Ignorant question about HF radio

Submitted: Tuesday, Jun 10, 2008 at 10:17
ThreadID: 58591 Views:2651 Replies:7 FollowUps:10
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Hi All!

Is anyone can suggest reasonably good reading about HF radio concepts? Manual definitely not that good – it explain well what functionality are but does not explain what they for. For example what are LSB, USB and AM modes and when I should use them? I been fiddling with my new-installed Barret 950 and discover that sound quality of AM station like ABS news much (and that means really much) clearer from my in-car “civil” radio then form Barret. Is it normal or I am doing something wrong? And I could not catch some stations at all. Sounds strange to me considering complexity of Barret versus “AM-FM radio”. Probably it something to do to SSB? And in general what is simplest way to check if it working well?

Anyone dare to explain or better still refer some good reading to me?

Thanks
Serg
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Reply By: Mike Harding - Tuesday, Jun 10, 2008 at 10:42

Tuesday, Jun 10, 2008 at 10:42
LSB = Lower Side Band
USB = Upper Side Band
AM = Amplitude Modulation

LSB and USB are low audio quality methods of transmission which minimise power usage and bandwidth. They are used by VKS737, Flying Doctor at al (they use USB). Amateur Operators and various other specialised users also use USB and/or LSB.

All public broadcast, ABC, BBC World Service etc use AM. If you try to listen to AM broadcasts on USB or LSB you will hear it but the quality will be poor - you MUST use AM to listen to these stations.

There is a good, free, PDF somewhere - I'll try and find it for you later when I have more time.

Mike Harding
AnswerID: 308974

Follow Up By: Member - Serg (VIC) - Tuesday, Jun 10, 2008 at 10:49

Tuesday, Jun 10, 2008 at 10:49
Hi Mike,

Thanks for replay. I been trying to use AM to listen to ABC, but sound quality still nowhere as good as from “AM-FM” radio. Awaiting for your “good PDF”.

Thanks
Serg
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Follow Up By: Mike Harding - Tuesday, Jun 10, 2008 at 16:51

Tuesday, Jun 10, 2008 at 16:51
Hi Serg

Take a look here:

HF Guidebook

Also some good info here:

Good info

And, of course, I can’t pass up an opportunity to put in a plug for Amateur Radio, you can programme you’re Barrett with Amateur frequencies.

Foundation Licence

With an Amateur Radio Licence you are not limited to the few VKS737 frequencies but have access to whole swathes of the HF band and are able to communicate with people across the world. One of the real pleasures of camping for me is being in the middle of the bush, miles from anywhere, and being able to chat with someone in Peru or Italy or Japan or America or…. :)

Mike Harding
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Follow Up By: Mike Harding - Tuesday, Jun 10, 2008 at 16:59

Tuesday, Jun 10, 2008 at 16:59
PS. Sound quality - none of the HF transceivers will have sound quality to match a car hi-fi. Their audio stages are usually low power and not that great on distortion etc, plus they have a small speaker with limited frequency response. Normally this doesn't matter because they are intended for listening to the voice from a simple communications perspective and are perfectly adequate for that.

A couple of things you can do: add a quality external loudspeaker or use an "FM transmitter" to send the HF radio audio to the car hi-fi.

Personally I find the output of my HF Amateur radio (Yaesu FT857D) to be quite adequate for ABC, BBC etc but I wouldn't want to listen to Chopin through it :)

Mike Harding
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Follow Up By: Member - Serg (VIC) - Wednesday, Jun 11, 2008 at 11:42

Wednesday, Jun 11, 2008 at 11:42
Mike,

Thanks a lot – great book and I will study it with great interest. As for inferior sound quality – I had throw away stock speaker without even connecting it! Apparently it related to antenna. When I listen to AM broadcasting immediately after switching transiver on then it is OK. Still not as good as “AM-FM” radio (strange indeed, considering that those radios fairly primitive comparing to my transmitter), but close enough. Problems begin after I press PTT button – antenna get self-tuned to transmitted frequency and became totally “detuned” for AM broadcasting. I been told by supplier that it is normal and there is no way to put antenna in “generic” mode (forget about tuning it on "prohibited" frequency!) except of power cycle transiver. Sounds quite moot indeed.

