Antenna question

[yankees6161]

I currently have a 536 with a sirio 1300 antenna in the attic using 30 ft lmr400 cable. I am wanting more gain on the 800-900mhz range. Thinking about a yagi to achieve the gain. Any one have a yagi in the attic? I know a antenna out side would be best but lightning has me concerned. What are your thoughts?

 

[hiegtx]

I currently have a 536 with a sirio 1300 antenna in the attic using 30 ft lmr400 cable. I am wanting more gain on the 800-900mhz range. Thinking about a yagi to achieve the gain. Any one have a yagi in the attic? I know a antenna out side would be best but lightning has me concerned. What are your thoughts?

While a directional antenna, such as a yagi, might give you more gain & signal strength, that only applies to sites in the direction you are aiming at. You will lose signal strength for sites in other directions, including any that are in the opposite direction of where you are aiming. I'll defer specific suggestions to those who have, or do use, antennas similar to what you need.

 

[DS506]

I was not able to get the local 7/800 MHz trunked system with my discone 38' above ground. I purchased a Wilson 301111 7/800MHz Yagi. Just to test it, I connected a jumper to the SDRs in the basement and I had a signal. I mounted it from the rafters pointed out the window at ground level toward the tower 10 miles away. Definite obstructions - see chart. Replaced the jumper with 25 feet of LMR-240. Even split the signal to 4 RTL-SDRs and I have had a very dependable signal for nearly 2 years. I can get a signal from another trunk system 110 degrees to the right about 60% of the time.

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[FKimble]

Why a directional antenna? Why not just a gain antenna so you can have 360 degree gain?

Frank

 

[yankees6161]

Frank,
What antenna would you suggest?

 

[n1chu]

A yagi gives better gain the more elements it has. You can see the differences in gain by comparing the spec sheets. You may be able to get away with a yagi pointed in a single direction and still hear the other stuff off the sides of your yagi if they are strong stations. I do this with my yagi and don’t even need the rotator I have as I never change the Yafo’s direction.

Your concern about lightning needs an update. Yes, you should be concerned about lightning protection for an outside antenna. But that same level of concern also applies to an attic mounted antenna. Just because it’s out of sight doesn’t mean lightning isn’t attracted to it, or less attracted to it. Agreed, the concept may be hard to accept but if you haven’t got grounding protection attached I caution trying to prove me wrong by consulting your local fire marshal or insurance company… they will both insist you ground the attic mounted antenna just as if it were mounted outside on the structure. And they both have their ways of enforcing what they say.

 

[yankees6161]

Thanks N1

 

[K5MPH]

Is your Sirio antenna outside.......

 

[jeepsandradios]

Is your Sirio antenna outside.......

I currently have a 536 with a sirio 1300 antenna in the attic using 30 ft lmr400 cable.

 

[yankees6161]

Is your Sirio antenna outside.......

It is in the attic

 

[lu81fitter]

I currently have a 536 with a sirio 1300 antenna in the attic using 30 ft lmr400 cable. I am wanting more gain on the 800-900mhz range. Thinking about a yagi to achieve the gain. Any one have a yagi in the attic? I know a antenna out side would be best but lightning has me concerned. What are your thoughts?

I use this setup and it works pretty well.

Larsen NMO150/450/758 - Receiver Scanner Mobile Antennas | The Antenna Farm

Laird TE Connectivity MBCN - Mobile Antenna To Base Convertors | The Antenna Farm

That base has the N connection on it. Make sure you get the connector that you need if you want to try it.

 

[yankees6161]

lu81
Where did you mount your antenna?

 

[lu81fitter]

Mine is mounted outside on a pole. It's about 6 feet above my roof line. I don't have any grounding on it right now, but I'm acquiring the stuff to do it.

 

[vagrant]

Search/watch eBay for a K&L 5IZ10-20/x1300 diplexer. (photo below) I use this with a discone and an omni 824-960 MHz 6 dBi antenna (L-COM HGV-906U). The diplexer was $35 and the antenna was $20 back in 2020. An eBay eagle eye RR member clued me into those two goodies. The one other thing you might need is a pass or notch filter if you have a painful cellular tower nearby and need to squash it.

* Adding an amplifier, or yagi may cause a problem if you're not filtering out a nearby cellular, or whatever interference you may have.

 

[prcguy]

Both the diplexer and antenna are hard to come by due to a certain RR member pouncing on the eBay ads and buying them all up. Not sure if he'll ever get his fill of these things.

Search/watch eBay for a K&L 5IZ10-20/x1300 diplexer. (photo below) I use this with a discone and an omni 824-960 MHz 6 dBi antenna (L-COM HGV-906U). The diplexer was $35 and the antenna was $20 back in 2020. An eBay eagle eye RR member clued me into those two goodies. The one other thing you might need is a pass or notch filter if you have a painful cellular tower nearby and need to squash it.

* Adding an amplifier, or yagi may cause a problem if you're not filtering out a nearby cellular, or whatever interference you may have.

View attachment 134722

 

[vagrant]

@prcguy - I'm waiting to purchase a ticket to that members transceivers, filters, and antenna museum. Hopefully, pictures are allowed as I'm sure there will be filthy antenna porn.

 

[GROL]

.

 

[yankees6161]

Thanks for all the input.