Date   
Re: Broadband HF Folded Dipole Antennas

ajparent1/kb1gmx
 

Also look at 4NEC2 Arie Voors, very good work and a serious too as well.


Allison

Re: Broadband HF Folded Dipole Antennas

iz oos
 

That is a model based on assumptions. The only way to establish how much power is dissipated into the resistor is to measure the heat produced. By the way it is true that at low frequencies, it dissipates much more. It behaves like a high pass filter. The 66feet version was sold by BW with a 5Mhz lowest frequently.


Il 12/mag/2018 19:44, "Bo Barry" <bobarr@...> ha scritto:
Probably worth a LOT more than two cents.
Especially for those with long coax lines.
Having a true matched coax and the impedance corrections done at the antenna make the most sense.

Unfortunately an economical outside tuner isn't around. I'm gonna research them anyway.

I'd love to experiment with Smith Charts again. I studied them in '65 &'70 in grad school.

The EZNEC program looks interesting but I haven't figured it out yet.
73 Bo W4GHV since '54

Re: boosting the power on 28 MHz #ubitx

Skip Davis
 

Allison I tried the 220pf cap on RV1 and didn’t see any gain at 28 MHZ. I also tried removing the feedback resistors in the finals suggested by Farhan without any gain. What I also have done was the capacitor/choke mod suggested by Howard for the driver stages and that has worked. With RV1 set to 10 watts on 40 meters I now get about 2.5 watts on 28 MHZ up from the 1.25 - 1.5 watts before. I also see about 8 or 9 watts on 20 meters. I’m running Ian’s firmware I think version 1.06 something.

Skip Davis, NC9O

Re: ubitx mic pre-amp not working, no SSB

Tim Gorman
 

DING! DING! DING!

We have a WINNER!

Don't know why, don't know how but R64 was shorted.

Replaced it and now everything working fine!

Thanks Ion!

tim ab0wr

On Sat, 12 May 2018 02:41:22 -0700
"Ion Petroianu, VA3NOI" <ion.petroianu@...> wrote:

Tim,
A short on C62 or R64 will do that.
73,
--
Ion

VA3NOI

Re: Broadband HF Folded Dipole Antennas

ajparent1/kb1gmx
 

Any time you include a resistor you loose some efficiency.    Having designed mil antennas usually
the source tolerates some maximum SWR without a tuner typical is 2.5:1  some its 3:1.  However
where you put the resistor and how you construct the system as a whole is important.  The B&W
is simple and does work and generally for various bands its not bad for the long version.  Like
all antennas the short version does NOT have the same low frequency capability and will be lossy
there.

As to modeling it, beware dragons may lie beyond.  The most common error is that NEC (V2)
does not alway shandle two parallel wires correctly if they are close.  The result then is invalid.
I've done an eval using the NEC4 engine and even then you have to pay attention to wires
close spaced though it handles it better.  Folded dipoles are tricky to model.

There are resistor loaded antennas that offer gain and are considered wideband as well.
One that comes to mind is the Rhombic.

Allison


Re: uBITX drive level.. #ubitx

Tim Gorman
 

Quick questions.

How do you know you are only putting out 5W? How are
you measuring that?

Are you working into a dummy load? Do you have an antenna tuner in
line, even to a dummy load? The ubitx is very sensitive to antenna
matching for maximum output power.

Do you have an oscilloscope by any chance?

tim ab0wr

On Sat, 12 May 2018 10:37:13 -0700
"KE0GYC" <@KE0GYC> wrote:

In am getting a bit under 5w on 80 and 40m.  Half that on upper bands.

Most seem to be getting 10w+ on 40m.

I experimented with boosting the voltage to my PA-PWR line, but even
pushing 24V to the PA only barely got me to 10w, and my audio was
distorted at that point.

Something must be awry somewhere, I am just at a loss for where to
look.

I did poke around with an old RF probe, and the RF level did not
change before or after the filters, so my filters are not attenuating
my signal.

It looks like the RF voltage into the IRF510 was roughly in line with
the following photo at around 1.5V by C94.  RV1 is turned all the way
up to get that much.

