Wednesday, September 11, 2013

September 7th MAD activities

Things did not go well this month.  I was operating from the Comfort Inn parking lot in EM58as near Edwardsville.   I was mainly trying to have a QSO with Herbert AF4JF who was at the YMCA in EM48sq.  I was able to hear the St. Louis beacon with an S3 - S6 signal.  I tried sending with my dish pointed towards the beacon, but Herbert was never able to copy me.  Using compass headings I move the dish a little bit south, but still no luck.  We switched to Herbert sending to me and I copied him.  I was not getting any reading on the S-meter.  I responded to his call, but he still could not copy me and I was not able to copy him again.  We had made this contact with no problem in July.   At that time Herbert had brought a 70cm beam to test and I had sent a signal on 70cm which he could copy and also get a starting point to aim his 10 GHz dish.  We were able to make the 10 GHz contact very quickly that day. The first picture below show where I was setup when we made the contact in July.  I tried that position again after we failed this time, but the foliage in front had grown about 3 feet in the mean time.  The second picture shows where I initially setup for this month.  

I had just replaced my 10 MHz oscillator before this test.  My previous oscillator had a LM-7812 on the voltage input.  It seemed like the voltage input to the LM-7812 was close to the edge of the voltage from my battery with the MFJ voltage booster.  I suspected there were issues with the voltage between receive and transmit. The new oscillator runs on 9 volts, so the input voltage is not an issue.   I tested it in my shop with a Tracor Voltage Difference Meter using my GPS disciplined oscillator as the reference and saw no change in frequency between receive and transmit.

After not being able to have a QSO with Herbert this month, I ran some tests at home with the limited test equipment I have and could not find any issues.  I plan on visiting Jim N0OBG this week and hopefully getting a better idea how well my 10 GHz system is working.  I will update with the results. 

Wednesday, September 4, 2013

Next SLAMS breakfast meeting

Next SLAMS breakfast will be held in Illinois at the "TA" truck stop in Troy, just across the interstate from the Cracker Barrel. There is a "fast food" establishment that serves "all you can eat breakfast buffet". We will have a breakfast there followed by a little demonstration/testing of our 10GHz stations. This serves two purposes - to show the local guys how we do 10GHz and to test that location in EM58.

More info will be published here before the next breakfast meeting, which is scheduled for Sunday October 6th.

73 Herbert