HF response over India.
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HF response over India.
In the process of getting area checked for the 737 based in the Middle East.
Needed to get in touch with OPS over central India. Tried a phone patch oh HF (on 22 different HF and VHF freqs) no joy. Is it normally this difficult to get in touch.
Needed to get in touch with OPS over central India. Tried a phone patch oh HF (on 22 different HF and VHF freqs) no joy. Is it normally this difficult to get in touch.
You don't say how much experience you have of HF but here goes.
Do you have a chart which lists range from the station you are calling against time of day to assess the best frequency? If the sun is high at the midpoint between you and station you want to contact then go for a HIGHer frequency, if the sun is LOWer go for a LOW frequency.
That said if you get no joy just try any frequency for really long range (several thousands of miles). I recall going down to Mombasa one night and decided to patch Ops via Stockholm to advise progress. Tried all the theoretical freqs with no success. So decided to try them all! Got Stockholm loud and clear on a very low freq (was it bouncing the long way round the world?).
Even HF SSB can be a bit hit and miss (you should have tried it when all we had was AM) but perseverence pays off in the end usually.
Good Luck!
Do you have a chart which lists range from the station you are calling against time of day to assess the best frequency? If the sun is high at the midpoint between you and station you want to contact then go for a HIGHer frequency, if the sun is LOWer go for a LOW frequency.
That said if you get no joy just try any frequency for really long range (several thousands of miles). I recall going down to Mombasa one night and decided to patch Ops via Stockholm to advise progress. Tried all the theoretical freqs with no success. So decided to try them all! Got Stockholm loud and clear on a very low freq (was it bouncing the long way round the world?).
Even HF SSB can be a bit hit and miss (you should have tried it when all we had was AM) but perseverence pays off in the end usually.
Good Luck!
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It is very hit or miss. And mostly miss.
For a company phone patch I would start with Stockholm and then try San Francisco, who has recently installed a remote on Guam. Calcutta and Karachi are very… frustrating.
For a company phone patch I would start with Stockholm and then try San Francisco, who has recently installed a remote on Guam. Calcutta and Karachi are very… frustrating.
I've crossed from Malaysia to the Middle East many many times and I'd say that I've had better success getting hold of Chennai over the Bay of Bengal, but not so much success with Mumbai over the Indian Ocean.
I'd say that about 10% - 20% or so of the time we've gone all the way from talking to Mumbai on VHF all the way to Muscat (and the reverse) without being able to contact Mumbai on any HF frequency once.
Quite often only one frequency will be working and the ATC bloke will be flat-out on it ..... you won't get a word in edgeways and will have to wait until they SELCAL you, and even then it may not work.
I'd say that about 10% - 20% or so of the time we've gone all the way from talking to Mumbai on VHF all the way to Muscat (and the reverse) without being able to contact Mumbai on any HF frequency once.
Quite often only one frequency will be working and the ATC bloke will be flat-out on it ..... you won't get a word in edgeways and will have to wait until they SELCAL you, and even then it may not work.
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HF Mumbai...
HF communications are not easy, especially around India.
Two reasons.
First is that Mumbai still uses year 1942 issued Cossor radios.
Second is pilot's knowledge of HF is limited to "higher sun, higher frequency".
Might help you a little. I am a "Radio Ham" on 10, 20 and 40 meters bands...
xxx
First, let us talk of Stockholm Radio. Everyone knows them.
Get their website to get the current propagation chart.
Initial call, say where you are, so they turn their antenna to receive/transmit better with you.
xxx
Mumbai Radio (some of this applies to Karachi and Chennai)
On the chart, you see "MumbaI" then a few frequencies.
MID2 denotes frequencies common to Middle East HF stations group 2.
As an example, Karachi is among MID2 stations, so is Tehran, and Bahrain.
in Mumbai, the antennas for MID2 are oriented to favor the direction of that traffic.
And as you mentioned, "the higher the sun, the higher the frequency".