As for ARL – I been fascinated by this stuff for ages, but frankly life not that long and free to fulfit 5 almost full-time hobbies. Probably when I get older and less mobile :-))))))

Cheers and thanks
Serg
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Reply By: Member - Ed. C. (QLD) - Tuesday, Jun 10, 2008 at 10:52

Tuesday, Jun 10, 2008 at 10:52
Available right here in the EO bookshop is
The Australian Guide to HF Radio
which may be of assistance to you...


Confucius say.....
"He who lie underneath automobile with tool in hand,
....Not necessarily mechanic!!"

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AnswerID: 308977

Follow Up By: The Landy - Tuesday, Jun 10, 2008 at 15:08

Tuesday, Jun 10, 2008 at 15:08
I found it a good book...co-authored by Doug Taylor from Lake Macquarie Communications (Radtel).
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Reply By: Member - Footloose - Tuesday, Jun 10, 2008 at 13:48

Tuesday, Jun 10, 2008 at 13:48
For a "no speakda radio mate" approach, take a peek here
http://www.jimshire.aussiewide.com/plain_english.html
AnswerID: 308998

Follow Up By: Member - Footloose - Tuesday, Jun 10, 2008 at 13:49

Tuesday, Jun 10, 2008 at 13:49
Oops...No speakada radio
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Follow Up By: Member - Serg (VIC) - Tuesday, Jun 10, 2008 at 14:21

Tuesday, Jun 10, 2008 at 14:21
Thanks Footloose, but that reference is way too “plain English” – I would not mind a bit technical info as well. :-))))))))

Thanks
Serg
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Follow Up By: Member - Footloose - Tuesday, Jun 10, 2008 at 14:40

Tuesday, Jun 10, 2008 at 14:40
How technical ? The gook on this site is good, but not that "technical." Try the ARRL Radio Amateurs Handbook for technical.
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Follow Up By: Member - Serg (VIC) - Thursday, Jun 12, 2008 at 09:53

Thursday, Jun 12, 2008 at 09:53
Footloose,

Thanks for exceptional hint. I did not know about this book. It is my best download ever – practical yet technical enough (but not too much).

Cheers
Serg
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Follow Up By: Member - Footloose - Thursday, Jun 12, 2008 at 10:08

Thursday, Jun 12, 2008 at 10:08
It's not bad. I have a ciopy somewhere around here that I refer to from time to time.
I think I had most of it memorized by the time I was about 15...but it was a bit thinner then...and so was I :))
There's also an antennae book by the same people which isn't bad.

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Reply By: Member - Warfer (VIC) - Tuesday, Jun 10, 2008 at 16:19

Tuesday, Jun 10, 2008 at 16:19
*Ignorant question about HF radio*


Hiya Serg

There may be a couple here that lay claim to fame that they know it all,LMAO

But mate you hav a question just ask it without feeling stupid !


Cheers
AnswerID: 309027

Reply By: Member - John (Vic) - Wednesday, Jun 11, 2008 at 12:03

Wednesday, Jun 11, 2008 at 12:03
Serg I believe there is also a Barret users group on the Yahoo users groups.
I don't know how active the group is but maybe they can answer your Barret questions in a more specific way??

The Codan/Yahoo users group is very active and very good but obviously geared towards Codan radios.

Do a search on Yahoo or maybe someone else on here can provide the link to the Barret Group to help you out.
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Reply By: John R (SA) - Wednesday, Jun 11, 2008 at 22:26

Wednesday, Jun 11, 2008 at 22:26
G'day Serg,

Sounds like I was in the same boat as you a month ago (I'm not sure I've moved to a more advanced boat yet though!).

From home, I could hear bugger all, though occasionally I could pick up a pretty rough ABC transmition out of Alice Springs or Tennant Creek.

Having read a bit through this forum, bought a copy of the hf radio training kit which was basic, but helpful.

Of most help though - going walkabout with a vks membership and tuned in to scheds. It's quite an education.
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Reply By: Member - Footloose - Thursday, Jun 12, 2008 at 10:19

Thursday, Jun 12, 2008 at 10:19
Comparing a 950 to an AM receiver is like comparing apples and lemons. Both are edible...but there's quite a difference.
Yes the SSB does make a difference. Because of the restricted bandwidth used, it is "communications quality" rather than Hi Fi.
The simplest way to see if it's working well. Which parts ? Selcall, Telcall, DSP,aerial, basic comms check ?
In HF radio , few things are simple.
Probably the easiest way of checking is to join 737 and call one of the bases. You'll soon get the hang of it.

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