My new G2 Ultra has a signal that wanders around the 4.020 to 4.450 MHz area, with no antenna connected. Or with one. Its present in both Thetis and piHPSDR. It interferes with the MARS frequencies in that area. Is this normal? Do others have this? Any Ideas on a remedy would be much appreciated.
Attached is a screenshot.
Dale
AA7GG
G2 Ultra Intermodulation?
G2 Ultra Intermodulation?
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Re: G2 Ultra Intermodulation?
It is present on my G2 Ultra as well with the antenna disconnected. But, hooking up my antenna the local noise floor covers it up. ( cannot hear it at all) I wouldn't think it would cause a problem as any signal would cover it up even more.
I imagine that the bandpass filters disengage above 4 Mhz and that is why it can be seen with the antenna disconnected.
James
WD5GWY
I imagine that the bandpass filters disengage above 4 Mhz and that is why it can be seen with the antenna disconnected.
James
WD5GWY
Re: G2 Ultra Intermodulation?
Doing a search here in the forums for birdies, I found a long thread about this very thing. It was about the problem being with a power supply in the Orion II boards. There wasn't a solution to eliminate it. Just a way to reduce it which requires SMD soldering. Since I don't participate in MARS it isn't a problem for me.
It looks like the design of the new boards in the radio didn't change to fix the problem. I imagine because there wasn't a great demand for it.
James
WD5GWY
It looks like the design of the new boards in the radio didn't change to fix the problem. I imagine because there wasn't a great demand for it.
James
WD5GWY
Re: G2 Ultra Intermodulation?
Yes, birdies!
Not intermodulation products (intermod's).
This is the thread that discussed where a lot of these come from and how to fix it, or at least move where the birdies reside:
[url]https://community.apache-labs.com/viewtopic.php?f=17&t=2922[/url]
It sure looks like this is the same sort of problem based on the type of noise described.
Since 90% of the Saturn board is a cut and paste of the Orion, this is not surprising at all. On the Saturn, the LTM4628EV is still labeled U36 on the schematic. The FSET resistor for U36 is labeled R196 on the Saturn schematic.
Assuming this birdie is noise from U36, changing R196 (within limits as specified on the U36 data sheet) should move that birdie one way or the other, but will not completely eliminate it. Care is indicated because it could become a game of "whack-a-mole" on other bands.
Not intermodulation products (intermod's).
This is the thread that discussed where a lot of these come from and how to fix it, or at least move where the birdies reside:
[url]https://community.apache-labs.com/viewtopic.php?f=17&t=2922[/url]
It sure looks like this is the same sort of problem based on the type of noise described.
Since 90% of the Saturn board is a cut and paste of the Orion, this is not surprising at all. On the Saturn, the LTM4628EV is still labeled U36 on the schematic. The FSET resistor for U36 is labeled R196 on the Saturn schematic.
Assuming this birdie is noise from U36, changing R196 (within limits as specified on the U36 data sheet) should move that birdie one way or the other, but will not completely eliminate it. Care is indicated because it could become a game of "whack-a-mole" on other bands.
Re: G2 Ultra Intermodulation?
James & Scott
Thanks for your quick response!
I read through the thread you provided about this issue. I had missed it with my searches.
Just my luck that this "intermod" or birdie is right at the frequency most used in my case. Surface mount mods are beyond my abilities. So I may have to abandon this Anan G2 adventure.
73
Dale
AA7GG
Thanks for your quick response!
I read through the thread you provided about this issue. I had missed it with my searches.
Just my luck that this "intermod" or birdie is right at the frequency most used in my case. Surface mount mods are beyond my abilities. So I may have to abandon this Anan G2 adventure.
73
Dale
AA7GG