Monday, November 13, 2023

More trouble!

 It was a nice day yesterday so I was able to test the 500' IFL to the 15/10/6 Fan on the top of the hill. 


 NANO to the SA 18" cable on the bench.










Top of the Hill ... 500' away. 










At 52 MHz there was 12 db of loss at 26 MHz there was 19 db of loss and at 1 MHz there as 23 db of loss!   


Needlesss to say I retired this IFL and connected the one that I tested a week ago that was feeding the 60m dipole!    More work to be done,  also have to rethink the LDF4 connections.   

Sunday, November 5, 2023

A shocking discovery!

 










I borrowed a Spectrum Analyzer from work to measure my IFL losses at HF.  I always figured the 500' runs of LDF4 to the top of the hill should only have a db or two of loss at the HF frequencies.  This hypothesis is a result of  the cable specs however in real life problems occur making the losses more then expected.

The NANO VNA made an excellent source.   Set it up to test from 0 MHz to 52 MHz and was presently surprised that this little guy spits out RF  when idle.  Below is the NANO direct to the Spec An though 18" of RG59.   





  





There are 2 1X4 switches located at the beginning of the forest about 100 ft from the ham shack.   The original one has all the IFLs going up the hill (100' to the switch and  400 ' of IFL to the top)  and I refer to it as the "hill" switch .   The other one is just behind the house ( 50' to the switch )   and the antennas are all located close by.   


The first test I did was the IFL to the "house switch "  and I was quite shocked.   I removed the IFL IP to the SW and connected it to the spec an and found the following ...










12db of loss ...HOLLY SMOKES SHOCKING.   I had just replaced this cable 2 years ago!    The IFL was in 3 chunks.  I automatically assumed that it would be the outdoor chuck ,  30' of some sort of hardline.   I almost untapped the outdoor joint but opted to test the first leg that joined just inside the house.   Again I was shocked because it was inside where the loss was.     The culprit tuned out to be a 18" chunks of IFL that ran from my 3X1 switch to my 4X1 switch a piece of RG58 that had to be 10+ years old or maybe more.   This cable had been in place since I installed the switch a decade ago.  

Unfortunately I didn't take a picture or test all the way to the switch but I did test to the end of the first chunk of IFL and had next to no loss.   I have some further testing to do and will test to the switch the next time I am at it.  


Next up was the IFL from the house to the hill switch.  

Nanao OP via 18" cable ...










IP to the hill switch ...










Below 26MHz there was less then 1 db of loss ,  above 26MHz about 1 db of loss ... please with this !


I have a direct500'  run of LDF 4 from my 3X1 switch in the shack to a 60m dipole at the top of the hill.  This is the one that I was most interested in testing!   

Again ,  op of  nano direct to spec an through 18" cable 










500' at the other end of the IFL















Below 26 MHz only 1 db of loss ...YIPPIE ,  better then expected.   And only 3 db loss at 52 MHz!

I still have a  few  of outstanding tests to do .....

1 - IFL to house switch
2- IFL to the 15/10/6 fan dipole at the top of the hill. 
3- 2 chunks of RG 6 that terminate just outside the house at the " satellite" pole
4- I am suspicious of the IFL to the 160m inverted L at the top of the hill.  Its a direct run of IFL to the switch.  I need to reterminate and throw some connectors on it ( Not happening this fall ) 
5- Test to the " House" 15/10/6 fan connected to the " Hill" switch.   It does not seem to perform as well as I would expect.   
6- Some random chunks of IFL that I have in storage to establish that they are good and what attenuation I can expect. 


Saturday, July 1, 2023

80 becomes 60

 I had 2 80m inv V antennas ,  the 80/40/20 Fan  Dipole  part way up the hill and the 80m inverted V at the top of the hill.  Initial WSPR testing I found that the antenna on the hill was better to the East by 1 db  and the antenna part way up favored the west by 2-3.     The antenna at the top of the hill has 300' more IFL then the one behind the house.  Its mostly LDF4 so its not lossy and looks good when swept.    I decided that there wasn't much to be gained by the 2 antennas and kept the Fan part way up the hill on 80 being that it had a significant advantage to the W SW and besides it would have been tricky to tune with the 40 and 20m elements.    

 Cut the Inv V on the top of the hill down to 2X44' segments creating  60m inv V.    Quick check of the VSWR was 1.3 : 1 ... good enough.   Did 1 brief SSB QSO and was pleased with the results.    

 Next up I need to mod the 450D  for 60m operation ...looks simple cutting a diode or a jumper!   Just another item on the Ham to do list!    

Monday, February 13, 2023

80m vs 80m...the battle of the dipoles.

