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Which antenna deployment is most likely to succeed?


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#1 krvw

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Posted 11 February 2020 - 09:42 AM

So, that DB-404 antenna sounds pretty amazing, Spaz, but it's a bit much $$$ for me to justify (yet).

 

Instead, I've ordered an Ed Fong DBC-1C kit (see https://bettersafera...ation-antenna/)

 

Reviews seem good, and it's the kind of kit project I'm happy to work on. Outsource the precise math to the PhD and do the PVC and cabling work myself...

 

Now, my question is this: Which of the following deployments is most likely to work for me?

 

Background: I'm trying to achieve simplex comms for emergency purposes with my wife at her office, roughly 3 miles away. Terrain is soft rolling hills in a suburban (northern Virginia) environment. She's already on the Alexandria repeater just fine, but I don't want to rely on that for emergencies.

 

Option 1 - Set up the antenna indoors near a bay window facing in the direction of her office.

 

Option 2 - Set up in my attic crawl space, semi-permanently mounted. (Town house with 3 floors. Attic is roughly 25 feet above ground.) The down side of this deployment is running the cabling.

 

Option 3 - Set up in the front or rear of the house, semi-obscured from view (so I don't get the wrath of the nanny state HOA). Again, cabling is an issue. I can put a hole in the wall, but I'd prefer to not add additional connections in the cabling. (Planning on a 20' stretch of high quality coax, with SO-239 connectors on either end.)

 

Side question - I've read in several places that the SO-239 connectors aren't optimum for modern UHF bands, but they seem to be the most common on antennas. Is it worth going with Type-N connectors at each end, or are the 239s adequate for normal use?

 

I should add I'm initially going to be working this with a BTECH GMRS-V1 handheld, hoping to get a 40-50 watt mobile at some point in the future.

 

First goal is simplex with about a 4 mile reach. (Yes, I said 3 above, but I'm adding a margin of error due to terrain and such.)

 

Clearly, I can test option 1 really easily, and if that does the trick, I'm home free. Both options 2 and 3 will require a fair amount of drilling. If option 1 fails miserably, are options 2 and 3 worth the effort?

 

Thanks for any advice. I'm a newbie, but I learn pretty quickly.

 

Cheers,

 

Ken

WRFC318

 



#2 Jones

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Posted 11 February 2020 - 10:59 AM

Height is everything.  The further up in the air you can go, the better, and longer range you will have.  On the roof would be ideal, if you can hide it somehow.  ...perhaps connect it to a vent pipe on the roof, and paint it some flat, light gray color so it doesn't show up unless you are looking for it.

 

The attic would be OK, as long as you don't have those metal-backed shingles on your roof.    Those will kill the signal.


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#3 marcspaz

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Posted 11 February 2020 - 11:18 AM

I have a few questions.

Are you trying to get coverage from building to building, specifically or are you looking to get coverage on the ride to/from home?

Is she using a mobile or handheld?

If she is using a handheld in he building, what floor is she on?

Where she works... are there buildings visually blocking the path to the house?

What is the elevation of the two locations.


I live in Woodbridge and commute to DC on occasion. The RF noise levels are very high in our area and the radically changing elevations as we make our way north/south makes continuous comms almost impossible on UHF while driving. Point to point fixed station requires elevation and good antenna placement.

#4 krvw

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Posted 11 February 2020 - 11:55 AM

Good questions.

 

1 - Building to building, mostly. She is on 2nd floor, but on the far side (from me). Building is 2 floors tall, as is my house.

 

2 - She has a handheld in her office in a charge cradle. Sits on her window sill.

 

3 - There is a small cluster of buildings more or less in line between home and her office, near the Franconia-Springfield Metro. Office buildings about 6-7 floors high, mostly.

 

4 - Elevation at home is 223 feet above sea level, and 249 feet at her office. Between here and there are very small rolling hills. Definitely not completely flat, though.

 

For driving, I'm fine with cellular and/or GMRS repeater. The Alexandria repeater gives me pretty darn good coverage, actually.

 

Cheers,

 

Ken



#5 berkinet

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Posted 11 February 2020 - 12:08 PM

In addition to @marcspaz's questions, I was wondering if you plan of being otherwise active on GMRS, or if the sole intention is to talk between two fixed locations?

 

If you will generally be active on GMRS, and/or if you will be contacting mobile or portable (hand-held) stations, then the Ed Fong antenna is an probably an excellent choice. Though, depending on your needs, you might want to consider a very basic 1/4 wave (6 inch) antenna for rooftop use . It could be mounted on a plumbing vent pipe and would attract very little attention.  The difference between the Ed Fong in an attic and the 1/4 wave on the roof will be minimal.

 

However, if your intended use is limited to two fixed stations, you should probably consider two directional antennas like a Yagi.  These antennas will be easier to mount in an attic and give you better performance than the Ed Fong.


Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth.

