up in minutes.
And battery current will get worse if you bump up power by using a boost converter
to power the IRF510.

I'd recommend jacking into the cigarette lighter for 12v if you are driving, bring a long cord.
If a short hike and a long operating session, maybe get a $20 lead acid riding lawnmower battery.
Or use the Li-Ion battery pack from a drill motor or impact driver.

Avoid feeding your rig much more than 12v.

Jerry, KE7ER



On Mon, Jan 15, 2018 at 03:01 pm, Simon Rumble wrote:
So my question is about off-grid power. Can I get away with 8x AA batteries in series or should I use a step up converter to keep the voltage up? Looking at amp hours on paper I'd get around 33 hours of operating (calculations here) though I imagine there'd be quite a voltage drop by the end of that, but even half that operating time would be pretty good.
 
Thoughts? I don't have time to set up a rechargeable option really.


--
-- 
Simon Rumble <simon@...>
VK2VSR

-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...

Re: Raduino v2.03 (BFO calibration for CW) released #bitx40

Steve MW0KST
 

Hi Allard and BITX gang,

Thanks very much for V2.03 - I uploaded it yesterday and all works well with the improved calibration procedure. I've done all the mods required to allow all the features of V2 to work - I really like the clarifier - it definitely helps a lot with both CW and SSB. Being quite new to the BITX and the Raduino, I have a couple of questions / comments:

- I first did the mods etc and tried V1.27. That went well, but in CW mode with semiQSK on, the sidetone was very quiet and built up slowly on key down. With semiQSK off, it was nice and loud all the time. I've connected it to a separate mini-speaker and though it's still quite quiet, it solves the slow volume build up problem. Looking through the various posts, I see this is a known issue, but wonder why it's all ok with semi-QSK switched off? When using V1.27, the power out on CW was very low, and was partially solved by going to V2.0.

- Still on V1.27, when I pressed and held the spot / fine tune button, the sidetone output was in beeps, as opposed to a constant tone. Is this as is should be? The fine tune part works perfectly. This remained the same on V2.02 and V2.03.

- On fine tune, now I've got it, I find I'm using it all the time. However, would be it possible to add an option for the main tuning to be displayed to a higher resolution, i.e. to one more decimal place, eg 7.025.45?

- In the calibration procedure, the VFO is set to the low side of the IF. Why is this? When I go back to the high side, the receive tone is slightly different, and the power out is less than on the low side. I'm not sure why this is happening - maybe the asymmetrical filter shape or a lower injection level when the VFO is on the high side? Would doing the calibration on the high side help?

- Again in calibration, when I adjust the BFO for max power out, it sets the BFO to a point where it is slightly 'off' on receive - with a fairly high pitched background tone. Again, this could be due to the filter shape, but I was wondering if it would be solved with a more complex calibration procedure where the BFO is set in each mode independently for transmit and receive. I have no idea about the practicality of this and it's easy to use the clarifier to get the receive audio sounding right. The CW cal. procedures have really helped - before 2.03 I could only get about 2 Watts out, where now it's about 5 Watts.

Thanks again for this version and all the efforts to make it work so well!

Best 73,

Steve MW0KST

Re: #ubitx Powering options? #ubitx

Simon Rumble <simon@...>
 

Thanks Jerry that's exactly the flaw in my thinking right there! It did seem a bit good to be true. So series wiring increases voltage but not capacity. Makes sense.

Amending my spreadsheet, two lantern batteries (6V, 26 Ah) might be the best option. Alternatively I'll have a look at some rechargeable options but I'm not sure I'll be able to sort that by the end of the week.


On Tue, 16 Jan 2018 at 10:22 Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
Simon,

If you stack eight  1.8AH  at 1.5V batteries in series, you get 12V at 1.8AH.
They would have to be in parallel to get 14.4AH, but then you only have 1.5V.

Also, those AH ratings are typically for 20 hour discharge rates,
if you are sucking a couple amps they will fold up in minutes.
And battery current will get worse if you bump up power by using a boost converter
to power the IRF510.

I'd recommend jacking into the cigarette lighter for 12v if you are driving, bring a long cord.
If a short hike and a long operating session, maybe get a $20 lead acid riding lawnmower battery.
Or use the Li-Ion battery pack from a drill motor or impact driver.

Avoid feeding your rig much more than 12v.

Jerry, KE7ER



On Mon, Jan 15, 2018 at 03:01 pm, Simon Rumble wrote:
So my question is about off-grid power. Can I get away with 8x AA batteries in series or should I use a step up converter to keep the voltage up? Looking at amp hours on paper I'd get around 33 hours of operating (calculations here) though I imagine there'd be quite a voltage drop by the end of that, but even half that operating time would be pretty good.
 
Thoughts? I don't have time to set up a rechargeable option really.



--
-- 
Simon Rumble <simon@...>
VK2VSR

Re: #ubitx Powering options? #ubitx

Jerry Gaffke
 

Simon,

If you stack eight  1.8AH  at 1.5V batteries in series, you get 12V at 1.8AH.
They would have to be in parallel to get 14.4AH, but then you only have 1.5V.

Also, those AH ratings are typically for 20 hour discharge rates,
if you are sucking a couple amps they will fold up in minutes.
And battery current will get worse if you bump up power by using a boost converter
to power the IRF510.

I'd recommend jacking into the cigarette lighter for 12v if you are driving, bring a long cord.
If a short hike and a long operating session, maybe get a $20 lead acid riding lawnmower battery.
Or use the Li-Ion battery pack from a drill motor or impact driver.

Avoid feeding your rig much more than 12v.

Jerry, KE7ER



On Mon, Jan 15, 2018 at 03:01 pm, Simon Rumble wrote:
So my question is about off-grid power. Can I get away with 8x AA batteries in series or should I use a step up converter to keep the voltage up? Looking at amp hours on paper I'd get around 33 hours of operating (calculations here) though I imagine there'd be quite a voltage drop by the end of that, but even half that operating time would be pretty good.
 
Thoughts? I don't have time to set up a rechargeable option really.

Re: tx pop

Nick VK4PP
 

Hi, would you be able to provide a schematic for this Mod please?