Waited until early eve then repeated the same test as this morning CQing every other minute each antenna for 30 minutes. Once again the fan on the hill wins. I had Oman and Italy answer my CQ using the old fan on top of the hill.
VA3IMI , fan on top of hill
VE3LDP, new fan.
Last antenna season I put a 15/10/6/2 Fan Dipole at the top of the hill. I was suspecting some losses in the 500' of mostly LDF4 but it seemed to work well but I seemed to always get signal reports that were 10 db less then what I was reporting..ie IFL loss.
I just cranked out a 15/10/6 Fan Dipole the same build more or less as the one on the top of the hill. I have mounted it about half way up the hill with about a 300'shorter IFL. This new antenna is pretty high at around 30ft maybe a wee bit higher above ground then the top of the hill. As a test I did alternating CQs between the 2 Antennas using my two call signs. I did this alternating between antennas every 90 seconds to 2 minutes over a 30 minute period. Should be enough to take propagation out of the equation.
VE3LDP the new fan is broadside 30 / 210 ( not quite running NNE / SSW ) where IMI the old fan broadside is 0 /180 ( runs east west ) . Not hugely significant!
VE3LDP is the new Fan ( shorter IFL, 200' and lower on the hill )
EU
VA3IMI is the old Fan ( top of hill 500' IFL )
EU
Clearly there is an advantage to the fan at the top of the hill , a bit of a surprise to me I was expecting less loss so better TX not thinking the position on the hill would make that much of a difference.
Swept both fans on 15 m.
VE3LDP is the new Fan ( shorter IFL, 200' and lower on the hill )
VA3IMI is the old Fan ( top of hill 500' IFL )
Return loss is an important number to look at in terms of the efficency of the antenna. The way I thinks about return loss is .
If the return loss is 10 dB, 10% of the power is returned. While different systems have different acceptable return loss limits, 15 dB or better is a common system limit for a cable and antenna system.
Both antennas range from 19 to 28 db return loss the new one is slightly better but the are both very close to each other.
Next up is to sweep both IFLs into load.
I built the 15/10/6/2 fan last fall in the basement. Fine tuned it then dragged it to the top of the hill and put it up and when it was lit up it behaved exactly like it did in the basement. Based on this I tried the same approach with the 80/40/20 fan and set it up just outside the house a few feet above the ground. When I strung the antenna up the tuning changed dramatically much to my surprise.
Below is the 80/40/20 fan dipole after if was strung up at its operating position BEFORE it was tuned.
Below is the 80/40/20 fan dipole after if was strung up at its operating position AFTER it was tuned. Might I add it took hours and multiple trips up and down the hill.
Played around the next day a bit more and ended up with....
LESSON LEARNED as I moved the antenna up and down the impedance changed and the 1:1 match was skewd +/- 150 KHz.
The problem with the 80/40/20 antenna and the lack of ability to tune the 80 meter segment was a result of a bad IFL. No big surrprise when its nearly 500' between the radio and the antenna.
First I terminated the IFL that runs between the house and each of the 4X1 switches.
Its about 100' to each 4X1 switch. So there was no problem between the house and both switches.
Terminated the 80/40/20 fan dipole IFL at that runs to the top of the hill...
Terminated the 15/10/6/2 IFL that run to the top of the hill ...
Put a solid 4 days in working on antenna projects a couple of weeks ago!
Built this in my basement...
worked this guy from my basement ....
Folded it all up an lugged it up the hill for install.
Here it is mounted.
2nd build this week , didn't like how the first fan turned so scrapped it and started again.
The 15m element is attached to the rope. The 10m and 6m segments hang below. The 2m segment is a vertical dipole. The antenna is completely built inside ready to go up the hill. Installation time ... 10 min.
I fussed over this thing with my NanoVNA and below is the results " In the Basement " and then after it was installed "Up the Hill Outside".
15m in the basement
2m installed outside on top of the hill , see ***** below
1-150MHz sweep inside
The results of the previous test were inconsistent with what I was expecting. Poking around I determined that the IFL was bad. Its only a little over 100' but the RG214 has been buried for 20+ years and has been dug up and weed whacked a few times I am surprised it lasted that long.
Replaced it with 40' of RG214 + 60' of smaller diameter hard line. Probably less then a db loss across the HF spectrum ...more then acceptable.
The results were more inline with what I was expecting. The Vertical is just up behind the house with a tilted GP towards the W SW. The Fan Dipole is at the top of the hill with EU and AUS off the broad sides and nulls towards AS and somewhere mid S Atlantic. The nulls off the end of the dipole are quite apparent and the low throw and tilted GP of the Vert stand out.
The Fan is best towards EU and AU , the Vert is best towards AS. The low throw of the Vert does give it a 360 degree DX advantage over the dipole. Both antenna work very well and both have certain advantages but overall we are talking a 3 db difference for the most part.
Spots Map Green=both Blue = Fan Dipole Red = Vertical
Simultaneous Spots
Top 10 DX Spots for each antenna , LDP Fan Dipole , IMI Vertical
