Transatlantic VHF/UHF DX

Discussion in 'Amateur Radio News' started by PY2ZX, Jan 12, 2009.

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  1. PY2ZX

    PY2ZX Ham Member QRZ Page

    Right now at least 3 expeditions are trying the Transatlantic QSO in higher bands such 2 meters and 70 centimeters between South America and Africa until January, 17; 2009.

    The idea begun with Dave N4BHC and ZS team of DXers setting one expedition to JG73NI to L├╝deritz Bay, Namib with callsign V5/KT6Q.

    Firstly devoted to EME, the African station is also prepared for monitoring and study the conditions of the long Tropospheric Duct that happens across South Atlantic.

    Several maps of Willian Hepburn daily show good previsions of propagation for that region like Europe - Africa and California - Hawaii well knew Tropo paths.

    From the American side the Japy DX Group is active with two expeditions from the hot spots HH18fd as ZY6Y in Bahia/Northeast Brazil and GG87xc as PT1A in Cabo Frio/Southeast Brazil.

    The last one is made under partnership between Japy DX and Rio DX.

    All stations are ready with directional yagis with horizontal polarization, PA and WSJT capability in 50 MHz, 144 MHz and 432 MHz, as well Internet connections for skeds.

    Many more stations are also checking the key frequencies. So despite the final results of these expeditions is expected that the number of the experiences could be higher for the next seasons.

    Updated and complete informations in English are on the following links:

    http://transatlantic.japydx.org

    http://tinyurl.com/v51-n7bhc

    Flavio PY2ZX
     
  2. AA1MN

    AA1MN Ham Member QRZ Page

    Why go through the financail, not to mention physical and problematic, expense of using amateur radio equipment to make a transatlantic contact when, for the price of a .42 cent stamp, a letter of correspondance would serve the same purpose with much less aggravation? Better yet, stop by the local library and send an email to anyone anywhere in the world for FREE!

    How is that some people just do things the hard way?

    Anyone overseas willing to prove just how easy it is to make a contact via email? If so, reply to this post and we'll exchange email addresses ...

    Chuck, AA1MN
     
  3. PA5COR

    PA5COR Ham Member QRZ Page

    Too easy...

    Why?
    Yes we can :D (try it) at least.
    I,m quite interested in their results actually.

    Cor
     
  4. G3XAP

    G3XAP Ham Member QRZ Page

    Why?

    Some of us are not content to do things the easy way. For me there is little or no satisfaction in "easy" QSOs. It took me 5 years to complete a 160 metre WAC using just 10 watts of CW. If you succeed in something really difficult, you'll never again ask "why" "!!!

    Phil, G3XAP
     
    KF4ZKU likes this.
  5. G7MZX

    G7MZX Ham Member QRZ Page

    Are you actually a radio amateur? I have never met one who doesn't understand why we do it!

    Any fool can sit at a computer with its physical links or satelite hook-ups and send an e-mail to anywhere. A little child can do that. I spent a very tough year studying hard to pass my RAE and I didn't do all that so that I could send an e-mail!

    The satisfaction of sitting in your home or car and talking to someone many miles away with absolutely no physical link between you whatsoever still holds the same fascination for me as it did when I did the RAE 18 years ago and on CB for many years before that.

    If you don't get it, perhaps you should reassess why you bother being a ham!

    Rob
    G7MZX
     
    KF4ZKU likes this.
  6. PY2ZX

    PY2ZX Ham Member QRZ Page

    Challenges on VHF

    Maybe that recent and very good article wrote by Mike Bosh via ZSVHF following that introduction could clarify why some DXers still facing new technical and geographical challenges, in my opinion one of the most exciting fields of amateur radio. Very sorry for this long posting but maybe it deserve our attention. PY2ZX

    --------------------------
    WHAT ARE THE REAL CHALLENGES ON VHF?

    By Mike Bosh ZS2FM via ZSVHF


    When new Radio Amateurs come on the air, they invariably start off with a 2 metre rig, a vertical antenna and establish two-way contacts via repeaters. After a while they arrive at the conclusion that this is all there is to VHF. They are unaware that there is another VHF world out there; they only had to start looking for it! Terrestrial repeaters of course, do have their uses such as mobile work and social chatting within the repeater range, but the degree of difficulty is zero!

    Satellites on the other hand are also repeaters, but they are in the sky or more correctly inner space. The challenge and the degree of difficulty are obviously a lot greater than terrestrial repeaters and therefore it is a good way to start more serious VHF work.

