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Transcript of Elements 201203
Cockenzie
& Port Seton Amateur Radio Club Elements
Cockenzie & Port Seton
Amateur Radio Club is
affiliated to the Radio
Society of Great Britain
and holds the call signs
MM0CPS and GM2T which
are used for our special
event and contest entries.
The Club was formed by
Bob Glasgow GM4UYZ in
1984 to help the local
amateurs get to know each
other.
Far from being just a local
club we have members
regularly attending from
the Borders, Dumfries,
Strathclyde, Fife and
Newcastle.
The Club meets on the first
Friday of every month
(Second Friday of January)
in the lounge of the
Thorntree Inn on the old
Cockenzie High Street from
7pm till late.
Editorial Onto another month and another editorial, already this is the third one for this year, my how time flies by!!!! One thing is noticeable and that the evenings are now beginning to “stretch out” and aiming away from what I call the winter doldrums. Thank goodness for that say’s I. In some respects I like the dark nights where one can get nice and cosy sitting watching the television but if I am perfectly honest I do prefer the light nights as it allows one to get out and about instead of vegetating in front of the “box”.
First of all this month I would like to pass on our deepest sympathies to Alex GM3GKJ and his wife Cecelia who sadly lost their daughter Leanne and to Cambell MM0DXC who has lost a dear cousin. It is a difficult time for all of those concerned trying to come to terms with their grief so all we can do is be there for them and offer our sympathies.
Ok then what have we been up to this month; first of all we will have had our annual radio check night run by John MM0JXI. It is a great event to put your radios through their paces so hopefully many turned up to take part.
Tomorrow, 3rd March, I start the last training session of the winter period by running an Intermediate Course with their exam being on the 31st March so it goes without saying that we wish them well with the course and the exam. My Foundation Course candidates will have sat their exam and hopefully everyone will have passed.
I will be setting out the future dates for the winter training period (2012-2013) hopefully
starting in September. I will announce these via a general email and via the cpsarc.com although if you know of anyone who may be interested get them to contact me direct. Our next event in March is a talk by Len Pagent GM0ONX on “Planning Permission”. This will be held in the Port Seton Community Centre Resources Room 1 on the 16th March between 19:30 and 21:30. This was the talk that was originally planned for November 2011 but Len had to cancel at the very last minute. I do hope many of you will make the effort to come along.
To the future for the 10 Pin Bowling in April (Saturday 21st April @20:00 Ten-Pin at Fountainbridge) I may not run it as at the moment I have little time to get it organised but don’t worry I have something else up my sleeve in its place which will be very interesting indeed for all ages but at present I am awaiting some confirmation before I announce it.
Lastly, if I have any thing to say this month it is the old hobby horse of looking for newsletter input. Thanks to those who have been contributing but we need more. Lots of people indicate that they will but never do. I do struggle from month to month to write articles and I really genuinely could do with some help so this is a plea from the heart for articles. It would be fantastic to have a good pool of articles that John can select from.
Right I think that is about it so enjoy club night and the newsletter.
Bob GM4UYZ
In this issue 2011 IOTA Contest P.2
WX Satellite Experience P.3
A Cheap Way in to HF? P.6
Clublog Tables P.7
Stubby Antennas! P.8
Test Your Knowledge P.9
Event Calendar P.10
V o l u m e 2 0
Ma rch
2 0 12
03
2
2011 IOTA Contest how we faired The provisional results are now in for the contest and we were
placed 6th:
Below was what we submitted but as it says it does not in-
clude duplicate QSO’s
Scores after checking….
BAND SSB/IOTA CW/IOTA POINTS AVG
----------------------------------------
80 228 46 152 29 2829 7.44
40 273 62 158 35 3513 8.15
20 667 92 409 50 5889 5.47
15 331 68 130 33 2919 6.33
10 148 15 16 13 981 5.98
----------------------------------------
TOTAL 1647 283 865 160 16131 6.42
========================================
TOTAL SCORE : 7 146 033
Dupes are not included in QSO counts neither avg calculations
So what is obvious is that we lost points along the way after
adjudication, so where did we lose them? What is produced
by the adjudicators is a file called a UBN file. This file is there
to help you see where you went wrong and give guidance in
what areas that need improvement.
