giving line of sight transmission

tigerduck

Senior Member
German / Switzerland
Hello

I'm having difficulties in understanding a phrase in an English book for electronics.

The phrase in question is 'giving line of sight transmission' and the whole sentence is:

For VHF, UHF, and microwave signals, only the space wave, giving line of sight transmission, is effective.

Does 'line' mean 'information' in this context? May somebody also be able to paraphrase the whole sentence or would you need to know the context for that?

Your help is much appreciated.
 
  • maxiogee

    Banned
    English
    No, a "line of sight" transmission means that the transmitter and the receiver must have unhindered 'view' of each other… they cannot be on different sides of a mountain, or have intervening buildings blocking a direct line between them.
    "Line of sight" is as good an expression as you can find. Any paraphrasing of it would be more cumbersome.
     
    I am not certain without a little more context, but the construction of the sentence may be somewhat poor (and therefore make translating or understanding it difficult). Regardless, the phrase "line of sight" describes the word "transmission" with the meaning of in a straight line or path (such that the eye could see along) unimpeded by the horizon or possibly other obstacles (usually geographical features). The word I'm having trouble with in the sentence is "giving"; I would think that the space wave would be following, not giving, line of sight transmission. I actually think the writer meant to say "given" line of sight transmission, which would make the whole sentence become clear to me. However, I must admit to only a limited electronics background...
    I hope this helps at least a little.
     

    Brioche

    Senior Member
    Australia English
    paulrobert said:
    I am not certain without a little more context, but the construction of the sentence may be somewhat poor (and therefore make translating or understanding it difficult). Regardless, the phrase "line of sight" describes the word "transmission" with the meaning of in a straight line or path (such that the eye could see along) unimpeded by the horizon or possibly other obstacles (usually geographical features). The word I'm having trouble with in the sentence is "giving"; I would think that the space wave would be following, not giving, line of sight transmission. I actually think the writer meant to say "given" line of sight transmission, which would make the whole sentence become clear to me. However, I must admit to only a limited electronics background...
    I hope this helps at least a little.
    As a former radio operator, I have to say that this is normal radio jargon.

    HF radio waves are reflected from the iononsphere and the earth's surface, thus giving global communication coverage.
    HF is used for "short wave" radio transmissions.

    VHF and UHF (and higher frequencies) are not reflected by the iononsphere, thus giving "line of sight" transmission.
    VHF and UHF are used for FM radio and television transmissions.
     

    panjandrum

    Lapsed Moderator
    English-Ireland (top end)
    You may have a sky wave, bouncing off the ionosphere, a surface wave hugging the ground, or a space wave directly from transmitter to receiver.

    For VHF, UHF, and microwave signals, only the space wave, giving line of sight transmission, is effective.
     

    DaleC

    Senior Member
    Oh, now with Brioche's and Panjandrum's explanations, we can see that the clause "giving line of sight transmission" is defective communicatively because the word "only" is missing from it. And in fact, perhaps the entire sentence is defective factually because it seems that other types of wave don't even occur under this extra-discourse condition (the condition that the signal is of particular frequency ranges). It's like the conversational exchange,

    A: Your my favorite son-in-law.
    B: I'm your only son-in-law.

    Even worse it is impossible to tell what the point of the sentence is. Which is the immediately preceding discourse context: (a) types of wave, (b) signal frequency bands, or (c) the physical requirements of transmitting TV signals between two points? Without knowing the point, your question cannot be answered with assurance.
     

    gs3

    Member
    spain
    tigerduck said:
    For VHF, UHF, and microwave signals, only the space wave, giving line of sight transmission, is effective.
    It is very clear and correct to me (electrical engineer & ham radio operator): For VHF, UHF and microwave, only line-of-sight transmission (i.e. space wave) is effective. In other words, transmitter and receiver need to have a clear, unobstructed, straight line between them (well, more or less). This is as opposed to short wave frequencies which will be reflected by the ionosphere.
     

    cuchuflete

    Senior Member
    EEUU-inglés
    tigerduck said:
    .

    The phrase in question is 'giving line of sight transmission' and the whole sentence is:

    For VHF, UHF, and microwave signals, only the space wave, giving line of sight transmission, is effective.

    Does 'line' mean 'information' in this context? May somebody also be able to paraphrase the whole sentence or would you need to know the context for that?
    I agree with Gs3. In answer to the specific question by Tigerduck, "Does 'line' mean 'information' in this context?" No, it does not. It is, as has been stated clearly, part of a common term, line of sight.


    "giving line of sight transmission" is NOT defective communicatively
    Defective communicatively? It clearly communicates what it means to.
     

    maxiogee

    Banned
    English
    I thought I answered the question asked when I posted what is post 2 on this thread.
    But maybe I'm the fool who rushed in where wise men never go!
     

    panjandrum

    Lapsed Moderator
    English-Ireland (top end)
    maxiogee said:
    I thought I answered the question asked when I posted what is post 2 on this thread.
    [...]
    You did, of course, but as I'm sure you realise by now, that never stops the rest of us from coming along and agreeing with you from our own point of view or indeed possibly disagreeing with you completely:D .
     

