Hi Take,

On 7/3/2018 8:03 PM, Tsutsumi Takehiko JA5AEA wrote:
Joe, Just “listened and watched the show“???

I saw a critical message last night on a Japanese SNS that KH1/KH7Z FT8 OP should pay their respect to K1JT repeated calls and must promptly return RR73.

Never fear, I have worked KH1/KH7Z on 20 and 30m already. I hope still to catch them on 40m. :-)

This is just my back-of-the envelope calculation, but the link-budget improvement can be 15dB, not 7dB at Nslots=5

Additional gain comes from:

 1. Adopt QRA64 or QRA128 utilizing 3kHz wide fox TX bandwidth : +4dB gain
 2. 65% packed message length base on Bill’s suggestion : +4dB gain

Then, the figure becomes -14 + 7 + 4  +  4 =  +1.

Of course I encourage you to design and implement a protocol that will achieve this sensitivity improvement!

However: I do not accept either of the +4 dB numbers you have given. Steve has already pointed out part of the problem. You give no details of where you think you can gain another +4 dB from changes in "packed message length". I do not think that's achievable, either, while still conveying everything (1 Fox callsign, 5 Hound calls with RR73, another 5 Hounds with a report) in a single message.

        -- 73, Joe, K1JT

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