Golborne Vintage Radio

Full Version: Mayhem on AmRad 40 m. band
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Date: Oct. 9, '13.
Time: 20:40 hrs., std. U.K. time.
Freq.: 7142 kHz.
Mode: SSB (LSB)
QSB: none.
QRN: very little.
QRM: loads - often S9+

I'm getting towards the end of the overhaul of a Racal RA-17W, so I thought I'd run a quick 'air-test' on it: tuned in to the Amateur Radio 40 m. band: absolute bedlam on 7142 kHz; classic pile-up. Somewhere underneath the racket there is a DX station. Just once, using the vertical aerial, I did manage to catch a bit of his call: I think his prefix was 'PZ', wherever that is. Blush Seemed like half of the Amateurs in western Europe were trying to work him. I head the usual German DK, DL, DJ calls; plus EA, CT, I1, I9, ON, HB9, F, etc. But, strangely, not one G: probably skip. So I switched over to the 'T' 'long-wire' aerial: nope, but the bedlam was weaker! Rolleyes

Al. / Skywave.
Sounds normal for 40 Al, those pile ups remind me of a female toad ready to mate.....Single side band = twice the bedlam....

I don't know if he is still around but I used to follow Roger (ON7TQ) he does DX from Belgium, tends to be the host on his DX contacts and tries to organize contacts to his DX contact for others in a structured order, he's a nice bloke, worth listening to if he is working DX. He some times hangs about on 80 and 20 but almost always on 40, more near the top end of 40 than down lower end where the Italians etc are.

Early morning on 20 is usually good for VK, ZL etc. I picked them up on my regenerodyne project receiver, my wife was impressed.

Lawrence.
For a while, when I as first licensed back in 1974 (strewth, forty years next year!), I found it quite exciting to have contacts with stations in Indonesia, Australia, Brazil, Africa and so on, and in a few months, gained the Worked All Continents Award and was working towards the DXCC Award (100 countries). I worked about 65 countries, then the penny dropped - anyone else sat where I was sat, using the same equipment and antenna, at the same time as me would get exactly the same results, so the point is? Hence, no skill involved - just a sedentary desk-bound hobby - fine for housebound old men, but it was making me old before my time.

DX 'pile-ups' bring out all that's worst in human nature - selfish bad manners and ego tripping to no good end. I find it bizarre that National Societies strenuously support 'DX-Peditions' whereby amateurs go to far away places, often devoid of amateurs, and spend every waking hour having contacts with hoards of shouty people which last no more than 10 seconds - a sort of on-air trainspotting. I just think of it as amateur radio's contribution to 'Care in the Community' - a day on the air for these characters is a day off for others who would otherwise have to cope with them.

These same national societies complain about poor operating and declining standards, seeing no irony in their own contribution to this debasement of what was once a technical, experimental and gentlemanly hobby, but has descended to becoming no more than 'Posh CB'. Or so it seems to me. But since I haven't been on air for years, I'm just a 'RHINO' - Radio Ham In Name Only' and the on-air antics of others does not in any way impinge on me, so good luck to those who do enjoy it shouting themselves hoarse in the hope of a ten second contact with some guy sat on a rock in the middle of the ocean somewhere, and the nervous anticipation of receiving a 'QSL Card' to show off to like-minded consenting adults.

Tony Hancock's 'Radio Ham' sketch wasn't comedy, it was a documentary - you couldn't make it up!

It could make me cynicalRolleyes
David, no skill in DX? Try telling that to someone who is doing their best to obtain an elusive DX contact. I don't buy the "using the same antenna argument" I'm afraid antennas and propagation is a bit more involved than that. Plenty going on on the amature bands that doesn't include cosy netting, both on phone, CW and other modes of transmission and that's the art...finding it that is.

Lawrence.
ON7TQ: that call-sign rings a bell.