Re: boosting the power on 28 MHz #ubitx

K9HZ <bill@...>
 

Did you try putting about 330pf across the primary of T11 (PA output transformer). That will make a big difference...


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
Like us on Facebook!

Moderator – North American QRO Group at Groups.IO.

email: @Doc_Bill

-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Skip Davis via Groups.Io
Sent: Saturday, May 12, 2018 1:27 PM
To: BITX20@groups.io
Subject: Re: [BITX20] boosting the power on 28 MHz #ubitx

Allison I tried the 220pf cap on RV1 and didn’t see any gain at 28 MHZ. I also tried removing the feedback resistors in the finals suggested by Farhan without any gain. What I also have done was the capacitor/choke mod suggested by Howard for the driver stages and that has worked. With RV1 set to 10 watts on 40 meters I now get about 2.5 watts on 28 MHZ up from the 1.25 - 1.5 watts before. I also see about 8 or 9 watts on 20 meters. I’m running Ian’s firmware I think version 1.06 something.

Skip Davis, NC9O




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Re: uBITX drive level.. #ubitx

KE0GYC
 

I do not have an oscilloscope, unfortunately

I am transmitting into a QRPLabs 20W dummy load.  It measures almost exactly 50 ohms with my DVM.

I had an old wattmeter/SWR meter that I was using to measure power.  It recently took a dive on me, and now I am using an old Fluke RF probe.  Both indicated the uBitX was putting out slightly less power than my stock FT817.  My RF probe is showing both at approx 3.6W, so I am sure it is out of calibration, but it should suffice for relative power measurements and at least get me in the neighborhood, I would think.
I am using my FT817 as a reference for these tools since I know it should put out slightly under 5W with a proper power supply.

Re: boosting the power on 28 MHz #ubitx

Skip Davis
 

No I haven’t Bill I’ll try that later tonight when I get some time. Right now I’m taking a break from outside yard work :)

Skip Davis, NC9O

On May 12, 2018, at 14:38, K9HZ <@Doc_Bill> wrote:

Did you try putting about 330pf across the primary of T11 (PA output transformer). That will make a big difference...


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
Like us on Facebook!

Moderator – North American QRO Group at Groups.IO.

email: @Doc_Bill



-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Skip Davis via Groups.Io
Sent: Saturday, May 12, 2018 1:27 PM
To: BITX20@groups.io
Subject: Re: [BITX20] boosting the power on 28 MHz #ubitx

Allison I tried the 220pf cap on RV1 and didn’t see any gain at 28 MHZ. I also tried removing the feedback resistors in the finals suggested by Farhan without any gain. What I also have done was the capacitor/choke mod suggested by Howard for the driver stages and that has worked. With RV1 set to 10 watts on 40 meters I now get about 2.5 watts on 28 MHZ up from the 1.25 - 1.5 watts before. I also see about 8 or 9 watts on 20 meters. I’m running Ian’s firmware I think version 1.06 something.

Skip Davis, NC9O




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Re: Broadband HF Folded Dipole Antennas

Gordon Gibby <ggibby@...>
 

Yes, it is a model.

1. One could measure the power sent to the antenna and then measure the RF voltage across the load resistor, and compute the power dissipated on the load resistor presuming that it is somewhat noninductive.     Repeat every quarter megahertz or so, from 3 MHz to 30 MHz.  

2. For somebody a little brighter than me, Open the antenna where that resistor is, measure the SWR with an antenna analyzer at every frequency; repeat with the resister connected back in, do you some fancy math and tell us exactly what the loss in the resister was to make the SWR looks so wonderful.

3. For a rough estimate, one could take a normal non-lossy antenna, and measure the background static on a receiver without automatic gain control.  Replace with the tilted folded dipole and see how much softer the background static is.  Although the patterns will not be identical, atmospheric noise  is probably somewhat Homogeneous.  

4. If one had a calibrated S meter they could do the same there.

5. We know from many many observations that it is considered a quiet antenna, giving experimental evidence to suggest the losses are quite noticeable. A 3DB loss would probably not be so noticeable.  

