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Re: Homebrew satellite control system that can run on sBitx
I have now gotten an elevation system working very well using a linear actuator (12V) from Amazon.? ?Also created crossed yagi's to allow for circular polarization.? ? Using "J" half-folded dipole driven elements has turned out very well.? ? The impedances of these driven elements wasn't as large as I had expected (they are dragged downward in impedance by the influence of the nearby reflector and director).? ?However a very fortunate outcome was that the impedance of putting each crossed yagi in parallel with the other resulted in nice combined impedance.? ?I chose to use short feedlines that (corrected for velocity factor) were 1/2 wavelength, for the purpose of allowing me to use a nanoVNA to try and estimate the actual feed point impedance.? ?It worked!
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Putting the yagis in parallel using a BNC T-connector resulted in an almost perfect SWR on my 70cm set and tolerable on the 2meter set.? ??
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Here is a photo of the final antenna, with the booms and yagi's now implemented in standard 3/4 inch Schedule 40 PVC from Home Depot:
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I'm still very very new at all of this, but I have now been able send and receive AX.25 (packet) to the ISS very easily on 2 meters.? ?This is an APRS digipeater, so acts a little differently than normal digipeaters I'm familiar with.? ? ?I'm still working on figuring out the best software with which to approach it -- there are LOTS of users so it is a big crowded!
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Working my way back up to attempting the LINEAR satellites.? ?In the meantime, I have now worked out how to control the rotators remotely over WIFI using a raspberry pi to run the rotctld.? ?That will be for another post here.
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So far the Yagi's seem to be working amazingly well for the homebrew way that i built them!? (the box on the base is just for stability weighting)
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Gordon KX4Z
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Re: zBitX offset waterfall passband
I think the RIT got turned on in the second photo (off in the 1st) as I was playing around trying to fix that display offset error. It made no difference.
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However, I did get the odd frequency fixed in the second photo. Connecting via sbitx.local and adjusting tuning seemed to get everything aligned on the display for the correct frequency on the HDMI screen matching the frequency tuned to, but the offset which only appears on the zBitX screen remains. I also got VNC connected, but I am having problems with that mode other than viewing. |
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Re: zBitx Power Supply?
On Fri, May 23, 2025 at 02:02 AM, Li Cao wrote:
I¡¯m using a PD power supply that comes with my MacBook computer along with a 9v trigger cable rated at 5 amps. But I cannot set Drive beyond 60 with FT8 on 20 meters. If is over 60, the zBitx restarts when transmitting . I don¡¯t know it¡¯s the trigger cable or the PD voltage drop. Exactly. The current consumption during transmission is higher than what your power supply can handle, which is why the voltage drops.
The device turns off due to the low voltage, as it drops out of transmission and the voltage increases again, which is why it starts again.
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Gyula HA3HZ |
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Re: zBITx First Impressions from M7NDB
#zbitx
On Fri, May 23, 2025 at 02:19 AM, Li Cao wrote:
For low power you need a well-radiating antenna, then you will be successful in the connection.
It is advisable to call the CQ station and not the other way around that you are CQing, then the QSO may be possible, but you must transmit on a clear frequency so that they can really hear you and your transmission is not suppressed by another station transmitting on the same frequency.
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Gyula HA3HZ |
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Re: Up and Running Fully Portable
Yeah, I ran into the same issue with that OTG adapter. I think it's not so much an OTG adapter as a crisp, tasty waffle. I had one around, and, like you, got my keyboard and mouse working. Then I paired a handheld keyboard with a trackpad built in, and I'll likely use that. I think I'm going to make a technical bag to go along with the radio's go-bag, one with an HDMI cable, a 14-inch portable screen, and a better bluetooth keyboard I have that's got a built in trackball. Each of those things is bigger than the repurposed photographer's bag I'm using for the radio and its immediate gear. I need to get the radio out and update the firmware and UI anyway, so I'll do the pairing for the new keyboard while I have it out. I got an 8-pack of 18650 batteries and a USB-C powered 4-place charger that has been a real workhorse. I like that it doesn't need a mains plug. I'm about halfway through assembly of a 5-band link dipole. Once I get the basic build put together, I'll run it up a telescoping mast and tune it up. Then I'll crimp on bullet lugs to make connecting the links easy, and it'll be in service. I've got a 3-band link dipole already, but I need to replace the connectors in the links, and it doesn't have my favorite bands in it. Besides, I made the new one out of Kev-Flex. Durable. -=-=-=-=-=-=-=-=- 73, Gwen, NG3P On Thu, May 22, 2025 at 11:24?PM Gary-KI7PBR via <ki7pbr=[email protected]> wrote:
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Up and Running Fully Portable
¿ªÔÆÌåÓýBitXers, ??? Been playing with and learning
my new zBitx and I am having a blast.? I have made a couple CW
contacts almost immediately after receiving my unit.? I had a
couple unexpected hiccups in that I wasn't prepared for the
"Mini-HDMI".? The other was the USB-OTG adapter that came with
it was bad.? Fortunately I had another stuffed in a drawer and
decided to try it.? Keyboard came right up and I was able to get
the unit up in Host mode.? I paired up my bluetooth keyboard so
I no longer have to deal with the USB port for that. I am running a portable 16inch (USB powered) monitor along with the wireless keyboard and can run the rig on either 18650 batteries or my Bioenno 1212Ah based battery box.? Got the clock sync'd up and started up FT8 on 20m and made my first contact within in a minute.... Great start so far.? It's not a KX2 but this little unit is a lot of fun especially with all the build in apps which I still need to play with. Attached is a couple of photos.
