Views on the Blogg over the last month and the most popular recent articles.
Sunday, October 31, 2010
Possible RAYNET activity
Global Simulated Emergency Test (GlobalSET)
This amateur radio emergency communications exercise is held twice a year, the next GlobalSET is on Saturday the 13th of November.
This amateur radio emergency communications exercise is held twice a year, the next GlobalSET is on Saturday the 13th of November.
The main change this time is that it will run 1100 to 1500 hours local time, of the stations taking part.
The operation will take place on and near the emergency Centre-of-Activity (CoA) frequencies on 80, 40, 20, 17 and 15 metres.
The objectives of GlobalSET are to:
Increase the common interest in emergency communications.
Test how usable the emergency Centre-of-Activity frequencies are across the three ITU regions.
Create practices for international emergency communication and Practice the relaying of messages using all modes.
IARU member radio societies, and emergency communications group stations intending to participate are requested to register through their IARU Regional or National Emergency Communications Coordinators.
Jim Linton VK3PC
Chairman,
IARU Disaster Communications Committee
If local RAYNET members would like to participate in this event please let gdonfn@manxbroadband.com know!
Thursday, October 14, 2010
RSGB increase membership cost!
Taking the headline from a recent government
announcement, “We have all got to share the
load”, the Society has had to make the difficult
decision to raise subscription rates by £3
across all grades from 1 January 2011.
We are greatly aware of the financial
pressures that we are all under during
these recessionary times, however, for
the RSGB to maintain the services that it
provides to its members at the same level
this rise is very necessary. Over the past
few years the RSGB been increasingly
more active in representing the interests
of radio amateurs, be it with Ofcom or the
UK government but also at European and
World level. This has been necessary to
ensure the maintenance of the spectrum
allocation we enjoy, the protection of our
spectrum plus negotiations to get more
spectrum. Recent successes at 7MHz, the
introduction of Special Contest callsigns,
the continuing allocation at 5MHz lay
testimony to this. You will have read in
the pages of RadCom of our fight against
the interference caused by the introduction
PLA/PLT devices, all of this work bites into
our income. The production of RadCom,
recognised as the best Amateur Radio
magazine in the world does not come cheap
and is a key part of the membership provision.
RadCom provides the very best articles and
news, over ninety pages every month and,
despite increasing costs, it is the Society’s
intention to continue to improve RadCom
at every opportunity. Alongside of this you
continue to enjoy the best advice available
should you encounter any problems in the
pursuit of your amateur radio hobby, and
you have free use of the QSL Bureau. The
RSGB also runs many contests and the IOTA
Awards programme for you to participate in
and enjoy. To help you locally you have your
RSGB Regional teams, this is very much
your national society local to you.
For the large majority of RSGB members,
membership currently costs approximately
12p per day for Direct Debit payers and
13p a day for those continuing to pay by
Standing Order or Cheque. The increase
in the subscription fee represents adding
another 1p per day to those figures. RSGB
membership, I think you will agree, continues
to represent extremely good value for money.
There are a number of ways that can make
payment easier. You can pay one sum up
front annually if you wish or you can spread
the payments, quarterly or monthly.
The Society appreciates greatly your
support and we hope that even it these
most difficult of times you will continue
to support the RSGB in its work on behalf
of its membership and the wider amateur
radio community.
Peter Kirby, G0TWW
General Manager
announcement, “We have all got to share the
load”, the Society has had to make the difficult
decision to raise subscription rates by £3
across all grades from 1 January 2011.
We are greatly aware of the financial
pressures that we are all under during
these recessionary times, however, for
the RSGB to maintain the services that it
provides to its members at the same level
this rise is very necessary. Over the past
few years the RSGB been increasingly
more active in representing the interests
of radio amateurs, be it with Ofcom or the
UK government but also at European and
World level. This has been necessary to
ensure the maintenance of the spectrum
allocation we enjoy, the protection of our
spectrum plus negotiations to get more
spectrum. Recent successes at 7MHz, the
introduction of Special Contest callsigns,
the continuing allocation at 5MHz lay
testimony to this. You will have read in
the pages of RadCom of our fight against
the interference caused by the introduction
PLA/PLT devices, all of this work bites into
our income. The production of RadCom,
recognised as the best Amateur Radio
magazine in the world does not come cheap
and is a key part of the membership provision.
