Date   
Re: #ubitx #ubitx-help Not able to set up extension switches using CEC firmware #ubitx #ubitx-help

Tom, wb6b
 

That is interesting. Maybe the processor chip is an outlier, with an exceptionally high internal pull-up value. You could connect your own pull-up, like 22k ohms from +5 volts and the function switch, and see if that helps.

Re: End Fed antennas w/ uBITX #ubitx

Warren Allgyer <allgyer@...>
 

Allison

Two other aspects I wanted to respond to but hit SEND too soon. 

A resonant end fed wire wire will have an impedance in the range of 2500 - 5000 ohms depending upon how it is mounted. That represents a 2:1 maximum VSWR using a 49:1 transformer which has an insignificant effect on the power acceptance of the wire. 

One S unit is 6 dB so, no, it is not a significant difference on 80 meters. On the other hand, 10 dB is what we buy when we add a kilowatt amplifier to our 100 watt rig. That is significant. 

wA8TOD

Re: End Fed antennas w/ uBITX #ubitx

Warren Allgyer <allgyer@...>
 

Allison

The transformer I used is the one advocated by the EFHW Antennas Facebook group and is purported to be a copy of the MyAntennas transformer. I have not confirmed that. One should not be surprised that it exhibits random resonances because it is fraught with stray capacitance and uses a parallel tuned circuit on the primary. It, and the design it is based on are, frankly, rubbish.  

The really insidious aspect of this transformer is it’s performance, if measured solely by VSWR, appears to improve the higher the loss it introduces. If, for example, one was to put a 2.0 dB attenuator in one’s transmission line there would be almost no wire configuration that would show an unacceptable VSWR. The higher the loss, the lower the measured VSWR. This is due to the double attenuation effect that any transmission line loss has on measured reflected power. 

A far far better transformer is one wound on a BN-43-7051 binocular core with a 14:1 turns ratio for 80 - 20 and 7:1 for 20 - 10. This transformer exhibits less than 1 dB loss on all bands. Because of the low loss it easily handles 100 and more watts. Also, because of the low loss it only works well on a single band with a resonant wire. 

The EFHW antenna is an excellent radiator. It is the phony baloney transformer that drags down its performance. 

WA8TOD

Re: Nextion 3.5 question #ubitx-help #ubitx

SV9CVJ Nikos
 

Re: End Fed antennas w/ uBITX #ubitx

Tom, wb6b
 

I think the end-fed non-resonate antennas referred to here are using carefully chosen lengths (not random) that avoid the situation of terminating a 1 to 9 transformer with a low impedance like 50 ohms.

I think the end-fed half wave antennas are, also, using carefully chosen lengths to avoid the 1 to 49 transformer being loaded with 50 ohms, as in your example. 

Here is the information Palomar Engineers has on end-fed antennas.
http://palomar-engineers.com/tech-support/tech-topics/best-end-fed-antenna-for-ham-and-swl

Tom, wb6b

Re: uBITX Increasing 28 Mhz output by changing C81 #ubitx-help

 

Allison :

I am running off of a 12v SLA so I am seeing an input voltage of maybe 12.3 V DC.

I get about 7+ Watts out on 80m, around 5 watts out on 40m and about 1 watt out on 10m with this DC voltage in and the stock components.

I made the mods twice, the first time without changing R83 and the second time with both R83 and C81 using the V4 board values.
In both cases I doubled checked the component values (and measured them) before installation and the soldering looked fine.
What I saw was  < 1 W out on 40m through 10m (didn't check 80m). Increasing RV1 improves that but I only have a few 
degrees of rotation before I hit max so it tops out at a little above one watt. 

Everything is back to normal when I restored the original components at C81 and R83, so Q90 is fine. 
I am seeing the original power out values but I am at a loss to explain why this didn't work if this is stock
on the V4 boards ? 

I don't see any other related changes in the V4 schematic, which is why I asked if anyone else has done this mod
to a V3 board. 

Cheers

Michael VE3WMB

Re: End Fed antennas w/ uBITX #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

Warren,

Also a 80M endfed at low height (under 50ft) will likely be less than 2500 ohms!
So the transformer need to be adjusted for that reality.  But did you compare that
to a balun (1:1)  fed dipole?  Also does 2db loss at 80m really make a large
difference at the receiving end?

Indeed you used a terrible transformer.  A copy of a copy that was copied.

Why it is bad?  First your loss show a  peak in the 10mhz range between 7mhz
and 14mhz.  That suggests a resonance in either transformer (reference or DUT)
or fixturing.  So I'd deem the test suspect not for not investigating the result and
cause.