  Just did a 2 day WSPR on the 80m Inverted V at the top of the hill vs the 80m Inverted V ( fan ) just behind the house.   The week before the test I worked a bunch of FT8  with both antennas.  The one at the top of the hill performed better towards the east  and the one behind the house ( part way up the hill ) performed better to  the west.   

Here is the 2 day spots map! 

Blue is House , Red is Hill and Green is both








IMI is the antenna just behind the house and LDP is the antenna at the top of the hill.   The hill made it to Africa and the house made it to Hawaii.    

Two antennas and the top 10 spots by distance...














Simultaneous Spots 















So overall the house was on average 0.76 db better then the hill.   


 I ended up with 8977 simultaneous spots between 0 and 180 degrees and 4,562 spots simultaneous spots between 180 and 360 degrees.     Note ,   the hill more or less runs North South and both antennas run parallel to the hill... all within 30 degrees of true N-S.   

 I averaged out the SNR comparisons  between the hill and house  from 8,997 simultaneous spots between 0 and 180 degrees and found on the average the hill antenna performed 0.67 db better then the house.   Next I averaged out the SNR comparisons  between the hill and house  from 4,562  simultaneous spots between 180 and 360 degrees and found on the average the house performed 3.56 db better them the hill.   

 The shack to the antenna just behind the house is about 100' to the 4X1 switch with a combo of about  30' of RG214 then 20' of hardline then from the switch to the antenna is about 50' of RG59.   The shack to the antenna on the hill is pretty much LDF4 all the way around 500'.   On paper there is very little loss and 3 MHz on the LDF.   Potentially there are losses on either or that I am not taking into account.   I need to at some point actually measure the loss.  None the less the Antenna on the hill was head in the Canary Islands and the Antenna behind the house was heard in Hawaii.    What I found was more or less my experience after operating from both antennas running FT8 last week.   


Thursday, September 22, 2022

IFL

  Doing some fall antenna work ahead of the winter weather.  After testing the 6/10/15 fans one at the top of the hill and one just up behind the house become quite apparent to me just how much better the antenna performs at the top of the hill ,   1 to 2 S units .... huge!   I currently have 6 IFL runs to the top of the hill.   The original has been there 20 years and no longer test good.   There is 2 connection  in the 500' IFL  so I am going to isolate which section is bad.   There is one IFL  that goes from the 4X1 switch that ends about 100' from the top of the hill.  Its has been protected from the weather and is probably good for future use.   There are 2 in use that test well ,  the 160m inverted L and the 15/10/6 Fan.   The other 3 terminate at the old 80m Vertical ( not in use IFL bad), then one IFL that ends to the left of the old 80m then another that terminates where the 6/10/15 is located.  I have a 80/40/20 fan just up behind the house that I would like to recreate at the top of the hill.  It will be really interesting to see if I get the same sort of improvement with it there.   Depending on when the weather closes in  am going to first get 1 or two of the existing IFLs to the top.  They are all put together in chunks so its just a matter of isolating the bad bits.  If I don't get there this fall then it will be next years project.     

Friday, August 26, 2022

Fan vs Fan

 Built another 6/10/15 fan more or less the same as the one at th etop of the hil.  New fan is just up behind the house about 35' above the ground and somewhere around 50' lower in overall elevation compared to the one at the top of the hill.   I had both antenna on the same 4 X 1 switch.  All of my signal reports on both antennas seemed to always come up about 10 db less then what I was reporting.   Propagation has a a lot to do with it however I was suspicious of the  IFL run between the house and the switch 100+' of a good diameter hardline.   

 First thing I did was to move the new antenna to my other 4X1 switch  but it didn't seem too make any difference still was getting on the magnitude of  -10 db over the reports I was handing out.    I terminated the IFL to the "hill" switch  with a 50 ohm  load and swept the IFL with the Nano.   I had a "spare " line of the same IFL and swept it too and compared both .   

IFL feeding the "hill" 4X1 switch 








Spare IFL 








So ya ,  both IFLs are good...phew.  Going from the house to the hill the IFL is burried ,  about 30' and its a pin to replace it.   

This morning I flipped between the new fan and the old one on top of the hill  over a 1 hour period.  15m propagation came into play from time to time but flipping back and forth keeping the transmission numbers about the same should take propagation out of the equation. 

Existing 15/10/6 Fan on the top of the hill. VA3IMI








New fan just up behind the house .  VE3LDP








I was really expecting the new 6/10/15 to outperform the old one just simply because the IFL was so much shorter but that isn't what happened.   The antenna on top of the hill has a 360 degree clear LOS vs the one behind the house that has LOS blockage from about 350 deg through 120 deg.    

So the new antenna is coming down and I am going to beef up the antenna on the hill and do a once over on the IFL to ensure its protected against the weather.