How high latency is tolerated?

Lasse Moell

I am off to a *very* remote place and will have Inmarsat terminal available. This means latency will be 3-500 ms but quite stable. Will this allow for connecting to my radio or is it a waste of time even trying? I really need this entity confirmed... but beeing at the wrong end
What did the folks at Herd use for remote control?

Jim Gilliam

Latency presents two problems:

1. When you reply to the other transmission, the other operator will wait for as long or longer of a half second for your reply.

2. After you finish your transmission, keep your transmitter keyed for at least an extra half second before you unkey.

It is a nuisance to do this but it, at least, gets you remoting.

Jim, K6QE

Lasse Moell

I am fully aware of the transmit/receive issues with high latency, but will SSDR allow for this? I have had SSDR drop connection when I had varying latency, going from a few millisecs to several hundreds. This time I assume it will be more constant but high latency.
Just to make things clear, this will not be the primary way of communication, but rather an experiment and allowing me to make a contact with this entity while using my home station.

KY6LA_Howard

While I have no experience running on an Inmarsat terminal, I do regularly remote via 3zG, 4G and Wifi from at least 6,000 - 10,000 miles from my SoCal Base. In fact. I am currently experiencing 500-700 ms latency from the South of France to SoCal. But I am able to communicate at least via SSB Unfortunately what you are talking about may be "Science Project" in which you may need to test it to see if it works. I also would.like to hear from the Heard Island team as o what they used.

ctate243

Sounds like if you are that remote you may be better off operating from.. that location? (rare, entity, grid, iota.. et al..)  ;-) ;-).

Michael Coslo

I'd certainly hate to contest with 300 ms latency.

Lasse Moell

I will operate from there, but as I said, I also need this entity my self hence remote using my home station

John - K3MA

On the plus side I bet you can arrange timing such that you have no pile up to deal with in order to make your contact and the DX will be on exactly the right band for the propogation at the time you call them.  

No such luck for the rest of us.

I think I would gladly deal with the latency issue to gain the above two advantages.  Might we arrange that you sign into our Smartlink enabled Flex stations and make the DX QSO for us?

You also might want to check that the contact will count against ARRL criteria if that is important to you.  My vague understanding is that it would not unless your client station is in the same country as the remote station.

Lasse Moell

John, never thought of the implication on having the client in a different country. Dang, I have to look into this. No biggie though, I'll never reach HR anyhow
Thanks for pointing this out. /Lasse SM5GLC

Lasse Moell

Guess I'm good to go
"“It has always been permitted for a QSO to count for both stations, if either station was operated remotely from a control point within the same DXCC entity,” Sumner explained. “Now the location of the operator doesn’t matter; the operator could be on the far side of the Moon if he or she could figure out how to remotely control a station on land back on Earth from there.” Transmitter location continues to define a station’s location, and, for DXCC purposes, all transmitters and receivers must be located within a 500 meter diameter circle, excluding antennas."
http://www.arrl.org/news/arrl-board-okays-changes-to-dxcc-program-vhf-and-above-contesting-rules

John - K3MA

Seems like you are.....good luck.

Ria

I did part of ARRL SSB from my apartment in Buenos Aires, about 5k miles away. Seemed to work well. Latency was pretty high.

Inmarsat may work, but it will definitely be a bit painful

Ria