The problem for me is that I need an antenna at work on many frequencies, not just the ham radio frequencies, so wide ranging losses aren’t  my best goal.

Perfect application: Give me a platoon of Marines who need to get antennas to work for ALE? I’ll send them out with the tilted folded terminated antenna every single time.  it is a perfect antenna for that kind of mission, absolutely perfect.  No muss no fuss, it works.  And since the military has money to burn, it fits perfectly.   Give me a government installation in the shares  system, perfect match also.    Give me a emergency operations center wanting to run shares and ham, with a bunch of hams with a little less experience, perfect application also.


Every antenna just like every boat, and every airplane, every ship, is a compromise.







On May 12, 2018, at 14:19, iz oos <and2oosiz2@...> wrote:

That is a model based on assumptions. The only way to establish how much power is dissipated into the resistor is to measure the heat produced. By the way it is true that at low frequencies, it dissipates much more. It behaves like a high pass filter. The 66feet version was sold by BW with a 5Mhz lowest frequently.


Il 12/mag/2018 19:44, "Bo Barry" <bobarr@...> ha scritto:
Probably worth a LOT more than two cents.
Especially for those with long coax lines.
Having a true matched coax and the impedance corrections done at the antenna make the most sense.

Unfortunately an economical outside tuner isn't around. I'm gonna research them anyway.

I'd love to experiment with Smith Charts again. I studied them in '65 &'70 in grad school.

The EZNEC program looks interesting but I haven't figured it out yet.
73 Bo W4GHV since '54

Re: Broadband HF Folded Dipole Antennas

Gordon Gibby <ggibby@...>
 

Thanks Alyson for that information!
I guess if you take any antenna with 15 dB  of gain and then throw in 3DB of loss, you still have 12 DB of gain!

In order to make my non-resonant dipoles tune with an MFJ auto tuner on just about any frequency, I almost always end up with a problem at one particular band, usually where the antenna is a full wavelength long.

I gave up, and just put in simple traps made out of RG 58 coax.  Undoubtedly, that adds some loss &  I think it’s worse near there resonant frequency I’m told, but I still think I’m probably better off than having an actual big resistor  somewhere.   The compromise of coarse is I have to spend a couple hundred dollars on a fallible auto antenna tuner.  So that’s a compromise!

But I think I have lower loss most of the time.  My gateway station get plenty of use, so it must be doing something right.

Gordon.  


On May 12, 2018, at 14:29, ajparent1/KB1GMX <kb1gmx@...> wrote:

Any time you include a resistor you loose some efficiency.    Having designed mil antennas usually
the source tolerates some maximum SWR without a tuner typical is 2.5:1  some its 3:1.  However
where you put the resistor and how you construct the system as a whole is important.  The B&W
is simple and does work and generally for various bands its not bad for the long version.  Like
all antennas the short version does NOT have the same low frequency capability and will be lossy
there.

As to modeling it, beware dragons may lie beyond.  The most common error is that NEC (V2)
does not alway shandle two parallel wires correctly if they are close.  The result then is invalid.
I've done an eval using the NEC4 engine and even then you have to pay attention to wires
close spaced though it handles it better.  Folded dipoles are tricky to model.

There are resistor loaded antennas that offer gain and are considered wideband as well.
One that comes to mind is the Rhombic.

Allison


Re: Should we adopt the KD8CEC firmware?

Tom Christian
 

Ashhar,
I have been using Ian's firmware because of the added features, especially CAT.  But, if possible, I would like to have the choice to use your preference for general coverage when changing the bands rather than steps to and from ham bands.  As much as I like Ian's software as a whole, I miss that part from your firmware.  Thanks!
Tom
AB7WT

Re: Should we adopt the KD8CEC firmware?

Mike Woods
 

Ian’s firmware has always had the option of toggling to general coverage RX (at least since v0.33 by my notes).  How to do this is documented in the manual.

M


On Sun, 13 May 2018 at 7:42 AM, Tom Christian <tmchristian@...> wrote:
Ashhar,
I have been using Ian's firmware because of the added features, especially CAT.  But, if possible, I would like to have the choice to use your preference for general coverage when changing the bands rather than steps to and from ham bands.  As much as I like Ian's software as a whole, I miss that part from your firmware.  Thanks!
Tom
AB7WT

Re: Should we adopt the KD8CEC firmware?

tony.vasile@...
 

