wb4huc

lake travis, tx

Topics:
RigExpert AA-170 Antenna Analyzer | Omni VII Second Receiver | N4PY Software | Picasa



March 28, 2014

RigExpert AA-170 Antenna Analyzer

My newest toy is the AA-170 analyzer which replaces a 20-year old MFJ-259. The MFJ analyzer was getting flaky in its old age so I decided to replace it with something a little more modern and with more functionality.

My main HF antenna is a Tennadyne T6 log periodic. This antenna has six elements on a 12-foot boom and is mounted on 4 sections of Rohn 25. The rotator, thrust bearing, mast, and antenna are actually mounted on a Hazer that is installed on the tower. So the antenna isn't very high, and it's offset from the tower, and it's been up for about 14 years. I haven't done any measuring in a long time since the MFJ 259 flaked out on me. Below are the SWR graphs that I made using the AA-170 this morning. I'm pleased to see that the antenna is well under 2:1 SWR across all bands. Fifteen meters is the worst, where it's almost 2:1 at the low end and drops as the frequency increases.

20 meters 17 meters 15 meters 12 meters 10 meters

Here's a plot all the way from 14mhz to 30 mhz. It doesn't rise above 2:1 SWR until 29 mhz. The lowest SWR values are actually outside the ham bands. Inside the ham bands, as shown in the individual band graphs, the worst is 15 meters which is still under 2:1 across the band.


One of the neat things about the analyzer is the mult-swr feature where it will show the SWR values for up to 5 frequencies simultaneously.

SWR at bottom of each band SWR at middle of each band SWR at top of each band


March 07, 2014

A Second Receiver/Panadapter for the Ten Tec OMNI VII

Computer screen showing N4PY, HPSDR, and Logic 9 
          software

The station as of March 2014
This is the station as of March 2014. Click the photo to see a larger image.

The transceiver is a Ten Tec OMNI VII. The amplfier is an Elecraft KPA500. The antenna tuner is an LDG AT-1000 Pro II. My cw keyer is an MSC Smart Keyer III that I've had since around 1990. I use Kent dual paddles that I've had since the mid-1980's. The station clock is a Heathkit that I assembled around 1984. For digial modes I use a SignaLink USB interface. From the OMNI VII display you can see that the radio is operating in serial remote mode and controlled using the N4PY software package.

I have added a second receiver to the OMNI VII. There is a modification that can be made to the O7 that will route the signal from the Antenna 1 jack on the O7 to the two spare RCA jacks on the back of the radio.

The antenna jack of the second receiver is connected to these two spare jacks using a Y cable. These jacks are protected when the O7 is in transmit mode.

I use an SDR Softrock Ensemble II as the second receiver. I bought the receiver and the matching enclosure. My computer is a five or six year old Dell XPS 400 with the sound card integrated into the motherboard. I bought a new sound card that supports a 192khz sampling rate since the sampling rate of the card determines the amount of spectrum displayed in the software panadapter.

The card I bought is an ASUS Xonar DX 7.1 PCIE Surround Sound card. I wasn't interested in the surround sound capabilities, just the signal to noise ratio and the maximum sampling rate.

The sound card installed without issues, but I did have a problem with some of the software for the Softrock SDR. After I got these problems solved everything started working.

I run the Omni VII under software control. I use the N4PY software. For the Softrock receiver I use HDSDR. You can use VSP Manager to define a virtual comm port pair so that the N4PY and HDSDR software will communicate with each other. This means that when I use the mouse to click on a signal in the SDR panadapter display the N4PY software will tune the Omni VII to that frequency. Likewise, when I tune the frequency of the Omni VII from the N4PY software the HDSDR sofware will tune the Softrock to the same frequency.

I can also turn off the communication between the two programs and use the Softrock to listen to one band while the O7 is on a different band.

The Logic 9 logging software will read the frequency and mode from the radio for each logbook entry.

So for not a lot of money I was able to add a second receiver and panadapter to the Omni VII and so far I'm happy with the results.



March 23, 2014

N4PY Software

I operate the Omni VII under software control most of the time. I use the N4PY software package. This software ties together all of the other software and most of the hardware I use in the station.

The N4PY software communicates with the HDSDR software that is used to control the Softrock Ensemble II. When I change frequencies or modes in HDSDR, these changes are communicated to the N4PY software and the OMNI VII also changes. If I change the OMNI VII to a different mode or frequency these changes are communicated to HDSDR and the Softrock receiver changes.

The KPA500 amplifier is connected to the computer using a serial cable. The N4PY communicates with the amp so that when I change bands on the Omni VII the amp changes bands. The software also reads information from the amp like operating temperature, power output and fault codes. If the amp encounters a problem that causes a fault, the software reads it. The software can also put the amp in operate or standby mode, and can power the amp on and off.

The software also provides the frequency and mode to logging programs so that this information is automatically read from the radio for each new logbook entry.

One of the things I like most about the software is that it provides separate controls for each front panel function. Most of the controls on the front panel of the radio perform at least two functions, but they can only perform one of these functions at a time. The software spreads the controls out so that there are separate controls for each individual function.

But the thing I really like is the Model 302R remote encoder keypad. This device has a tuning knob, 12-key keypad, and three programmable function keys. The menu in the radio lets you select from three or four choices for programming the function keys. The software gives you a list of almost 50 different functions to choose from.

The software also lets you assign functions to 11 of the 12 keys on the keypad. The only key you can't assign is the 'E' or Enter key. If you program the function and keypad keys to those controls you use the most, you can almost operate the radio totally from the remote encoder keypad.

In my mind, the remote control is a necessity if you operate the radio under software control. It just makes things so much easier.

I'm hoping that whenever LDG brings their upcoming USB-100 interface to market that this can be incorporated into the N4PY software for automatically changing bands and antennas under software control.


Here are some photos of some of my past ham stations:


Ten Tec OMNI VI station with Model 253 automatic antenna tuner, Model 705 microphone, and Model 301 remote tuning encoder. A Ten Tec Scout is sitting on the middle shelf and an Argosy is on the top shelf.


Ten Tec OMNI VI station with Ameritron AL-811H amplifier and Ten Tec Model 238A antenna tuner.


Ten Tec Jupiter station with Ameritron AL-811H amplifier and LDG AT-1000 automatic antenna tuner.


Ten Tec Orion and Ten Tec Jupiter station with Ten Tec Model 238A antenna tuner.


Icom IC-756 Pro II station with Ameritron AL-811H amplifier and LDG AT-1000 automatic antenna tuner. A Yaesu FT-897 is sitting on the shelf above the Icom.

Picasa

Instead of putting a lot of photos on the web page I've been putting them on Picasa. I add to it from time to time, so here's the link:

Photos on Picasa