Category Archives: VHF

VHF Winlink

I started looking into how to use VHF Winlink with the Icom 7100 and it’s built in sound card. I am close to getting this working. The Mail server nodes are all in the Harlingen Tx area about 30-40 miles from my QTH. The closest working digipeter is in La Feria, TX. Sadly, there does not appear to be a working digipeter in Brownsville. In order to get everything working you will need the following:

  1. CAT7200 software – This creates a virtual serial port that maps to the IC-7100 USB CV-I interface. Pretty handy software and should work for other older programs as well. Good overview of the setup can be found on WB4SON’s blog.
  2. UZ7HO SoundModem – This is a software TNC that connects to the virtual port created above and to the RMS Express software via TCP connection. W2YG has some good material on setup for Signalink hardware.
  3. RMS Express – I have used this before for HF email using WINMOR. For VHF at 1200 baud you will need to use packet winlink.

For setup info recommend seeing the video by K4REF showing an overview of the usage. I cannot report 100% success at this time. I am able to connect to the mail server and start handshaking with it. Unfortunately, no mail has been exchanged. I suspect that packets are being lost in the exchange resulting in retries and eventually it gives up. I’ll be playing with this some more and see if I can get a message through. Hard part is done with the rig and software setups.


IC-7100 now on VHF/UHF

It took long enough but I finally setup the IC-7100 for VHF/UHF use. The rig was programmed with the local repeater frequencies using RT-Systems programming software and a download from Repeater Book. Pretty straightforward overall. I should be able to use the IC-7100 on digital VHF nets run hear locally. There is a 6:30 net on Wednesdays through the repeater and a Simplex net on Thursdays at 7pm. I will still share the discone between this rig and the Yaesu FT-2900R.

One thing I noticed thus far is that he IC-7100 is hitting the repeaters in Harlingen and in South Padre Island. Not sure why this is but glad it seems to work.

Next up I’ll try and configure DStar.

Update on APRS

About a year ago I got APRS working with a Baofeng radio, a Easy Digi interface from N5CEY and a surplus iPhone running PocketPacket. I basically set it up, tested it and put it away.  In December, I put the APRS system back together and nothing seemed to work right. Over several days nothing but frustration. I decided to try this again this afternoon. This time I got it working the first time. Go figure. For future reference things are setup as follows:

Baofeng UV-5R:  VOX=1 volume up about halfway.

PocketPacket: Tracking ON, Report Altitude ON, TX interval 15 minutes, APRS-IS DISABLED, Audio Modem ENABLED, Transmit ENABLED, VOX trigger 500mS, Digipeater path Via 1 = Wide1-1; Via 2 = Wide 2-1.

Iphone volume full.

Next I will look for a way to strap the components together for portable use.

2m Tropo Ducting is On!

Tropo Ducting is on this morning (8:30am) in our area on 2m. Check it out:


Setup APRS Station

I finally broke down and bought a digital interface from Cliff, N5CEY that connects my Baofeng UV-5R to an iPhone. The iPhone is an older 4S model that is now retired after having been upgraded. It does not connect to a phone service but the WiFi and GPS work fine. I installed the Pocket Packet app and after a bit of fiddling with the radio and the app I started successfully sending APRS packets to the local digipeter.Mission accomplished as I now have a low cost dedicated APRS system to play with.

Worked the local VHF Digital Net

W8WKE runs a Wednesday night digital net at 6pm on our local repeater system. I had been wanting to try it for sometime but did not have an interface for my VHF rig. Clifford, N5CEY, hooked me up with one of his Easy Digi USB interfaces for my Yaesu FT-2900R rig. I set up Fldigi on my radio laptop and set it all up to the rig. The net uses MT63-2000L protocol. When the net started I was able to start decoding the transmission without any issues. Unfortunately, I could not transmit. The Interface handles the PTT with the rig and appears to the PC as a serial COM port. I had both DTR and RTS enabled but nothing worked. Then I noticed a small enable check box above the COM setting. I enabled it and the transmit started working without a hitch. I have played with HF modes on DM780 so I need to now learn Fldigi. When I get back from my next business trip I plan to hook up the VHF antenna to the IC-7100 and try and work it from there with HRD. Working this net was a lot of fun and I am looking forward to trying it again.

2m Tropospheric Ducting!

I finally experienced VHF tropospheric ducting tonight. I worked a station near San Antonio on simplex FM on 2m. I also heard and made contact with several stations in the upper valley that I had never been able to contact before. This was on 75W with my discone antenna up about 15ft. One of these days I need to get my 2m Moxon up to thirty feet and try it with the Yaesu at 75W.

A couple of new projects to think about…

I have been looking into making a custom air variable capacitor for an improved magnetic loop antenna. This looks like it would be entirely feasible and allow me to make a loop that could handle 100W. At 100W the voltage across the capacitor is just under 3.9kV at 14Mhz. The plate separation for this would be about 55-60mil. It would be a fairly large capacitor but it could be made fairly easily from sheet aluminum.

Just ordered a 2.5mm stereo plug to finish my wiring harness to connect my iPhone to my Baofeng HT to use with APRS. Been wanting to try Pocket Packet app for some time now and this will be my chance.

Also finished making an air choke for the 2m Moxon out of a coax patch cord. This is ready to test out with the new mast.

2m Moxon Update

I did some tests of the 2m Moxon with the FT-2900R and an SWR/Watt meter. I wanted to check the SWR to evaluate the overall matching. I set the antenna up indoors on a tripod up about 4 feet and connected it to the radio through the meter. Starting on low power 5W at the simplex frequency of 146.52Mhz I had an SWR of 1:1. Same on 10W. At 30W I was reading an SWR of 1.5:1 and at 75W the SWR was close to 3:1. This was not unexpected behavior as the way I built the Moxon I have the feedline running through the middle of the RF field. This is not an issue with low power but at high power it puts RF on the feedline. I wound about 6 turns of coax on the feedline and the SWR dropped to about 2:1. Adding a snap on ferrite bead with three turns of coax running through it further reduced the SWR at 75W to about 1.6:1. Aside from this issue, which is easily solved with an air choke on the feedline, it looks like the 2m Moxon is ready for testing at some height and will be ready for full power from the FT-2900R.

Upgraded my 2m Base station

I setup a new Yaesu FT-2900R 2m base station in the shack here today. The unit is built like a tank and the 75W easily lets me reach the SPI and La Feria repeaters with the existing discone antenna. Looking forward to using this on Simplex.I am interested to see if I can hear any better with this than the Baofeng. The Baofeng HT I was using as a base has returned to service as a spare HT. Hopefully I can use it to experiment with packet once I get some cables wired up. Here is what the shack is looking like now…