UBN stands for –
U = Unique
The number of unique call signs that are in your log that were
not worked by any other contest entrant
B = Broken
Entries in the log which when compared with the other station
contacted do not compare i.e. serial numbers, IOTA Reference
missing, etc, etc
N = Not in Log
Our Callsign does not appear in the other stations log.
Output from the UBN Report
Total QSO’s submitted (including 25 dupes): 2520
The robot/human team has adjudicated 1722 QSO’s
(68%)
QSOs in non-recommended frequency sections (i.e. 3560 -
3600, 3650 - 3700, 14060 - 14125 and 14300 - 14350 kHz):see
Rule 3 (You have NOT lost any credit for these QSOs). = 2 **
two OOPS!!! We must be more careful **
UNIQUES: Your log contains 78(3.0%) unique. (You have NOT
lost any credit for these QSO’s).
You have lost 19 multiplier credit(s) and 59 QSOs credit(s) as
follows:
(Not so good this year as an increase of from 2010 were we
lost 8 Multipliers and 59 QSO credits. Multipliers are “King” so
loosing 19 multipliers means a huge drop in score)
BAD CALL SIGN 24
BAD SERIAL NUMBER 20
BAD IOTA REFERENCE 2
BAD COPY OF EXCHANGE 2
NOT IN LOG 11
Out of the 52 QSO’s they were
CW 29
PHONE 23
The worst areas as you can see are the BAD CALL SIGN & BAD
SERIAL NUMBER and this is mostly down to recording the con-
tact, otherwise our bad typing. On the CW side it was putting
the wrong number in, like entering a 7 instead of an 8. At
30WPM plus it is easy to do believe you me.... To be honest I
think it is nigh on impossible to have no errors at all so our
aim is to have as little or none at all. I really must congratulate
the whole team on the standard of the logging to achieve
what we did.
How the Score is worked Out…
Summary of score using the following formula:
((non-IOTA QSOs+ QSOs with same IOTA)x3 + QSOs with other
IOTA x15) x mults)= Final score
Score before adjudication from 2509 valid QSOs is:
( (1792+8) x 3 + 709 x 15) x 4442 = 7087470 points
Score after adjudication from 2450 valid QSOs:
[FINAL SCORE] is: ( (1762+8) x 3 + 680 x 15) x 423 = 6560730
points (-7.43%)
From the above we actually lost 7.43% of our score which is
nearly double of our 2010 score which was 3.92% of our
score. At least from the UBN file it identifies weak areas and
from this in future contests they can worked on to make sure
they are alleviated. We are looking for the ideal of no errors.
Bob GM4UYZ
6 EU008 Tiree IOTA DXPN MS MIX 24H HP
2450 423 6560730
WX Satellite Experience
One of the many things that I wanted to do was receive weather satellite pictures, basically my interest to do this stems back many years as I have always been interested in watching the weather forecasts on the television particularly when they display the weather charts and more so now where they show the cloud cover from the satellites. I decided that the best way forward to do this was as a project for the winter months, so I took the plunge whilst at the Leicester rally back in 2002 and joined RIG (Remote Imaging Group) and bought their RX2 WXSAT Receiver. Like many kits not all the parts are available so again from the above rally I purchased a good box to fit the receiver into plus I raided my junk box for other bits and pieces i.e. signal strength meter from an old scrap CB, PL259 Chassis socket and switches and sockets.
The RX2 kit receives signals from the National Oceanographic and Atmospheric Administration (NOAA) of the United States of America satellites. NOAA supports several Weather Satellites in Low Earth Orbit. Currently these are NOAA-15, NOAA-18 and NOAA-19, NOAA-17 is no longer in use.
All three satellites broadcast using a system termed Automatic Picture Transmission (APT) in which they scan the Earth, 840 kilometres beneath them, continuously. This results in images that build up line by line, rather like the image on a TV screen. However, a complete APT image takes 12 to 14 minutes to build up at a rate of two lines per second. These transmissions are received on frequencies in the 137MHz band.
A typical NOAA satellite APT images consist of two frames, side by side as shown in the pictures taken from a the 3rd February 2012 from the NOAA-19 12:31 pm pass . The left-hand image was acquired in visible wavelengths; that to the right was imaged in infrared. These images are transmitted as greyscale images (i.e. no colour). With the exception of the winter months, when solar illumination is relatively weak, software can be used to combine these two monochrome images into a colour composite like the one shown.
