Sunday, 14 October 2018

4 antennas feeding done

Today I managed to test the feeding I want to use for a 4 bay array.
As my stacking distance in horisontal plane is not an multiplier of a 1/4 lambda i made the vertical feeding wires slightly longer and bent them toward eachother slightly.


















The matching was some -25dB return loss but I did not try to tune it further but discovered that the vertical lines was slightly to long so I need to shorten them to fit perfectly.
Will continue making the other 4 dipoles and wires for thoose and also make the wires to connect the 2, 4 bays together.
Need to make some support for the balun and cables as the feedpoint will be at some distance from the main horisontal support boom.































The wires are interconnected with M4 screws and toothed washers and it seems ok but its a test but after looking at DL7APV solution using 4mm copper wires and soldered interconnections it looks as a much better solution.
Will ask the local electrical motor repair shop if they can get hold of 4mm copper wires to make a test later on.

Tuesday, 9 October 2018

New dipoles

Last weekend I adjusted the elevation axis rotor and I can stand and reach the horizontal antenna dipoles very easy from the ground.
During the process I accidentally got stuck in a support wire for a HF vertical while rotating in azimut bending one antenna slightly but it was easy to bend it back again.





















Earlier test dipole I used 4.76mm copper tubing but have now tuned the antenna and bending fixture to 6mm tubing and it seems to work fine.
Tested to mount one dipole with through hole screws and nuts but discovered that the on the backside where the open wire line later goes the extruding bolt and nut was very close to where the feedline later goes.
I need to use inserted rivet nuts on the boom to avoid extruding anything in that direction but I have not been able to test that yet as the wind has increased and I do not want to elevate fully in high winds.



































The time is running out for the first part of ARRL contest so I need to step it up  and make the feedlines any day soon.
I have made the feedline distances yesterday and will try to stack 2 antennas together and measure the matching and if everything is as expected continue with 4 this week.
Decided to go for 200 Ohms feedlines and with 6mm wires the cc is 16mm.

Need to make some support for the feedlines when I drill and thread then in the lathe to avoid bending or braking them while the lathe rotates.
My idea is to use massive 6mm aluminium for the feedline and drill and thread in the end of each piece and then drill through the junction piece and with toothed washer just bolt everything together.
Will try to weather protect each junction with isolating spray.

Tuesday, 2 October 2018

Antennas up again :)

Today I lifted the stack up again.
Managed it just before it started to rain so I need some time to level everything and adjust the readings of the indicators.
A Quick test showed a 2 degree offset on elevation and 5 on azimut.
Also tested to elevate maximum and I got Close to 70 degrees and thats enaugh to access the dipoles on the horizontal antennas from the ground.





















Weather proofed all connectors and matching close to the ground was fairly OK but could not measure after the lift as it started to rain quite a lot so that needs to wait to a better day.
Picture below is before weatherproofing connectors.

















Will continue with folded dipoles and open wire feedings and the new switch n´box.

Friday, 21 September 2018

Thunderstorm

Intended to continue the work with the antennas this afternoon after work but after an hour a thunderstorm was approaching from west.
Normally it is no problem but today we took a direct hit in what I have found out in a lightning pole on the front of the yard.
Some damages on switched PS and TV recevier and internet modem as well as the robotic lawn mower was damaged.
I hope its only the PS to the lawn mover so it will be an easy fix but whoos lucky. Not me:)
All outdoor lightning broke and two night light switches too and when I tried to exchange the bulb in the lighning pole the lid was welded shut so it needed to be broken free with force.
Thats why my guess is that it entered that way and the YL was standing in the stable door at the time and saw a huge flash and big smoke from the pole itself.

We got 12 mm of rain in 10 minutes and heavy winds caused a huge tree falling on my daughters yard but fortunately away from the house.



Tested all radios but could not find anything broken so I think we where lucky anyhow.
Have not tested everything yet but I normally switch all power off to the schack and all SDR radios have their ethernet cables disconected.
Need to go and source some new parts tomorrow and fix the stuff that broke so maybe no antenna work but sunday is free so hopefully I will get the antenas up.



Thursday, 20 September 2018

Antennas done

Finally all antennas are done to be put back in the mast.
Had some problems tuning the vertical antennas and at one point I thought I lost my mojo tuning these antennas but it turned out that for some reason I made all dipoles with to much angle to the back.
So I needed to make new dipoles and the problem was solved and all antennas are better then 35dB return loss.
Started yesterday evening to put them back and finalized the 4 upper ones and will continue with the lower ones today or tomorrow.
The time was late so it was dark out so not photos of the work.

Had some rainy days last week too so I made a bending fixture for the folded dipoles I will use.
Made it adjustable for material diameter and total length so I can use it for other 70cm antennas as well.
Tried to bend a 6mm solid aluminium rod without any problems at all and the 6mm copper tubing I will use was very easy to bend.

















One rainy day was spent making new stacking cables too but I wanted to measure the exact length when the antennas where in place, I only put connectors in one end and will make the other end now when I know the exact length.
Will use the same combiner as last year was used for the horizontal antennas and I will also make new 1/2 inch cables combining the two 4 groups.
Hopefully I will have the array up this weekend so I can continue with the folded dipoles and the open wire feeding.

Monday, 3 September 2018

Power limitations

Swedish PTS has decided that a general output power limit for amateur radio in Sweden will be 200W only on all bands from the 1 of November.
If you have specific needs to use higher power you need a special permit but up to now no information on how, what fee and to who to apply for this permit.
So this could be an interesting future for EME in Sweden.
Hopefully the permit would be an easy formality and the handling time not too long.

Another funny thing I noticed the other day was a note in the June issue of the 432 and up EME newsletter that I am mainly QRV at contests and dxpeditions.
I have participated in 1 contests and worked 3 dxpeditions the last year but a total of close to 300 QSO's on the moon in the same time.
I do not know where it comes from but there is a higher activity on the band at contests and when dxpeditions are QRV so of coarse I am QRV then too but most of the time on the moon is spent any average day.
Maybe its from this blog where I maybe make notes and comments of dxpeditions and not so much otherwise.
So I need to be more active in between events :)

Saturday, 1 September 2018

Some progress.

All antennas are done with regards of placing elements but the dipoles are not done yet.
The delivery of bulkhead connectors for the semi rigid .250 Cables was delayed so I decided to continue with RFC400 cables instead.
Had some issues at first tunig dipoles with the RFC Cable but sorted it out and has designed and are printing out mounting plates for the dipole elements and have prepared all 1/4 stub cables.


Sourced a pile of new relay too as I need at least three for the switching of polarisation and RX/TX switching.
Will have separate preamps and RX lines for both polarisations so I need two RX/TX relays and a third to switch the TX polarisation.
Will only switch between the polarisations at RX at first but will try to get some receiver so I can listen to both simultaniusly in Linrad.
I have a set of WSE receiver boxes for 2m and one option is to build a dual RX converter from 70cm to 2m or maybe an SDR radio with 2 RX port which can be used at the same time.



Will try to get the antennas up as soon as possible and preferable next week so I can continue with the building of folded dipoles and the new feeding.
The sleeve balun that will be from the 100 Ohms connection point to coaxial is allready done.
Need to build a fixture for the folded dipoles too but have one for 2m I build a few years back that I will reuse.