Date   
Re: Thunderbolt and lightning, very, very frightening me

Matthew Stevens
 

Back in 2012 my next door neighbors maple tree was hit. It ran down the tree into the ground. To the north it ran along the galvanized water line where it blew the water meter and a chunk of the curbing across the street. To the south, it ran towards the house, jumped across the 8’ wide concrete porch into the DOORBELL BUTTON.... blew a 4” hole in the concrete block wall, burnt all the interior house wiring (like, black scorched marks on the walls), shattering light bulbs and burning up light switches etc. burned the breaker panel out behind the house. It went from there into the phone line... to the pole in the street where it blew the cover off the 1940s era lead telephone junction box (found that down the street about 30yards).

Went into my house via the phone line from that pole, tripped GFCIs in the back of the house, broke two light bulbs in the ceiling, and then through the cable line fried the cable modem-and literally scorched the on-board NIC off the motherboard on my fileserver which was connected directly to the modem/router. So yeah... I have a healthy respect for lightning :-)

My radio in the front of the house was unplugged at the time - and fine. Not to say that a nearby strike can’t cause issues even with an unplugged rig. But I think it’s better than leaving it plugged in. At least it makes me feel better even if it’s not accomplishing anything haha.

73,
- Matthew nj4y


On May 8, 2018, at 16:53, ajparent1/KB1GMX <kb1gmx@...> wrote:

I've worked with shelters and all for land mobile.  They are ringed underground with rods and wires,
same with surfaces and corners and then everything that goes into teh building is though a copper
plate with with polyphasor or similar before it geto to anything inside. IT's bonded to the tower with
copper straps usually wide like 4 to 6 inches and more than one.  They can take a direct hit.

Many years before a AM BC station.  You have the filed with the 120 wire ground plane,
ground rods most 12ft abound.  Tower is up on insulators for base feed but thereis an
arc gap from each leg spaced maybe 3 inches  the feed sire goes to the load coil in the
doghouse next to the base and that has straps to ground for RF and sparks.   The feed lines
are arranged to arc ro ground before the TX shed.  Been there during a storm, the
sparks are impressive and frightening.  About 1 in 10 caused the big 5kw RCA to shut down
usually a reset of breakers was all it took to start running the heaters(tubes) then B+ and
the modulator.  About twice a year the power company feed was a problem so we were
1KW off genset backup.

Me I've gotten hit twice one direct to the house antenna, fried the #6 wire to BBs and
much of the electronics in the house.  Second time it hit a pole down the hill before
it went underground about a mile away the surge got me, mostly minor.

The big thing is to protect so two things happen.  You do not burn the house down.
Your insurance then will cover any damage (or they do their best to weasel out).
Complying with NEC code is more for the prevention of insurance issues.

Call me pragmatic.  Prepare for the worst be, happy if it doesn't happen.

Allison

Re: #ubitx Powel Levels after SImple Mods #ubitx

astronuticus@...
 

If anyone is curious, here are some two-tone test (700 and 1900 Hz) scope captures after the above mods:



I'm a rookie at reading these scope traces.  But they don't seem terrible to me.  (Sorry, but I don't have a spectrum analyzer.)

Note that I backed off on my audio drive level a bit on each band to avoid flat-topping.  So the power output, as indicated by each image filename, was not quite as high on each band as listed in my earlier post. (Those tests were conducted using a single tone at 1500 Hz, the sweet spot.)

By the way, WSJT-X decoded a great many FT8 signals while I was connected to nothing but my dummy load for these tests.  So I sure can't complain about the sensitivity of the uBITX.  I'm also very happy with output power levels now.  The below PSK Reporter screen capture shows my reported signal strength while transmitting into a coarsely tuned attic dipole that is under a concrete tile roof and at the other end of an embarrassingly long RG-59 feedline (re-purposed video cables running from my home office down to the basement and then back up to the third floor attic).

Re: Thunderbolt and lightning, very, very frightening me

R. E. Klaus <reklaus@...>
 

Should be Motorola R56 Standards and Guidelines for Communication Sites:

www.repeater-builder.com/antenna/site-stuff/are-fifty-six-man-2005.pdf

And the electrical code falls under NEC 810.

73 K1AUS

Re: SWR

Jack, W8TEE
 

Heh...heh...heh...

Jack, W8TEE


On Tuesday, May 8, 2018, 10:30:17 PM EDT, Kees T <windy10605@...> wrote:


Maybe we need a dedicated $2.50 Nano for this ? ....and just pass the screen data to the main one ? Or a here is where we have a new Raduino or Protoneer, or ?  Phooie, the plan just imploded.