-- "POWER, WE DON'T NEED NO STICKIN' POWER" - EVERY KX2 OWNER Always respect the airwaves, 73 de KI7PBR, Gary |
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Re: Safe to buy?
So if we are talking about the HRCC video and how his radio was resetting, he posted a follow up video and admitted that he used a 1A power supply. When he connected a 3.5A power supply, problem solved. ? ?I agree just having a solid aluminum baseplate as a heatsink with no mechanical ventilation could be an issue, I ordered a thermoelectric cooling fan that will attach to the back of the radio and that does add about 2 ounces. Despite these issues, I don¡¯t mind tinkering with radios and think it will be a fun experiment.? ? I can always take my G90 out if it doesn¡¯t work out. ? Best ?regards & 73 Jay KK7BVY On Thu, May 22, 2025 at 6:04?PM Jens/HB9JOI via <hb9joi=[email protected]> wrote:
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Re: Safe to buy?
From: Dave, N1AI via groups.io
Sent: Thursday, May 22, 2025 7:03 PM
Subject: Re: [BITX20] Safe to buy? ?
On Thu, May 22, 2025 at 08:57 AM, Jay Bremner wrote:
I ordered one because I can deal with these minor issues, it weighs under a pound, so perfect for POTA/SOTA and self-contained digital modes. ?
Personally I think the issues with current draw and heat generation make it
less than perfect for POTA/SOTA and self-contained digital modes.? The
review I linked has these two items as the first two negative points for the
radio.
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Hopefully these things will be improved over time, but from what I read
here it sounds like most people are operating them from home using wall current
and have added cooling solutions that add weight, as opposed to attacking the
root cause of excess current draw and heat generation.?
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Regards,
Dave, N1AI |
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zbitx gps module
I haven't received my zbitx and haven't had my hands on it yet, so maybe my question is moot.?
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With inexpensive and reliable GPS Modules such as the GT-U7, is there a way to implement it into the zbtix for time sync or maybe even location??
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The GT-U7 can ouput NEMA data via serial USB or TTL. I have used this module (with Arduino) and it has been sensitive enough to use inside my house.
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My first thought is to use an Arduino as an NTP server for the zbitz to sync to. However, I am curious if a more direct way could be possible so it can be used without networking.
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Ed
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Re: zBITx First Impressions from M7NDB
#zbitx
Shielding between the display and the RPi and shielding of the flexible connecting wire.
For sbitx I use copper foil and Kapton foil as electrical insulator because it can withstand temperatures better.
Another consideration is a single point ground, similar to the single point grounding of the station. Ground loops should be avoided.
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Gyula HA3HZ |
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Re: zBitX offset waterfall passband
On Thu, May 22, 2025 at 08:35 PM, Vic WA4THR wrote:
More anomalies. I connected the zBitX to an HDMI monitor/keyboard/mouse and now when looking on that screen the LSB signal on 7250 is correctly shown in the passband, while the zBitX screen is still offset, but the frequencies at the top of the HDMI display show the signal as being 7275, not the 7250 shown in the frequency display. What am I doing wrong here? On the zbitx, the RIT switch is in the ON position, is this intentional?
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Gyula HA3HZ |
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Re: zBitX offset waterfall passband
There are a number of issues that need to be?resolved... Open a issue with anything you find at:? On Thu, May 22, 2025 at 2:35?PM Vic WA4THR via <vhklein=[email protected]> wrote:
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Vic WA4THR
HA3HZ
Gwen Patton
Gary-KI7PBR
Jay Bremner
Jens/HB9JOI
Ed K.