Personally, I think there is great value in maintaining the original "factory" code base, simply because this is a hacker's dream!

Delivering with your original core software takes nothing away from those that wish to adopt Ian's, or anyone else's mods (inclusing their own).

The only drawbacks I see are:

1) Ian (or others) would have to maintain their branches if you were to make any changes to the core that would "need" to be proliferated. This can be achieved by ensuring that any changes you make to the core are communicated (documented).

2) Those enthusiasts who wish to use alternate firmware, but are not comfortable with, or equipped to, modify the Raduino may be discouraged from becoming a BitX enthusiast.  Possible solutions are building a stronger community of support (which is essentially happening with this online community), or in the extreme some of us becoming a pass-through for Raduino uogrades.

Just some thoughts!

Tony, KB9A 

UBitx #1:  Cigar Box case, KD8CEC firmware
Bitx40 #1: Grey case kit from Amateur Radio Kits, PE1NWL firmware
UBitx #2: Maroon case kit from Amateur Radio Kits (still under construction)

On May 12, 2018 3:42 PM, "Tom Christian" <tmchristian@...> wrote:
Ashhar,
I have been using Ian's firmware because of the added features, especially CAT.  But, if possible, I would like to have the choice to use your preference for general coverage when changing the bands rather than steps to and from ham bands.  As much as I like Ian's software as a whole, I miss that part from your firmware.  Thanks!
Tom
AB7WT


Re: uBITX drive level.. #ubitx

Tim Gorman
 

I would think you could get more than 5watts out on 80m.

You might still try an antenna tuner between your ubitx and the dummy
load. It's possible the ubitx wants something other than a 50ohm
antenna/dummy load for its best match.

The other thing you could try is to use your rf probe to ensure all
stages are contributing gain. Check the in/out rf voltage on each stage
to see what is happening, especially at Q90.

tim ab0wr

On Sat, 12 May 2018 11:55:34 -0700
"KE0GYC" <@KE0GYC> wrote:

I do not have an oscilloscope, unfortunately

I am transmitting into a QRPLabs 20W dummy load.  It measures almost
exactly 50 ohms with my DVM.

I had an old wattmeter/SWR meter that I was using to measure power.
It recently took a dive on me, and now I am using an old Fluke RF
probe.  Both indicated the uBitX was putting out slightly less power
than my stock FT817.  My RF probe is showing both at approx 3.6W, so
I am sure it is out of calibration, but it should suffice for
relative power measurements and at least get me in the neighborhood,
I would think. I am using my FT817 as a reference for these tools
since I know it should put out slightly under 5W with a proper power
supply.

Re: boosting the power on 28 MHz #ubitx

Tim Gorman
 

How do you recommend doing that? A disc ceramic between IRF510 pins?
Can you get an smd cap between the pins on the bottom of the ckt board?

tim ab0wr

On Sat, 12 May 2018 13:38:52 -0500
"K9HZ" <@Doc_Bill> wrote:

Did you try putting about 330pf across the primary of T11 (PA output
transformer). That will make a big difference...


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
Like us on Facebook!

Moderator – North American QRO Group at Groups.IO.

email: @Doc_Bill



-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Skip
Davis via Groups.Io Sent: Saturday, May 12, 2018 1:27 PM
To: BITX20@groups.io
Subject: Re: [BITX20] boosting the power on 28 MHz #ubitx

Allison I tried the 220pf cap on RV1 and didn’t see any gain at 28
MHZ. I also tried removing the feedback resistors in the finals
suggested by Farhan without any gain. What I also have done was the
capacitor/choke mod suggested by Howard for the driver stages and
that has worked. With RV1 set to 10 watts on 40 meters I now get
about 2.5 watts on 28 MHZ up from the 1.25 - 1.5 watts before. I also
see about 8 or 9 watts on 20 meters. I’m running Ian’s firmware I
think version 1.06 something.

