Tuesday, October 27, 2015

40m 1/4 Vertical gets 4 new radials

Added 4 new radials to the 40m 1/4 gp.

Freq         SWR Before    SWR after
7.0 MHz       1.05:1             1.70:1
7.1 MHz       1.05:1             1.30:1
7.2 MHz       1.10:1             1.10:1
7.3 MHz       1.30:1             1.00:1

Adding the radials appears to have shifted the best match up about 300 KHz .  Not  a big deal because the radio tunes it out flat across the band with the full power output.

 Lesson learned ....  always start with 8 Radials then tune the GP!

Also found the vertical element wrapped around the tree that supports it and missing a bit of its counter weight definelty  anything but vertical.   Changed the counter weight and unwrapped it from the tree ...all good now!

 First QSO with the radials added was EI3KG in Ireland he was a 549 and he gave me a 559....pretty cool eh!  

Paper Logs - Forget about it!

Paper logs are so yesterday.   I much prefer the digital log but there is one caution and that it keep it backed up!!!!

So with all the activity with the new radio here is what I have done since I fired it up...

Wednesday, October 21, 2015

30m 1/4 Vertical gets more radials

Just added another 4 radials to the 30m  1/4 Vertical for a total of 8.  They were cut to just a little over 23' the same as the other 4.  

VSWR results ...

Freq             before           after
10.1   MHz     1.05             1.20
10.15 MHz     1.05             1.15  

The TS690s radio still tunes to a flat 1:1 VSWR and most important it still delivers the full 100 Watts.  

In theory this should buy me about a db of performance well worth the couple of hours of effort.

Up next the 40m 1/4 gp vertical gets 4 more radials then its time to build a 20m 1/4 gp!  

Monday, October 12, 2015

AZ Map

I was looking for one of these ... the flat version is a little easier to display then a globe.

Sunday, October 11, 2015

20m 5/8 gets more radials

After the success achieved adding radials to the 17m 1/4 GP I decided to do the same with the 20m 5/8 GP.   They had the same affect on the VSWR....

Freq      4 Radials       8 Radials
14.0         1.3:1             1.2:1
14.1         1.5:1             1.4:1
14.2         1.8:1             1.6:1

17 Meter 1/4 GP Vert - 4 More Radials

Just added 4 more radials to my 17m vertical now I have the minimum of 8.  Probably gained somewhere around a db but thats a pretty cheap db!   Checked the VSWR prior to adding the radials and after and was pleased with the results so much so that I am going to add another 4 radials to the 40m,  30m and 20m verticals that I recently built.

Freq              before the addition of radials          after the addition
18.0                          1.25:1                                         1.05:1
18.068                      1.25:1                                           1:1    WOW!
18.2                          1.3:1                                            1.1:1


Tuesday, October 6, 2015

Power Meter Lies

 Have an old SWR/Power Meter... sometimes it seems to read correctly and sometimes not.  There seems to be around a 3-5 db swing depending on the frequency.  To test my theory I checked the power meter against the old 141T Spec An and found less then a db of change vs the suspected 3 or so db's.   I think I need a better way of measuring power.

The spec an is 10 db /div ... its old but functional.   As I tune across the 20m band the power meter is all over the place but the spec an varies less then a db.

5/8 20 Meter GP

Built yet another Vertical Antenna this time it was a 5/8 Ground Mounted Vertical for 20 Meters.

This is the design I followed ...

The vertical radiator was 585/14 = 41.8'
The radials were 246/14 = 17.6'
The matching transformer L1 122/14= 8.7' and L2  75/14 = 2.1'

Could have used the matching Q section instead of the Xfmer using 75/14 = 5.4'

The 5/8 GP has an impedance of 1600 ohms and the coax is 50 ohms so the calculations above are good to match the low impedance  feed line with the higher impedance antenna... simple.

Getting the vertical radiator up 42' in a tree was a wee bit of a challenge with a 24' ladder.  Cut down a skinny tall 24' poplar with a Y at the top.  Dangled the counter weight over the Y part and ever so carefully raised the poplar from the top of the ladder to get over a branch that was about 43' above the ground!   I think I could use this same method to go 50 or even 60 feet .... I have some very tall trees on my property.  

The vertical radiator is about a #12 insulated copper wire.   The base is a 1 ft chunk of 2X6 pressure treated.   The vertical radiator is connected to the base with a large crew and washer .   There are 4 Screws/Washers surrounding the center where the radial connect... get the picture!   I will take a picture and post at some point!  

The book that I took the design from seemed pretty reputable but I was a little bit leery of the matching transformer.  Way way way back when I did understand the theory but I have forgotten far mar then what I know but I did recall this design so what the heck ... gave it a shot.  

So how did it work ....  fired it up at 14.1 Mhz and had a horrible VSWR 3.5:1 or there abouts ...figured I would be removing the transformer and cutting it down to a 1/4 Wave.   Tuned up to 14.3 and the VSWR got worse ,  tuned down to 14 and it got better ... kept going and found that the antenna was very nicely tuned for 13.4 Mhz ...YIKEs.   The original design was using a pipe as the vertical radiator and the GP was assumed to be a resonable ground.  Whilest I was using some #12 wire and I have a lousy ground,  its all about the radials!

So I started cutting and cutting and cutting.  Results below...

Freq      Initial   -6"    -6"   -6"   -6"   -12"   -12"   -12"  -12"   -12"
13.3           1.4   1     1.7     2     2.2     3        3      3.1    
13.4           1.2   1.2   1.4    1.6   2       2.4     2.6    3.1    3.1
13.5           1.3   1.2   1.15  1.3   1.5     1.9     2.3    2.9    3
13.6           1.6   1.4   1.2    1.1   1.2     1.5     1.9    2.1    2.6    3
13.8           2.5   2.2   1.9    1.6   1.35   1.1     1.15   1.4   1.6     2
13.9                                   2     1.7     1.3     1.1     1.1   1.3     1.5
14.0                                   2.6  2.1     1.6     1.35    1.1   0.5    1.15  
14.1                                         2.6      2.1    1.6      1.35  1.1    1
14.2                                                            2.1      1.6    1.35  1.15
14.3                                                            2.5      2       1.6    1.4

Needless to say I took about 7' off the 43' vertical radiator ending up with a 36' vertical that was really really well tuned.   Flat VSWR at 14.1 Mhz.  

The California SSB QSO party was going on so I had a chance to work a few QSOs as seen below ...

So I was pretty happy with the antenna unfortunately I didn't get any signal reports working the Calif QSO party.

Being attached to a moving object I had to use a pulley and counter weight to keep the antenna in place.  The counter weight I choose was a metal disc that was about 6 inches in diameter and weighed a pound or two.  The way the disc worked out it was next to the top of the vertical radiator and it appears when I added the weight it affected the tuning as the optimal VSWR dropped a few Khz.

Next step is to get the ladder back out ,  drop the vertical element then replace the counter weight with a brick!  

More to come!