Re: vara
#Software
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On Sep 1, 2019, at 1:16 PM, David Michael Gaytko // WD4KPD <wd4kpd@...> wrote:
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Re: vara
#Software
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On Sep 1, 2019, at 3:54 PM, KC9SGV <kc9sgv@...> wrote:
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For Sale: Funcube Pro Plus #FS Funcube Pro Plus
#fs
Tony
All:
I have a Funcube Pro Plus Dongle for sale. Covers 150 kHz ~ 1.9 GHz. Best offer shipped CONUS. Tony -K2MO
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Re: For Sale: Funcube Pro Plus #FS Funcube Pro Plus
#fs
any takers yet?
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Re: For Sale: Funcube Pro Plus #FS Funcube Pro Plus
#fs
Tony
Barney et all:
The Dongle was sold.
Thank you.
Tony -K2MO
On 9/6/2019 4:16 PM, Barney wrote:
any takers yet?
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Over-Driven FT-8 QRM #FT8 QRM
#FT8
Tony
All:
The interference caused by over-driven FT-8 signals is concerning. The distortion that shows up on either side of the FT8 watering hole is often stronger than the signal one is trying to copy down the band. The attached image shows an example of the bandwidth occupied by distortion products that are well beyond FT8 operating frequencies. This has been going on for some time now and it seems most prevalent on weekends when there's lots of activity. Am I the only one noticing this? Tony -K2MO
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Wa4kfz
I suspect too many hams are operating with the SSB compressor on. One advantage of the newer gear is that it supports a defined digital mode where the compressor is always off.
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73, Mark wa4kfz
On Sep 21, 2019, at 4:50 PM, Tony <DXDX@...> wrote:
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Posted to the Opera facebook page's
Today SV8RV did copy my 0.2mW signal in OP05 via QO100. Dish is 2 meter
Peter, reports the 200 uW carrier power was measured at the feed point of his 2 meter dish, [noting , that in terms of energy expended , power deployed equates to 100 uW ] SV8RV , taking the signal off air at 10GHz
Quite outstanding , taking the frequency and path involved , not to mention the AO100 sat !
73-Graham
Spots in the EA data base, show a series of -20 / -21 dB spots from SV8
2019-09-22 10:44:19 PA1SDB JO33KH SV8RV KM07KS 2.035 1.296.600 -11 Op05_||||||||||||||||||_~11dB 2019-09-22 10:44:19 PA1SDB JO33KH SV8RV-1 KM07KS 2.035 1.296.600 -11 Op05_||||||||||||||||||_~11dB 2019-09-21 16:48:14 PA1SDB JO33KH SV8RV KM07KS 2.035 1.296.600 -20 Op05__~21dB 2019-09-21 16:48:14 PA1SDB JO33KH SV8RV-8 KM07KS 2.035 10.368.000 -21 Op05__~21dB 2019-09-21 16:47:41 PA1SDB JO33KH SV8RV-8 KM07KS 2.035 10.368.000 -20 Op05__~20dB 2019-09-21 16:47:41 PA1SDB JO33KH SV8RV KM07KS 2.035 1.296.600 -19 Op05__~20dB 2019-09-21 16:47:41 PA1SDB JO33KH SV8RV-1 KM07KS 2.035 1.296.600 -18 Op05_||_~19dB 2019-09-21 16:47:07 PA1SDB JO33KH SV8RV-1 KM07KS 2.035 1.296.600 -18 Op05_||_~19dB
2019-09-21 16:47:07 PA1SDB JO33KH SV8RV KM07KS 2.035 1.296.600 -18 Op05_||_~19dB
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Graham
Its only single tone , no intermod products , don't matter where the alc is set, that's harmonics , due to the aggressive tone switching , mfsk produces a similar set of sidebands , but not as bad ,, wspr2 makes the same , but the rate is slow, so no one notices ..interesting arrl have issued a statement , stating its not compatible with there data award's ?
73-Graham G0NBD
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
I check my transmitted digital signals (FT8, etc) with a US$30 SDR USB dongle and SDRSharp freeware. The cheapest dongles don't receive below 25 MHz, but that doesn't matter. Put a dummy load on your transceiver, select 10 meters, send CQ's or VVV's in your chosen mode, and view your transmitted spectrum in SDRSharp. (This is a poor-man's spectrum analyzer.) Avoid overloading the dongle; if the dongle is close enough to your dummy load, you won't need to connect a whip antenna to the dongle.