I took two PAR EF 40/20/10 and did the end to end test and divide by 2 and
did not get that loss peak. Until I took the ground from the two connectors
of the matching units apart.  Then the cables became part of the common
ground and I got that loss peak.  And the loss peak frequency varied if I
use 1M cables or longer 3M cables.   Do we blame the transformer or fixture?
I go with fixture as the ground loop is measurable error source.  I've said this
before there is no such thing as ground. It is a term for circuit common.  The
test leads become part of circuit common loop.  Without the the jumper of
heavy braid between the two transformers our results are unusually high
loss that goes away when replaced.

The mismatched loss is a confirmation of what been said and expected.  Lets face it 
a 2500 to 50 ohm is a SWR of greater than 49:1.   It would have been correct to try 
that with a 1:9 as then the SWR is at most under 10:1 and the losses less egregious.

FYI I get about 2 DB at 28mhz, not great but acceptable.   The EF40/20/10 uses
a smaller lower loss transformer with a 25W CW limit.   However I rarely use
it above 14mhz as I have a K6STI 10M loop that is nearly as portable and has
a better more predictable pattern.  It only  takes one rope to raise and it has
a little gain over a dipole if the bottom is at least 16ft up.

An aside:  I prefer the end fed not for efficiency but my case here is that wires
hanging down in the middle of the yard are untenable.  Its ugly and makes yard
maintenance hard and easily adds 60ft of coax over whts used now as well.  The
End fed half wave is a solution.  At least for me.  For field work its easier to loft
one end than two and less fussy to keep the feedline under control in trafficked
areas.  Would I use a End fed for a KW, no!  If I could afford a KW I'd put a
tribander and a two element 40M beam on the tower first. 

Allison

Re: Ubitx...is the red wire from the audio connector used ??

Kevin Rea
 

Thanks Nick.

 

Kevin

 

 

From: BITX20@groups.io <BITX20@groups.io> On Behalf Of Nick VK4PLN
Sent: Tuesday, July 24, 2018 9:50 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Ubitx...is the red wire from the audio connector used ??

 

No, Its a spare GND connector. You can just pop it out of the plastic connector with a small screwdriver or pin.
73 Nick VK4PLN

Re: SUBSCRIBED: [BITX20] Emailing: 1031Ex133, 1031Ex134, 1031Ex120, 1031Ex121, 1031Ex122, 1031Ex123, 1031Ex124, 1031Ex125, 1031Ex126, 1031Ex127, 1031Ex128, 1031Ex129, 1031Ex130, 1031Ex131, 1031Ex132

rtjj@...
 

Mr. Hagen,

I get mails from posts on BITX20, are you aware your PayPal ID and someone's SSN is available for all to see?
I sent this email from BITX20 to the Norton shredder.
Jim

-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Michael Hagen
Sent: Wednesday, July 25, 2018 9:43 AM
To: motdog@... <BITX20@groups.io>
Subject: SUBSCRIBED: [BITX20] Emailing: 1031Ex133, 1031Ex134, 1031Ex120, 1031Ex121, 1031Ex122, 1031Ex123, 1031Ex124, 1031Ex125, 1031Ex126, 1031Ex127, 1031Ex128, 1031Ex129, 1031Ex130, 1031Ex131, 1031Ex132


Your message is ready to be sent with the following file or link
attachments:
1031Ex133
1031Ex134
1031Ex120
1031Ex121
1031Ex122
1031Ex123
1031Ex124
1031Ex125
1031Ex126
1031Ex127
1031Ex128
1031Ex129
1031Ex130
1031Ex131
1031Ex132

Note: To protect against computer viruses, e-mail programs may prevent sending or receiving certain types of file attachments. Check your e-mail security settings to determine how attachments are handled.

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

Re: End Fed antennas w/ uBITX #ubitx

Steve Black <kb1chu@...>
 

But it could probably pull a phone pole out of the ground. Steve kb1chu



Sent from the smartphone I said I'd  never get.

-------- Original message --------
From: Arv Evans <arvid.evans@...>
Date: 7/25/18 1:07 PM (GMT-05:00)
To: BITX20@groups.io
Subject: Re: [BITX20] End Fed antennas w/ uBITX

Not the kind of transmission we normally associate with a BITX.
_._

On Wed, Jul 25, 2018 at 9:49 AM John <johnk5mo@...> wrote:

"The mechanical analogy to this issue appears to be the transmission installed between an engine that revolves at several thousand rpm and the large wheels on the attached vehicle that revolve at 1 rpm. Sure, such a transmission can be built but how much power is lost in the transmission and never makes it to the wheels?"

