Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1] 2 Next   Go Down
  Print  
Author Topic: Watch the band edges  (Read 11682 times)
K8AC
Member

Posts: 1472




Ignore
« on: March 25, 2012, 01:32:28 PM »

I was amazed this morning listening to VK7ZX sitting on 7.126010 running US stations at the rate of about 100 per hour.  Transmitting on that frequency on LSB results in radiating quite a bit of sideband power well below the 7.125 limit for US stations.  The transceiver frequency reads the carrier frequency and a bit more care needs to be exercised when operating LSB near a bottom band edge or USB near the top edge. 
Logged
KG4RUL
Member

Posts: 2722


WWW

Ignore
« Reply #1 on: March 26, 2012, 10:32:30 AM »

I don not know what they teach Hams in other countries but, the Technician Class exam has this question (hint, the first answer is correct):

T1B09: Why should you not set your transmit frequency to be exactly at the edge of an amateur band or sub-band?

All of these choices are correct

To allow for calibration error in the transmitter frequency display

So that modulation sidebands do not extend beyond the band edge

To allow for transmitter frequency drift
Logged
K8AC
Member

Posts: 1472




Ignore
« Reply #2 on: March 26, 2012, 01:18:13 PM »

But - you could miss that question and still pass the test!  And, just what is meant by "exactly at the edge..."?  A reasonable person could say that 7.126010 isn't exactly at the edge.  Just what the lower limit is in this case depends upon one's voice characteristics, how high you have the processor set, etc.  In some cases, 3 KHz might be too close, but in nearly all cases, just over 1 KHz assures that a significant portion of the sideband is outside the limit. 
Logged
K1ZJH
Member

Posts: 984




Ignore
« Reply #3 on: April 06, 2012, 01:57:51 PM »

  In some cases, 3 KHz might be too close, but in nearly all cases, just over 1 KHz assures that a significant portion of the sideband is outside the limit. 

Not for lower sideband on 40 or 75 meters on the low end of the band!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Logged
W9KDX
Member

Posts: 770




Ignore
« Reply #4 on: April 07, 2012, 11:54:47 AM »

I am grateful that the N. Cook Islands had the common sense to transmit on the absolute low end of 40 meters, but were listening 10 up.  Never would have made the contact otherwise.
Logged

Sam
W9KDX
K6OK
Member

Posts: 62




Ignore
« Reply #5 on: April 09, 2012, 11:47:57 AM »

Is this like petty theft vs. grand theft?  7.126 LSB is indeed poor practice because the sideband spills into the CW segment. Ultimately though it's hams interfering with other hams, so there's no damage to the real world. This is not as serious as operating at 14.349 USB because there the sideband spills outside of the amateur band and could interfere with other non-amateur services.
Logged
K8AC
Member

Posts: 1472




Ignore
« Reply #6 on: April 09, 2012, 12:13:15 PM »

Quote
Is this like petty theft vs. grand theft?  7.126 LSB is indeed poor practice because the sideband spills into the CW segment. Ultimately though it's hams interfering with other hams, so there's no damage to the real world. This is not as serious as operating at 14.349 USB because there the sideband spills outside of the amateur band and could interfere with other non-amateur services.

Smells like a troll, but deserves a response.  Both petty theft and grand theft are crimes.  The only difference is the dollar value involved.  Operating LSB on 7.126 is not just poor practice - it's a violation of the rules we operate under.  It's not up to us to judge which rules we choose to follow, nor decide which violations might cause the greatest problems.  It's a good idea for everyone to follow the rules as they're laid out.  I'll wager that every one of those who responded on 7.126 did so out of ignorance, not because he thought he could get away with a petty violation.  My post was an attempt to elighten some who either were not aware of the fact that 7.125 is the lower band edge for SSB operation in the USA, or that their LSB extends far below the carrier frequecy their display reads. 
Logged
K6OK
Member

Posts: 62




Ignore
« Reply #7 on: April 10, 2012, 11:50:25 AM »

Smells like a troll, but deserves a response.  Both petty theft and grand theft are crimes.

I don't think I smell like a troll -- I do use deodorant every day  Cheesy  I was serious in my comments. You're right, both 7.126 LSB and 14.349 USB are rules violations and both are wrong. I was just pointing out, for discussion purposes, that the consequences of one is more serious than the other.
Logged
KC9TNH
Member

Posts: 304




Ignore
« Reply #8 on: April 11, 2012, 04:16:42 AM »

My post was an attempt to elighten some who either were not aware of the fact that 7.125 is the lower band edge for SSB operation in the USA, or that their LSB extends far below the carrier frequecy their display reads. 
Your post was appreciated. From what you describe there wasn't spillage; the station was flat-out in the wrong area according to his/her own band plan as well. Doesn't usually affect all but up in "da Nortland" it can be a bit irritating to get one's CW QSO stomped on by a SSB ragchew in the wheelhouse of what seems to be a well-known CW area in the US band plan (7050 etc) but perfectly in line with the RAC plan for voice. Your example seems to be outright ignorance by the station, the CW/SSB conflict thing is a problem at a higher level. When that happened recently I did a couple minutes research fortunately before keying up & learned something as a result.

Your post was a good reminder for all, thanks.
Logged

73
Wes -KC9TNH
"Don't get treed by a chihuahua." - Pete
K0SPN
Member

Posts: 12




Ignore
« Reply #9 on: April 25, 2012, 11:25:54 PM »

American amateurs are responsible for operating within their legal privileges just like the VK station was responsible for operating within their own privileges.
Was it the best place for the VK to choose to try operating Americans?  Obviously not, but they have no responsibility to police Americans and make sure said Americans are obeying their own rules.

