Saturday, October 31, 2009

EI8GHB Anthony works DL7SP Holger in Germany on 20 metres



This is me having a QSO with a German station, contact number 13 on HF since I got my licence.

My first session on 20 metres

Worked an hour on 20 metres this morning putting out a CQ call and got about 20 contacts into Europe. Here's the callsigns logged:

IS0SWW
DH9NBU
DH8WW
UA4PF
IK2XRJ
DK2RMP
DL4MAU
DL6MRS
F4DDZ
IZ1GCN
SM5BNK
DL7SP
IZ2ACM
IZ0DIB
EA8CDI
DL1ALN
IK4EWN
SP6BXP
RA3ANL
DJ8RP

Friday, October 30, 2009

Worked my very first HF contact just now on 40 metres

Having worked six stations on 2 metres already since I got the callsign this evening, I've now worked my first HF contact.

At 23:17 I worked EA5BRE on 7.121 LSB with only 20 watts into a half-size G5RV. He was patient with me despite the fact he was looking for DX. Thanks Luis. I recorded the latter part of the QSO for posterity, it being my first contact on HF with my callsign.

On 2 metres I have worked:

EI4DIB (No surprises there - thanks Tony!)
GI4SZW Seamus
EI4IP Sean
EI4HX Peter (hello again Peter!)
EI8IZ Darragh (mobile heading to Dundalk)
EI3GHB Alan in Maynooth, who was blasting in and gave me an excellent report. He also noted that we are both Golf Hotel Bravos!! Thanks for the welcome.

Just got confirmation of my new callsign - EI8GHB !!

Well the call finally arrived. At 4.45pm Derek from Comreg rang to confirm my new Amateur Station callsign - EI8GHB - Echo India 8 Golf Hotel Bravo!!

I like it!

It rolls off the tongue. I knew it would be EI8G something B. Hotel is alright by me.

I had my first QSO on the way home. I worked Tony EI4DIB mobile on the M1 (I was mobile) through the Dundalk Repeater on 145.675 and then Seamus GI4SZW joined in. After all the dreaming and study and apprehension, I'm finally on the air.

Looking forward to doing a bit of HF over the weekend.

Update: callsign on its way soon

I phoned Comreg today and a very nice gentleman informed me that there had been some system problem and that this had put a slight delay on the processing of my Amateur Station Licence application. However, he said he would do his best to have it processed today and hopefully I will know my new callsign very soon, possibly this afternoon, if not on Monday or Tuesday.

I told him if he could do anything to have it processed today I'd be very grateful. I'd love to be on the air over the weekend !!

Tuesday, October 27, 2009

My first (somewhat modest!) amateur station begins to take shape at home


OK, I'm giving you a world exclusive now. This is a real first for all you web surfers, amateur radio operators, short wave listeners and the general public! I'm going to give you a sneak peek at some radio equipment I've acquired for the operation of my new amateur station, for which I am just awaiting my licence in the post.

The main rig is the HF radio. It's a TS-570D from Kenwood. A nice transceiver which is a sort-of mid market product, better than an entry-level HF rig but obviously not as good as some of the bigger and more expensive models.

Above that is the Alinco DR-510 dual bander which I hope to use as my home-base 2 metre radio. Above that is the Icom IC-207 which I have a loan of from Peter EI4HX. Thanks Peter. And beside those two is my "handy", a slightly battered but very capable 5watt 2 metres handheld - the ADI AT-201.

Wonder what callsign I will be given?

Well now that I am waiting on my new licence, my thoughts have finally come around to what callsign I will be given. After the June exam, a lot of the new callsigns were EI7 (Echo India Seven) Golf something Bravo. So I assume that Comreg fill out the EI7G's and then move onto EI8G on the basis that EI8GAB has been assigned but nothing after it. Also, everything up to EI7GZB has been assigned but no EI7Hs.

So it seems likely I will be EI8G?B and given that my application was in last Wednesday, the same day I got the results, it might seem logical to suggest I will get an early letter. So here are some of the possibilities:

EI8GBB - Echo India 8 Golf Bravo Bravo
EI8GCB - Echo India 8 Golf Charlie Bravo
EI8GDB - Echo India 8 Golf Delta Bravo
EI8GEB - Echo India 8 Golf Echo Bravo
EI8GFB - Echo India 8 Golf Foxtrot Bravo
EI8GGB - Echo India 8 Golf Golf Bravo

Do I have a preference? Not really. I'm glad just to be getting a callsign to be honest. Golf Bravo Bravo is perhaps a tad tongue-tying, while Golf Golf Bravo is nice, but really I'm just looking forward to receiving my licence and putting out some calls!!