15-20% of the flywheel power.

It can be significant....

John K5MO

Re: End Fed antennas w/ uBITX #ubitx

Gordon Gibby <ggibby@...>
 

Wow! What a cool set of experiments!


On Jul 25, 2018, at 14:26, ajparent1/KB1GMX <kb1gmx@...> wrote:

Gordon,

RF transformers are like the iron cored brothers at 50/60 or 400hz.  If they 
are getting hot there is something wrong or the heat is not being adequately
dissipated.

The amount of heat as power to cook a FT200 core in a closed IEC box on
a sunny summer day would surprize most.  It is not all that much as an
enclosed core has little ability to dissipate the heat and suffers a large
temperature rise.  I managed to do it with 20W into a highly capacitive
load (an effective RF short).  FYI the temperature for most ferrites loosing
their properties is 150C after that the heating will be worse.  If you know
the loss its fairly easy to predict the heat gain for both matched and
mismatched cases.  If the core is in a case getting the heat loss is a 
whole new set of calculations.

So if a balun core gets warm it may mean something.  Or it could be a
non quantitative summation of the abuses it was subjected to.  That
assumes it was designed right from the start and not a copy that was
a copy of a copy.

Measuring field strengths was what I got paid to do.  It is not impossible and it does
get done if some one pays....   How is it done?  About the same way Krause and 
others before me did it Design an experiment, do a lot of grunt work.  Then sitting
down and grinding on the raw numbers to make them meaningful.  Helps if a good
quality simulation has been done to insure it will net results.

I'd point out that at lower HF it is only hard as you need a very large open area as in 
many acres and the right gear to setup towers and a good measuring tools help
as well. Things like remotely controlled RF source and a spectrum analyzer with
data collection automation is very handy.    Doing it slightly higher frequencies
like 15 or 10M is much easier as the space needed is not out of reach.  Also
the results will scale if needed.    The main matter is getting the antenna to
a realistic height and enough distance to get out of the near field.  Typically
a few watts power is more than enough.  

Generally gain is harder than pattern to measure.  Where does one get a standard
gain antenna for 1.8mhz?  You make it, and that is generally true to about 20mhz.

For hams its mostly meaningless as we don't generally use ground wave
or direct wave at HF as it dissipates quickly and is very sensitive to terrain.  We
rely on skywave and that is not as predictable and varies greatly over the course
of the day and solar cycle never minding solar events.   Hence pattern being
more important than outright gain.  

For example today 6 was open and talked with friends 1000 miles south west,
and for laughs did the can you hear me now down to the radios lower limit of
about 1.2W and was still being heard well over their noise floor.  Propagation
when its there, it just works.  

Allison

Re: Nextion 3.5 question #ubitx-help #ubitx

Kevin Rea
 

I think I've seen this problem before, on this form, I believe the answer was that you didn't download all the files that were necessary.

Re: End Fed antennas w/ uBITX #ubitx

Warren Allgyer <allgyer@...>
 

If the transformer is replaced with a tuner then the loss will be well under 1.0 bB on all bands when the tuner is adjusted for minimum VSWR on the band of interest, depending of course on the tuner quality.

WA8TOD

Re: End Fed antennas w/ uBITX #ubitx

ajparent1/KB1GMX <kb1gmx@...>
 

Gordon,

RF transformers are like the iron cored brothers at 50/60 or 400hz.  If they 
are getting hot there is something wrong or the heat is not being adequately
dissipated.

The amount of heat as power to cook a FT200 core in a closed IEC box on
a sunny summer day would surprize most.  It is not all that much as an
enclosed core has little ability to dissipate the heat and suffers a large
temperature rise.  I managed to do it with 20W into a highly capacitive
load (an effective RF short).  FYI the temperature for most ferrites loosing
their properties is 150C after that the heating will be worse.  If you know
the loss its fairly easy to predict the heat gain for both matched and
mismatched cases.  If the core is in a case getting the heat loss is a 
whole new set of calculations.

So if a balun core gets warm it may mean something.  Or it could be a
non quantitative summation of the abuses it was subjected to.  That
assumes it was designed right from the start and not a copy that was
a copy of a copy.

Measuring field strengths was what I got paid to do.  It is not impossible and it does
get done if some one pays....   How is it done?  About the same way Krause and 
others before me did it Design an experiment, do a lot of grunt work.  Then sitting
down and grinding on the raw numbers to make them meaningful.  Helps if a good
quality simulation has been done to insure it will net results.

