New VARA HF released 4-3-0 #VARA
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Graham
New VARA HF released 4-3-0
New for 2021 , additional 2750 Hz bandwidth mode added to the VARA family utilising available bandwidth, maximum rate is increased to 8489 Bps in 2750 Hz centered on 1500 Hz mid point tone. The Modem architecture , being optimised to maximise the available bandwidth with new carrier number's / bps rate combinations, all the facilities of the VARA system are maintained , monitor , chat module, bps , and winlink connectivity. Note the level numbers are, then, not directly related Compatibility with existing installations is maintained , by automatic mode detection , as per existing 2300 <>500 mode switching . Rig compatibility , ic7300 may be directly set to the required b/w, where as the ic7100 , requires the use of the SSB voice non standard bandwidth settings of 100 Hz <> 2900 Hz , further details are contained in the pdf documentation 73 -Graham g0nbd
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Siegfried Jackstien
hmm .. its a tad bit wide to be used on qo100 ;-) ... ok ok its
vara HF ... not vara shf hi hi 100 to 2900 ... sure can you set that in your sdr setup (example a pluto) ... but we should not use more as 2.7 there ... hmmm on the other hand there are stations splattering as wide as a barn door so as long as we keep it linear and not splattering then i guess nobody would moan about using 2.9kc ... wow ... not bad ... 8.5k in a 2.9 kc wide channel ... greetz sigi dg9bfc Am 02.01.2021 um 14:54 schrieb Graham:
New VARA HF released 4-3-0
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Andrew O'Brien
does this keep us in the USA "legal" in terms of FCC imposed baud rates. I can't remember those pesky rules ANdy K3UK
On Sat, Jan 2, 2021 at 12:16 PM Siegfried Jackstien <siegfried.jackstien@...> wrote:
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Andy
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Graham
HNY Sigi
Well , AO-100 has wide and narrow band areas, there are already VARA SAT , which has extended AFC and some link delay measuring modules as well , will also work with any steam powered ssb set ups that need very long tx/rx times , that is more suited to the sat link, as was designed specially for the sat , but , no reason why the high speed varafm-96 could not be used in the wide band section ? I would think the power density of a wide band FM signal is similar to the TV broadcasts ? and zero netting problems , being fm ? 73 -Graham g0nbd Ive never seen the AO-100 transponders full , there is a ROS-HF mode qso running, with prog set to 2 meters no different to the on-air modem, just the highest qrg coded these days .. and with ROS -HF more than one qso can be running at the same time in the same channel
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Graham
HNY Andy
Yes , just the same as the other vara HF modes , the individual carrier rates are 42 baud , 300 never really made much sense, other than b/w linked to speed / rate , far to high to be robust on HF ..but yes, crazy amounts of data in a speech channel , nearly as quick as the old 9600 on UHF Seems to be being driven by the emergency & ham<>mil users ..? 73 -Graham G0NBD
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Siegfried Jackstien
an fm signal is way narrower as the tv datv signals is so you
will have a way higher signal as the tv beacon (and other user
will be a bit "pissed") ... on the other way if you lower your
level to the same as the tv beacon ... its then only a few db over
noise giving not enough signal to noise for a good fm
decoding/demodulation ... so using the wideband transponder does
not work a well tuned setup should be spot on (also on qo100) ... how much mistune can the modem handle (if used on normal ssb mode?!? if say 50 hz plusminus is ok ... then also netting should work in vara mode on the narrowband transponder ... if not in the new 2.9 kc wide mode ... then use the 2.3 kc mode ... that should work in any case extended afc in vara sat?? ok then they arelready dealt with the
mistune (and the time delay over the qo100 sat) i did not try it yet ... so i can not say details or how well it
works ... HNY graham greetz sigi dg9bfc Am 02.01.2021 um 17:55 schrieb Graham:
HNY Sigi
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Andrew OBrien
Yes Graham . I just received a private email from USA air force MARS person interested in testing VARA FM on MARS repeaters . Interesting idea .
toggle quoted messageShow quoted text
Andy
On Jan 2, 2021, at 1:02 PM, Graham <g0nbd@...> wrote:
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Graham
Interesting Andy
Any of the VARA modes will run over FM link , during testing , with local station on 6 metres , who , was suffering from solar panel qrm , during the day, 'we found that switching to FM gave a significant speed improvement VARA-FM , has ' No Afc' , as is not needed for fm link , as the recovered tone range is not affected by the transmission , Hence 'designated 'fm' But , variations on the theme , could be AM , or pilot tone ssb ? the FM mode has much higher tolerance to switching times , to accomodate repeater usage , so, yes , will be ideally suited for MARS usage , Considerable work was carried out , modifying the vara-hf mode to vara-sat , to use with the ao-100 satellite , providing a ping system, that measured the frequency off set and the link 'round' delay time.. the tests where posted to one of the amsat groups , not sure if the ground station remains active ? 73-Graham nb: this version , could be used for any transmission path, I don't think there is a minimum delay ..
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James Clark
Is selection of the new 2750 mode automatic?
When I start my registered copy of Vara V4.3.0 with Winlink Express V1.5.33.0 the speed displayed below the Vara waterfall is 2300 and I cannot find a method to select 2750, Winlink Express permits switching between 2300 and 500 but nothing else?
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Graham
Apparently it's 'listed in the beta version , not yet embodied in the current release.
73 Graham G0nbd
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Graham
On Sat, Jan 2, 2021 at 05:16 PM, Siegfried Jackstien wrote:
nobody would moan about using 2.9kc ...Hi Sigi , The channel could be 2.9 k , the VTAC modem is 2.795 KHz but probably would not work, due to the circuit delays VSAT is based on the 2KHz b/w HF modem and supports the extended delay and provides auto capture and net ... May be when the Moon repeater is installed , the 4 seconds will also be catered for -) 73-Graham
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