2014 February 23

KXPA100 with Optional Antenna Tuner

I am a little late getting this posted because I have been busy setting my station up for RTTY operation (a new mode for me) for the NAQP RTTY contest.

However, last week I received the Elecraft KXPA-100 amplifier which was backordered at the time I ordered the KX3. The KXPA100 is a compact 100 watt amplifier designed to boost the QRP signal from the KX3 up to the 100 watt level of a standard transceiver. It is primarily designed for those wanting to use the KX3 as both a portable QRP rig and a primary home transceiver.

KX3 and KXPA100
In Operation

The KXPA100 when inter-connected to the KX3 using the CAT 5 interface cable will work seamlessly with the KX3. Once the KX3 and KXPA100 are connected all of the functions of the KXPA100 are controlled from the KX3; including the amplifier on/off, band changes, antenna tuner and output power adjustment. When the KX3 power is increased above 10 watts the KXPA100 kicks in. When the power is set below 10 watts the KXPA100 is internally bypassed. The optional internal antenna tuner (located in the KXPA100) will automatically track and adjust with band changes. Like most automatic antenna tuners it contains memories that remember the settings per frequency segment and antenna selected (Ant 1 or 2). If the tuner does need to re-tune the process takes just a few seconds. The turner is wide ranged and should be able to match any reasonable antenna.

I wanted to give the new KX3 and KPA100 a try so I decided to make a few contacts during the ARRL CW DX contest last weekend. I had only planned to make 90 to 100 contacts but once I started, I was having so much fun with the KX3 that I found it hard to quit.

The KX3 is a marvelous CW rig. When combined with the KXPA100 it is a near perfect CW contest rig. I found it’s CW operation more enjoyable than my Icom 756 Pro III. The KX3’s receiver is very quiet and does an extraordinary job separating strong signals that are copious during contest operation. I didn’t experience any receiver de-sensing by strong adjacent signals as I sometimes do with the Icom 756 Pro III. I’m not putting Icom 756 Pro III down because it also does a great job in crowded band conditions, the KX3 with it’s roofing filter and latest generation DSP outperformed the 756 Pro III in my hands on testing.

Here is a summary of my results:

ARRL CW DX Contest – ALL Band, Low Power, Assisted (S&P)

Band	QSOs	Points	Countries
40m	46	138	25
20m	110	327	46
15m	94	282	43
10m	126	378	49

Total	376	1125	163

Total Score: 183,375

73,

Fred, KC9QQ

KC9QQ
Ready for NAQP RTTY Contest

After the CQWW WPX RTTY contest I decided to modify my RTTY setup so that it could operate FSK instead of AFSK. I wanted to do this because in the CQ WPX RTTY contest I had experienced several cases where the SSB filters (the only filters available during AFSK operation) didn’t provide the desired selectivity. In a previous post (SignaLink™ USB Not Transmitting) I talked about the modifications made to my SignaLink™ for FSK operation. I decided to tryout the modification in the NAQP RTTY contest on Saturday.

I didn’t have a lot of time to operate because I needed to take several hours off to attend our monthly astronomy club meeting. However, I was able to spend enough time with the new setup to realize that being able to use the RTTY filters in the Icom 756 Pro III resulted in a substantial improvement over the SSB filters.

The RTTY filters were able to do a much better job providing error free copy of stations adjacent to other strong signals. In a few instances, I used the Icom 756 Pro III’s dual peaking filter to pull weak stations out of the noise. I was impressed. There were a couple of stations that I was only able to copy about 50% of their transmission, but after I activated the dual peaking RTTY filter I copied them error free. I limited my use of the dual peaking filter because it did make it a little more difficult to tune in stations, but it was just a click away when I would run across a weak station that needed a little boost to be pulled out of the noise.

A Lesson Learned

I want to thank the station that took the time to tell me that I was off frequency. I was about 50 contacts into the contest, but seemed to be having problems being heard on the first or second call. Several stations had sent Agn? Agn? after I made my call. After I called one very busy station at least four times he came back and told me that I was off frequency. I looked at my radio and realized that I had left the RIT on! I turned the RIT off and stations quit asking me to repeat my call and report! Murphy is alive and well. I didn’t plan on setting any records; I just wanted work a new mode, hand out a few contacts and have some fun. All three objectives were accomplished.

Here is a summary of my results:

NAQP RTTY February 2014: Low Power, All Band

Band	QSOs	Points	Sections
80m	24	24	18
40m	43	43	22
20m	15	15	12
15m	30	30	13
10m	24	24	9

Total	136

Final Score: 10,200

KC9QQ

Adventures in Ham Radio

Daily Archives: February 23, 2014

KX3 / KXPA100 Given First Workout in ARRL DX CW Contest

Using a Modified SignaLink™ for FSK Transmission