The sunspot activity has been deplorable recently, and I kept jokingly telling my radio friends that it was waiting for me to get my licence to start lifting.

Well what do you know, there are 29 sunspots today, up from 0 two days ago, according to the Dundalk Amateur Radio Society website. Hopefully HF will get a good lift now over the winter months!

Friday, October 23, 2009

Application delivered & received - callsign next week hopefully

I've spoken with Comreg who tell me they have received my application for an Amateur Station Licence and all seems in order. I should have my new callsign and licence some time next week hopefully.

I look forward to many QSOs on the air, with ham operators local and worldwide, on HF and VHF.

Wednesday, October 21, 2009

Here's me with my results form


One for the record . . .

If I look a bit tight in the face, forgive me. It's not intentional. I was holding the Nikon D200 with flash attached in one hand because there was no-one else around to take the photo!

Just an official photo of muggins with his results. I think I might pour myself a wee glass of wine now and enjoy the feeling of having passed.

I PASSED - WITH FLYING COLOURS!

The results just came. My XYL is reading them out on the phone.

Section A: 26 out of 35 - 74.29%
Section B: 12 out of 15 - 80%
Section C: 9 out of 10 - 90%

So that's not just a pass, but a good one! 60% needed in each of the three sections. My total is 78.3% (47 questions right out of 60). Brilliant. Delighted.

Wooohoooo!!!!!!!!!!

Needless to say I'm over the moon. I was told by Thos EI2JD today that I was the only one who doubted myself - everyone else knew I had it in me. I'm delighted with the scores, particularly with Section A where I thought I scored less. Congratulations to those who have passed and commiserations to anybody who didn't make it this time round. I'm keeping my fingers crossed for Michael in Kilkenny who hasn't received word in the post today. Hopefully tomorrow Mick - good luck!

I took a slightly extended lunch break today to deliver my licence application directly to the Comreg offices. I figured with the way the post has been lately it would cut some time out of the equation. I left my completed application with a nice young lady called Aisling. Hopefully I will be on the air very soon.

Thanks to all who phoned or texted today - word travels fast - and hopefully we'll all be having nice QSOs on the air in the coming days.

I'm delighted with my scores in Section B - where I got 12 out of 15 - and Section C - where I missed just one to score 9 out of 10. I had a funny feeling I had done well in those sections. It was Section A that had me worried. But I needn't have stressed.

Tuesday, October 20, 2009

No post today - unfortunately ! :(

Countup Timer: 2 weeks 0 days since the exam

The XYL is just on the phone now (12.09pm) telling me that there was no post. The postman did deliver one item of (unwanted) post but regrettably there was nothing from Comreg.

It's agonizing, all this waiting . . .

Monday, October 19, 2009

Welcome news re training from the IRTS

This welcome news was included in this week's IRTS news:

Train the Trainers

The Society is considering running a "Train the Trainers" session for theory tutors intending to run classes and who wish to use the Society's CD Exam Course Guide. This may also be of interest to those unable to attend classes and who wish to use the Guide as a study aid for the Theory Examination.

The two-hour session would most probably take place on a weekend afternoon and would demonstrate how best to use the CD Guide and also practical matters relating to
preparing students to sit the Exam. If you are interested in participating in such a Training Session please drop an email to Paul EI2CA or Seamus EI8BP or indeed any of the Committee Members. Their contact details are on the IRTS website and in the latest issue of Echo Ireland.

I have to say I think this is fantastic news. There were no theory classes operating in my area while I was studying for the exam, so I would have absolutely availed of the above suggested service. Let's hope it gets off the ground.

Watching and waiting for the post . . .

Countup Timer: 1 week 6 days

Tomorrow will mark two weeks since the exam, and I am waiting with much anticipation on the post. I am at work, so I have asked the XYL to keep a close eye for the postman at home. The post is normally delivered some time in the morning at home. Lately, the postman has been around early, before I depart for work, but not this week apparently.

I have given fairly direct instructions to her good self, which she said she would oblige in doing. I told her if she sees an envelope from Comreg, just to open it and find out whether I passed or failed, and then to phone me, and just utter two words: either "you failed" or "you passed". No beating around the bush, no delays, no procrastination. Just give me the result as soon as I answer the phone!!

