G8JNJ

Hi Lonecrow,

That doesn't sound good.

If you open up thew new Signal Generator extension and switch it on using the default settings you should see a carrier at 10MHz on the waterfall with a level of about -60dB.

Regards,

Martin - G8JNJ

Hi Lonecrow,

OK that's good so it doesn't look like anything major is broken.

I'd suggest that as you are making a lot of changes to the config, it may be a good idea to buy a few decent quality SD cards so that you can backup an image of the whole KiWi and then you can recover, or at least quickly get back to a known good state without any hassle.

I'd save the current config to a new card and then load up the original config from the SD that came with the KiWi and update it to the latest version and then do all the basic setup so that you have a working KiWi. Then save that version to another new SD card.

You then have the original SD card supplied with the KiWi (get out of jail), a working basic recent config (gets you quickly to a good starting point for anything else on another card, and finally another with your most recent VHF config.

Yet another card would allow you to backup your most recent working version, so you can very quickly get back to where you were, if you do accidentally mess something up. You can then rotate the two VHF SD cards so that you are only a few steps behind if things go wrong.

I'm not a proficient coder, but I do mess around with my KiWi's from time to time and having a few backups on SD has saved me big time on more than one occasion when I thought I'd bricked the KiWi.

Regards,

Martin - G8JNJ

Hi Lonecrow,

If they are fairly short patch cables it won't make much practical difference. Ideally you would use the correct impedance throughout, but it's less critical for receive only purposes.

Note that frequencies on the airband commonly have off-sets to accommodate 8.66KHz channel spacing within 5KHz frequency steps supported by older aircraft radios and also to allow multicasting from several sites on the same frequency (typically for wide area stuff like Volmet).

Aircraft and some ground based transmissions (typically at smaller or grass strip airfields) also have slight frequency errors that can often be observed on spot frequencies.

Regards,

Martin - G8JNJ

Hi Lonecrow,

Yes you can use the airband and FM band filters together, if the airband filter is good enough you may not need the FM band notch.

I think the reason you don't see it with the dongle and SDR Sharp may be an issue with the KiWi that you probably wouldn't otherwise notice, but this is what I'd hope to test.

To get the frequency off-set correct you may need to either adjust the transvertor reference frequency and / or the KiWi Frequency scale offset (kHz) value.

Regards,

Martin - G8JNJ

Hi Lonecrow,

I think the problem could be a very strong out of band VHF Digital TV signal that is being down-converted to a frequency that is being aliased by the KiWi to the frequency range you are seeing.

The reason for trying the Airband filter is to see if it reduces the unwanted signal that may not be suppressed sufficiently by the transvertor's built in filters.

The 30MHz low pass filter will help test to see if the problem is the down-converted un-signal that is being aliased by the KiWi sampling frequency from somewhere around 70MHz to 18MHz.

As I say, it is only a theory at the moment.

Regards,

Martin - G8JNJ