Monday, February 4, 2008

Equipment performance

We have received a number of requests for reports on the performance of our equipment. With the exception of our beach verticals which were damaged by the high winds and surf, and a laptop that failed, all of our radio equipment held up beautifully.

Here was the station set up:

E51MMM
Icom IC-7000 transceiver
LDG AT-7000 tuner
KD9SV Dxpedition II 80/160m preamp
Acom 1010 amp
Daiwa vswr meter
Dunestar bandpass filter
Microham CW Keyer
Heil Proset Quite Phone
Bencher paddle
Astron SS-30 power supply
Sony Vaio laptop running Win-test

E51NNN
Elecraft K2 transceiver
K9AY 80/160m preamp
Acom 1010 amp
Dunestar bandpass filter
Microham CW Keyer
Bose headset
Bencher paddle
Astron SS-30 power supply
Dell laptop running Win-test

Antennas - all beach mounted verticals near the high tide line
Force 12 Sigma 40XK - set up for 40m
Force 12 sigma 40XK - set up for 20m
Sigma 5 - band switchable from 20 to 10m remotely from in the shack
15m 1/2 wave vertical dipole built on a MFJ telescoping pole, and Fosters beer bottle balun
80m 1/4 wave vertical held up with a Spyderbeam 60 ft. telescoping pole
160m 1/4 wave inverted L held up with a Spyderbeam 60 ft. telescoping pole
17m / 30m dipole

Electrical Power - Shortly after checking into our motel room and before plugging in any of the equipment, we measured the 220 vac and found it to be about 204 vdc. It measured about 204 vdc on two different voltmeters. This concerned us somewhat, but there wasn't anything we could do about it, so we powered up the equipment with this as the mains voltage. We considered changing the primary voltage strapping in the Acom 1010 amps, but decided to give them a try first. The amps never complained, nor did the Astron 12 vdc supplies.

Once we had the equipment powered up, we did not turn it off during our 3 week stay. Our motel room was not air conditioned, and the humidity level was quite high. Turning off the equipment would have caused condensation to form and, potentially, cause electrical failures when turned back on, especially in the amplifiers. From previous DXpeditions to J7 where we also had had high humidity, we learned to keep the equipment powered up during the entire time of the stay.

IC-7000 transceiver - this radio performed well. It has an amazing amount of functionality for such a small package. It contains DSP, so there is no need for optional filters, thus allowing a wide range of bandpass options for various receiving conditions. Generally, I operated on CW with 700 hz or 500 hz bandpass, although occasionally, I would go down to 300 hz if the noise level was high, but that was rare.

This is a menu driven radio, and becoming familiar with all the various menu selections took time. This was a new radio for me, and I had used it only sparingly from the home station prior to the trip to E51. From home I concentrated on how to set up the radio for working split and adjusting the receive bandpass, as this would be key for working the pile ups. Once in E51, these menu functions quickly became second nature.

My only complaint with the IC-7000 was the effect strong stations would have on receiving. They tended to overload the front end and obliterate the other stations in the pile up. I had to "ride" the RF gain control down to levels where I could better copy the strong stations and work them quickly to get them out of the way. We have all experienced this effect, but I felt that it was worse than I had seen with other radios, especially my home station IC 756ProII. The dynamic range just wasn't what it should have been. In retrospect, I did not try operating with the AGC turned off; maybe that would have helped.

99% of our QSOs were on CW. I did work some SSB on 40m and 20m. The radio performed well in both modes. We did not operate any digital modes.

Acom 1010 - These 700 watt-rated amps performed without a hitch. We ran them anywhere from 500 to 700 watts for the entire operation. The amps will withstand up to 200 watts of reflected power before faulting off. These are sturdy units, and withstand the rigors of shipping without problems. It is not necessary to remove the single tube for shipping. One amp was packed in a GemStar case, and the other in a Pelican. In a GemStar case, the amp weighs in at about 51 lbs, so it not subject to overweight charges with the airlines. What more can I say!

Antennas - The beach mounted verticals performed spectacularly well....when they worked! We were loud. The only difficulty that we had with them was keeping them up in high winds and pounding surf, and preventing salt spray from shorting out connections. It took us 5 days to fully set up the 6 verticals. We initially set them up on the beach at the high tide mark. However, after a week of calm seas, the weather changed and high winds set in, making it difficult to maintain the verticals in the rough surf. We had numerous failures of PL-259 connectors due to salt spray shorting them out. We finally resorted to eliminating many of the PL-259s and twisting wires together and taping them with electrical tape to prevent the failures. On the Monday morning after the CQWW CW contest, four of the verticals had blown down. The next morning, the two Spyderbeam telescoping poles snapped in two like toothpicks.
The F14 Sigma 40XKs must be taken down and coils or horizontal elements changed to change bands. Taking the 40XKs down proved to be too difficult and time consuming for the two of us to do quickly or easily, so we simply fixed one on 40m and the other on 20m. Unless there is a lot of time and manpower available for antenna maintenance, any thoughts of using these antennas on multiple bands should be quickly squelched, in my opinion!

The F14 Sigma 5 worked well until salt spray shorted out the pc board on which the coils and relays are mounted. After several days of running this antenna with the amp (500 to 700 watts), an arch-over happened on the pc board resulting in high vswr. We disassembled the unit and found a carbon trace burned into the board. Although we could have scraped away the carbon trace, we figured that it would arc again, so we completely removed the board and reassembled the antenna without the coils and relays. The antenna resonated at 32 mHz. We added 10" wires to each of the four horizontal elements, and this brought resonance down to 28 mHz. Thus it became our 10m antenna. However, without the band switching, we no longer had the other bands, namely 17m, 15m and 12m that we needed. To compensate, we built the Foster's vertical dipole for 15m, and a dipole for 30m and 17m.

4 comments:

Anonymous said...

Hello George
Just found that you upload your E51MMM log to LOTW.
But our contact on 40 M in not confirmed by system.

RV6LFE E51MMM 2007-11-14 04:44 UTC 40M CW 7.00604

Could you tell me what is wrong? my callsign or date/time stamp?

Thanks in advance.
Tim
RV6LFE
mail: rv6lfe(at)novoch.net

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