So, here I am busying myself with work, hoping the envelope will arrive sooner rather than later. I find myself watching the phone, thinking I might have missed a call or a text message. In fact, it's now 12.18pm, so I must give her a buzz and see if any post came.

UPDATE: 12.26pm - the XYL is on the phone, telling me there's no post! :(

Saturday, October 17, 2009

The long wait continues . . .

I had been doing a "countdown timer" in advance of the exam, and now that it's over I should be doing a "countup timer". The wait seems eternal. It is now 11 days since I sat the exam and, it being the weekend, I know I will not receive any notification from Comreg before at least Monday.

My recently-licenced friend, Brian EI7GVB, tells me it was 17 whole days after the exam when he finally received his "golden envelope" from Comreg. By that measure, it would be next Friday before I find out. Hopefully not. The wait is agonising.

However, I'm a bit more relaxed about it now. I realise that although I found Section A tough going, I think I did enough to pass it and I reckon I did well enough on Section B and Section C. Fingers crossed.

In the meantime, I've been doing a wee bit of listening, as usual. While HF has been quiet all week, VHF has been more exciting. Most of the HF bands were closed a lot of the time, although right now, as I write this, there is good activity on 20 metres, and there were some openings earlier on 17 and 15 metres. On VHF, there seems to have been a resurgence of interest in 2 metres. I was particularly interested to hear a gentleman called Terry on the air, using his father's callsign - EI8Z - a nice short one!! Some of the people licenced after the June exam are regulars, including Nick EI7GOB in South Dublin, who can regularly be heard operating through the Dundalk Repeater EI2CCR. There are some new operators north of the border too who have recently joined the hobby. One local operator who had been licenced earlier in the decade - Darragh EI8IZ - is back on the air after a long break and can regularly be heard on 2 metres also. I look forward to working you Darragh IF I get the licence!! I hope also that you get set up on HF soon.

On Monday of this week, Short Wave Listeners, myself included, were delighted to hear so many people call in after the IRTS news - a total of 20 callsigns were registered. Peter EI4HX (EI0RTS) was kept busy for a long time after the news bulletin with all the callers. Ironically, the news itself was short this week.

Just checking the Dundalk Amateur Radio Society website, I see there are ZERO sunspots. This has been the norm this year. We are in a very prolonged period of low activity. Hopefully, things will begin to lift soon and we'll see some spectacular aurora - and some spectacular conditions on HF!!

Life hasn't been quite the same since Tuesday 6th October for me. I have not been doing any study!! So things have been a bit easier, a little less pressurised. I don't miss the study really, although I did learn a lot and am grateful for the experience. I hope I don't have to pick up the books again next year to try again. Obviously, as soon as the post comes with the results, I will let you know.

In the meantime, I'm trying out a new High Definition video camera. Maybe I'll point it at the sun, and see if I can see some sunspots!!

73 de
EI1597

Thursday, October 15, 2009

CQ CQ Shortwave listeners of Ireland . . . yes you!

I have received this correspondence from Brendan Nutley EI1429 and considered it worthy of propagation.

CQ SWL’s of Ireland!!!

Recently I had a conversation with Dave Moore EI4BZ regarding the lack of Short Wave Listeners on the DXCC listing in the Echo Ireland. It turns out that up until I picked up the phone no one has enquired about it… WHAT?
I find it strange given that there is so many of us in Ireland not a soul has made this inquiry or even submitted their confirmed DXCC list?
Now I understand that we are unable to transmit, and that we have to have a “Babysitter” with us when we want to use a transceiver but “does we all know” that there are awards out there to be won? I am guessing not as I do not see SWL’s applying for the positions except one that I know of EI1588 Shauna Baynes. She won the 80m Counties SWL in June this year, with only 11 QSO’s...! “Shauna its mine next year, hands off!”
So you see it’s not tough and it would make things a little more entertaining. Every contest that has taken place this year SSB, CW, and RTTY, I have done my best to work it, and permitting that I have the good fortune to be able to have time off to sit through the entire length of the contest, I will.
Ask my XYL, it drives her mad! "Sorry Love!"
Only last week I entered the SKCC WES CW Sprint, In 24hrs I only managed to receive 12 contacts, but it earned me an SWL 2nd place and currently 33rd in the world (of SKCC Members). I am not anyway good at CW, in-fact I am appalling, but when you know the call sign of the Ham you are looking for it makes it easier to hear them, and you get the benefit of learning the sounds and how they are send, for me that is a big bonus as I have a learning difficulty.