Below is how I went about building the receiver:
My first task was to build the kit and by following the comprehensive instructions I managed it with quite an ease, but there again over the years I have built numerous bits and pieces, repaired lots of kit so soldering is not a problem.
The next task was fitting it into the box that I had chosen. My mechanical skills are not the best I may add particularly trying to deal with rectangular holes but I managed it in the end. Both the front and rear of the box was given two coats of white enamelled paint. I then used Dymo Letra Tag for all my labelling before giving both the front and back covers a final coat of varnish. I must admit for my standards I was pleased by the outcome. See the pictures later on.
The next task was to fit the PCB and all the connectors then cable it all up. Attached the power lead and switched on, phew! No puffs of smoke! I then followed the instructions for setting up the receiver but could not understand why I wasn’t hearing anything out of the loud speaker yet I knew audio was being sent to the volume control. This turned out to be bad connection on one of the pins
(Continued on page 4)
2
Our club has been added
to the excellent Clublog
system developed by
Michael Wells G7VJR.
www.clublog.org
The system allows
members to upload their
logs in ADIF format and
have them displayed in a
table with all the other
club members.
Clublog also has great
facilities for tracking your
DXCC status etc so is well
worth taking the time to
register and get your log
uploaded.
To update your log with
the next set of contacts
(SSB, CW or Data) you can
simply upload your whole
log again and the system
will take care of the
duplicates. Alternatively
you can export the bits
you want from your own
log and just upload that.
The tables we’ll publish
here will be the club,
filtered by the current
year, so everyone starts a
new year at 0 contacts.
Club Attire
The club has a design for
Club Tee-shirts, Polo-
shirts, Sweat-Shirts, Fleec-
es and Jackets and all of
these can be obtained
from the address below.
When making an order
please quote ‘Cockenzie &
Port Seton Amateur Radio
Club’ as this will ensure
that the Club Logo will be
placed on the required
ordered garments.
If you wish to add your call
-sign to the logo then
please ask at the time of
the order.
Cost will depend on gar-
ment and should cover the
garment and logo, call-sign
addition will be extra.
Order from:
PATRICIA BEWSEY DESIGNS,
UNIT 11,
FENTON BARNS RETAIL
VILLAGE,
FENTON BARNS,
NORTH BERWICK,
EAST LOTHIAN
EH39 5BW
Tel/Fax: 01620 850788
Mobile: 07970 920431
4
on the 10-way connector. At last everything was ready to go live. I must say at this stage setting up the receiver was made easier for myself as I have a Marconi Signal Generator and other tools to make the job all that bit easier.
The first aerial, as you will see in the picture was just a rough made up dipole pinned to my shack roof so I was certainly not looking for to receive great pictures. I have done it this way basically as a test to see that it all works before I build a decent aerial.
The software program that I decided to use back then was the “Demo” version of JVCOMM32. My success rate of actually receiving a picture was absolutely dismal but then I received my first decent picture, it was still not tremendous and I couldn’t make out where it is but I could see cloud!!!!!!!
Even at that poor quality I was thrilled to bits to see that I had at least captured something from the kit that I built. The whole project although it took a few months to get to that stage overall it gave me great enjoyment.
My next aerial and the one I am still using today:
I built the proper aerial obtaining the information from the following web site:
http://www.david-taylor.pwp.blueyonder.co.uk/wxsat/equipment.htm
The antenna is a QFH – Quadrifiliar Helix originally designed by Bill Sykes G2HCG and Bob Coley G0HPO made out of 8mm Copper pipe (micro bore).
The pipe was off an old aerial for 70cms, which had been left after a junk night. I bought the 8mm copper pipe from B&Q as they did a 10M length and the 8 x 90° angle bends (I went for the compression type a lot cheaper) from a plumber’s merchant. The picture above shows the final outcome with the aerial in place.
The next task was to see how it would
(Continued from page 3)
(Continued on page 5)
4
perform. The answer is I have been really impressed. The picture below, which I received from the NOAA-12 Satellite going overhead on the 18th February 2003 at 10:18 is still one the best I have ever received. As you can see the UK really stands out...