73 Kees K5BCQ 

Re: SWR

Kees T
 

Maybe we need a dedicated $2.50 Nano for this ? ....and just pass the screen data to the main one ? Or a here is where we have a new Raduino or Protoneer, or ?  Phooie, the plan just imploded.

73 Kees K5BCQ 

Re: Thunderbolt and lightning, very, very frightening me

Gordon Gibby <ggibby@...>
 

I understand that, it’s just that my station has to run 24/7/365.   (2 WINLINK gateways). So we do the best we can.   In the 19 years we’ve lived here, the trees have now grown considerably higher than the house, and the 3-story house has $thousands of dollars worth of lightning rods/ground wires.  The antennas are lower than the trees and not really that much higher than the house.  One of them has a good ground path before entry into the house, the other not so good.  In the 19 years, I think the only thing that ever even seemed to have been harmed, was a DSL modem connected to the telephone lines.   I’m not even sure it was harmed.  Once the solar power system got screwed up by a powerline hit, but it worked fine after being reset.   I have two complete sets of transient control systems on every input or output of the solar power system.

I can’t say enough how I think the best thing you can do is grow pine trees taller than your antennas.




On May 8, 2018, at 17:04, R. E. Klaus via Groups.Io <reklaus@...> wrote:

Great post. For anyone that would like to know how the pros do it, look up the Motorola rc56 manual.
73 K1AUS

Re: SWR

Kees T
 

As a minimum, I would display Forward and Reverse power in dBm ......that's all. If you want to know Watts you can have a look-up table or graph on the bottom of your UBITX.....0 dBm is 1mW, 10 dBm is 10mW, 20 dBm is 100mW, 30 dBm is 1W, and 40 dBm is 10W.

73 Kees K5BCQ

Re: SWR

Jerry Gaffke
 

Good luck shoehorning any of that into the uBitx's Nano.
For starters, it does the computations in floating point,
vs the 32 bit fixed point of post 48223

Be aware that 48223 has a bug in the display routine:
<  lcd.print((val/div) + 0x30);
>  lcd.print(val/div);

Jerry, KE7ER


On Tue, May 8, 2018 at 06:14 pm, Nick VK4PLN wrote:
Some one has already done some nice SWR work with the Arduino. I am implementing this in my uBITX

http://www.kk5jy.net/swr-meter-v1/

Re: SWR

Kees T
 

With all the diode non-linearity in directional couplers and my desire to not do another "n" polynomial curve fitting program and look-up table mWattmeter (which, by the way, worked great)......I decided to look into the following approach:

1) Can be housed under the covers of a UBITX .....maybe around 1" x 2"
2) Use the double-dual FT-37 #61 material Stockton Bridge
3) Use 2 AD8307s
4) Use one MCP3422 18bit  ADC or similar?? with a I2C interface.

Now the catch is that someone has to write the firmware and that someone is not me.

73 Kees K5BCQ

Re: FT8 on uBITX experiences

Bo Barry <wn4ghv@...>
 

I think the vast majority of FT8ers are hoping their contacts are logged into LOTW for awards sake.

The latest and craziest one in my opinion is the working of all the grid squares on the earth! 

But I will admit to doing the county hunters stuff for years. There were 3079 of them. 😏

But don't feel obligated, enjoy it the way you want. 73. Bo W4GHV since '54

Re: ND6T AGC implementation for uBIT-X

Kees T
 

Tim,

I've looked at the numbers and think I can do it ...INCLUDING.... covering PayPal charges (nearly everyone wants to use that) and postage to you in the USA at $5 for 2 kits (either 2 AGC kits or, 1 AGC kit and 1 Click kit or, 2 Click kits). That way it keeps it all simple too .....which I need with about 330 kits requested to date. I still have to figure out overseas postage which may have to be a padded envelope for customs reasons. 

Everything gets firmed up after testing.

73 Kees K5BCQ 

Re: FT8 on uBITX experiences

Rob Snow
 

I've been running my uBITX stock hardware @ 12v since I fired it up.  I've got Ian's wonderful firmware and I soldered up a EasyDigi and plugged it into a SFF PC running Ubuntu.  The uBITX runs through a 1.7MHz HPF (Local broadcast interference) and out to a EFHW in an inverted L.  I'm up over 700 FT8 contacts on 80/40/30/20/17/15.  I'm at 48 of 50 WAS (AK, RI missing) and have gotten some of the same DX as others to the Caribbean, Europe, South America and Oceania.  It has been amazing fun already.

I'm in the process of trying to get ARIM/ARDOP running, just for giggles.

I've got my CW key printed up, but I haven't wired it up yet, so I've got to do that.  I don't have a SSB QSO yet, but it'll happen.  I have a local ham who has offered to be it, but I want it to be a surprise when it happens.

