Monday, November 30, 2015

Log Book Update

 Worked a bunch of stations at the end of the CQ WW CW contest over the weekend.   Did a little on 10 meters but focused on 15 meters hearing stations on just about every continent.  The highlight of  Sundays session was working a couple of Japanese stations.  I was using my 14avq on the top of the hill.   I am really beginning to think that the location of this antenna is really  making a huge difference.    Next summer I want to add a 4 way antenna sw and move some of the 1/4 gp to the top to compare the 14avq them.  

Saturday, November 7, 2015

20m 1/4 Vertical - NEW Antenna

 Did one of my last  2015 Antenna projects last week building a 20 meter quarter wave ground mounted vertical.  Based on what I learned recently I added all 8 radial before I tuned the antenna.

Started with the vertical wire 18' long and the 8 radials  are 17'6".

VSWR results .....

Didnt need to cut the vertical element which was quite a surprise,  It seems to be optimum around 14.2 MHz.  I may try 6" on the vert el before the tuning is completed.

Freq           Initial ( 4 radials )    Initial ( 8 radials )    - 6" Radials    - 6" Radials   - 6" Radials
13.8 MHz            2.1                         2.45                         2.1                     2.1               2.4
13.9 MHz            1.9                         2.1                           2.0                     2.0               2.1
14.0 MHz            1.8                         2.0                           1.9                     1.9               1.9  
14.1 MHz            1.7                         1.8                           1.7                     1.7               1.7
14.2 MHz            1.6                         1.7                           1.6                     1.6               1.6
14.3 MHz            1.8                         1.7                           1.6                     1.6               1.6
14.4 MHz            na                          1.8                           1.7                     1.7               1.7
14.5 MHz           na                          1.9                           1.9                     1.9                1.9  

 So it sure doesn't look like tuning the radials had much of an affect.   The VSWR is OK  where it is now however the experience I had with the 4 other verticals I recently built was very much different then this one.    This antenna is connected to the MFJ switcher  that also has the 20m 5/8 Vert so I am goign to be able to do some A/B testing which was one of the reasons why I purchased the switch.   On receive it doesnt seem to make much of a difference ,  5/8 or 1/4 but the shorter one seems to ever so slightly edge out the 5/8 in receive performance.  

 The 5/8 an the radios antenna tuner didn't seem to get along.  Under 50 watts output power is solid and the VSWR constant  but when I crank it up to 100 watts using the built in tuner it starts clawing back TX P top 70-90 watts and the VSWR climbs.   I thought it was a function of the  antenna but the new 1/4 antenna exhibited  the same sorts of characteristic.   When I bypass the tuner the  phenomena goes away.  

 May or may not tinker with this antenna further.  The night that I tuned it was wet and wet seems to change the characteristics of these antennas ... a little bit anyhow!

Log update ...

To date since the last "Log" post ...