As you will see that picture has the word “DEMO” all over it and that is because I was using the Demo Version of JVCOMM32. I am not sure if it is the best program or not but at least it let me “find my feet” as they say.
Today I use the WXtoIMG program which I have done for a long time now. It is far superior and it allows colour pictures to be created from the received images. The following are pictures that I received on the 3rd February 2012 from the NOAA-19 12:31 pm pass.
I hope you have enjoyed my adventure into receiving weather satellite pictures from a receiver on the 137MHz bands. There are far better ways of getting clearer and better pictures by using a Satellite Dish and the respective software.
Maybe one day I will give it a go but up to now I am happy with what I have. I still today find it amazing watching the picture getting built as the satellite goes overhead and
knowing that I am receiving real live pictures. Do I understand what I see? well that is another story.
If you are interested why not give it a go... good luck.
Bob GM4UYZ
The Club
The Club is run in a very
informal way, just a group
of like minded people
doing something they
enjoy!
This does not mean that
we don’t do anything, we
enter (and win!) contests,
train newcomers, hold
talks and video nights and
run a popular annual Junk
Sale. Our newsletter has
won the Practical Wireless
‘Spotlight’ competition on
several occasions.
The Club supports the
British Heart Foundation
in memory of a member
who died from heart dis-
ease by donating the
profits from some of the
events we hold, we have
raised over £14,795 since
1994.
Supported by BT Community
Champions
Eighteen months ago during my Foundation course I started looking at some radio kit to get on the air, I wanted something that could be limited to 5W to comply with the founda-tion licence. As I was just starting out in Ham Radio I didn’t want to spend a fortune so my budget was £”as little as possible”.
During my search I can across the Clansman RT-320, the transceiver at the centre of the British Army’s PRC-320 man portable HF ra-dio pack. The Clansman radio system was the core of the Army communication from 1976 to 2010.
The RT-320 is a 2 – 30MHz transceiver with AM, USB, CW modes, a built in ATU and an output which can be set to 3W or 30W. There is an accompanying range of handsets, headsets, long wires, dipoles, baluns and coax feeders. It is powered by a 1AH or 4AH battery for portability, and as the MOD is now adopting the Bowman radio system the clansman sets are being sold off relatively cheaply. Several web sites suggested these were excellent radios in their own right…
http://g4oep.atspace.com/rt320/rt320.htm
http://g0ozs.org/clansman/rt320/index.html
One downside is the lack of LSB mode, there are several published modifications to add LSB to the set but these can’t be applied with a foundation license.
Never the less this seemed like a good op-tion.
Ebay is a plentiful source of RT-320s so I con-tacted a vendor and negotiated the purchase of a tatty example (I didn’t care what it looked like) for £115 + £10 postage. This came in a DPM rucsac. To get on air I then also had to buy
1* battery £15 + £7 P&P
1* battery charger £22 + £5p&p
2* antenna elements £20 + £5 p&p
1* balun £6 + £4 p&p
1* feeder coax £12 + £4 p&p
1* noise cancelling headset £25 + £6 p&p
At this point I had spent £256.
(I could probably have saved on the antenna bits but buying ‘compatible’ stuff seemed the best way to get on air quickly).
The battery charger I bought is the 24V ver-sion. This was designed to be charged from a military vehicle, most of which run 24V, there is a 14V version available but this is much more expensive. I have two HP power supplies in work that are capable of supply-ing 2.5A @ up to 15V so I wired these in se-ries to charge the battery. During charging the current limited a fair bit (I presume that the military want their batteries charged ASAP) and I was never happy that the battery had been properly charged (the lights on the charger I got never indicated the charge was done). The problem with buying second hand rechargeable batteries is not knowing their condition. Setting up the HP power supplies is also a lot of hassle, especially if I have them set up for use in other projects.
On the antenna side, the dipole elements are cleverly designed dual winders with Kevlar wrapped antenna wire on one side and para-cord ‘throwing wire’ on the other side.
There is a table on the back of the set which gives element lengths for dipoles at different operating frequencies. This allows a soldier in the field to unwind the appropriate length
(Continued on page 7)
6
A Cheap Way in to HF?