I'd point out that at lower HF it is only hard as you need a very large open area as in 
many acres and the right gear to setup towers and a good measuring tools help
as well. Things like remotely controlled RF source and a spectrum analyzer with
data collection automation is very handy.    Doing it slightly higher frequencies
like 15 or 10M is much easier as the space needed is not out of reach.  Also
the results will scale if needed.    The main matter is getting the antenna to
a realistic height and enough distance to get out of the near field.  Typically
a few watts power is more than enough.  

Generally gain is harder than pattern to measure.  Where does one get a standard
gain antenna for 1.8mhz?  You make it, and that is generally true to about 20mhz.

For hams its mostly meaningless as we don't generally use ground wave
or direct wave at HF as it dissipates quickly and is very sensitive to terrain.  We
rely on skywave and that is not as predictable and varies greatly over the course
of the day and solar cycle never minding solar events.   Hence pattern being
more important than outright gain.  

For example today 6 was open and talked with friends 1000 miles south west,
and for laughs did the can you hear me now down to the radios lower limit of
about 1.2W and was still being heard well over their noise floor.  Propagation
when its there, it just works.  

Allison

Re: End Fed antennas w/ uBITX #ubitx

Warren Allgyer <allgyer@...>
 

An EFHW for 80 meters will be approximately 132 feet long. If fed with the popular transformer it will introduce 1.9 dB of loss if the wire is trimmed to resonance.

Attached is a summary of my test data on this transformer.

Re: End Fed antennas w/ uBITX #ubitx

iz oos
 

Gordon, I fully agree with you. Antenna analyzers say just a part of the story... Heat explains the rest.


Il 25/lug/2018 19:29, "Gordon Gibby" <ggibby@...> ha scritto:

​I think it is almost impossible to measure field strengths accurately enough to mean anyting.

But if you hold the key down for 10 minutes at 50 watts with a short piece of coax between you and that transformer and tell us the temperature afterwards.....we'll know how lossy or not it is!!!

You could still have some ground losses if you use a "ground" instead of a counterpoise....



Conservation of Energy is a very useful concept!!!!

What doesn't go into heat (somewhere) had to get radiated.  


From: BITX20@groups.io <BITX20@groups.io> on behalf of Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io>
Sent: Wednesday, July 25, 2018 1:23 PM
To: BITX20@groups.io
Subject: Re: [BITX20] End Fed antennas w/ uBITX
 
The resonant EFHW-8010 from myantennas.com described in the March 2016 QST review is good across
much of 80,40,20,15, and 10m without a tuner, giving under 2:1 SWR.
Inside the box, it's a 1:49 transformer.

I've experimented briefly with low (10' off the ground at the ends, 20 in the middle) and high (100' in the middle).
I'm sure the radiation pattern varies significantly, but the SWR readings were similar in both configurations.

In corresponding with Danny, I found that the SWR graphs on his product page were made with 100' of RG8X
which significantly affects the peaks and valleys, especially at the higher frequencies.
My measurements were made with about 3' of coax into the matchbox, resonances were more pronounced
but very usable.

Fig 2 of the review shows a bunch of hardware added to ensure the coax gets grounded, but there is a very solid
connection inside the box from the SO-239 shell to the ground wing nut.  The extra hardware of fig 2 is not needed.
 
There's a coil in the antenna wire plus caps across the transformer to keep things resonant on the high bands,
hard to get right across all bands as the chatter in that facebook page makes clear.
    https://www.facebook.com/groups/EndFedHalfWaveAntennas/ 

Will definitely need a tuner if the antenna is non-resonant, such as the 53 foot piece of wire in Allison's post:
    https://groups.io/g/BITX20/message/54821

Jerry


On Wed, Jul 25, 2018 at 09:28 AM, Ashhar Farhan wrote:
The end-fed antennae WILL work if used properly. The big advantage is that you can tune up any harmonic. However, you will have to use an antenna tuner, not a transformer. My favourite field antenna is an L matching unit with 66 feet of wire and 6 feet of counter-poise. Once tuned, it works pretty well. 
For the best broadband antenna that gives a low VSWR across all bands and is very compact, just use a dummy load. 
 

Re: uBITX Increasing 28 Mhz output by changing C81 #ubitx-help

ajparent1/KB1GMX <kb1gmx@...>
 

Two things did you get decent power on 80 and 40 before the mod?  Decent is more than 8- to 10W on 80.
Is it possible while making the cahges you could have broken a trace or caused a short or the extreme 
burnt out Q90?

