Date   

Welsh Village Traces 18 Months of Internet Outages to Old TV

Brad (the Voice of the Village) Berger
 

This sounds familiar to our repeater interference problems with cheap over-the-air Chinese antenna amplifiers.

https://www.pcmag.com/news/welsh-village-traces-18-months-of-internet-outages-to-old-tv?utm_source=email&utm_campaign=whatsnewnow&utm_medium=title



Nets tonight

David Andrews
 

Don’t forget tonight’s radio and Zoom nets.

 

Join Zoom Meeting

https://us02web.zoom.us/j/83006146324?pwd=elY5VVNETUZKYUxpcW54dFhQV0hvZz09

 

Meeting ID: 830 0614 6324

Password: 099892

One tap mobile

+19292056099,,83006146324#,,1#,099892# US (New York)

+13017158592,,83006146324#,,1#,099892# US (Germantown)

 

Dial by your location

        +1 929 205 6099 US (New York)

        +1 301 715 8592 US (Germantown)

        +1 312 626 6799 US (Chicago)

        +1 669 900 6833 US (San Jose)

        +1 253 215 8782 US (Tacoma)

        +1 346 248 7799 US (Houston)

Meeting ID: 830 0614 6324

Password: 099892

Find your local number: https://us02web.zoom.us/u/kbJYC2Q4s7

 


Emailing: Sweetwater Tailgate Hamfest 2020.pdf

David Andrews
 


Antenna

Eric Ressler
 

Does anyone have a 2m antenna that would fit a windowsill that I may borrow? I have one on order!
Thanks 
Eric Ressler
--
Chaser

--
KD8LHZ 


Dr HEIL INTERVIEW TONIGHT HAMNATION

Bob Wilson-KK4XA
 

Tonight at 9pm eastern there will be a live interview with Dr Heil on Hamnation on utube.
W4DXY DixieDX will be there.

73
Bob Wilson
KK4XA
Maryville, TN





--
Bob Wilson - KK4XA


A quick correction

WK9M
 

Hi all; something I noticed late last night after I re-read that article below.  And a little correction.

When comparing VSWR voltages, you have to compare apples to apples.  i.e. peak voltage to peak voltage; not compare the rms (the DC equivalent) to peak voltage.  The article mentions the rms formula and then goes on to compare it to the peak formula.  Just using the same formula below with SWR=1 is more straightforward.  So...

1:1 Vpk=sqrt(100*100*1)=100v
3:1 Vpk=sqrt(100*100*3)=173.2v

Now you see this is even less dramatic than 3x the voltage.  Ironically it's 73% more voltage.  I've seen that 73 number somewhere before.

'73
Randy

On 9/22/2020 5:10 PM, RK wrote:
Sounds good Allan; the actual loss depends on transmission line quality and frequency then as we chatted on the phone when I was by Ralph's earlier.  i.e the losses would be much greater with a long run at 440MHz and 3:1 as it bounces back and forth.  Maybe we should just superconducting coax and then the answer is always 100%?  Ok so maybe not practical on that one.  :)

I found the actual article on voltage, VSWR, and surge suppressors that I had talked about during the presentation if anyone is interested.  The formula is (2) on page 4 of this document for the techies in the club:
http://www.arrl.org/files/file/QEX_Next_Issue/2016/July-August/Hinkle.pdf

Vpk=sqrt(100*PWR*SWR)

So on a 100W signal into 50 ohms at 1:1, the common Ohm's law formula states 70.7V (P=(V^2)/R); solving for V.

At 3:1, the voltage isn't 70.7*3=210.9V but 173.2V...a little less than 3X as you noted.

With 1.5kW, it's an amazing 671V.  So that's why you always tune high power.

'73
Randy

On 9/22/2020 2:29 PM, John Haskell via groups.io wrote:
Randy,

Thanks for your thoughts.  Good point on the peak voltage being higher with a non-perfect match.

The  4-11-25 "rule" works well if the line is very lossy.

I must say though that the 4-11-25 "rule" doesn't quite cut it for low loss transmission lines.

For example, consider a lossless line with a 2:1 SWR.  What percentage of the transmitter's power is radiated?  Answer:  All the power is radiated [not 90%].

What about with a 10:1 SWR?  The loss is again zero!   All the power is radiated.  Think open wire or ribbon line.  This is an important concept.  Even with a high SWR,  100% of the power is radiated.

What really happens is the reflected power is re-reflected at the transmitter [near 100% of it] and is not lost to dissipation in the transmitter.  The reflected power, when it reaches the transmitter, is reflected back in the forward direction where much will be radiated when it again reaches the antenna.  Eventually all the power is radiated in spite of an SWR greater than 1 except for the portion dissipated in the transmission line.  Just think of the energy ping-ponging back and forth with some being radiated when the energy hits the antenna each time.