PLANNING PERMISSION Talk by Len Paget GM0ONX
16th MARCH 2012 RESOURCES ROOM 1:
19:30 to 21:30
Len is the Regional Manager for the RSGB District 1 area which covers the Lothians. Len also deals with the ques-tions and problems on behalf of the RSGB arising from
trying to obtain Planning permission for towers, etc. His talk offers the opportunity to ask all those awkward questions that could possibly arise. This talk was the one previously planned for the 18th No-vember 2011 which Len had to cancel at short notice. I am sure it will be a very informative talk so I hope you will all come along and support the evening.
6
Clublog DXCC Tables
This is the new Clublog table for 2012, as you can see, only a
few members have uploaded any of their QSOs for the new
year.
To make the table really interesting it needs as many mem-
bers as possible to keep uploading their logs, CW, SSB or DATA
You can see that there is a rising amount of activity on the
higher bands so if you’re thinking about getting active on 10m
or 15m then now would be a really good idea!
Callsign 160 80 60 40 30 20 17 15 12 10 6 4 2 70 DXCCs Slots Range
GM4IKT 0 0 0 0 0 16 1 16 0 7 0 0 0 0 36 40 8 yrs
M0RNR 0 0 0 0 0 1 0 12 0 0 0 0 0 0 13 13 13 yrs
GM4UYZ 0 3 0 0 0 0 0 0 0 0 0 0 0 0 3 3 32 yrs
MM0XXW 0 0 0 2 0 0 0 0 0 0 0 0 0 0 2 2 6 yrs
for the element then use the throwing wire to secure each end of the dipole. I used a 9m fibreglass pole to support the balun and erected an antenna in the back garden.
I got on the air and have made quite a few QSOs around northern Europe with the set with reasonable reports. One major handicap is that the set doesn’t have a LSB mode which restricts operation to >10MHz, I found 20m to work fairly well. I did have a few reports that my audio was dropping off fairly soon after a charge, a pointer to it being near the end of its life? Another major handicap is that when using the noise cancelling headphones and straining to hear faint remote sta-tions your wife and daughters never tire of sneaking in and surprising you!
I took the set to John’s radio test day last year and found that my particular set was not operating as the technical specs suggest it should, it was way down on receive sensitivity. It looks like there are RT320s and RT320s, which you might ex-pect bearing in mind that many have had a hard life. There are ‘serviced’ units available, with LSB added, but these can cost up to £475.
I have since bought a ‘main station’ rig in a silent key sale and have found this much easier to use and make QSOs. This is a much more flexible set with 100W output, but it doesn’t have the ‘charm’ of the RT-320. I have since bought a new battery for the RT320 and have just got a ‘beefy’ 24V supply from
Geoff MM5AH0 so am keep to get the battery properly charged and to get portable and see how the set performs using the full 30W output! Also having got my intermediate licence I’m keen to explore a mod to give LSB.
In summary:
If you have a foundation licence and just want to get on the air it might not be the cheapest option. When you’ve bought all the bits it isn’t as cheap as it may initially appear and you can’t guarantee the performance of second have equipment but it’s a reasonably cheap way of getting a very robust porta-ble set up.
Portable operation here I come!
Nial Stewart MM0KPZ
Next instalment…. Cheap Way In to VHF/UHF?
Further reading…
http://www.eham.net/reviews/detail/7905
http://www.youtube.com/watch?v=1Rl_UZxWPkQ
http://www.armyradio.com/arsc/customer/product.php?productid=2252
http://www.clansman-radios.co.uk/manuals/prc320-1user.pdf
(Continued from page 6)
8
Stubby Antennas!
Late afternoon, Thursday 16th February 2012 saw me out on the highest mountain in Scotland which has not yet had a summit radio broadcast (www.sota.org.uk), the remote Sgùrr nan Ceathreamhnan (1143m) 40 miles west south west of Inverness.
The name Sgùrr nan Ceathreamhnan has been problematic, for non Gaelic speakers, and is lazily christened Chrysanthemum by many linguistically challenged hill walkers! The Anglo-Saxon translation is "Peak of the Quarters" referring to the large areas of land it rather confusingly divides with its five; not four long ridges.
The name is pronounced Sgurr nan Keravan (SOTA ref; GM/WS-006) and it is found at the head of Glen Affric in the Scottish Highlands (Latitude: 57 15 17 N, Longitude: 5 13 22 W. Grid Reference: NH 057228, QTH Locator: IO77JG).