RadCom provides the very best articles and
news, over ninety pages every month and,
despite increasing costs, it is the Society’s
intention to continue to improve RadCom
at every opportunity. Alongside of this you
continue to enjoy the best advice available
should you encounter any problems in the
pursuit of your amateur radio hobby, and
you have free use of the QSL Bureau. The
RSGB also runs many contests and the IOTA
Awards programme for you to participate in
and enjoy. To help you locally you have your
RSGB Regional teams, this is very much
your national society local to you.
For the large majority of RSGB members,
membership currently costs approximately
12p per day for Direct Debit payers and
13p a day for those continuing to pay by
Standing Order or Cheque. The increase
in the subscription fee represents adding
another 1p per day to those figures. RSGB
membership, I think you will agree, continues
to represent extremely good value for money.
There are a number of ways that can make
payment easier. You can pay one sum up
front annually if you wish or you can spread
the payments, quarterly or monthly.
The Society appreciates greatly your
support and we hope that even it these
most difficult of times you will continue
to support the RSGB in its work on behalf
of its membership and the wider amateur
radio community.
Peter Kirby, G0TWW
General Manager
Monday, September 20, 2010
Foundation and Intermediate Examination
Congratulations to all those who passed the examinations this weekend.
Friday, August 27, 2010
SWR and Max power out?
Bil Paul, KD6JUI, of Dixon, California, wrote to the ARRL's Doctor, noting that he noticed when he was tuning for optimal background noise while in receive mode, it came close to -- but didn't match -- the dial positions for minimal SWR while transmitting. He asked which of the two antenna tuner dial settings would result in the most transmitted energy while in transmit mode. He also wants to know if minimal SWR always indicates the most transmitted energy going to the antenna system.
Here's what the Doctor had to say:
In answer to the first question, by setting the antenna tuner to an SWR of 1:1, you have transformed the impedance at the bottom of your antenna feed line to 50 ohms, just what your transceiver is designed to deliver its rated power into. If your receiver input impedance were exactly 50 ohms, then that setting would likely also be the position that would yield maximum receiver noise. As it happens, there is no such guarantee that the input impedance of the receiver will be exactly 50 ohms. Although it should be pretty close, a slight change may yield a stronger signal into the receiver
Regarding the second question, the transceiver is rated to provide its design output power into 50 ohms, usually within a specified SWR range. As was pointed out by Eric Nichols, KL7AJ, in a QST article last year ["Keeping Current with Antenna Performance," Feb 2009, pages 34-36], an SWR of 1:1 does not generally result in the maximum power output. By building a transmission line current meter, such as described by Eric, or later by Paul Danzer, N1II ["A Simple Transformer to Measure Your Antenna Current," Sep 2009, page 35], you can actually tune the antenna tuner to get the highest output. This corresponds to the maximum current into the antenna, which may occur at some setting different from either of the above.
Be careful, though: If you exceed the maximum rated SWR, the resulting voltages or currents in the final amplifier or output filter of the transceiver will exceed design specs and damage may result. The likely small increase in transmitted power is likely neither worth the trouble nor the risk, in my opinion.
Here's what the Doctor had to say:
In answer to the first question, by setting the antenna tuner to an SWR of 1:1, you have transformed the impedance at the bottom of your antenna feed line to 50 ohms, just what your transceiver is designed to deliver its rated power into. If your receiver input impedance were exactly 50 ohms, then that setting would likely also be the position that would yield maximum receiver noise. As it happens, there is no such guarantee that the input impedance of the receiver will be exactly 50 ohms. Although it should be pretty close, a slight change may yield a stronger signal into the receiver
Regarding the second question, the transceiver is rated to provide its design output power into 50 ohms, usually within a specified SWR range. As was pointed out by Eric Nichols, KL7AJ, in a QST article last year ["Keeping Current with Antenna Performance," Feb 2009, pages 34-36], an SWR of 1:1 does not generally result in the maximum power output. By building a transmission line current meter, such as described by Eric, or later by Paul Danzer, N1II ["A Simple Transformer to Measure Your Antenna Current," Sep 2009, page 35], you can actually tune the antenna tuner to get the highest output. This corresponds to the maximum current into the antenna, which may occur at some setting different from either of the above.
Be careful, though: If you exceed the maximum rated SWR, the resulting voltages or currents in the final amplifier or output filter of the transceiver will exceed design specs and damage may result. The likely small increase in transmitted power is likely neither worth the trouble nor the risk, in my opinion.
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