When some line loss is present the reflected power does suffer some loss in the transmission line on the way back and forward, and that is what the additional loss beyond the SWR 1:1 case represents.  As long as the line has, say, less than a dB or two of loss the additional loss caused by SWR can pretty much be ignored.

73,
Allan



Re: [SMARC] Sevier County Amateur Radio Society Hamfest-DixieDX W4DXY

David Andrews
 

Well done Bob.

 

David N1ESK

 

From: TLARC@groups.io <TLARC@groups.io> On Behalf Of Bob Wilson
Sent: Tuesday, September 22, 2020 10:48 PM
To: TLARC@groups.io
Subject: [TLARC] [SMARC] Sevier County Amateur Radio Society Hamfest-DixieDX W4DXY

 

Hello TLARC. Thought I would share this with you. Feel free to forward. Really a nice gal coming along in the hobby with her own utube channel as you will see

Be sure to reach out to her too.  

 

73

 

---------- Forwarded message ---------
From: Robert Wilson via groups.io <kk4xa=icloud.com@groups.io>
Date: Tue, Sep 22, 2020 at 10:04 PM
Subject: [SMARC] Sevier County Amateur Radio Society Hamfest
To: SMARC@groups.io Not. <smarc@groups.io>



In case you weren’t at the Sevier county hamfest check out this video including a interview with me.  The earlier version I sent was the “Raw” footage.



Here is the completed video.



https://youtu.be/okyGb7SV4jY



73

Bob Wilson

KK4XA

Maryville, TN
















--

 

Bob Wilson

KK4XA

Maryville, TN


--
Bob Wilson - KK4XA


[SMARC] Sevier County Amateur Radio Society Hamfest-DixieDX W4DXY

Bob Wilson-KK4XA
 

Hello TLARC. Thought I would share this with you. Feel free to forward. Really a nice gal coming along in the hobby with her own utube channel as you will see
Be sure to reach out to her too.  

73

---------- Forwarded message ---------
From: Robert Wilson via groups.io <kk4xa=icloud.com@groups.io>
Date: Tue, Sep 22, 2020 at 10:04 PM
Subject: [SMARC] Sevier County Amateur Radio Society Hamfest
To: SMARC@groups.io Not. <smarc@groups.io>


In case you weren’t at the Sevier county hamfest check out this video including a interview with me.  The earlier version I sent was the “Raw” footage.



Here is the completed video.



https://youtu.be/okyGb7SV4jY



73

Bob Wilson

KK4XA

Maryville, TN

















--

Bob Wilson
KK4XA
Maryville, TN

--
Bob Wilson - KK4XA


Re: Does a low SWR mean your antenna is a great performer?

WK9M
 

Sounds good Allan; the actual loss depends on transmission line quality and frequency then as we chatted on the phone when I was by Ralph's earlier.  i.e the losses would be much greater with a long run at 440MHz and 3:1 as it bounces back and forth.  Maybe we should just superconducting coax and then the answer is always 100%?  Ok so maybe not practical on that one.  :)

I found the actual article on voltage, VSWR, and surge suppressors that I had talked about during the presentation if anyone is interested.  The formula is (2) on page 4 of this document for the techies in the club:
http://www.arrl.org/files/file/QEX_Next_Issue/2016/July-August/Hinkle.pdf

Vpk=sqrt(100*PWR*SWR)

So on a 100W signal into 50 ohms at 1:1, the common Ohm's law formula states 70.7V (P=(V^2)/R); solving for V.

At 3:1, the voltage isn't 70.7*3=210.9V but 173.2V...a little less than 3X as you noted.

With 1.5kW, it's an amazing 671V.  So that's why you always tune high power.

'73
Randy

On 9/22/2020 2:29 PM, John Haskell via groups.io wrote:
Randy,

Thanks for your thoughts.  Good point on the peak voltage being higher with a non-perfect match.

The  4-11-25 "rule" works well if the line is very lossy.

I must say though that the 4-11-25 "rule" doesn't quite cut it for low loss transmission lines.

For example, consider a lossless line with a 2:1 SWR.  What percentage of the transmitter's power is radiated?  Answer:  All the power is radiated [not 90%].

What about with a 10:1 SWR?  The loss is again zero!   All the power is radiated.  Think open wire or ribbon line.  This is an important concept.  Even with a high SWR,  100% of the power is radiated.

What really happens is the reflected power is re-reflected at the transmitter [near 100% of it] and is not lost to dissipation in the transmitter.  The reflected power, when it reaches the transmitter, is reflected back in the forward direction where much will be radiated when it again reaches the antenna.  Eventually all the power is radiated in spite of an SWR greater than 1 except for the portion dissipated in the transmission line.  Just think of the energy ping-ponging back and forth with some being radiated when the energy hits the antenna each time.