Walking in from Loch Affric in the east, rather later than planned, I decided to go up the linked Corbett; Sgurr Gaorsaic first (Sota ref; GM/WS-158; 839 metres, which translates as Horror Peak; not sure why!!!). The logic being it would allow a break in the climb and that the fresh westerly wind would be at my back for the return journey; which indeed proved to be the case.
Sgurr Gaorsaic is completely encircled by higher hills; Munros over 914m (3000ft in imperial units) so there is no line of sight to anywhere making VHF contact unlikely. Therefore, I started calling CQ on 40m just after 14:00 hours and made 14 QSOs in 25 minutes. Most were in the UK but one was in Holland, Ireland and another in Switzerland. You only need 4 contacts to document a successful transmission.
Despite the rising wind I quickly packed and set off for the main summit buoyed by the speed and number of QSOs on the first hill. I had to use crampons on some ice but reached the top less than 2 hours later and set up the 40m inverted dipole on the lee side of the summit cairn. By now it was snowing, which with the wind meant blizzard conditions. Despite calling for just over an hour I had only 2 contacts; one in Ireland, the second in Surrey. The number of overseas stations blasting in swamped my 5 watt output so, finally accepting it was time to change frequencies, I reluctantly came out from under the shelter of my bivvy bag and looked for the small kit bag with the stubby 2m whip for my FT817. It was nowhere to be found and I can only assume it had blown away taking a couple of coax leads as well. There was little point searching because of the vertiginous 500m drop just a few metres downwind.
All was not lost as I could still use the rear port for my 3 element VHF YAGI, but by now the wind was too strong to safely assemble it. In fact I was surprised the inverted V dipole was still in one piece! The hour was late and I was in danger of being marooned at the top of the highest and most remote mountain in the area. Discretion is the better part of valour, according to Falstaff, so it was time to just accept defeat and swiftly retreat.
Needless to say I got down safely, although it was dark for most of the descent, but I usefully used the time to do two things; first review the order of the hills I had climbed that day (maybe the wrong sequence with hindsight) and second to calculate the length of a home brew ¼ wave antenna to replace the commercial aerial. A bit of stiff copper wire and a BNC plug should do the job; maybe even add a counterpoise wire! Or so I thought. First thing was to work out the length of the wire; the lost antennae being about 20cm long.
300 X 106 /145.500 MHz = 2.0162m for wavelength
2.0162 / 4 = 0.50405m for ¼ wavelength
0.50405 x 95% = 0.4788475m as speed of signal is lower in copper.
However, a 47.9cm whip antenna is more than twice as long as the FT817 stubby antenna and it seems the commercial whips (rubber ducks) are "normal mode helix" antennas.
A helical antenna is a conducting wire wound in a constant parallel spaced helix or spring. In most cases, helical antennas are mounted over a ground plane and that was me with the FT817; essentially humans are a bag of isotonically salty water and are useful as a ground plane for handies. Helical antennas can operate in one of two principal modes: normal mode or axial mode.
In the normal mode or broadside helix, the dimensions of the helix (the diameter and the pitch) are small in comparison to the transmitted wavelength. The diameter of my lost antenna being less than a centimetre and the pitch but a few millimetres. The antenna acts like a whip and the radiation pattern is omnidirectional, with the maximum radiation at right angles to the helix axis. The design is reported to be efficient as a practical reduced-length radiator when compared with the operation of other types such as base-loaded, top-loaded or centre-loaded whips. They are typically used where reduced length is important.
In contrast the axial mode helix uses helix dimensions at or above the operating wavelength. The antenna produces radio waves with circular polarisation and the radiation pattern is along the axis of the helix. They are often used where the relative orientation of the transmitting and receiving antennas are unknown or cannot be easily controlled, such as in spacecraft. Just make sure it is a compatible right or left handed helix!
So, with my home brew whip antenna should I head back up Sgùrr nan Ceathreamhnan for a second attempt? Perhaps I should just buy a new stubby, £12 from Jaycees!
Thanks to Campbell MM0DXC, Adrian MM0DHY and Andy MM0FMF for their unwitting, but essential help, in inspiring this report.