If you're splattering, it will be obvious in the SDRSharp waterfall display. With this setup a ham can easily adjust the audio levels between the computer and the transceiver to achieve a proper RF signal -- without having to wait for other hams to tell you that you're splattering. These SDR dongles are Swiss army knives for hams. I encourage everyone to get one, unless you have the luxury of a real spectrum analyzer in your shack. The dongles don't make calibrated measurements, but I seldom need calibration. Relative measurements are good enough. 73, Chuck, K4RGN
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Chuck,
If you run one of the RTL $10 dongles, you can select , direct conversion in the driver , and the device will Rx from ~~ 0 to 25 MHz ish , it cuts out the front end and just uses the back a/c convertor Usually enough stray coupling to work, if not , you can attach a line to the board , if you google RTL direct conversion, there are various shots of where to connect to Perhaps a better display is the Spec-Lab software , justlink the SDR sharp detector audio with virtual audio cable , then you have a choice of decoder , I think the audio b/w of the sdr sharp system is constricted , not wide enough to monitor say VARA FM 9600 mode , , which is often deployed via constricted audio b/w Scope probe and pc sound-card , with Spec-lab , makes a very good audio measuring tool as well , check the data input audio b/w against the recovered off air 73-Graham g0nbd
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Tony
Graham:
Single-tone modulation shouldn't
produce inter-mod products, but some of the FT8 signals behave
that way as if there were 2-tones in play. Could you elaborate on
aggressive tone switching and it's effect?
Tony -K2MO
On 9/22/2019 12:15 PM, Graham wrote:
Its only single tone , no intermod products , don't matter where the alc is set, that's harmonics , due to the aggressive tone switching , mfsk produces a similar set of sidebands , but not as bad ,, wspr2 makes the same , but the rate is slow, so no one notices ..interesting arrl have issued a statement , stating its not compatible with there data award's ?
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Graham
Hi Tony The modem in ROS is Phase continuous , may be other systems are also, but , the ROS system , embodies design features that are missing/not as developed from other systems , ''Gray noise'' is the general term However , fluctuations may be observed on the TX power meter , these , appear to be a by product of the filtering in the TX . the abrupt changes in Tone , appear to be subjected to the filter characteristics , phase shift , group delay etc, which in turn , adds phase / time distortion , the resolve of which is amplitude variation Racal listed various option fit filters , some , voice , some data , so i suspect the problem was known about some time back , two filters in the tx/rx path , 40 MHz roofing and the 1.4 MHz pass/band , using the widest possible filter , can reduce the ‘side bands’, the DSP compensates for disturbance , but , from a transmission aspect, its better to maintain the ''waveform''
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GEO satellite for the Americas.
#digital
If you are interested to find out more about the efforts to secure our own GEOstationary satellite over the Americas, please join the new GEO IO group.
All digital modes will be possible through it. Save those old Direct TV dishes... https://groups.io/g/GEO KC9SGV
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Tony
Graham:
Thank you for that explanation. I can
see how the CW hard-keying analogy could apply to digital. If this
is something inherent in FT8, the side-bands would worsen with
stations running high-power.
I was surprised to see that some hams
run near legal limit with FT8 and I'm not sure if the developers
intended the mode to be used that way.
Tony -K2MO
On 9/23/2019 2:46 PM, Graham wrote:
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Re: Over-Driven FT-8 QRM #FT8 QRM
#FT8
Graham
Tony .
These modes are ' base band heterodyned' as in the generation is performed at the base band , in this case audio , the ' waveform' is then heterodyned / mixed to the wanted frequency , the opposite of the RX process , where audio is presented to the DSP , after the RX has recovered the 'Audio wave' , Tx power should not alter the side band ratio , as long its its linear , Alc could provide a leading edge over shoot and tilt of the TX envelope , that's something, the on/off keying , deployed in Opera is susceptible too , its necessary to reduce the drive to the onset of ALC to prevent a spike on the leading edge,if the audio keying is used , Replacing the CW-Key on the other hand , the signal utilises the TX envelope shaping , the system was developed , using the 20 wpm test signal from the racal ma1723 as the standard 'shape' Power wise , that's a unfortunate situation , the concept of narrow b/w short burst signal is really counter productive , as can be seen from the levels deployed , multiple access at low s/n is best provided by the appropriate techniques , making use of the SSB b/w channel , requiring a second layer in the coding applied to the 'modem' ie the tone placement routines . 73-Graham g0nbd
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Re: GEO satellite for the Americas.
#digital
Echostar 9 So, there is a proposal out from ORI (Open Resource Institude) for rented bandwidth on Echostar 9 at 121 deg West. All the FLdigi modes will be able to be repeated by it. The uplink is via an aggregator on commercial frequencies. The downlink is direct on 12 GHz, but you must homebrew your receiver. This could be a SDR dongle and SDR# Windows software. Join the GEO.IO Group to read more. https://groups.io/g/GEO
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Re: GEO satellite for the Americas.
#digital
Andrew OBrien
Very interesting, thanks for the info and the link .
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Andy
On Oct 1, 2019, at 6:16 PM, KC9SGV <kc9sgv@...> wrote:
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QRPGuys DSB Digital Transceiver
Ken wa4mnt <wa4mnt@...>
Gang,
We are pleased to offer the QRPGuys DSB Digital Transceiver kit. It includes three easily changed FT8 band modules for 40/30/20m. The kit uses all thru hole components. Price is $40. We are also offering bare band module pcb's for those wanting to experiment with different bands and modes, 4 for $10. Come by and see it at <https://qrpguys.com/digital-transceiver>. ken - wa4mnt www.qrpguys.com
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Re: GEO satellite for the Americas.
#digital
Theodore A. antanaitis
aggregator on commercial frequencies Not sure what this implies. Any guesses? Ted WA7ZZB
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