When some line loss is present the reflected power does suffer some loss in the transmission line on the way back and forward, and that is what the additional loss beyond the SWR 1:1 case represents.  As long as the line has, say, less than a dB or two of loss the additional loss caused by SWR can pretty much be ignored.

73,
Allan


Re: Does a low SWR mean your antenna is a great performer?

John Haskell <jasm2213@...>
 

Randy,

Thanks for your thoughts.  Good point on the peak voltage being higher with a non-perfect match.

The  4-11-25 "rule" works well if the line is very lossy.

I must say though that the 4-11-25 "rule" doesn't quite cut it for low loss transmission lines.

For example, consider a lossless line with a 2:1 SWR.  What percentage of the transmitter's power is radiated?  Answer:  All the power is radiated [not 90%].

What about with a 10:1 SWR?  The loss is again zero!   All the power is radiated.  Think open wire or ribbon line.  This is an important concept.  Even with a high SWR,  100% of the power is radiated.

What really happens is the reflected power is re-reflected at the transmitter [near 100% of it] and is not lost to dissipation in the transmitter.  The reflected power, when it reaches the transmitter, is reflected back in the forward direction where much will be radiated when it again reaches the antenna.  Eventually all the power is radiated in spite of an SWR greater than 1 except for the portion dissipated in the transmission line.  Just think of the energy ping-ponging back and forth with some being radiated when the energy hits the antenna each time.

When some line loss is present the reflected power does suffer some loss in the transmission line on the way back and forward, and that is what the additional loss beyond the SWR 1:1 case represents.  As long as the line has, say, less than a dB or two of loss the additional loss caused by SWR can pretty much be ignored.

73,
Allan


Re: IRS Determination Letter

Brad (the Voice of the Village) Berger
 

Congratulations David and thank you for getting this 501 (c)(3) together. Not only did you do an outstanding job, but you are now officially our club attorney.

The Hon. David F. Andrews Esq.
Now about that speeding ticket I got...


Brad B.


Re: Does a low SWR mean your antenna is a great performer?

WK9M
 

Yes I think that a presentation would be a great idea--TLARC is looking for new presentations.  I myself put in memory the 4-11-25% rule.  i.e. 1.5:1 is 4% loss, 2:1 is 11% loss, and 3:1 is 25% loss.  I found a document online that confirms my memory is correct:
http://www.packetradio.com/pdfzips/SWRvsPowerNwatts.pdf

And as you point out, 2:1 is a .5 dB loss.  Even 3:1 is only a 1/5 of an S-unit (1.25dB loss); I'd say that a computer can hear that difference but probably not a human.

Many modern radios will start cutting power back at even moderate VSWR levels.  So as you say, watch the power out.  Both of my Kenwood HF radios are picky on 6m for example.

VSWR can have a bad effect on surge arrestors if you happen to buy a low power one and operate it with high VSWR.  (3:1 is literally 3x the voltage).  But I doubt any of us would do that, at least on purpose.  I went over that in my surge presentation about a year ago.

'73,
Randy

On 9/21/2020 12:48 PM, John Haskell via groups.io wrote:
What George quoted from ham.stackexchange is correct.

To take it a bit further, SWR can be pretty much ignored.  If your solid state transmitter functions with normal output power versus shutting down, then SWR really does not matter much for most installations.  This is particularly true at HF where cable loss is minimal.  At UHF and with a long transmission line SWR can cause unacceptable losses.  

Here are a couple of examples of SWR versus loss using inexpensive RG-58.

Assume 7MHz and 75 feet of RG-58.  The cable loss is .9dB with a SWR of 1.

But what if the SWR is 2:1?  The extra loss due to this SWR is .2dB, e.g., negligible.


For a mobile set up on 442.1MHz..   Many people go nuts with low loss cables.  Not me. I use RG-58 in the car.  Here is why.  For 442MHz, 10feet of cable, and a 2:1 SWR, the additional loss due to the 2:1 SWR versus a perfect match is .2dB.  I do not believe you will notice that extra loss.


I have been considering putting a transmission line/SWR presentation together for TLARC in hopes of dispelling some of the common myths.  If there is interest let me know.  Maybe that will get me off my butt.

73, K1AT


IRS determination letter

David Andrews
 

Folks,

 

I am pleased to share with you the attached correspondence from the Internal Revenue Service officially designating TLARC as a 501(c)3 organization. This culminates the efforts of the past many months, including becoming a Tennessee Non-Profit Corporation, revising our organizing documents, and providing multiple submittals as part of the IRS exempt application.

 

Respectfully,

 

David Andrews N1ESK, Secretary


Re: Does a low SWR mean your antenna is a great performer?

John Haskell <jasm2213@...>
 

What George quoted from ham.stackexchange is correct.

