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55 built merlin base antenna

Posted: Tuesday 4th Mar 2008, 15:37
by frogman296
Today I had good weather, and time. So I decided to put up the new 55 merlin. Which is a 1/4 wave base antenna. That is capable of unlimited power by hooking the coax directly to the antenna mast. Prior in the morning I was attempting to talk some poor condition skip. Uniden 78 into a magna 100. I think I got out once. Current base antenna is the interceptor 10k. Tower, 75 ft to the bottom of the antenna.

The top of the antenna looks basically like the Immortal. All aluminum. Cross on top. 2 turn coil just like the mobiles ( this is the new immortal and 100k watt whipping stick design) The top is a 1/2 in shaft aluminum. Bottom is 1 inch. Very heavy duty. Total tuned length is 72 inches from the top of the insulator. The 3 ground radials drooping at around a 45 deg angle are 101 in long. This antenna is short (1/4 wave) and easier to hide.

I got on the air and started talking. Conditions weren't the greatest, basically the same as the morning. There was about 2 hrs in between the 2 antennas set ups. Got my name called several times. Was once told I had a great, clean sounding station. I even got called 3 times on ch 6 with 45 bird watts 120 peak. I never get called on ch 6 with that power on the I10k. 55, 557, wild thing ( he was the one played in primes room locking down skip in a diesel car with an immortal, and had Texas on lock down and recorded) have noticed that the top load design works awesome in skip, and my first 1 hr of testing has immediately shown this also. In weak conditions I never get out in skip. So far so good.

Local.. once skip dies down I will do my local transmission testing. I have one guy 45 miles away who I have done signal testing with the I10k and have a good baseline. 5/8 wave antennas are bad for bleeding down the coax and in general. I have one BIT*# of a neighbor with an aerial antenna for TV that gives me fits with any power. But being she is very inconstant with her info, it may be hard for me to give accurate enough info on bleadover.

Tunning.. this antenna can be tuned with a tape measure and be about dead on. 71-72 in from the insulator should do the trick. 101 on the ground radials. And if any adjustment is needed it will be very little. swr was 1.0. Forget the mfj, the bird meter is more accurate. 45 bird I had 1/10th of a watt reflection. .9 is 1.3 swr. .4 is 1.1 swr 1 watt slug for measurement.

Day 2
tested the antenna locally. conditions were bad due to recent skip. A fair amount of constant static. But I was still able to hit a local 45 miles away with the same signal and audio. more fair based testing to come

day 3
Well I have gotten the antenna fine tuned. with the ground radials at 101 in. and the stinger adjusted to 73 1/8 its dead centered on the cb band.

mfj says
27.265 50 ohms x=0 and 1.0 swr lowest reflect here also, 80 rms and hardly moved the needle on the bird with a 1 w slug 1/10th max reflect
my stinger is at 72 7/8 for a reason. 73 1/4 for ch 6

27.185 48 ohms and x=0 1.0 swr

26.000 44 ohms x=0 1.3 swr

28.000 55 ohms x=10 1.3 swr

26.9 to 27.5 1.0 swr

the ohms can be fine tuned by lengthing the radials about 1/4 in and then the stinger would need a slight adjustment.

Well to test the neighbor issue I put some mild improper english out ( yes i know im a bad boy) to try and prevoke her to call. She is a pain in the butt and when i put out my " please ring my phone 2 times" announcement she doesnt always call. not a plesant or cooporitive person. Any how no phone call. So far so good with bleed over with a uniden 78 and magna 200.. Note the lop of coax. this was needed with the I10k to cut down on bleeding since 5/8 wave antennas are notorious for signal comming down the coax. I just didnt take it out and have to restrap the whole tower again.

signal reports so far are identical to the intercepter 10k. Remember this is a 1/4 wave antenna. But it is wayyyyyy more broadbanded then the I 10k. And is much less wind load then the I10k. In the same day I changed antennas we had skip, nothing on the I10k, changed to the merlin and I got out on ch 6 with my uniden and magna 100.

This antenna needs to be tuned at 15 ft or more above the ground. But if you set it up with a tape measure to 73 in you should be about dead on first shot.

Which antenna will I use, hhmmmmm I don't think I need to put the I10k back up.

Power rating.
if you hard mount the coax to the antenna, unlimited watts. Which is very easy to do.

Local test.

Ok I just did the local test. Being conditions change and such and its to hard and time consuming to take down the one and put up the other it cant be dead acurate.
But the 55 is appering to do as well as the I10k localy at 45 miles. So as of right now its not comming down!

When 2020 had his imax and went to the I10k there was a very noticable difference in TX. this is not the case here.

One benifit is the day I did change it skip was running and I did not get out on any channel with the I 10k and I did on ch 6 with the 55

Someone asked how it can be better then a 24 ft antenna.
Im not saying the 55 is way better. it is equal and more will tell when skip comes in, so far the top load design has proven very effective.

what the merlin does bring is more versitile installs in certain aplications, like hoa's for one. height restrictions, following the ffc rules of 60 ft max to the top of the antenna, you can now have the feed point at 55 ft instead of 36 ft. the radials dont have the same overall diameter so tighter areas are posible. and it is easier to tune.

btw receive was equal also.

hope you enjoyed the test

Another person tried one.

i got the 55 merlin up this morning and with 4 of the 11 locals i wrote my tx & rx down with, i gained 1/2 # with 3 of the 4 both recieve ant transmit, and the one it was the same as my wolf .64. I have only 6 watts reflect with 3kw on ch19 to ch1, it goes up a little from ch20 to ch40.
thanks 55

i just put it together on 55's marks, and thats how close it was. i'll fine tune it when the snow is gone. I always tore up the phone and tv before, but now i dont go thru the tv at all, and my girlfriend says she can barely hear some static when I key everything up on the phone. so i'm convinced

pm me for more info

Posted: Wednesday 5th Mar 2008, 19:50
by frogman296
bump to the top...interesting info here