Twin Panadapters

Click above to enlarge.

This screenshot shows the simultaneous capture of panadapter views at WA5MLF and W4UOA this morning. A QSO at 3745 kHz had one station that was strong enough for Carl to hear as splatter in the 3740 pass band. See Carl's screenshots here for better views of the effects at his location.

The station was not strong enough to be heard at WA5MLF below 3742. John's screenshot (panadapter with waterfall) shows some other random noise below 3740 (we were not transmitting at that time). The wiggly line around 3742 on John's waterfall display is RFI from an APC UPS in the other room.

- John

Splatter on 7191 kHz

This morning, during the RV Service Net on 7191 kHz a strong (S9+20) station on 7195 kHz generated some audible splatter on the net audio as heard at my location. Below are two different displays I captured from my Flex-3000, showing the energy that was received below 7192 and above 7195.

Click above to enlarge.

 The above image is the panascope display with the 5 kHz receiver bandwidth setting. I added a green horizontal line for reference to the noise floor on vacant frequencies below 7189. I set the receiver to display the peak received signal at each frequency sample.

Click above to enlarge.

This image is a capture of the waterfall display. The elapsed time from top to bottom is 30 seconds, for the window size (not full screen) that I was using. Splatter from the 7195 station is clearly visible above 7195 and below 7192.

Static Crashes on 3740

Here is an annotated screen shot of the waterfall display showing the static crashes as pale or brighter horizontal strips. The time scale is about 47 seconds from top to bottom.

QRM on 60 m

Here is a screen shot of waterfall display during KE4ID's turn on 60 m. Some Spanish speakers were operating 2 kHz above -- at 5405.5 kHz at 0734 CST.

Microphone specs & equalization

Since obtaining my Flex-3000 transceiver months ago I've been using the supplied FHM-1 hand microphone.  Early reports from my ham friends said that my voice sounded muffled compared with how I sounded using the old desk microphone with my Heathkit SB-104A. Below is a copy of the microphone specs graph from FlexRadio.  A switch on the microphone has two positions for what they call "tone settings":

• Setting 1 has a flat frequency response of 60 Hz to 16 kHz.
• Setting 2 rolls off some of the low end frequencies (-6 dB at 300 Hz) and provides 3 dB of boost at 2 kHz for "optimum articulation needed for DX / communication quality audio".

On-air reports indicated no appreciable difference between these two settings.

I explored the transmit audio equalization settings in the Flex-3000 to compensate for the microphone's apparent poor high frequency response.  I tried several configurations to boost the treble, up to the available maximum of +15 dB. Although I thought I had all the right boxes checked and buttons clicked, the audio reports were still unsatisfactory. I began to test some quick and dirty arrangements to use either my Andrea NC-61 headset or my original dynamic desk microphone in place of the FHM-1 microphone. These efforts indicated a need for better impedance matching and better shielding to prevent hum. My most recent inclination was to build a microphone preamp circuit in a metal box to accomplish impedance matching, gain, and powering (for the Andrea's electret element). The Flex-3000 front panel jack has 5 V DC available along with PTT, ground, and a balanced microphone input. A rear panel line audio level input is also available.

While reviewing the transmit audio equalization settings early this week I observed the audio closely on the audio spectrum display of the PowerSDR program and listened to myself on the SB-104A. The saved audio profile that I created months ago was not doing what the equalizer curve said it should. I created a new profile from scratch and found that it really did improve the audio spectrum appearance and sound. On air tests the next day confirmed this.  Below is a screen shot of the equalizer settings I am now using.

Note that the audio is boosted 15 dB at the 2 kHz and 4 kHz bands of the equalizer, and is cut below 500 Hz. The little Enabled check box can toggle this equalization with one mouse click. I found that this box was unchecked on the profile I had previously created and saved. I don't know if I lost track of that box during multiple changes followed by multiple saves or if I toggled it off for working digital modes. For the latter, I am now using saved profiles that set frequencies, bandwidth, equalization and audio paths (virtual audio cables) to ensure correct operation while making it easy to return to voice modes.

Thanks to all for their helpful signal reports!

John

FlexRadio 3000 operation

Here is a full screen shot from this morning's operation on 60 m. Click on the image to enlarge it. The main window shows the receive audio spectrum display. To the right are two open configuration windows, with my notes added in red text. Near the bottom left of the full screen is the mixer window, which provides one of the places to set microphone gain.

I'll continue to read about and tweak the settings per owner's manual and W1AEX.com documentation. When I get the right connectors together, I'll try my old desk microphone, too. I plan to do some testing on my dummy load while listening on the Heathkit transceiver via headphones.

Thanks for everyone's signal reports and audio recordings!

John