Sky wave
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Joined: Mar 2004
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From: india
Sky wave
If the transmission frequency of a signal sent by both surface wave and skywave is doubled what will happen to the dead space?
this question is from the GSP - radio aids edition 6.
please explain with detail the answer thanks
this question is from the GSP - radio aids edition 6.
please explain with detail the answer thanks
Joined: Apr 2009
Posts: 13,226
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From: down south
Surface wave attenuation will increase as frequency increases. Therefore the surface wave range will decrease.
Ionospheric refraction will decrease as frequency increases and attenuation will also decrease. Therefore the skywave range will increase.
Since the dead space is from the end of the surface wave range and the first returning skywave, then the dead space will increase.
Ionospheric refraction will decrease as frequency increases and attenuation will also decrease. Therefore the skywave range will increase.
Since the dead space is from the end of the surface wave range and the first returning skywave, then the dead space will increase.
Joined: Jul 2008
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From: Skating away on the thin ice of a new day.
With the limited info given lightning mate is pretty right but that is far too generalised to give a categorically correct answer.
Any mention of actual frequency used and time of day or night would make it more definite. ie If the starting frequency is quite high doubling it could see skywave diminish or non existent.Daytime has a dramatic effect on longer wavelength signals too.
Any mention of actual frequency used and time of day or night would make it more definite. ie If the starting frequency is quite high doubling it could see skywave diminish or non existent.Daytime has a dramatic effect on longer wavelength signals too.
Joined: Apr 2009
Posts: 13,226
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From: down south
Yes, I know exactly what you are saying, but I make the assumption that the question refers to the usable HF band.
This is typical of some ill thought out questions. This is not the case in the JAA examinations.
This is typical of some ill thought out questions. This is not the case in the JAA examinations.
Last edited by Lightning Mate; 16th January 2011 at 12:47.
Joined: Mar 2000
Posts: 8,571
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From: Arizona USA
The sky wave can be very potent on twenty metres, HF band.
I have had crystal clear contacts from aloft over the Indian Ocean to North America, Texas/California/Oklahoma, specifically.
Australia...nearly every night.
OTOH, Bombay was dead as a doornail.
Just as well with the latter folks.
I have had crystal clear contacts from aloft over the Indian Ocean to North America, Texas/California/Oklahoma, specifically.
Australia...nearly every night.
OTOH, Bombay was dead as a doornail.
Just as well with the latter folks.
Joined: May 2009
Posts: 611
Likes: 62
From: Down under
If the transmission frequency of a signal sent by both surface wave and skywave is doubled what will happen to the dead space?
There is something called the Skip Zone which is possibly what the above question is alluding to. If this is correct, any attempt at a reasonable answer will need to explore a wide range of possibilities since it will depend on the reference frequency chosen for the exercise.
Frankly the question as it stands seems both strange and irrelevant. Has something been lost in the translation somewhere?
FoR
Joined: Jul 2008
Posts: 1,146
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From: Skating away on the thin ice of a new day.
full opp rudder, lightning mate et al,
I've been doing radio on aircraft for >30 years and a ham operator for just as long and the term "dead space"
was new to me too!
Reminds me of some of the plainly stupid questions and terminology the DCA, DOTATG, CAA, CASA (whatever they were then) would throw at you doing the radio basics and specifics.
English was one of my better subjects at school and at times the exams appeared to have been written by a moron.
20 metres is one hell of a band for skip.
I've been doing radio on aircraft for >30 years and a ham operator for just as long and the term "dead space"
was new to me too!Reminds me of some of the plainly stupid questions and terminology the DCA, DOTATG, CAA, CASA (whatever they were then) would throw at you doing the radio basics and specifics.
English was one of my better subjects at school and at times the exams appeared to have been written by a moron.
20 metres is one hell of a band for skip.