To take it a bit further, SWR can be pretty much ignored.  If your solid state transmitter functions with normal output power versus shutting down, then SWR really does not matter much for most installations.  This is particularly true at HF where cable loss is minimal.  At UHF and with a long transmission line SWR can cause unacceptable losses.  

Here are a couple of examples of SWR versus loss using inexpensive RG-58.

Assume 7MHz and 75 feet of RG-58.  The cable loss is .9dB with a SWR of 1.

But what if the SWR is 2:1?  The extra loss due to this SWR is .2dB, e.g., negligible.


For a mobile set up on 442.1MHz..   Many people go nuts with low loss cables.  Not me. I use RG-58 in the car.  Here is why.  For 442MHz, 10feet of cable, and a 2:1 SWR, the additional loss due to the 2:1 SWR versus a perfect match is .2dB.  I do not believe you will notice that extra loss.


I have been considering putting a transmission line/SWR presentation together for TLARC in hopes of dispelling some of the common myths.  If there is interest let me know.  Maybe that will get me off my butt.

73, K1AT


Does a low SWR mean your antenna is a great performer?

George N2APB
 

FYI … I was recently in a roundtable on 75M and a perennial topic was discussed at some length ... "If my antenna has an SWR of 1:1 is it a great performer?"

 

The answer is simple ("not necessarily") but the reasoning is summarized well in the following post from the ham.stackexchange list.

 

I thought this would be of interest to all, but mostly for those on the HF bands where the science of homebrewing antennas is more often practiced.

 

72, George N2APB

 

======================================================

What is the relationship between SWR and receive performance?

 

If an antenna analyzer shows 1:1, does that mean it's an ideal receiver as well?

 

No.

 

Assuming we're talking about a characteristic impedance of 50 ohms, a 50 ohm resistor (otherwise known as a dummy load) will show a SWR of 1:1, although it will almost certainly perform very poorly as either a receive or transmit antenna.

 

The low SWR simply tells you that there are no impedance mismatches along the path from the transmitter (antenna analyzer in the case of your question) to the antenna feedpoint, at the current operating frequency.

 

And what about the converse, will a well performing receive antenna show a 1:1 SWR?

 

Yes and no.

 

Yes, a SWR of 1:1 means that you aren't losing signal to impedance mismatch reflections.

 

No, another issue is how efficient the antenna is at picking up the (desired) signal, preferably (especially in the case of directional antennas) while rejecting undesired signals as well. An antenna that is 5% of a full half-length dipole isn't going to pick up as much RF as the full-length dipole, let alone a full-sized directional antenna pointed in the proper direction, simply due to the much smaller physical (antenna aperture) size.

 

Generally speaking … if an antenna analyzer or (other) transmitter shows that the antenna output presents a SWR of 1:1, then what you have is probably about as good as it gets. That does not necessarily mean that what you have is a good antenna setup as exemplified by the extreme example of a dummy load.


Space Station pass @ 8:15 tonight!

George N2APB
 

David KF4DKW reports that there’s going to be a decent pass of the ISS tonight. The cross-band repeater is back on the air too. Maybe you can hear some traffic on the downlink:
Uplink Frequency: 145.990 MHz, PL 67.0 Hz
Downlink Frequency: 437.800 MHz

This time the ISS will start in the West and arc over to the NE ... all within 6 minutes!!

If you can’t get out to see it, just dial your UHF radio over to 437.800 and give a listen!

Either way, let us know what you find.

73, George N2APB


Lenoir City Street Festival

 

Come join in on the fun at the Annual Lenoir City Street Festival in beautiful downtown Lenoir City Saturday, October 10, 2020 from 10am until 2pm.

Classic/antique car show, live music, arts and crafts, vendors, children's play area and food vendors.
--
73,
Michael J. Foley, K4MJF
Tellico Lake Amateur Radio Club
Smoky Mountain Amateur Radio Club
470 ARG


Re: A Lot of Hams Near Me

 

No wonder I can't hear anything!! Hokie Smokes, Bullwinkle.......
--
73,
Michael J. Foley, K4MJF
Tellico Lake Amateur Radio Club
Smoky Mountain Amateur Radio Club
470 ARG


Brief Meeting Recap

George N2APB
 

If you missed the meeting on Wednesday, you sure missed a good one!  You can see a brief recap of the shenanigans on our TLARC home page ... https://www.tlarc.org/

 

73, George N2APB

TLARC ... https://www.tlarc.org/

 

PS:  Who was that person in the mask???

 

PPS:  Also note the latest Membership roster and the official Minutes from August.


Re: A Lot of Hams Near Me

Lou Devillon
 

WOW!


On Fri, Sep 18, 2020, 5:35 PM Juan Lopez <jloz34@...> wrote:
Plug in your callsign to see that hams that live nearby. No wonder I have so much QRM.

Sent from my Verizon, Samsung Galaxy smartphone
Get Outlook for Android

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