My viewpoint on DX-chasing, operating and Amateur Radio in general is somewhere between what David and Lawrence have each written. But for me, Amateur Radio as a transmitting Amateur lost its appeal many years ago. I used to be very keen on seeing how far I could get on 2m. with home-built kit and using AM or FM. But when repeaters came along, that was the end of my interest. Looking back now, to me it just seems that the existence of repeaters was simply 'converting' Amateur Radio into CB: taking the 'Amateur' out of Amateur Radio. But contests and DX-chasing for the sake of 'awards' never appealed: I'm not competitive; I like to think I have a co-operative personality. During my transmitting days I met many Amateurs who would go out of their way to make my life as unpleasant as possible. They all had one thing in common: over-sized egos.

But I like tinkering around with quality comms. radios. I enjoy the technical challenges; I like to study the designs and to appreciate the quality of the engineering and the personal effort that went into those designs. And then using them, occasionally, just to discover what is 'out there'.
Which, for me, as a youngster, what what started the whole radio interest off in the first place. And it's still there, 55 years later.

Al. / Oct. 10. '13.
(09-10-2013, 09:25 PM)pwdrive Wrote: [ -> ]David, no skill in DX? Try telling that to someone who is doing their best to obtain an elusive DX contact. I don't buy the "using the same antenna argument" I'm afraid antennas and propagation is a bit more involved than that. Plenty going on on the amature bands that doesn't include cosy netting, both on phone, CW and other modes of transmission and that's the art...finding it that is.

Lawrence.

No - no skill at all. We should not confuse knowledge and experience with skill. You need knowledge and experience to know about propagation conditions and to set up a station to best advantage within your financial and geographical limitations, but that isn't at all the same thing as skill. If you're a train-spotter or plane-spotter or 'twitcher' you have to know where to be to see what you want to see, but again it isn't 'skill' - it's knowledge and experience.

Particularly since the advent of internet, up to the minute information about DX conditions, where particular DX stations pop up at any particular time, DX-Peditions and so on has never been more accessible.

People who are interested in DX will do what they can to make the best of the limitations of their location and will aim to erect the best possible antenna. Few UK amateurs even bother to use the maximum power available within the terms of their licence by adding a linear amplifier - most use modern transceivers with solid state PA stages which put out (nominally) 100 Watts PEP and progressively limit that output in the event of a mismatch to the 50 Ohm output. I'd wager that few amateurs use the legal limit of 400 Watts (or as the licence puts it, 26dB Watts) - that went out when valved PAs went out. But then 400 Watts is not 4 x the RF output of 100W. 100 Watts is double that of ten Watts, and 1kW is double that of 100Watts. It's why QRPers get by quite happily working the world at under 5 Watts, mostly using homebrew equipment on CW. Now that is skilled. Sending CW at 18 - 25 WPM on homebuilt equipment is a different order of magnitude from pressing the PTT and talking into a mike on shop bought equipment which often has an automatic ATU built in.

The fact that there are pile-ups on DX stations is sufficient indication that DX stations aren't secret. The stations that have most success are those who have the best location, equipment and above all, antennas to have the edge on others. Shout loud enough through a 'loudenboomer' into a huge antenna array, and you'll be heard above others.

As I say, not so much 'skill' as resources, knowledge, experience, and time spent on air. I suppose some might argue that in broad terms, these factors together do indeed amount to a 'skill'.

It's not like they've found a cure for cancer is it?

Interesting to read adverts for amateur radio gear which play to the vanities of those with deep pockets - 'Command the band', 'winkle out the DX' and so forth.

Just my point of view - I don't expect everyone to share that view.

As I said earlier anyone else sat where I'm sat, using the same equipment and antenna, at the same time, on the same frequency would achieve the same result, as indeed they would. But the fact that some amateurs find DX enthralling and a useful use of their time doesn't impinge on my life - they only cause problems to each other - DX Pile-ups are nothing more than 'in-band' QRM which some amateurs choose to inflict upon themselves and each other out of choice. Arguably, they deserve each other!

