Hallo Group,
a short report of the last weekends LF test by DL0UL/p.
We started building up the UHF antennas for contest operation. There was a
12m and a 17m mast with yagi groups installed. On satuday we brought up the
LW ant. I was fixed between a fir abt 15 m and the 12m mast. the spacing was
abt 120m. From the 12m mast the wire was fed over a 50 m distance to the
station. On the opposite side 4 radials each abt 150 m were spread.
TRX was a TR7 with PA.
The formation was easy to tune for matching to the 50 ohm output of my PA.
The antenna current was abt 2 A peak. But: the noise was S9 to S9 +20 dB.
And: there were interferences from the UHF station (432 MHz) . The noise was
caused by the AC generator and the different computer monitors and switching
powersupplies but the UHF operators were not willing to switch off for a few
hours.
To heare any signal on the band we had to turn on a 30 dB attenuator. So we
only could work a few stations in the suoth germany area. There was
DJ7RD at 0605 got 589 gave 559
DJ2EY at 0615 589 539
DJ2LF 0623 569 539
DF2PY 0803 549 539
After one hour of calling CQ the Equipment started oscillating on abt 50 khz
during the unkeyed gaps. So we stoped the operation.
Result:
It is not possible to run a big VHF or UHF contest station parallel to a LF
station.
So: For the next LF fieldtest we are going to use only battery supply, no
computers and any other trouble making equipment.
We are going to Implement bandpass filters to the RX ant TX path. A loop
antenna is under development, may be only for RX operation or for RX and TX.
We will see. And we are planing to run a KW station for X-band operation
next event.
Fortunately the weather was dry and sunny. A few of us ever got a sunburn.
So the whole equipment (LF and UHF) including the tents was easy to
dismantle.
We are planing to make a new LF test with improverd equipment.
73 de DL1SAN
| 