eHam.net News

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IARU Continues Preparations for WRC-19:

Posted: 13 Dec 2016 04:09 PM PST
http://www.eham.net/articles/38229


IARU's prime roles are to work in the areas of spectrum privileges (gaining
or retaining spectrum for the amateur radio services) and spectrum
protection (making sure that our spectrum remains available for use and
free from serious man-made interference). To do this we work in the
international standards bodies (CISPR, CENELEC and ETSI), the Regional
Telecommunications Organisations around the world (eg CEPT, CITEL, APT,
ATU) and of course ITU. The ITU is the United Nation's specialised agency
for telecommunications. Its Web Site contains a considerable amount of
material and documentation of interest to the amateur service. In the last
month, IARU representatives have attended the CEPT Electronic
Communications Committee (ECC) -- the policy-making body of CEPT, one of
the many CEPT committees at which IARU is present. IARU was also present at
ITU Working Parties under Study Group 5, whose remit is to study matters
relating to terrestrial radiocommunication services, which includes the
amateur service. WP5A is working to prepare for the World
Radiocommunication Conference in 2019 with a focus which includes the
Amateur Radio Services.


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Ham Radio -- A Wide Band Aerial for VHF or UHF Bands:

Posted: 13 Dec 2016 04:09 PM PST
http://www.eham.net/articles/38228


I was recently asked to help out a newly licensed radio ham with his VHF
and UHF aerial system, he was finding that a Disc-cone aerial which he had
been using for a number of years as a Short Wave listener was not doing a
good enough job of transmitting his VHF l and U.H.F. signal. Here is a
suggestion of how you can improve your Ham Radio aerials. The Disc-cone is
a well-known wide band aerial used by many people who enjoy scanning the
VHF and UHF part of the Radio Spectrum for commercial traffic and Ham radio
transmissions. The Disc-cone works well if you are nearby to radio masts
that repeat the broadcasts from commercial or Ham Radio bands but they vary
in their bandwidth and sometimes fail to give adequate matching at ham
allocations. I have seen Disc-cone S.W.R. (Standing Wave Ratio) readings at
5 to one on two metres or 144 Megahertz, this can severely impair both your
output signal and received signal. Most Ham radio Transceivers are designed
with 50 ohm output connections using SO-239 sockets, these allow easy
connection to coaxial cable used by many operators as their means of
feeding their transceiver power into an aerial. A 5 to one impedance match
at VHF is not desirable; it indicates the load you are transmitting into is
either 5 times 50 or 50 divided by 5. 250 or 10 ohms will not deliver all
of your power into your aerial and conversely it will not gather the
voltage required by your receiver for optimum efficiency. Radio
transmissions need to be correctly matched, maximum transfer of power only
happens when the feed line sees the correct load, in our example 50 ohms.
Here is a simple aerial, which can be built inexpensively from a length of
square wooden post. The aerial will transfer power correctly and at the
right load, I.E. 50 ohms. Using this aerial I have seen my signal meter
improve on two metre transmissions at 144 Megahertz and the rest of the
frequency bands it was designed for.


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Ham Talk Live #43 Comedy and Clubs:

Posted: 12 Dec 2016 04:00 PM PST
http://www.eham.net/articles/38227