    DaleC

    Senior Member
    It is nonsense to say "for VHF, only space wave transmission is effective" because for VHF, the other wave modes are not ineffective, but nonexistent.
    gs3 said:
    It is very clear and correct to me (electrical engineer & ham radio operator): For VHF, UHF and microwave, only line-of-sight transmission (i.e. space wave) is effective. In other words, transmitter and receiver need to have a clear, unobstructed, straight line between them (well, more or less). This is as opposed to short wave frequencies which will be reflected by the ionosphere.
    I think you are not distinguishing between what you know on the one hand and the wording of the sentence on the other hand.

    " For VHF, UHF, and microwave signals, only the space wave, giving line of sight transmission, is effective." This wording entails that these three signal categories travel in multiple wave modes, but that only the space wave mode is effective for some purpose unspecified. This entailment is invalid according to you and another commentator because you two say that space wave mode is the only wave mode these three signal bands travel in. Ergo, the sentence has either defective syntax or defective conception. The wording cajoles us to combine extralinguistic knowledge, spanning both common sense and elementary physics, to DEDUCE its implication. I think 90 percent of us would deduce a paraphrase to the effect of,

    "VHF, UHF, and microwave signals, propagating only in space wave mode, can only propagate by line of sight transmission."

    The phrases "effective" and "giving line of sight transmission" are vague in the absence of context -- and there is an absence of context. The device in formal written English of substituting a participial phrase for a relative clause or an adverbial clause is a dangerous tool in careless or unskilled hands precisely because its possible meanings (causality, temporality, etc.) are so varied. Too often, people use this substitution to sound elegant, and end up muddying the waters. In this case, we can (if I have not misunderstood the sentence) tease out the intended statement despite the prose craft, not because of it.
     

    gs3

    Member
    spain
    DaleC said:
    It is nonsense to say "for VHF, only space wave transmission is effective" because for VHF, the other wave modes are not ineffective, but nonexistent. I think you are not distinguishing between what you know on the one hand and the wording of the sentence on the other hand.
    Oh come on! The wording of the sentence is just fine. "for VHF, only space wave transmission is effective" is fine and is true. For UHF are other forms of wave effective? No, they are not. Therefore the phrase is true and correct.
     

    panjandrum

    Lapsed Moderator
    English-Ireland (top end)
    I agree with gs3.

    The reason the other modes are not effective is because of high losses, not because they do not happen at all.

    Taking that into account, and considering that the sentence would not occur in isolation but in a text explaining propagation characteristics of different frequencies, it conveys its meaning precisely and concisely.

    Am I bringing additional information to bear in my assessment? Yes of course I am - exactly as would any other reader who came across this sentence.

    Am I mistaken? Well that's entirely possible, for it is rather a long time since I last had to know this stuff, so the additional information I bring to my understanding of the sentence could be flawed. But I am confident that in its own context that sentence is clear and unambiguous to a native-speaker with specific interest in the topic.
     

    gs3

    Member
    spain
    panjandrum said:
    I agree with gs3.
    No you don't! ;)
    The reason the other modes are not effective is because of high losses, not because they do not happen at all.
    No, the fact is that the other modes are ineffective and whether they are ineffective because they experience high losses, or because they are non-existent, or for any other reason is immaterial. The fact is that they are not effective and the only other option is that they would be effective, which they are not.

    To the question "are other modes effective, yes or no?" there is only One answer: "NO, they are not effective"

    And if anyone would say "But they are non-existant!" I would "retort you have just made my case; how can they be effective if they do not exist?" and the court would rule in my favor.

    Suppose my company wants to build a road and I propose that an efficient way to build it would be to import several million little green men from Mars as laborers. I am quite sure my boss would say that is, most definitely, NOT an efficient way to build a road because the only other option is that I am correct and it IS an efficient way to build the road. It is no way to build a road, efficient or otherwise so it is definitely not "an efficient way to build a road.

    If I say "Cyclops could not see well" am I right or wrong? I am right. They never existed so they could not see well. In fact, they could not see at all.
     

    panjandrum

    Lapsed Moderator
    English-Ireland (top end)
    I still think I agree with you, despite your protest:p
    I agree that the reason the other modes are ineffective is immaterial:D

    The important point on which I will insist we agree is:

    gs3 said:
    Oh come on! The wording of the sentence is just fine.
     

    gs3

    Member
    spain
    Ok then. We agree that the phrase is effective. I can now go back to investigating more effective techniques of twiddling my thumbs while I remain in ambush for anyone who would disagree.:)
     
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