Rob AG5OV

Re: ubitx audio #ubitx

pat griffin
 

Thanks for the comments and thanks for the suggestions.  I'll  probably try them both after a few days getting my sea legs with it.

73, Pat AA4PG


Pat Griffin
http//www.cahabatechnology.com/aa4pg.html


From: BITX20@groups.io <BITX20@groups.io> on behalf of Michael Maiorana <zfreak@...>
Sent: Tuesday, May 8, 2018 6:27:10 PM
To: BITX20@groups.io
Subject: Re: [BITX20] ubitx audio #ubitx
 
Great looking case.

I would suggest you calibrate the bfo first to see if that improves the audio. My ubitx bfo was substantially off from the factory. I used a pc and the spectrogram software to center the receive audio. That worked great, even with stock firmware.
Mike Ku4qo 

On Tue, May 8, 2018, 2:54 PM pat griffin <patgriffin@...> wrote:
I finally got the ubitx finished.  It is mounted in a Ten-Tec clamshell box such that it can be opened for service.  Other than a 4-line display and rf gain control (not connected) for future work, it is stock.  First contact from Birmingam AL to east Texas last night.  So far, no problems have surfaced with the Cat5 cable connecting the display and board.
For my bit40, I used the VK3YE mod (https://www.youtube.com/watch?v=IELJwapv5qs) in which the local oscillator frequency is shifted slightly to enhance the 2K audio region.  I claim this made a difference in my transmit audio based on anecdotal reports.  I assume to make a similar mod to the ubitx would involve modifying the software to change CLK#0.  I haven't looked at the software yet.  Any opinions (are you kidding!!??) about whether this audio mod is necessary on the ubitx and if so is moding the software the way to go?
Thanks es 73,
Pat AA4PG

Re: SWR

Tim Gorman
 

While I agree with most of your post, measuring PEP power from a
modulating audio signal is not quite as simple as it looks. The terms
"peak" and "average" power typically are associated with a CW signal.

If you are using the nano as a DC voltmeter then you are probably
measuring a CW signal, not modulated SSB signal.

Measuring a CW signal doesn't help much in setting mic gain to prevent
IMD distortion in a SSB signal.

While all kinds of stuff can be calculated from forward and reverse
power, much of it doesn't help much with someone trying to make a
contact on 7277khz. What you *really* need to know at that specific
point in time is if your tuner is providing a proper match between the
antenna and the transmitter. And it is reverse power that is the best
measure of that.

tim ab0wr

On Tue, 8 May 2018 18:26:01 -0600
"Arv Evans" <arvid.evans@...> wrote:

Tim AB0WR, and others...

Peak power is based on a calculation from average power, or from a
peak power
(doubler) type detector. The Arduino provides capability to do that
calculation,
either from peak to average or from average to peak. By using a
calibrated detector
to measure RF voltage and a current transformer to measure RF current
it is possible
to use software to calculate feed-point impedance at the measurement
location.

Dr. Bill will probably be quick to point out that this does not take
into account any phase
relationships, but neither do traditional forward and reverse power
meters. If your
forward power peak and reverse power dip do not coincide then there
may be a
problem with impedance match involving phase angle errors in the
measurements.

An SWR bridge can be designed to subtract reflected power from forward
power, or
to provide separate readouts for each of them. If using a NANO as
the DC voltmeter
it becomes possible to use forward and reflected power to provide many
different
displays (DB, FWD, REF, SWR, RF Volts, RF Amperes, Watts, Efficiency,
Impedance,
etc.).

It is also possible to install a 1 meter long pickup antenna a few
yards from the
antenna to monitor near-field signal strength and display it on the
NANO DC meter
reading, in DB, Volts, or some other relative field intensity
measurement. Using such
a pickup will tell you whether the FWD peak or REF dip represents
maximum power
into the aether.

Antennas, feed-lines, output filters, and final amplifiers are complex
interrelated
subjects that usually require complex analysis of each component to
arrive at an
accurate statement of fact.

Arv K7HKL
_._


On Tue, May 8, 2018 at 4:47 PM, Tim Gorman <tgorman2@...> wrote:

How are you going to get pep power on voice using the nano in order
to set your mic level? How many ubitx users have even implemented a
mic gain control?

Not everyone uses an antenna that is perfectly resonant on all
frequencies. If you never see any reverse power then your antenna
setup is probably unique.

I'll repeat, probably 99% of people that think they are seeing SWR
on their consumer swr meters are actually seeing nothing but a
reverse power reading. You are saying that most amateurs are not
getting sufficient information from their swr meters.

I disagree. They are getting exactly what they need.

tim ab0wr

On Tue, 08 May 2018 15:08:42 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:

Yes, you want peak power to minimize distortion.
But peak or average, some indication of forward power is better
than none for this.