As to contests - don't get me going on that! The bands become unusable to normal amateur radio activity, often at the weekends - the only time some amateurs have to get on air.
David, for the average educated bloke like me knowledge and experience is skill, I am a skilled chainsaw operator, that came about by gaining knowledge and experience of using a chainsaw.
Don't quite follow the watts thing.....
As said, there is plenty of other stuff going on in the amature bands apart from pile ups.

Lawrence.
David - I understand the points you are making and indeed agree with most of them. But I think that you are over-looking one highly-relevant point. To find a weak station and be able to listen and understand what is being said, especially during the mayhem of a DX pile-up, requires significant skill by the operator of that receiver: the precise adjustment of that receiver's controls and auxiliary apparatus, together with a knowledge of just what each component part of that receiving equipment plays in obtaining the clearest reception.
In transmission, a different set of skills are required. Having the strongest signal in a pile-up will certainly help establish a contact, but there is more to obtaining that contact that mere 'volume'. The timing of one's calls, their rate of announcement, the choice of phonetics, etc. all contribute.

The selection of the operator-controlled variables - for the successful reception a weak signal in difficult conditions and subsequent successful replying transmission - is not only based on knowledge, experience and available equipment, but also skill: choosing when, what, why and how. In summary, the precise control of those variables that are under the operator's control: that requires skill.

Al. / Oct. 10, '13 //
Re your skills as a chainsaw operator, as you of course well know, they go far beyond mere knowledge and experience and include considerable manual dexterity and an overriding need to be safety conscious at all times, working at heights, handling timber often weighing tons. You can - and people do - kill themselves (even professionals) with chainsaw accidents - you can't by pressing a PTT on a mike! I hope that doesn't sound too pedantic or perverse.

As to RF power, n terms of the received strength of an RF signal, it isn’t directly proportional to the transmitted power in Watts. EG:

1 Watt = 30 dBm (0 dBw)
10 Watts = 40 dBm (10 dBw)
100 Watts = 50 dBm (20dBw)
1000 Watts = 100 dBm (30dBw)

That assumes no transmission losses, which inevitably arise between the transmitter and antenna, especially in amateur radio stations. Radio amateurs seem to think that if they use an ATU to reduce the standing wave ratio to 1:1 that all the power from their transmitter goes to the feed point of the antenna.

Complicated business, which I profess no deep knowledge of myself, and have no particular interest in as the maths makes my eyes glaze over:

http://en.wikipedia.org/wiki/DBm

http://www.rf-amplifiers.com/index.php?topic=rf_power

http://www.evaluationengineering.com/art...ineers.php

I don’t think the average radio amateur – DX chaser or not, trouble themselves with these niceties – they just string together shop bought stuff and away they go. They’re hobbyists after all – few these days are professional RF engineers. Remember that the training and assessment for an amateur radio licence is pitched at the lowest possible level to minimise or obviate risks to other spectrum users, notably the emergency services and Air Traffic Control. The restrictions that public bodies such as regulators (Ofcom etc), place upon any of us must be based on the principle of proportionality and can go no further than that.

I support the licence structure, but it is not – as many imagine - a training course to enable radio amateurs to become competent at understanding RF engineering – it’s for the reasons stated. Some may want to read up beyond that – most (in my experience), do not. So long as they’re having fun, it’s of no great importance.

The RAE is a very elementary qualification which is why the C&G dropped it. We are constantly being regaled by the likes of RSGB with pictures of bright eight year old kids who have passed the foundation licence – the only test that is mandatory – the other two bolt onto that).

"Radio amateurs seem to think that if they use an ATU to reduce the standing wave ratio to 1:1 that all the power from their transmitter goes to the feed point of the antenna."

Surely not all radio amatures David.

Am still confused about the original watts statement

"100 Watts is double that of ten Watts, and 1kW is double that of 100Watts."

Lawrence.
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