Skip Davis, NC9O




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Re: boosting the power on 28 MHz #ubitx

K9HZ <bill@...>
 

I just put mine at the base of T11 but there are many ways of doing it depending the type of part you use... I also replaced T11 but let's not go there yet.


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
Like us on Facebook!

Moderator – North American QRO Group at Groups.IO.

email: @Doc_Bill

-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Tim Gorman
Sent: Saturday, May 12, 2018 4:31 PM
To: BITX20@groups.io
Subject: Re: [BITX20] boosting the power on 28 MHz #ubitx

How do you recommend doing that? A disc ceramic between IRF510 pins?
Can you get an smd cap between the pins on the bottom of the ckt board?

tim ab0wr

On Sat, 12 May 2018 13:38:52 -0500
"K9HZ" <@Doc_Bill> wrote:

Did you try putting about 330pf across the primary of T11 (PA output
transformer). That will make a big difference...


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
Like us on Facebook!

Moderator – North American QRO Group at Groups.IO.

email: @Doc_Bill



-----Original Message-----
From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Skip
Davis via Groups.Io Sent: Saturday, May 12, 2018 1:27 PM
To: BITX20@groups.io
Subject: Re: [BITX20] boosting the power on 28 MHz #ubitx

Allison I tried the 220pf cap on RV1 and didn’t see any gain at 28
MHZ. I also tried removing the feedback resistors in the finals
suggested by Farhan without any gain. What I also have done was the
capacitor/choke mod suggested by Howard for the driver stages and that
has worked. With RV1 set to 10 watts on 40 meters I now get about 2.5
watts on 28 MHZ up from the 1.25 - 1.5 watts before. I also see about
8 or 9 watts on 20 meters. I’m running Ian’s firmware I think version
1.06 something.

Skip Davis, NC9O




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Re: Should we adopt the KD8CEC firmware?

Jerry Gaffke
 

Partition the code so the keyer or CAT stuff or whatever can be ifdef'd out.
Then experimenters will have plenty of room to play.

Jerry



On Sat, May 12, 2018 at 09:14 am, Tim Gorman wrote:
No matter what you do, Ian's software is going to fill up the nano's
memory space. That *will* limit the ability of novice and intermediate
coders to make changes that they would like.

In essence it will push the ubitx to being more like a
kenwood/icom/yaesu rig where the software does not lend itself to
experimentation by the user.

Ian's software is quite easy to install if one is not interested in
experimentation.

Perhaps make it an ordering option? Basic software for experimenters
and Ian's software for appliance operators.

Re: Should we adopt the KD8CEC firmware?

K9HZ <bill@...>
 

Or WSPR code…

 

 

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

Like us on Facebook! facebook icon

 

Moderator – North American QRO Group at Groups.IO.

 

email:  bill@...

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jerry Gaffke via Groups.Io
Sent: Saturday, May 12, 2018 5:35 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Should we adopt the KD8CEC firmware?

 

Partition the code so the keyer or CAT stuff or whatever can be ifdef'd out.
Then experimenters will have plenty of room to play.

Jerry



On Sat, May 12, 2018 at 09:14 am, Tim Gorman wrote:

No matter what you do, Ian's software is going to fill up the nano's
memory space. That *will* limit the ability of novice and intermediate
coders to make changes that they would like.

In essence it will push the ubitx to being more like a
kenwood/icom/yaesu rig where the software does not lend itself to
experimentation by the user.

Ian's software is quite easy to install if one is not interested in
experimentation.

Perhaps make it an ordering option? Basic software for experimenters
and Ian's software for appliance operators.


Virus-free. www.avg.com

can I bypass the CP2102 chip on the NANO with an FTDI based serial adapter? #arduino #cp2102 #ftdi #nano

freefuel@...
 

Hi all, 

I'm having trouble getting the CP2102 chip on my Radunio to be recognized by my Mac Mini, however the Arduino IDE program can see my other Arduino boards and my FTDI based USB to Serial adapters just fine, I want to know if I can use jumper leads to connect to the NANO without damaging any of the chips. 

-Justin N2TOH