lake travis, tx

Automatic Antenna Switch | Current Station | FT-817ND | RigExpert AA-170 Antenna Analyzer | Omni VII Second Receiver | N4PY Software |

January 18, 2015

Automatic Antenna Switching

K7AGE has a video on his YouTube channel that describes how he added automatic antenna switching to his station.

This seemed like a pretty cool thing to do so I thought I'd see if I could add automatic antenna switching to my Omni VII.

I use N4PY's control program to operate the Omni VII. This software supports a serial relay board called the ADR2200. I ordered one and wired it to the control box of my Ameritron RCS-8V remote antenna switch and it works fine. Now when I change bands using the software the Ameritron switch will select the desired antenna for that band.

The nice thing is that the operation of the Ameritron switch is unaffected. It can still be used in manual mode by using the selector knob on the switch to change antennas.


K7AGE YouTube video

ADR2200 Relay Board

Current Station

I took a new station photo and captured a better quality image of the computer display.

The station as of February 2015

This is the station as of February 2015. Click the photo to see a larger image.

On the table top, from left to right:

  • Ten Tec Model 937 PS for accessories; Astron SS30M PS for the OMNI VII.
  • LDG AT1000Pro II automatic antenna tuner; Elecraft KPA500 Amplifier; Ameritron RCS-8V antenna switch control box;OnTrack ADR 2200 serial relay board for automatic antenna switching.
  • Ten Tec OMNI VII transceiver; SignaLink USB digital interface.
  • External speaker for OMNI VII;Ham IV rotor control box.
  • Heil Gold Line microphone and boom.
  • Softrock Ensemble II SDR underneath the computer monitor.

I have three antennas. All of them are supported by a Rohn 25 40-foot tower. A Hazer is mounted on the tower so I can lower the antennas to work on them from the ground instead of having to climb the tower.

I use a Tennadyne T6 log periodic antenna for 20 through 10 meters. The six meter antenna is a Diamond A-502HB 2 element beam which is mounted above the T6. The last antenna is a 40/30 meter dipole.

Here's a better image of the computer screen than the one in the above photo. This screen shows three software packages running. Click the image for a larger view.

Screen image showing the station software

The HDSDR software that operates the Softrock Ensemble II is shown in the upper left part of the screen. This radio is used as a second receiver/spectrum display for the OMNI VII. See the section below that describes the Softrock SDR.

The HDSDR and N4PY software packages can talk to each other. I can point and click on a signal in the HDSDR spectrum display and the N4PY software will tune the radio to that frequency. I can change modes in the HDSDR software and the N4PY software will follow.

The same is true when using the N4PY software. A frequency or mode change here will also change the HDSDR software.

The HDSDR/N4PY software link can be deactivated. When the link is turned off each radio can be tuned independently. The Softrock can be tuned to any frequency within its range and the Omni VII can be tuned to any other frequency within its range.

The N4PY software is in the lower left of the display. This software controls the OMNI VII transceiver. It also talks to the HDSDR software, the Elecraft KPA500 amplifier, and the Logic 9 logging software. On the right side of the N4PY window you can see the control buttons and information for the KPA500. See the section below that describes the N4PY software.

The right side of the screen shows the Logic 9 logging software. I've been using the Logic software for about 15 years.

August 03, 2014

New QRP Radio

I have sold the Ten Tec R4040/YouKits HB-1B CW qrp radio and replaced it with a Yaesu FT-817ND. I decided I wanted a multi-mode radio and I wanted to operate on more bands than the CW radio has.

I owned an FT-817 ten or twelve years ago but sold it to get an FT-897, and I sold the FT-897 last year. So now I'm back to the FT-817 which I plan to keep.

My first two QSO's were at 2.5 watts. The radio was connected to a 13.8 volt power supply and connected to the log peridic antenna. I contacted S51DX on 20 meter phone just after midnight yesterday, August 02, and then worked K4P yesterday during the day.

I have a weekly schedule on Sunday mornings with a friend over in Kerrville, TX on 40 meters. Kerrville is about 75 miles away from my QTH as the crow flies. He was using his FT-817 at 2.5 watts and I was using mine at 5 watts and we each had 5 by 7 signals on the other for the whole QSO.

I'm working on putting together a portable station with the FT-817, a 7ah gel cell, an end fed wire antenna for 40/20/15 meters and a Buddipole vertical.

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

Screen image showing the station software

I have added a second receiver to the OMNI VII. There is a modification that can be made to the Omni VII that will route the signal from the Antenna 1 jack on the radio 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 radio is in transmit mode.

I use an SDR Softrock Ensemble II as the second receiver. I bought the receiver and the matching enclosure. 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 transceiver 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.