Dulplexer question

[Bill_G]

Yes, but get the building super to approve first, of course.

Have you ever drilled concrete and set anchors? Got a hammer drill?

[Max]

Now that i have the good coax,can someone suggest the best way to anchor Andrew LDF4 - 50A 1/2" Heliax Coax to the mast from the antenna down to prevent any strain on the n- connector attached to the antenna.
The mast is only 8 feet.


Max

[RFguy]

For strapping the Heliax to the mast,, we use heavy duty Panduit Ty-wraps, like the TY527MX.

Don't forget the drip loop.

[Max]

Thanks RFguy.
Can you provide a link that explains the purpose for a " drip loop "


Thanks
Max

[Bill_G]

Drip loop link goodness

Teh Google is your friend.

[crash]

More than the weight, what is the wind loading? Anchor bolts might handle
static weight, but what about the torsional load when the wind blows?

As you already have limited access, going low quality is not a good idea,
and if you have a failure due to engineering, you may loose that access
if there is damage from a failure.

Try to imitate a commercial installation as closely as possible. The cost
will be higher to begin with, but the longer it lasts, the lower that cost
is over the years.

Your question about gain figures on antennas is a valid one. The lower cost
antenna with high gain figures could be marketing hype. One manufacturer
uses one reference antenna, while another manufacturer uses another reference.
If you read the fine print, you will 'maybe' see this mentioned, maybe not.
What this does, is give a false sense of getting something better for less, when
the truth is, you are getting less gain than what you thought.

Sad to say, even with todays knowledge, the buyer has to watch for such tricks.

[Max]

I'm lucky to have access to such a wide variety of knowledge from all the members on batlabs.

I have listened carefully to all that replied to this topic and bought a new antenna,coax,duplexer etc....all being of good commercial quality compared to what I have now.

It won't be long before the warmer weather is here and I'm looking forward to installing everything.

I will post some pic's of the install and post results of any tests we do.

Thanks again to all that took the time to reply.


Max

[Max]

With the warm weather here, I'm putting together my antenna and hoping to install it this month.
I have a question about the mounting clamps that came with the antenna.After putting them on today, I notice a bit of a gap between the bracket and the antenna mast after I tightened the bolt.
Is this gap normal ?

I included a picture of the model number on the antenna and the model number on the package the mounting clamps came in so it will show I have the correct parts.

Thanks in advance once again for any help.

Max

[Will]

Looks normal to me, most have some gap due to manufacturing tolerances.

[Max]

I finally got my Comtelco BS450XL6-C installed using 75' of Andrew Heliax LDF4 a 1/2 inch semi rigid coax.

My friend who had a TELEWAVE INC Wattmeter Model 44A was not able to stop by and check the antenna with his meter, so we used

a T100 Vector Antenna Impedance Analyzer. I will post the 3 reading I took, I have never used this type of antenna analyzer before so I'm

hoping someone can give me their interpretation of the readings.

1- is the SWR
2- is the return loss
3- is the Impedance

[Bill_G]

no pictures.

[Max]

[quote="Max"]I finally got my Comtelco BS450XL6-C installed using 75' of Andrew Heliax LDF4 a 1/2 inch semi rigid coax.

My friend who had a TELEWAVE INC Wattmeter Model 44A was not able to stop by and check the antenna with his meter, so we used

a T100 Vector Antenna Impedance Analyzer. I will post the 3 reading I took, I have never used this type of antenna analyzer before so I'm

hoping someone can give me their interpretation of the readings.

1- is the SWR
2- is the return loss
3- is the Impedance

[URL=http://s261.photobucket.com/user/J ... .jpg[/img] [/url]
[URL=http://s261.photobucket.com/user/J ... .jpg[/img] [url][URL=http://s261.photobucket.com/ ... .jpg[/img][/url]

[Max]

What about now, are the pictures showing ?

[Max]

I can't figure out what i'm doing wrong.Cant seem to post the pictures.

[Bill_G]

Well, I went to photobucket, and could see the return loss screen, but the links to the other two failed to load. Overall, the measurement isn't horrible. It's usable. It's obviously best at 463.050, and at 8 or 9 megs down. Between those two freqs, the RL is always greater than 20db. Below that second dip all the way down to 420mhz, the antenna and line are always between 10 and 20db. Depending on your freq of interest, this may work for you.

[Max]

Thanks Bill, you should be able to see all 3 pic's now.
Thanks for the feed back, i will be using the antenna around 465Mhz, should be fine.
Just waiting for the duplexer to finish everything.

Max

[RFguy]

Anything better than 16 dB RL would be considered good (it's actually 14 dB, but you have to account for 2 dB of loss in 150 feet of LDF4 at 450 MHz, 150 feet being the distance to the antenna and back again)