If I have blown a PA fuse, I'd expect to see zero reverse power.
And if that is all I could see, I'd think all was well.

Once you have the two ADC voltage readings from a Tandem match,
the resources required for computing forward and reverse power
and SWR are given in post 48223. Quite insignificant. And I
have the Nano pins.

SWR is an easy and customary way of showing at least some aspects
of how the antenna system is doing. Most hams are comfortable
with it. For me, showing forward and reverse power would be
sufficient. Also showing SWR seems a reasonable thing to do, and
trivial. Just reverse power, not enough information



Re: SWR

Nick VK4PP
 

Some one has already done some nice SWR work with the Arduino. I am implementing this in my uBITX

http://www.kk5jy.net/swr-meter-v1/

73. Nick VK4PLN

Re: SWR

Tim Gorman
 

On Tue, 08 May 2018 16:24:59 -0700
"Jerry Gaffke via Groups.Io" <jgaffke=yahoo.com@groups.io> wrote:

If they have no mike gain control, they might well be twiddling RV1
instead to get somewhat more uniform power output across the bands.
Any forward power indication be it peak or average or somewhere
inbetween would help here.  Perhaps set it while in CW mode.
How do you set mic gain in CW mode in order to minimize distortion?
What does RV1 have to do with mic gain and distortion?



I never suggested that I have a perfectly resonant antenna.
An SWR indication is a clue about how far off resonance an antenna is
that most hams are familiar with.  Just seeing reverse power 
would be rather confusing, as an acceptable number there would
vary from rig to rig depending on whether it is putting out 1W or
100W. 
No, reverse power is the indication of how far off resonance an antenna
is that most hams are familiar with. They just don't know it.

I use the 10watt reverse power setting on my MicroMatch with both my
ubitx and my AL811H. I use the tuner to minimize reverse power in both
cases. When the tuner has matched the antenna system, reverse power
should be zero whether you are running 1W or 1000W.


I haven't bought a lot of consumer SWR meters, but I'm pretty sure
they all make an attempt to show SWR.   Not just reflected power.
What the meter label shows has nothing to do with what they are
measuring. Again, you get 1:1 SWR when reflected power is zero
regardless of what the forward power is. You don't adjust your tuner
for maximum power out, you adjust it for minimum reflected power.



At any rate, build what you wish.
I have no problem with that.
And the rest of us will do the same.

I'm done here.

Jerry
Calculating SWR when it is not needed could prevent implementation of a
feature I would rather see. I will continue to advocate for what I see
as the most efficient feature design.

You may advocate for what you to see as the most efficient feature
design as well.

That's how the free market works!

tim ab0wr

Re: ND6T AGC implementation for uBIT-X

Tim Gorman
 

Have you figured out what the price will be?

I assume you'll take paypal?

tim ab0wr

On Tue, 08 May 2018 17:33:28 -0700
"Kees T" <windy10605@...> wrote:

DHL tracking says the AGC and Click boards will be here by the end of
the day Wed May 9th, 2018.

73 Kees K5BCQ

Re: ND6T AGC implementation for uBIT-X

Kees T
 

DHL tracking says the AGC and Click boards will be here by the end of the day Wed May 9th, 2018.

73 Kees K5BCQ

Re: boosting the power on 28 MHz #ubitx

docame12@...
 

Just out of curiosity, what sort of power levels can be had with the finals wide open without doing the rest of the mod? Not that I am planning on doing that. Just wondering.

Dave, WS1ETI

Re: ubitx audio #ubitx

Michael Maiorana
 

Great looking case.

I would suggest you calibrate the bfo first to see if that improves the audio. My ubitx bfo was substantially off from the factory. I used a pc and the spectrogram software to center the receive audio. That worked great, even with stock firmware.
Mike Ku4qo 

On Tue, May 8, 2018, 2:54 PM pat griffin <patgriffin@...> wrote:
I finally got the ubitx finished.  It is mounted in a Ten-Tec clamshell box such that it can be opened for service.  Other than a 4-line display and rf gain control (not connected) for future work, it is stock.  First contact from Birmingam AL to east Texas last night.  So far, no problems have surfaced with the Cat5 cable connecting the display and board.
For my bit40, I used the VK3YE mod (https://www.youtube.com/watch?v=IELJwapv5qs) in which the local oscillator frequency is shifted slightly to enhance the 2K audio region.  I claim this made a difference in my transmit audio based on anecdotal reports.  I assume to make a similar mod to the ubitx would involve modifying the software to change CLK#0.  I haven't looked at the software yet.  Any opinions (are you kidding!!??) about whether this audio mod is necessary on the ubitx and if so is moding the software the way to go?
Thanks es 73,
Pat AA4PG