Receiver gaps - TUNING ISSUE

[vk2kyp1]

I have a Chinese clone of a HackRF with a H2 portapack R9 and I have found the following gaps in the receiver, using the sound App. 945 to 1999 MHz 2171 to 2300 MHz 2701 to 2920 MHz 4201 to 4720 MHz

I am using a Sytron Donner 1720 Sythesiser with the output set to -70dBm. Mayhem version 1.8 of the firmware The gaps are sharp and I feel the sythesiser is not being programmed correctly? Thank you regards Gary vk2kyp

[NotherNgineer]

Can you please try the latest Mayhem firmware? I don't seem to have this issue on my Chinese clone H2+/R9. ADS-B RX wouldn't work, for example, if it couldn't receive 1090MHz.

[vk2kyp1]

Hi, Thanks for suggesting a firmware upgrade now running 1.9.1. 1090 and 1296 Mhz are now working on the sound and signal generator apps Regards gary vk2kyp

[NotherNgineer]

@vk2kyp1 Are you still unable to receive the other frequency ranges?

[vk2kyp1]

Hi I have not had time to check the other frequencies, hopefully later today

[vk2kyp1]

Hi I have just checked for receiver gaps with the 1.9.1 Mayhem firmware these are:

2171 to 2170 MHz 2700 to 2936 MHz 4201 to 4560 MHz

The HackRF looses sensitvity on the higher frequencies, I would like to hear from anyone to confirm my results

Thank you Gary vk2kyp

[NotherNgineer]

@vk2kyp1 Is there a typo in the first one 2171-2170?

I confirm that two PortaPacks cannot communicate with each other on some frequencies. However, I do not know yet if it's a transmit or receive problem (or both), and if only R9 is affected.

[vk2kyp1]

I am sorry for the Typo, the results should be 2171 to 2300 MHz 2700 to 2936 MHz 4201 to 4560 MHz

thank you for spotting this

gary

[NotherNgineer]

There is certainly an issue, and it seems to affect other HackRF board models as well.

For example, when I set the Audio app for WFM, 200K BW, at 2170.8 MHz, I see a little birdie or something around 2170.9. But the birdie does not move as I increase the frequency from there, until I get to 2300 MHz. But then if I turn the frequency down from 2300 Mhz, then whatever it was receiving at ~2301 MHz continues to be received at all frequencies until I get down to ~2170.8 MHz again.

Also, if I manually enter a frequency that has a strong signal such as 2450 MHz, and then manually enter a frequency between 2171-2300 MHz, it seems that the tuner is still receiving the 2450 MHz signal.

So it would seem like setting the frequency to a value in the ranges you've mentioned does not result in any tuning change of the radio receiver, at least within a certain band.

It might be interesting to test this in HackRF mode versus running Mayhem firmware.

[NotherNgineer]

Just looking at the birdies, it doesn't look like this issue occurs in HackRF mode, when HackRF is attached to a computer running CubicSDR.

[NotherNgineer]

Please re-test this after nightly firmware n_240128 comes out later tonight. PR #1819 should fix at least some of these dead bands.

[gullradriel]

Close due to fix and inactivity of op