Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Shortwave (HF) broadcasters and SSB

  • 02-04-2011 11:17pm
    #1
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭


    Years ago I seem to remember reading about some WARC decision that all Shortwave broadcasting was to revert to SSB by 2015.

    Is this still the case and if so do they plan on keeping the 5KHz channel spacing (Always thought 5 was a bit narrow for AM but 4 or even 3 should be sufficient for SSB) ? Does it include the "tropical" bands ? Is "Compatible" or reduced carrier operation going to be allowed or will it be suppressed carrier only (cant see that working for music)

    The bands seem to be a lot emptier now than when I was a regular listener back in the 1980's ?


Comments

  • #2
    watty
    Registered Users, Registered Users 2 Posts: 32,417 ✭✭✭✭watty


    "Revert"?

    Most Broadcasting has always been AM, only marine, Aeronautical and Amateur has been SSB.

    DRM is supposed to be be the future of LF/MF/HF?

    Or do you mean Amateur? There is only AM on a couple of locations (Boat Anchor enthusiasts) and "All" can't be right. What about DRM, PSK31, SSTV, Oliva, RTTY, CW?

    2.5kHz is "possible" for SSB. 3kHz is possible.
    5kHz is possible for AM. 9kHz is nicer.
    Basically as you probably know, AM needs exactly twice the RF bandwidth for the same max Audio frequency as SSB and in addtion SSB saves a further 300Hz to 700Hz at the carrier frequency.

    My Sony ICF2001D and my Yaesu VR500 both have regular (9kHz?) and narrow AM IF settings. Certainly the "narrow" setting sounds very narrow.

    405 Line TV used about 20kHz wide AM for sound carrier (10KHz audio bandwidth) I think...


    A lot of services gone to FM, Satellite or completely gone. BBC World closing a lot.


  • #3
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    Yes I meant broadcasting (as in BBC World service, VOA , Radio Moscow/Voice of Russia etc)

    DRM is a possible alternative but for analouge broadcasting SSB was mooted as a way to deal with the heavy overcrowding that existed on shortwave back in the 1980's

    although from recent observations that doesnt really seem to be much of a problem anymore ?


  • #4
    watty
    Registered Users, Registered Users 2 Posts: 32,417 ✭✭✭✭watty


    Indeed.

    SSB isn't going to ever happen now for ordinary Broadcasting. I was about 10 when I developed an interest in Radio & Electronics. I swapped a transistor radio I got on my 11th birthday for a R1155 set to listen to shortwave.

    http://www.vq5x79.f2s.com/greenradio/Wireless21a.html

    It was also the era of Radio Luxembourg 208, Caroline, Nord See, start of BBC2 and Cold War.

    Today's equivalent is a Motorised Satellite dish (have one) instead of the WWII receiver and washing line and tinkering with web 2.0, irc and skype (got hosted servers and my own websites etc).

    Nothing stays the same. After about 75 years we are now seeing the end of Analogue TV in UK (Modern Electronic Raster TV started 1936, proposed 1905).

    I think FM Radio for Broadcast and Mobile/Marine will survive Analogue to Digital transition era, but AM Broadcast will not. I wonder how long AM for 110 ... 137MHz Aircraft will last?


  • #5
    watty
    Registered Users, Registered Users 2 Posts: 32,417 ✭✭✭✭watty


    Co-incidently today
    http://www.reghardware.com/2011/04/04/marconi_type_702_under_the_hammer/


  • #6
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    watty wrote: »
    Co-incidently today
    http://www.reghardware.com/2011/04/04/marconi_type_702_under_the_hammer/

    Did you spot the journalistic/historical gaffe in that article ?
    Unfortunately for Davis, Crystal Palace burned down 3 days after he bought it, meaning he couldn't receive signal until after the war - a wait of ten years.

    The Crystal Palace fire had nothing to do with the suspension of TV broadcasting as It wasnt used for TV until the 1950's

    Personally I can see AM (for broadcasting) outliving FM but both still have a long future (despite what some in the UK government might wish)
    watty wrote: »
    I wonder how long AM for 110 ... 137MHz Aircraft will last?

    I can see that lasting quite a long time as well.


  • Advertisement
  • #7
    watty
    Registered Users, Registered Users 2 Posts: 32,417 ✭✭✭✭watty


    Alexandra Palace I think was where the transmissions came from?

    I thought that was an odd comment as 405 TV was I think only closed at Sept 1939 and may have been most of the time the only 405 TX before WWII?

    ITV started in 1954 or 1955?
    Crystal Palace TX maybe 1956



    Yes, AM and FM don't even have a sell by date.

    DRM might oust AM, but adoption of DRM is very very slow. So I'd not place any bets.


  • #8
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    watty wrote: »
    but adoption of DRM is very very slow. So I'd not place any bets.

    TBH DRM is going to face an uphill battle for acceptance as the non-technical public (who have even heard of it) are likely to confuse it with DAB.

    The fact that it shares an acronym with an often pretty controversial (albeit unrelated) piece of technology cant help either.


Advertisement