So. . . . I want from you,
* Your name
* your call sign
* and your (Confirmed) DXCC total’s for 2009 to date

I have been told that if I manage to get “3 SWL’s” or more we will get a mention in the ‘auld Echo Ireland!
That would be nice. . . What’ a think?

Regards,
Brendan Nutley
EI1429 (EI-Half-Past-Two . . . in a minute!)

Friday, October 9, 2009

Pensive but philosophical three days on

Well, it's now three days since the exam and, although I am still filled with apprehension about the results, I am trying to get into a mindset where I am not expecting anything.

I have been able to remember almost all the questions from Section A, and the answers that I gave, and I realise that it's very tight. I know I got some right, I think I got some others right, and there are others I'm not sure about. Plus there are a number which I know I got wrong.

The main conclusion that I've drawn is that, in Section A at least, it's so close that I couldn't possibly call the result. I may fail by just a question or two. I was disappointed that I got three out of the four measurements questions wrong. The propagation section was tougher than I thought and there's at least one question there which I'm not confident about. In the first ten questions, I am certain about only five - that's just half. I am puzzled about a question about what the purpose of a capacitor in a transformer was. I put down "to reduce hum" and am not confident. Also, there was the diagram of an audio amplifier asking what two capacitors and a resistor were for. They looked a bit like a pi network or low pass filter so I gave the answer "to limit the AF bandwidth". Another possible answer related to RF feedback so I assumed that to be wrong.

The first question in the whole test asked what a radio wave was:

a) an electromagnetic field
b) an electric field
c) a magnetic field
d) an electro-somethingorother field. (Can't remember the fourth answer).

I gave a) an electromagnetic field

In feeders and antennas, I think I was right in answering that the characteristic impedance of a quarter wave electrical feeder was determined by its dimensions and the spacing of the conductors rather than the other options which were: its length, the power used and something else, maybe the SWR.

Also, a feeder open at the far end would show low impedance at the near end. I looked that up when I got home and discovered I got it right.

An FM transmitter amplifier works in Class C because? Well I answered that it was rich in harmonics. An FM transmitter uses frequency multiplication which requires harmonics, so I might be right on that one.

There were three separate questions about band plans and power etc, two in Section B and one in Section A. To my absolute disgust, I found that I only got one right. 15 metres is 21.000 to 21.450. I was asked what the maximum power was on 1.9 MHz. I said 100 watts but the answer is 10 watts. I was asked what mode was 29.520-29.700 reserved for. Having initally given the correct answer - FM - I then doubted myself and opted for QRP instead. Again this was simply down to me not knowing my stuff well enough. Plus, in an exam situation where you have no books or internet or notes to refer to, self doubt creeps in when there is the slightest suspicion about a wrong answer.

There was a question, I'm not sure whether it was in propagation in Section A or not, about what the frequency 14.100 was reserved for. I answered beacons, which I believe is correct.

The end result of all my investigations since the exam is nothing but anxiety. And that's because I didn't give enough correct answers to give myself a comfort zone. I got two simple answers wrong - one was the graph for the current through an inductor, the other about AM being a carrier plus two sidebands. (I said carrier plus one sideband. Where the hell did I get that idea? Silly mistake which might have cost me the whole bloody exam.)

Another question in Section A was about the intermediate frequency of a CW transmitter, or something like that, maybe the difference between the oscillator frequency and the IF. There were four possible answers: 10MHz, 0.8kHz, 455kHz or 1Hz. I thought 10Mhz and 1Hz looked like completely spurious answers and I knew in all the superhet receiver questions that 455kHz was always mentioned so I went for that.

My little "Man United's New Players" mnemonic helped me answer a question which asked about what value a 1000 uF capacitor had. The answer was 1 nF. Great!

In the safety part of Section C, the first question asked how to wire a plug. The second question asked something like what was most likely to give you an electric shock in a circuit, and the answer was capacitor. The third question asked the purpose of a fuse in the plug of a transceiver. The most legitimate answer looked to me to be that it protected the transceiver from voltage or current overload, something like that.