Allison

Nextion 3.5 question #ubitx-help #ubitx

Doug Wright
 

I'm using CEC 1.095 and the Nextion ubitx_35.tft.  Any idea why the display is not being fully utilized (see attached)?
Thanks

Re: End Fed antennas w/ uBITX #ubitx

Gordon Gibby <ggibby@...>
 

​I think it is almost impossible to measure field strengths accurately enough to mean anyting.

But if you hold the key down for 10 minutes at 50 watts with a short piece of coax between you and that transformer and tell us the temperature afterwards.....we'll know how lossy or not it is!!!

You could still have some ground losses if you use a "ground" instead of a counterpoise....



Conservation of Energy is a very useful concept!!!!

What doesn't go into heat (somewhere) had to get radiated.  


From: BITX20@groups.io <BITX20@groups.io> on behalf of Jerry Gaffke via Groups.Io <jgaffke@...>
Sent: Wednesday, July 25, 2018 1:23 PM
To: BITX20@groups.io
Subject: Re: [BITX20] End Fed antennas w/ uBITX
 
The resonant EFHW-8010 from myantennas.com described in the March 2016 QST review is good across
much of 80,40,20,15, and 10m without a tuner, giving under 2:1 SWR.
Inside the box, it's a 1:49 transformer.

I've experimented briefly with low (10' off the ground at the ends, 20 in the middle) and high (100' in the middle).
I'm sure the radiation pattern varies significantly, but the SWR readings were similar in both configurations.

In corresponding with Danny, I found that the SWR graphs on his product page were made with 100' of RG8X
which significantly affects the peaks and valleys, especially at the higher frequencies.
My measurements were made with about 3' of coax into the matchbox, resonances were more pronounced
but very usable.

Fig 2 of the review shows a bunch of hardware added to ensure the coax gets grounded, but there is a very solid
connection inside the box from the SO-239 shell to the ground wing nut.  The extra hardware of fig 2 is not needed.
 
There's a coil in the antenna wire plus caps across the transformer to keep things resonant on the high bands,
hard to get right across all bands as the chatter in that facebook page makes clear.
    https://www.facebook.com/groups/EndFedHalfWaveAntennas/ 

Will definitely need a tuner if the antenna is non-resonant, such as the 53 foot piece of wire in Allison's post:
    https://groups.io/g/BITX20/message/54821

Jerry


On Wed, Jul 25, 2018 at 09:28 AM, Ashhar Farhan wrote:
The end-fed antennae WILL work if used properly. The big advantage is that you can tune up any harmonic. However, you will have to use an antenna tuner, not a transformer. My favourite field antenna is an L matching unit with 66 feet of wire and 6 feet of counter-poise. Once tuned, it works pretty well. 
For the best broadband antenna that gives a low VSWR across all bands and is very compact, just use a dummy load. 
 

Re: End Fed antennas w/ uBITX #ubitx

Jerry Gaffke
 

The resonant EFHW-8010 from myantennas.com described in the March 2016 QST review is good across
much of 80,40,20,15, and 10m without a tuner, giving under 2:1 SWR.
Inside the box, it's a 1:49 transformer.

I've experimented briefly with low (10' off the ground at the ends, 20 in the middle) and high (100' in the middle).
I'm sure the radiation pattern varies significantly, but the SWR readings were similar in both configurations.

In corresponding with Danny, I found that the SWR graphs on his product page were made with 100' of RG8X
which significantly affects the peaks and valleys, especially at the higher frequencies.
My measurements were made with about 3' of coax into the matchbox, resonances were more pronounced
but very usable.

Fig 2 of the review shows a bunch of hardware added to ensure the coax gets grounded, but there is a very solid
connection inside the box from the SO-239 shell to the ground wing nut.  The extra hardware of fig 2 is not needed.
 
There's a coil in the antenna wire plus caps across the transformer to keep things resonant on the high bands,
hard to get right across all bands as the chatter in that facebook page makes clear.
    https://www.facebook.com/groups/EndFedHalfWaveAntennas/ 

Will definitely need a tuner if the antenna is non-resonant, such as the 53 foot piece of wire in Allison's post:
    https://groups.io/g/BITX20/message/54821

Jerry


On Wed, Jul 25, 2018 at 09:28 AM, Ashhar Farhan wrote:
The end-fed antennae WILL work if used properly. The big advantage is that you can tune up any harmonic. However, you will have to use an antenna tuner, not a transformer. My favourite field antenna is an L matching unit with 66 feet of wire and 6 feet of counter-poise. Once tuned, it works pretty well. 
For the best broadband antenna that gives a low VSWR across all bands and is very compact, just use a dummy load.