Five or Six Feet Higher?

[737mech]

I'm considering raising my DPD LP five or six feet higher from my current five feet above my roof. This kinda stresses the rotator and wind load of the setup in my opinion. I'm interested in opinions good or bad if I should do this? I get my trunked systems no issue, I'm trying to reach further into the MilAir 225-400 MOA'S north of me by 100 miles plus. I know higher is better but will a few feet really be worth the effort?

 

[kb5udf]

Plug in some test numbers here: VHF/UHF Line of Sight Calculator

I suspect the 5 feet won't make much difference.

 

[vagrant]

If the aircraft are 5000 feet AGL or higher, the line of sight should be fine to receive them 100 miles away with the antenna as-is on you roof. Going from 25' to 30' AGL is about one mile further distance.

I use an AT-197/GR mil air discone that is one foot above my roofline and receiving 100 miles away is not a problem. I RX much further than that actually. I use LMR-400 for the 75' run and a PAR mil-air filter for 225-400 (I have noise here). I use a preamp, but if I could get my hands on an Angle Linear LNA for 225-400 MHz I would be set. While your terrain and mine are not the same, I'm figuring that log periodic really helps, but I wonder how much it hurts due to the directivity with that many elements. It's like trying to find a plane in the sky using a telescope when one could simply look up and see it. It does get a broader view further away, but sounds like an A/B comparison project is needed with a discone.

Do you have a structure or terrain nearby that is in the way/higher than your antenna and where you want to RX?
Do you have a discone on the roof you can switch back and forth to check the RX?
Have you swept the LP from 225-400 MHz? I'm figuring it is fine because it is a LP, but best to check.

 

[iMONITOR]

I'm considering raising my DPD LP five or six feet higher from my current five feet above my roof. This kinda stresses the rotator and wind load of the setup in my opinion. I'm interested in opinions good or bad if I should do this? I get my trunked systems no issue, I'm trying to reach further into the MilAir 225-400 MOA'S north of me by 100 miles plus. I know higher is better but will a few feet really be worth the effort?

Lucky you to own a DPD Log Periodic antenna. I wish DPD still offered them! I had about 10 years ago, great performer very well made! Like everything I buy I evidentially got bored, sold it.

I'm assuming you get some pretty high winds in NV? The pro's might now outweigh the con's.

 

[spanky15805]

Location, location, location. Having spent way too much time in North Vegas, for whatever "flag" was going on, if you live along the 95 corridor, 5 feet of mast will help you, since the air corridor will be wide open to the North. try 5 feet of thin wall aluminum pipe or carbon fiber pipe.

 

[atech]

Ok with the beam? Aircraft altitude vs terrain between you and it? If its a straight shot / no problem current install! But if its below the terrain (other side of the mountains).. Or the control twr at dreamland? The height adjust might make a little change. Again whats between you and the thing you want to hear? Then also the pwr / antenna gain / and signal of the transmitter? Making it over the terrain to you? Like we said the terrain vs distance vs signal quality? All you need to decide on? Hearing a fixed ground station over the terrain it might help per the distance and whats between you and it? Line of site no real difference!

 

[iMONITOR]

Location, location, location. Having spent way too much time in North Vegas, for whatever "flag" was going on, if you live along the 95 corridor, 5 feet of mast will help you, since the air corridor will be wide open to the North. try 5 feet of thin wall aluminum pipe or carbon fiber pipe.

DPD's LP is pretty hefty. 1/2" thin-wall might not be strong enough.

 

[737mech]

Ok with the beam? Aircraft altitude vs terrain between you and it? If its a straight shot / no problem current install! But if its below the terrain (other side of the mountains).. Or the control twr at dreamland? The height adjust might make a little change. Again whats between you and the thing you want to hear? Then also the pwr / antenna gain / and signal of the transmitter? Making it over the terrain to you? Like we said the terrain vs distance vs signal quality? All you need to decide on? Hearing a fixed ground station over the terrain it might help per the distance and whats between you and it? Line of site no real difference!

I understand and agree. The mountains to the north will be impossible to seek over. The DPD LP antenna is not like mentioned a telescope it is actually very good for all my needs. I can hear the planes going to my favorite base but not the tower. I recently went to a nearby place with the DPD Omni X Miltenna and heard them just fine. I was 30 plus miles away without mountains. That antenna worked great maybe I swap for a trial period here at home? Get back to you guys in a couple weeks.