When you call Mumbai, tell them on which frequency you are transmitting.
The operator might be monitoring several radios, needs to know which one to answer you on.
Example "Mumbai, this is Speedbird 123 on 56, good evening". (56 for 5658) -
xxx
The other frequencies for Mumbai, i.e. AFI3 or INO1 might not be usable for you.
This because the frequencies are not monitored at the time, or wrong antenna orientation.
Happy contrails
Two reasons.
First is that Mumbai still uses year 1942 issued Cossor radios.
Second is pilot's knowledge of HF is limited to "higher sun, higher frequency".
Might help you a little. I am a "Radio Ham" on 10, 20 and 40 meters bands...
xxx
First, let us talk of Stockholm Radio. Everyone knows them.
Get their website to get the current propagation chart.
Initial call, say where you are, so they turn their antenna to receive/transmit better with you.
xxx
Mumbai Radio (some of this applies to Karachi and Chennai)
On the chart, you see "MumbaI" then a few frequencies.
MID2 denotes frequencies common to Middle East HF stations group 2.
As an example, Karachi is among MID2 stations, so is Tehran, and Bahrain.
in Mumbai, the antennas for MID2 are oriented to favor the direction of that traffic.
And as you mentioned, "the higher the sun, the higher the frequency".
When you call Mumbai, tell them on which frequency you are transmitting.
The operator might be monitoring several radios, needs to know which one to answer you on.
Example "Mumbai, this is Speedbird 123 on 56, good evening". (56 for 5658) -
xxx
The other frequencies for Mumbai, i.e. AFI3 or INO1 might not be usable for you.
This because the frequencies are not monitored at the time, or wrong antenna orientation.
Happy contrails
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When you call Mumbai, tell them on which frequency you are transmitting.
The operator might be monitoring several radios, needs to know which one to answer you on.
Example "Mumbai, this is Speedbird 123 on 56, good evening". (56 for 5658)
The operator might be monitoring several radios, needs to know which one to answer you on.
Example "Mumbai, this is Speedbird 123 on 56, good evening". (56 for 5658)
Just a tricky way to "encourage" their answer I've some times experienced.
After useless attempts declare "Mumbai, this is Speedbird 123 on 56 TRANSITTING BLIND... ... ..." curiously somebody replied quickly
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6624 is long time gone... I remember that one...
But 11300 still exist. I heard a few guys last year around Khartoum.
Yet I was around Sal (Cape Verde).
You never know how far HF will go, or not go.
Not long ago, got STO radio on 11345 from Northern Argentina.
xxx
Happy contrails
But 11300 still exist. I heard a few guys last year around Khartoum.
Yet I was around Sal (Cape Verde).
You never know how far HF will go, or not go.
Not long ago, got STO radio on 11345 from Northern Argentina.
xxx
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You never know how far HF will go, or not go.
Two years ago, over the Indian Ocean, worked 20 metres, aeronautical mobile, clear as a bell with a ham operator in Austin Texas.
73's
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But 11300 still exist
Very often used to connect gnd atco without phone line link. What a chaos !
Generally we can get Chennai radio over the Bay of Bengal on our outward leg from SIN with a 1300 UTC dep. Coming home 1800 UTC, lucky to get anything. Sometimes get a relay through Columbo on HF, or other aircraft on VHF.
Most of the time nothing until we get Jakarta or KL on VHF. We do try all the frequencies.
Bit of a busy airway to be out of coms for an hour or two.
Most of the time nothing until we get Jakarta or KL on VHF. We do try all the frequencies.
Bit of a busy airway to be out of coms for an hour or two.
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Thanks for the replies so far.
FFB - Did everything you mentioned...went through 19 HF freqs in all (situation was a tad important).
Which agency looks after 11,300?
FFB - Did everything you mentioned...went through 19 HF freqs in all (situation was a tad important).
Which agency looks after 11,300?