There was a question about a HF transmitter interfering with a TV which was tuned to certain frequencies (I think one was an 800 mhz band). The most appropriate action, in my opinion, was to fit a high pass filter to the downlead of the TV antenna.

The first question in Section C was about the primary purpose or issue of concern with regard to Electromagnetic Compatibility. One answer was the protection of human health from emissions, but to be honest the more likely answer to me was the prevention of spurious emissions, so that's the one I gave.

If I can remember any more questions I will note them here. Hopefully that will provide some assistance to people who intend to sit the next exam. I might well be sitting it with you!! . . .

Tuesday, October 6, 2009

Done and dusted - a difficult exam


Well, it's finally over. I'm sitting here at home after a long day, and one full of anticipation and tension and nerves. I was glad to have the company of Michael from Kilenny in the coffee shop on O'Connell Street to kill the time running up to the exam.

When the time finally arrived, and the exam started, I decided I would turn over the paper and have a read through it. I read all 60 questions. When I came to the end, my first thought was "this is going to be tough". And indeed it was. I found Section A particularly gruelling. This was not helped by the fact that I was uncertain in a number of answers (some of which I later discovered I got wrong, after I had left the test) and there were a number of questions which completely stumped me. I had hoped that the fact the test was concentrating more on the practical and a little bit less on the theoretical would help me, but I ended up with the feeling that I might have failed.

At this moment in time, I can do nothing else but be philosophical. I got a few questions wrong that I should have got right. For instance, what power can be used on 1.9 MHz? Answer: 10 watts, but I said 100. What mode can be used on 29.520-29.700? I changed my answer to QRP, having initially ticked the correct answer, which was FM.

I got the graph for current through an inductor wrong. Basic stuff, but I got mixed up and might end up paying the price for it.

Some of the early questions were straightforward. The resistor question asked what was the current through one of two resistors in series. The inductance question asked the total inductance in a circuit containing two parallel inductors. Straightforward stuff. One question asked to identify the waveform which would result from a certain circuit diagram containing a diode and a resistor. I made a guess at it.

I was happy enough with the propagation section - 6 questions in total. One interesting question asked which of the following would be the least likely to cause DX on VHF (or something similarly worded)

The Moon
Meteors
F2 Layer
E Layer

I answered F2 layer.

In measurements we were asked what a two-tone test oscillator is used to measure. Two of the options were : carrier suppression and SSB suppression. I guessed the latter.

There were some extremely difficult questions. At least they seemed difficult to me because I had not come across them in all my weeks of study. One asked what would happen if an antenna resonant at frequency fMHz was lengthened by 5%. The available answers were something like:

It would go open circuit
It would present pure resistance
It would have capacitive reactance
It would have inductive reactance

I hadn't a clue on that one and took a complete guess.

There was a question about what would affect the low-angle, long distance radiation pattern of a vertically polarized antenna. Again I was completely stumped.

Overall, the test was more difficult than I expected. There were no questions about the selectivity or sensitivity or gain of a receiver. There was a question asking us to identify a certain block in an SSB transmitter. I answered correctly - "Mixer" - phew! At least I know I got one right . . . There were no questions about transistors, insulators, conductors. There was one question asking the impedance of a folded half-wave dipole. I answered 300 Ohms which I think is the correct answer.

The prefixes question was European. it was a CW call SP9??? DE OH5??? - a Finnish statin calling a Polish station. Another question asked to identify the callsign which did not conform to the ITU standards. I went for WAB7 because I think the third character must be a numeral if memory serves me right.

In the final section, there was a safety question which asked the correct wiring of a plug. I'm glad to say I knew that one!

Overall I thought it was a tough exam. I was taken aback I have to say. Certainly when I got to the last question in Section A - question 35 - I had already left out six or seven questions which I decided to return to later, simply because I was unable to answer them. I proceeded to Section B and then Section C before returning to Section A to have another go. There was a circuit diagram showing an audio amplifier which asked what was the function of two capacitors and a resistor in the circuit. I thought they looked like a low pass filter or a pi network and guessed that they were for limiting the AF bandwidth. A guess based on a wee hunch.

It's been a long day, and a long ten weeks. I'm exhausted. I'm also apprehensive, but there's nothing I can do now only wait. And if it's not to be this time round, I have to wait until next June before I can sit the exam again. I have to say it's a prospect I'm not looking forward to. If by some mircale I pass the exam, I will be absolutely overwhelmed with joy, but I'm not holding my breath.