I don't know the VK rules and allocations, so I can't comment on the legality of the operations on that particular frequency.
Logged
VK4NEF
Member

Posts: 9




Ignore
« Reply #10 on: September 17, 2012, 03:34:48 AM »

I don't know the VK rules and allocations, so I can't comment on the legality of the operations on that particular frequency.

I know its a bit late, here is the Australian (VK) Band Plan for 40 Metre.
40 Metre Band – All licence classes
7.000 - 7.300 CW
7.030 - 7.040 Digital data modes (Note 2)
7.040 - 7.300 SSB
7.075 WICEN frequency
7.110 IARU Region III emergency centre frequency
7.130 - 7.150 WIA news transmissions
Note 2: Modes
"Digital Data Modes" includes all modes such as RTTY, packet and Amtor, using FSK or PSK and with
bandwidths up to 2 kHz. The SSB segment can also be used for digital voice modes and image transmission
modes such as SSTV or Fax, using bandwidths up to 4 kHz, or for AM.

For a pdf of Australian Bandplans, go to this link:http://www.wia.org.au/members/bandplans/about/ then click on Bandplan Data (left hand side).

Myself when trying to work stateside from VK I try to be around 7.170 MHz or higher.

Now 80 Metre DX Window is a different kettle of fish in VK
3.776 - 3.800 DX Window SSB and CW.
NOTE: DX WINDOW
Emissions must not extend below 3776 kHz. Therefore when using LSB, the suppressed carrier frequency
should be no lower than 3779 kHz.

Also the Oceania DX Contest is being held on these dates,

PH - The first full weekend in October each year from 0800 UTC Saturday to 0800 UTC Sunday

CW - The second full weekend in October each year from 0800 UTC Saturday to 0800 UTC Sunday

Log deadline for PH and CW logs - 28 days after the end of the CW contest.
For more info go to the web page: http://www.oceaniadxcontest.com/

Regards
Eric
Logged
ZENKI
Member

Posts: 935




Ignore
« Reply #11 on: September 18, 2012, 02:10:12 AM »

Hopefully you dont have the ESSB idiots in VK. Its so ridiculous hearing  6khz wide ESSB idiots with  bassy audio trying to work DX with their selfish bandwidth practices. The DX window is so narrow and is expressly a DX window. Why these ESSB stations want to take out the DX window with excessive IMD/splatter and excessive occupied bandwidth is beyond belief.  If some of these ESSB stations operated in VK they could not really operate anywhere in the VK DX window because their signals are so wide.

I always use 1.5 X TX Audio bandwidth to be safe  that  allows for any IMD splash, you can never get into trouble doing this.  I use 2.4khz wide audio at all times  and my signal has very low IMD.

""
Now 80 Metre DX Window is a different kettle of fish in VK
3.776 - 3.800 DX Window SSB and CW.
NOTE: DX WINDOW
Emissions must not extend below 3776 kHz. Therefore when using LSB, the suppressed carrier frequency
should be no lower than 3779 kHz.

Also the Oceania DX Contest is being held on these dates,

PH - The first full weekend in October each year from 0800 UTC Saturday to 0800 UTC Sunday

CW - The second full weekend in October each year from 0800 UTC Saturday to 0800 UTC Sunday

Log deadline for PH and CW logs - 28 days after the end of the CW contest.
For more info go to the web page: http://www.oceaniadxcontest.com/

Regards
Eric

[/quote]
Logged
W8JI
Member

Posts: 9296


WWW

Ignore
« Reply #12 on: October 05, 2012, 08:09:02 AM »

K8AC's post was accurate and perfectly correct. The USA stations were transmitting out of the band. 

I'm sometimes amazed at how people no longer respect the band edge, or perhaps are so stupid they do not know what the band edge is.

The law is we cannot have modulation products extend out of the authorized band or segment available to the operator. Even for the Extra class of license in the USA, this means NOTHING can appear below 7.125 MHz. Zero detectable emissions from phone can extend below 7.125.

This means, for exceptionally clean LSB transmitters with a highest modulating audio frequency of 3 kHz, the suppressed carrier frequency would have to be above 7.128. In reality, with a good antenna and/or higher power, even 7.130 is pushing it for most rigs. Rigs just aren't that clean and, with a strong signal, it is easy to have products above background noise.

Years ago I used to listen to some people in the eastern USA meeting every day on 7.200 kHz LSB when the phone band used to only go to 7.200.  One day they stopped showing up, and I found them up on 7.205 complaining that they all received FCC "show cause" notices.

Too bad the FCC doesn't still do this.

73 Tom
Logged
KB5ZSM
Member

Posts: 70




Ignore
« Reply #13 on: November 14, 2012, 11:47:08 PM »

I can see one other cause for the out of band problem. Excitement!!! Even I was guilty of it once (not being out of band, BUT!). When I was a new general class I heard a DX station with a pile-up on 14,215. I got excited and didn't even think about it till after the fact and I did make contact on the second call but I was out of my band privilege's. As I said, it never occurred to me till it was all done and over with. I felt bad (but good for the DX contact). Since then it has been something I pay better attention too. Just got caught-up in the action and didn't think!
Logged
WS4E
Member

Posts: 223




Ignore
« Reply #14 on: November 15, 2012, 12:46:44 PM »

YOU KNOW... in this day and age with all the CPU POWER in the modern rigs, it would not be anything for them to put in automatic band edges that account for what mode your in...  I mean REALLY how hard would it be to have a little more intelligence for the radio to know that "OK, the absolute edge is 14350, if the radio is in USB mode, then don't allow transmit above 14347 instead".

I mean its a simple bit of automatic MATH for the radio to do.

Right now they just are dump and do simple rules of no xmit above 14350 etc..
Logged
Pages: [1] 2 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!