-- Marcus Aurelius


#6 marcspaz

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Posted 11 February 2020 - 12:24 PM

I don't think it's going to work, regardless of where the antenna is in the house.  Around here my handheld only gets out about 1 mile on average.  On a great day, I'll have splashy comms at about 2.5 miles... but that is purely outdoors with minimal obstructions or elevation changes. 

 

The reason the repeater is working for you is because its using a great antenna on the roof of a building that is close to 100' above the ground.

 

 

 

Have you done any testing yet?



#7 krvw

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Posted 11 February 2020 - 01:15 PM

@Berkinet, yes I do plan on being GMRS active. The main justification was for emergency comms, but I'm at heart a hobbyist and want to dive deeper in here. I'm already on one of our local repeaters and am hoping to get onto 2 others a bit farther out of town. Clearly, repeaterland is where the fun is. I just don't want to have to rely on that for emergencies.

 

@Spaz, I've done a bit of testing, but am equipment constrained. When I send a test tx from our top floor, she gets static at her end, despite squelch turned up to 4 (out of 5). That is with the NA-701C antenna on both handhelds.

 

Oh, and Google Maps puts the drive (nearly direct up Beulah St.) to her office at 2.1 miles, so my earlier estimate was too far.

 

Thanks for the suggestions, everyone. I appreciate the guidance from those with far more experience than I.

 

Once the Ed Fong kit arrives, I'll report back on my success or failure. Honestly, if I can get it to work without having to put it outdoors, I'll be happier. But, we shall see.

 

Cheers,

 

Ken

WRFC318



#8 scottmckinney67

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Posted 12 February 2020 - 07:42 AM

I'd start here  https://www.scadacor...-line-of-sight/   That should at least get you in the ball park to see if your antenna placement will be effective.

 

I just went through a similar scenario and I had a hard time getting 3 miles simplex with my son.  I ended up with a midland whip on a ground plane adapter kit in the attic.with LMR400 to my 40 watt mobile.  I got my son a tram 1480 antenna outside about 20 feet high and we're able to talk, but some channels have lots of interference.  We have 3 channels that are fine with a little bit of noise but no issues understanding every word.

 

Good luck!



#9 krvw

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Posted 12 February 2020 - 11:13 AM

Wow, that's a helpful site, @ScottMcKinney67, thanks.

 

I placed an antenna at my wife's office and one at my home, and then I estimated heights. My wife is on the 2nd floor of her building, so I estimated 4 meters above ground.

 

And then I tried different heights at my end. When I hit 5 meters, I got a green line of sight. I can achieve 5 meters in my attic.

 

Let's hope that pans out in practice.

 

Oh, and I did ask my HOA about an antenna on my roof. Surprisingly, they didn't just say no. If I ensure it won't be an eyesore and that the cabling would be well hidden, they will approve it.

 

So there's hope.

 

Thanks for all the great advice here. I'll post after I've built the Ed Fong.

 

(I'll add this... Whenever I've explored a new technology and/or hobby, I've always sought Internet fora to discuss with those more experienced than I. I've been on the Internet since the 1980s, and this has always been helpful to me. I appreciate this kind of human advice based on experience and tribal knowledge immensely, folks. Thank you all.)

 

Cheers,

 

Ken

WRFC318



#10 scottmckinney67

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Posted 12 February 2020 - 11:57 AM

Wow, that's a helpful site, @ScottMcKinney67, thanks.

 

I placed an antenna at my wife's office and one at my home, and then I estimated heights. My wife is on the 2nd floor of her building, so I estimated 4 meters above ground.

 

And then I tried different heights at my end. When I hit 5 meters, I got a green line of sight. I can achieve 5 meters in my attic.

 

Let's hope that pans out in practice.

 

Oh, and I did ask my HOA about an antenna on my roof. Surprisingly, they didn't just say no. If I ensure it won't be an eyesore and that the cabling would be well hidden, they will approve it.

 

So there's hope.

 

Thanks for all the great advice here. I'll post after I've built the Ed Fong.

 

(I'll add this... Whenever I've explored a new technology and/or hobby, I've always sought Internet fora to discuss with those more experienced than I. I've been on the Internet since the 1980s, and this has always been helpful to me. I appreciate this kind of human advice based on experience and tribal knowledge immensely, folks. Thank you all.)

 

Cheers,

 

Ken

WRFC318

 

Glad I could help.  I had tried different things and was having trouble and when I plugged in our locations, the root problem became clear to me.  Forums are my go to also :)


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#11 krvw

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Posted 12 February 2020 - 01:03 PM

Inspired by https://www.scadacor...-line-of-sight/, I decided to run another test quickly. Grabbed a ladder and climbed up into the attic crawl space. Sent a GMRS check to my wife.

 

In the past, it did not even rise above her squelch level, but this time she at least got a staticky signal.

 

Hoping the improved antenna will clean that up further so that simplex comms are workable.

 

Plus, having the antenna better placed, I'm hoping for more hobby time on a couple repeaters in my area.

 

Cheers,

 

Ken


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#12 Ian

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Posted 19 February 2020 - 01:16 AM

Regarding rooftop antennae?

 

www.ventenna.com


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