I should know within two weeks. Hopefully, it will be sooner rather than later. Put me out of my misery !

One lesson from all this is that this is just a blog. A blog written by an enthusiast. An enthusiast who has no formal training in this stuff. So by all means take advice from this blog and try to learn something from it, but don't swear by it! I wanted to share my experience as someone who was taking this on from scratch (although fair enough, I was a short wave listener before I started studying). I hope that you have enjoyed reading it, and that you have indeed learned something from it. I followed my own advice by and large over ten weeks and have ended up with the feeling of being short-changed.

Whether that's just because of my own shortcomings or whether it's a mixture of factors I cannot say clearly. I would imagine there is scope to hold more than two exams in the year. If I fail this time, it will be eight months before I can sit it again. By that time I might have lost all enthusiasm, plus I would forget a lot of what I've learned in the meantime. There are no classes taking place in my region to help me. Michael in Kilkenny says there's nothing down his way either. At the end of the day, enthusiastic guys like him and me are left to our own devices to wade through a huge amount of material in an effort to get that all-prized licence. I know, and can state with certainty, that I would be a good operator, and would be a welcome addition to the hobby. If I fail this test, which is a distinct possibility, I would like the opportunity to be able to do a resit within a month. I think many would be in the same position. A resit in a short space of time would make sense because as I said above, a lot of the information currently stored up in my brain like current in a capacitor will have disippated (as heat!) I feel that if I had to leave it until next June, it would be like starting from scratch all over again. Michael was talking to another two repeaters (excuse the radio pun!) after today's exam and they all agreed that this exam was even tougher than the June exam.

However, not to end negatively, I have enjoyed the journey. Not knowing the destination can sometimes be fun, but sometimes it can be daunting. Right now, I am daunted. I feel that there's nothing else to do than to try and put it all out of my mind and turn to other things, at least until an envelope with IRTS on it arrives at my house some time in the next fortnight . . . At this precise moment in time, I am listening to a QSO on 2 metres between some of the local operators. So I haven't ditched the hobby on the basis of a difficult exam!!

I hope to work 11 metres later on. Yes, I know what the Ham operators are going to say . . . the last refuge of the desperate !! But no, there are some decent operators on 11m and some good DX to be had if the conditions are right.

And if I remain in positive mood, I might just take a scan through the ham bands and see if there's any interesting listening :D

Monday, October 5, 2009

One tiny last bit of cramming!!

Ok, I just had this idea that I didn't do enough on safety, relying too heavily on QADV, so I whipped out the IRTS disk and did a bit more study. A few interesting things turned up.

One is that the human body has a low resistance, of around 500 ohms. Voltages of as little as 30 to 50 volts can kill, but it's the current that usually does the job. Remember this:

"It's the volts that jolt and the mils that kill". That should help you remember it.

If you have to ground something for lightning strikes, make sure the rods are between 5 and 8 feet long.

Oh, and if you need to stay a mast, it must be stayed at a height of 60-80% of its overall height.

Just a day away now - good luck everyone !

Countdown Timer: 0 weeks 1 day to go

Well, we're almost there at last. Hasn't time flown? I'm still studying. No, I think you could call it "cramming" at this stage. There are a few things I'm still not sure about, but hopefully I've done enough to pass.

Make sure you bring your paperwork (would have been sent to you in the post by IRTS) and of course your photo ID (driving licence, passport etc). I intend to get a bus from Drogheda in the morning. I hope to get an early bus just in case of delays. I'd rather be there early and hanging around than to be late and find the exam has started without me!

I will report afterwards on how I think the exam went and what sort of questions came up. Remember that there are only 10 questions on theory now and 6 on propagation etc. See previous posting.

Just before I go, a little bit on transistor connections, which might well come up:

Common-base connection:
Low input impedance, high output impedance.

Common-emitter connection:
Input and output impedance similar (medium value).

Common-collector:
Input impedance high, output impedance medium.

A quick note on propagation layers.

Lowest is D. Disappears pretty much at night, ionised during the day. When heavily ionised, prevents signals reaching higher levels.

D layer - 80km above ground
E layer - 120 km above ground
F1 layer - 200 km above ground
F2 layer - 350 km above ground

F layers combine at night. Their ionisation is weakest just before dawn.


OK, I'm off now to do some study on QADV and cram in some more !!!