Colwyn Jones MM0YCJ 24/2/2012
1. Harmonic radiation from a transmitter may be reduced by
a. Adjusting the receiver’s audio gain control setting
b. Fitting a low pass filter in the antenna feeder to the transmitter
c. Placing a high pass filter in the mains lead
d. The state of the sunspot cycle
2. The drawing shows a block diagram of a TRF (Straight) receiver. Which one of the blocks selects the radio signal?
a. Tuned circuit
b. Detector
c. Audio amplifier
d. Headphones
3. A radio receiver is set to receive a signal of 14.1 MHz and the local oscillator is set to a frequency of 13.6 MHz. What will the intermediate frequency be?
a. 500kHz
b. 13.6MHz
c. 14.1MHz
d. 27.8MHz
4. The demodulator for a FM receiver
a. Requires a beat frequency oscillator
b. Requires a narrow band pass filter
c. Could be a frequency discriminator
d. Could be an envelope detector
5. The block diagram shows a Morse Code transmitter. Which one of the following does block X represent?
a. AF Oscillator
b. RF Oscillator
c. Demodulator
d. Modulator
6. A carrier wave on 28400 KHz is amplitude modulated. The upper sideband is 28402KHz the lower sideband is
a. 28396KHz
b. 28398KHz
c. 28404KHz
d. 28406KHz
7. A station in the 23cm band is being interfered with by an amateur transmitter on the 70cm band. This could be due to the:
a. Receiver audio gain control setting
b. Transmitter using narrow band FM
c. Presence of a harmonic in the transmitter output
d. State of the sun spot cycle
8. To minimise the radiation of harmonics, which one of the following filters might be fitted between the transmitter output and antenna?
a. High pass
b. Key click
c. Braid breaker
d. Low pass
9. The drawing shows a block diagram of a simple Super-hetrodyne receiver. What is the block marked X?
a. Detector
b. Audio amplifier
c. Tuned RF amplifier
d. Loudspeaker
10. The intermediate frequency of a superhet receiver is the
a. The sum of the RF and the local oscillator frequencies
b. Difference between the RF and the local oscillator fre-quencies
c. Sum or the difference between the AF and the local oscillator frequencies
d. Sum or the difference between the RF and the local oscillator frequencies
Test Your Knowledge
8
Tuned Detector Audio Headphones
Contacts
General correspondence,
training and contest en-
tries
Bob Glasgow
7 Castle Terrace
Port Seton
East Lothian
EH32 0EE
Phone: 01875 811723
E-mail:
HF Contests
Cambell Stevenson
VHF Contests
John MacLean
Club Tables
Bob Purves
Contest Reports
Robin Farrer
Newsletter, website,
event calendar
John Innes
2 March 2012 Club Night
3 March 2012 Intermediate License Course begins
(fees to be paid by 4 December)
16 March 2012 Talk by Len Paget GM0ONX on “Planning Permission” Port Seton Community Centre Resource Room 19:30 to 21:30
6 April 2012 Club Night
7 April 2012 Intermediate License Exam
21 April 2012 10 Pin Bowling Night (TBC)
4 May 2012 Club Night
11 May 2012 FIRST 144Mhz DF Hunt Meet in “The Old Ship Inn” Car Park (East) 18:30 for 19:00
1 June 2012 Club Night
2 June 2012 Port Seton Gala Day
10 June 2012 PW 144MHz QRP Contest
16/17 June 2012 Museums on the Air Weekend
Museum of Flight—East Fortune GB2MOF
20 June 2012 CPSARC HF Activity night
19:00—22:00
29 June 2012 Club Night (moved to accommodate VHF Field Day)
7/8 July 2012 RSGB VHF Field Day
28/29 July 2012 RSGB IOTA Contest
Island of Tiree GM2T
3 August 2012 Club Night
10 August 2012 19thANNUAL MINI-RALLY NIGHT
18/19 August 2012 Lighthouses Weekend
Barns Ness Lighthouse GB2LBN
7 September 2012 Club Night
28 September 2012 SECOND 144Mhz DF Hunt Meet in “The Old Ship Inn” Car Park (East) 18:30 for 19:00
Events Column Answers from March 2012 newsletter “Test Your Knowledge”.
1B, 2A, 3A, 4C, 5B, 6B, 7C, 8D, 9A, 10D