    But the real VHF world is vast and lies just beyond the radio horizon and will startle you once you get weaned from repeaters. It is highly technical and very challenging, just like Amateur Radio when it first started over 100 years ago which was based on experimentation, pioneering and research. The biggest challenge at the time was to extend the range on the various VHF bands and above. In the early days it was believed that the maximum range on VHF was limited to line of sight plus about 30 per cent. Ross Hull of the ARRL proved that the range on 5 metres (60 MHz) could be extended to 160 km and a few years later to several hundred kilometres. He accomplished this by building more sensitive receivers, more efficient VHF transmitters and added beam antennas for greater ERP, and in the process discovered Tropo propagation. Since then many new types of propagation have been discovered on VHF especially 50 MHz, and most of them were pioneered by Radio Amateurs. Beginners could start with simple equipment and gradually work up the scale as their know-how increases.

    Today the maximum terrestrial ranges achieved on VHF and UHF are as follows:

    50 MHz (6M) - 19921 km on F2 (ZL to EH)
    70 MHz (4M) - 4406 km on Es (SV2 to CU8)
    144 MHz (2M) - 7784 km on TEP (I4 to ZS3)
    432 MHz (70cm) - 4150 km on Tropo Ducting (KH6 to XE2)
    1296 MHz (13cm) - 4150 km on Tropo Ducting (KH6 to XE2)

    On microwaves the terrestrial record was set up on the 10 GHz (3cm) band and currently stands at 2079 km via Tropo Ducting (4X to I).

    The maximum range achieved so far on Tropo Ducting on 144 MHz is 4754 km (Hawaii to USA). The 144 MHz, 432 MHz and 1296 MHz records of 4150 km were established between the Hawaii and Mexico by the same two stations and on the same day.

    EME (Earth-Moon-Earth) was the most difficult and challenging mode on VHF and above for many years. It required low noise masthead amplifiers, high power and very high gain Yagi arrays. Initially moonbounce contacts were only made on 144 MHz and above on slow speed CW mode.

    With the advent of Digital Data communications the degree of difficulty on EME has been greatly reduced so that many more amateurs can now make EME contacts with modest equipment even on 50 MHz. The Joe Taylor Digital data modes can detect a signal well below the noise floor i.e. -20db to-30 dB; the efficiency of the digital modes cannot be questioned!

    The question now arises are there anymore challenges left for VHF Amateur Radio? The answer is yes there are lots of exciting and thrilling pioneering contacts to be made! For example, on VHF, UHF and Microwaves there are many records that can be conquered, all that is required is the improvement of equipment and perseverance. It will also call for the sharpening of your technical skills to upgrade your receiving and transmitting systems, the construction of high gain horizontally polarized Yagi arrays and the study of the vagaries of many different types of propagation on VHF and above.

    On the terrestrial level the greatest challenge and degree of difficulty currently exist during Tropo Ducting across the oceans: the Pacific Ocean (Hawaii to USA) - 4754 KM, the Atlantic Ocean (USA to Europe) (?) and the Indian Ocean (RSA to Reunion Island) - 2875 km. All the above records have been accomplished with analogue modes and could be broken. VK VHF amateurs believe that it should be possible to work the RSA via Tropo Ducting over the 8000 km sea path on 144 MHz. This could be the supreme terrestrial test for VHF amateurs and will require very efficient equipment and high ERP to accomplish such a feat, but digital modes would be a prerequisite. Who will be the first to set up this record?

    When the first settlers arrive on the Moon in the year 2020, then quite a bit of traffic could develop in space between them and us Earthlings. Communications could be accomplished on VHF with analogue modes because the path loss and therefore the degree of difficulty would be greatly reduced. Ordinary EME could completely disappear in time.

    NASA expects to make the first Martian landings around 2030. This could open up the most challenging SHF communication path for us and most certainly will have the highest degree of difficulty. This Earth/Martian space path will call for the most sensitive receivers on microwaves, possibly 10 GHz (3cm), Travelling wave tube (TWT) transmitters, dish antennas and only Digital Data and Voice modes would cover the distance of 56 million km to the planet Mars at perigee.

    I believe that Radio Amateurs of the future will meet the challenge. Amateur Radio is not just a little hobby as some uninformed may believe, but is a challenging and ever growing experimental field in radio science!

    73 Mike Bosch ZS2FM
    PORT ELIZABETH
    SOUTH AFRICA
    ---------------
     
  7. W8NSI

    W8NSI Ham Member QRZ Page

    Why Bother

    Why bother with ham radio when you can use one of the VOIP chat program (like EchoLink)... no radios or antennas to set up?

    No thanks, I'll keep my ham equipment, though I do use computers too.
     
    KF4ZKU likes this.
  8. AA1MN

    AA1MN Ham Member QRZ Page

    What do you mean too easy? Why make things more difficult than they need to be?

    Chuck, AA1MN
     
  9. AA1MN

    AA1MN Ham Member QRZ Page

    So do you still get your meals using a bow and arrow?

    Chuck, AA1MN
     
  10. AA1MN

    AA1MN Ham Member QRZ Page

    And any fool can waste their time and energy tackling things in the most difficult way possible because they don't have the common sense to do it any other way ... maybe you should reassess which one you are, G7MZX?

    Chuck, AA1MN
     
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