Re: Vacation update - Hendricks Qrp BitX20A correction

k9jri@att.net <k9jri@...>
 

The original BFO frequency was 10999.250 rather than 10999.450. can't read my own notes :)

--- In BITX20@..., "k9jri@..." <k9jri@...> wrote:

We just returned from two weeks on "The Isle of Palms", SC where we stayed at the Wild Dunes resort. Band conditions were terrible and the hi rise condo that we stayed in seemed to be a better shielded enclosure than E.F. Johnson used to put around Viking II.

I had two antenna tuners with me. An Elecraft T1 and an SGC-239. The antennas were a 20M dipole connected directly to the T1 and a W3EDP multiband antenna connected to the SGC-239. The 20M dipole was used with the BitX20A and a SWL PSK-20 with N3ZI DDS2 vfo. The W3EDP was connected to my SWL Retro-75, 75M AM rig.

I also had an aluminum MacBook with me for logging and digital modes.

No contacts were made with any of the rigs. The antenna environment was terrible. The 20M dipole was on the balcony (3rd floor) and the W3EDP could only be strung at night.

Some observations about the BitX20A were that I had several probably answers but the comment was that they could not copy my audio. When I would listen to myself on the other radio it always sounded like there was severe RF in my audio. I believe that the BitX20A does not like to be right next to the antenna even though my DC power cord has a ferrite sleeve choke and the front panel mic connector has a ferrite sleeve choke inside the cabinet. I was using a 7.5 AHR Glass Mat battery as my small 2.9A switching supply clobbered to entire band with noise. Again, it was right there with the antenna.

I believe that I also had the BFO frequency set too low and did not have much low frequency audio response. I have reset the BFO to 10999.50 since I returned home and have better LF response. It had been set at 10999.450. I also tested with the rig in the near field of an antenna and found that my electret mike (Heil HM-iC) is much more susceptible to RF than is my D-104/T-UG9. Naturally I had taken the smaller electret mic on the trip.

Digital operation with the PSK-20 was terrible as well due to RF getting into the MacBook. Everything was on a steel table on the deck with a 3' piece of coax connecting the tuner to the rig.

I believe that the important lesson learned was to test the gear with the intended antenna setup to see if it will work. Another lesson was that a laptop and sound device (Griffin iMic in this case) just add fuel to the fire as regards RF interference.

I hope to be in better shape for the next trip as I have a NADC-40 and a PFR-3A ordered from Hendricks QRP. I believe I will be in much better shape with an all-in-one CW rig like the PFR-3A.

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