28Mhz Yagi Build

couple of weeks ago i completed the build of a 3 ele 28mhz yagi.
i had been looking to buy a yagi from innovantennas, but i decided to try and build one.
using mmanagal antenna modelling software i optimized a 3 ele design.
my main parameters were, having a 50ohm feed point and a good bandwidth.
i could of got more gain but the feed point impedance dropped and i would of needed to use some sort of matching device. i dont like using matching devices.

so, here are the dimensions I ended up with from mmana gal.

these are the final dimensions

PLOTS, SWR, FB/GAIN

i had been given a 3 ele yagi years ago and never used it. it is a trapped yagi of some design, but with a phasing line from center element to the rear element.
i dragged it out of the sehd and dismantled it. the inner sections were just right for the element lenghts. it also had the boom, boom to mast bracket, element clamps which are insulted.
time to set about putting it togethere for real.

elements. boom.

 

element clamps. test set up

 

 

test set up. checking with MFJ 259B.

 

 

Balun. FT240-43. RG142.

 

Stub mast to boom bracket set up.

 

element detail. 1" 1/5 dia.

 

 

 

More to follow.

 

73

 

UKEICC DX Contest

Any users of DXLog this coming weekend 22/23rd April you will have to modify the contest database to correspond with a change made by the UKEICC organisers.
I did send it to kris 9A5K for inclusion in latest release but it has not appeared.
the change is the regional locator in NORWICH, NR to NK.

below is a step by step of how to update the contest logfile for the UKEICC DX Contest.

WARNING- if you are not competent with a PC or just not confident doing this, THEN, DONT DO IT. you have been warned.


locate your DXLog database file on your PC.

 

once you have located the DXLog database file, DOUBLE CLICK "CONTEST"

 scroll down that page opened in NOTEPAD or any other text editor.

OPEN "UKEIDX" open it in a text editor, I used NOTEPAD.

scroll down the page to find NORWICH.

delete NR and replace it with NK.
you will probably have to save your altered file to your PC and add it to your DXLog directory in a minute.

save it to your desk top.

go back and reopen your DXLog CONTEST file, scroll down to find, UKEIDX again.
DELETE this file.
now drag and drop your recently saved UKEIDX file from your desktop into the open CONTEST, file.
reopen the UKEIDX file to check that NR is now NK.

now close all files.

open your DXLog logger and set up a contest file for UKEICC DX Contest.
enter some dummy QSO's with NR as locator, it should not log it, it should log as NK.

IF you have done it correctly, then all should be ok.

screen shot showing NR as INVALID MULTIPLIER

screen shot showing correct MULT, NK

also these changes will update the MULTIPLIER list.

73.

RDXC 2017

The russian DX Contest must be, outside of CQWW/WPX the biggest contest. every year great support from Russian Hams.
band conditions though were not the best. 20 meters being the main stay for QSO's.
i did plan on doing 24hours, but at 2000z conditions on 40/80 and 160 were poor and i only have wire antennas on these bands, so QRT then and back sunday morning.
sunday morning was good with plenty of stations to work on CW and SSB.
in total i did 9.5 hours in the chair.

screen shot of final score for M7O.

this is one contest that goes into the diary every year without doubt.

73...

ARRL CW

with the addition of the OP-DES 14mhz yagi installed, I would put an entry in the ARRL DX CW 2017 contest. Single band entry 20mtr's Un-assisted as per the rules and high power.

I started on Saturday at 1100z.
the first hour went slow, but as expected. 1200z and the sun was shining on NA east coast and signals were getting stronger.
things started to pick up and so did the pace. from 1300z the rate meter never dropped below 60 Q's/Hr and for two hours it was over 100 Q's/Hr. I stopped at 1900z as the band was dropping out and signals becoming weaker.
I closed Saturday with 673 Qso's.

Sunday started slow and remained slow. very few Qso's being made. but it appeared that 15mtr's was busy. the A was up to 20 and the K was at 4 for most of the weekend.

I have done some RBN analysis for the 18/02/2017 using K1TTT.

you can see both peaks in the morning and the evening.

the shot below is from RBN sunday the 19th. really low at the start and peaked just after 1200z, but reasonable signal all the way through until I finished sunday afternoon.

some notes. i should have done longer in the chair on the Saturday.

after the weekend I was really happy with the innovantennas OP-DES 14mhz yagi.


73 simon.

 

 



14Mhz OP-DES Yagi Cont'd

Built and in the air, time to test the antenna with my MFJ259 antenna analyser.

Innov states 1.5:1 or better, well it is better, 1.1:1 across the whole of the 14Mhz band. cant get better than that.

for comparison I still have my cushcraft A3S antenna on another tower.
for the OP-DES yagi I ran 90meters of Messi & Paloni coax Ultraflex 10.  at 14mhz they state a loss of 1.4db per 100meters. if I had used RG213 then the loss would have been more than double of the messi and paloni coax. money does buy a db or two.

the tests I have done are not scientific but switching antennas and seeing what the S-meter says on my transceiver, K3S.
the OP-DES yagi out performs the A3S and the further away the station is the better it gets.
up to an S point or two better at times.
the front to back is amazing, upto 30db 5 S-points and the side rejection is also excellent.

one thing I have noticed from the A3S is, how quiet the OP-DES yagi is on Receive, upto an S point better. on a couple of occasions I cannot hear the station on the A3S but I could hear it on the OP-DES yagi.

Innov Antennas OP-DES

i recently brought an Innov Antennas OP-DES 14MHZ four element yagi with an 8.2Mtr boom.
OP-DES YAGI

fairly straight forward to put together, but i had to email Innov for a build sheet for element lenghts.

all tubing is aluminum, boom is aluminum square box, stainless tube clamps and nuts and bolts.
element placings along the boom are predrilled, but i did check to make sure i had them correct.

there is some theory behind the OP-DES design, ends of the driven element are bent 90degres towards the reflector. ill let justin tell you what its all about OP-DES THEORY

once i had the parts iddentified and placed on the floor it was just a matter of putting it together.

below, boom with start of elements

some more photos from my antenna build. As you can see it comes very well packaged.

All parts seperated and laid out on the floor.

First tubing added.

close up of the boom to element mounting detail.

driven element

boom jointing detail.

close up of the element clamping

end of the bent driven element. its insulated from the reflector. The insulator also adds support to the end of the driven element.

 

 

picture below shows a nearly finished yagi on a saw horse.

 

 

Finally built and on the tower.

 

more to follow.

 

 

 

 

 

Towermate

Towermate is a new design for your mast. it is a tilt plate that when you luff over your tower or mast the ariel stays parralel to the ground. this is good for easy maintanance, adjustment of yagis. more so when in high wind, just luff over and your antenna is about 6ft over ground.

it's locking device is automatic once up and in the vertical postion. once you start to luff over, the pendulem moves and unlocks itself.

take a look
Towermate

73 si.