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Re: A couple QDX questions: 60 meters? & 9v vs 12v
WA8LMF wrote something about our presence on the 60-meter band that hams in the U.S. should keep in mind.
The 60 meter band is part of the larger 5.060-5.450 MHz band, which is a federal/non- federal shared band that is allocated to the fixed service on a primary basis and to the mobile (except aeronautical mobile service) on a secondary basis. The 5.060-5.450 MHz band is primarily used by federal agencies for ship-to-shore and fixed point- to-point communications. Non-federal use of the 5060-5450 kHz band includes state government licensees and licensees in the Industrial/Business Pool that operate standby and/or backup communication circuits for use during emergency and/or disaster situations, entities prospecting for petroleum and natural gas or distributing electric power, coast stations and aeronautical fixed stations. The Commission added the Amateur Radio Service as a secondary allocation after determining that such frequencies could be useful to the Amateur Radio community for completing disaster communications links at times when existing frequencies in the 3.500-4.000 MHz (80 and 75 meter) and 7.000-7.300 MHz (40 meter) bands are not available due to ionospheric conditions. It concluded that such an allocation represented the best compromise available to give the amateur service access to new spectrum while assuring the federal government agencies that their use is protected. |
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Re: A couple QDX questions: 60 meters? & 9v vs 12v
Whether FT8 is legal on 60 meters depends on where you live. In the US and the other countries in the Americas that have mirrored the US rules (including Canada, but not Mexico which has a full band allocation), the legality of FT8 operations is questionable. Those rules allocate 5 channels on the 60 meter band, and it is specified that CW and digital operations must be at the center of a channel. That appears to allow only one FT8 signal per channel, right in the middle,?which is not how FT8 is normally done. The ARRL does not currently recommend FT8 operation on 60 meters in the US, but a number of hams are using the mode and are not sticking to the 1500 Hz offset. The power limit on 60 meters in the US is 100W ERP referenced to a half wave dipole; you won't exceed that with a QDX and any likely antenna on that band. (If you have an antenna on 60 meters that can exceed that limit when driven with a QDX, I want to meet you!) The customary channel for FT8 operation is channel 3; 5357 kHz USB, with the center of the channel at 5358.5 kHz. (Set WSJT-X to an offset of 1500 Hz to be strictly legal in the US.) All of the FT8 operation I have heard is on that frequency, regardless of country. It's often busy but not overloaded, so there is no need to spread out to other frequencies. A number of countries, including most of the nations of the EU, have a full band allocation on 60 meters rather than a few discrete channels. In most cases it's the?range from?5351.5?¨C 5366.5 kHz that was approved at WRC-15.?FT8 operation on 60 meters is fully legal in those countries with no restrictions other than license class (check your rules) and the 15W EIRP power limit in many countries. Unlike the US power limit, that's based on an isotropic antenna rather than a half wave dipole. The limit could make the use of a 60 meter Yagi or other beam antenna with your QDX illegal. If your QDX is producing 5W output, using an antenna system with more than?+5dBi gain (including feedline losses, and tuner losses if used) would exceed the power limit. You'll be fine with the usual simple wire antennas, including half wave wires with any feed arrangement. The UK went its own way, with a number of frequency blocks of varying sizes available. One of those is 5354 to 5358 kHz, which appears to allow FT8 operation on the usual frequency IF an offset of 950 Hz or less is used. (The FT8 signal is about 50 Hz wide so you have to stay a bit away from the edge of the block.) Presumably it's legal to have a QSO with a non-UK station that is?using a larger offset. The rules also limit antenna height to 20 meters above ground, but allow 100W PEP and 200W EIRP. Hans is in Turkey, one of the nations with the full ITU-allocated band and a 15W EIRP power limit. He doesn't have to worry about restrictions on FT8 operation while he is there but does need to be aware of the power limit. The Wikipedia article about the 60 meter band has a list of the countries with allocations on the band:? On Wed, Nov 10, 2021 at 12:37 PM Fred Spinner <fred.spinner@...> wrote:
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Re: Order "in transit" at Grace-Hollogne for 3 weeks?
Well, a day after I wrote to Hans with my concern. The package arrived at my front door a few minutes ago.? Great Job, Hans. As you can see it arrived a little worse for wear which might explain its delay. Internally, it appears OK, we will see.? So, it has arrived.? Looks like that Grace-Hollogne can a pretty tough place.
Kent. |
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Re: QDX , Lost my TX power
I have re wound L14, I have 2 watts on 80M 2 Watts on 40M 2 Watts on 30M and 4 Watts on 20M, I am not fussed about 3dB, I am running at 9V. Current drawn on 4 Watts is 1.1A, on 2Watts 300mA, so I am not losing the power in the lowpass filters! odd 20M is the loudest band. I will learn how to calibrate and see if I can receive any FT8 on 20m. I can only assume when running 5 Watt it was hooting!
I will measure the harmonic and share the plots 73 Andrew G8UUG |
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Re: QDX Extremely Low Receive Volume
#qdx
I don't know if this is related, but I noticed a while ago, when working with other SDRs, that the signal strength of the stations I was trying to monitor would vary depending on the strength of background noise. I discovered that my computer sound card driver had a checkbox to turn on or off an AGC for the mic input, and it was checked. When I unchecked that, I was able to adjust the levels manually to get more consistent receive results in WSJT-X.??
-- 73, Dan - W2DLC |
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Re: A couple QDX questions: 60 meters? & 9v vs 12v
Just like with any other regulator design you want to use low ESR capacitors.? MLCCs usually are, tantalums usually are, and disk ceramics usually are.? Verify before whipping something together out of junk box parts.? That schematic is fine for use with a low ripple input supply or battery.? ? If building an AC to DC linear supply much more capacitance is needed on the input and it doesn't hurt on the output.? Fred W0FMS? On Wed, Nov 10, 2021, 10:21 AM Gregg Myers <gregg.w7grm@...> wrote:
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Re: QDX - rig control error
I don't know exactly why, but when I've had issues getting rig control to work on MacOS or Linux I've found that FLRIG is more forgiving.??
Try setting up FLRIG to control it and then set WSJT-X to work with FLRIG. Also from experience, I've learned that I need to reboot between settings changes when things don't work on some systems.? It seems to lock up the I/O in some cases. In those cases port failure can be mistaken for wrong settings. --Neil, W2NDG |
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Re: A couple QDX questions: 60 meters? & 9v vs 12v
I am building mine for 9V for the same reason, to use with batteries.? I have a couple of different switching converters and can always do a linear regulator for home use. I also think that 9V will be better for the AMS1117 regulators over time than 12V will be.? Fred W0FMS? On Wed, Nov 10, 2021, 9:26 AM Bill Lamm <kd9mdl@...> wrote: Gregg W7GRM..? I have been thinking on the same lines.. possibly overthinking as I look at your picture.. I have some 3s LiFiPo surplus batteries that should power the QDX and Raspi for a weekend.. |
Mike Perry, WA4MP
Shirley Dulcey KE1L
Retired Doc
Andrew Lenton
Daniel Conklin
Fred Spinner
Neil Goldstein