VHF/UHF and 800 Mhz Separate Antennas?

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JimD56

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I'm looking for some advice from others that know better than me with antennas.
Is it worth it to have 2 separate antennas for VHF/UHF and 800 Mhz? This will be for a base application and in the attic.
I have an all-band mobile with a ground plane currently using as my base on a 10-foot mast BUT I got busted by the HOA, so now a whole new antenna array is being considered.
Right now I'm considering a Tram 1410 Discone for VHF/UHF and a Yagi for 800 Mhz. I'm in a tight metro area of Miami/Fort Lauderdale where signals are strong on all bands. Will the Discone be fine? Do I need to split the VHF/UHF from the 800 mhz for optimum reception?
My listening habits are VHF Air, Mil Air/Feds/Mil Ground 200-300 mhz, UHF 450-460 mhz and 700-900 mhz Trunked P25 II.
Also, have a homebrew ADSB antenna into an RTL-SDR V3. No transmitting at all.
Thanks to all.
 

chief21

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You'll probably be OK with the discone for VHF/UHF, but discones are not known for their performance on 700-900. I see you're considering a Yagi antenna, which would be very directional. Are all of your 800 MHz+ targets in the same direction? If you end up using two separate antennas, consider a diplexer to combine the signals into your receiver.
 

prcguy

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Your distance to the 800 transmitters is not all that far and a Discone outdoors in the clear should work fine. Antennas in the attic can degrade quite a bit depending on wall and roof construction, etc. You might install the Discone and see how it performs on 800 in the attic and I think its the best choice for the broad range of VHF/UHF frequencies you want to hear. It would be ideal if one antenna can do everything.

Worst case if the Discone is marginal in the attic is you can add a gian type Omni to cover 700/800 and diplex it into the same feedline out of the attic. I would only consider a Yagi if all the 800 stuff is in one direction and you can get everything without rotating the antenna.

My closest Trunked Motorola Smart Zone and P25 Antenna is 3km away, the others are no closer than 9km, so I'm thinking one Yagi pointed at the closer one.
 

sflmonitor

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I lived in Sunrise about 17 years ago. I also lived in an HOA and had all my antennas in the attic. I used a discone for my scanner needs and it wasn’t terrible. My roof was mostly wood and tile so the signals were not terribly attenuated. But then again everything was analog so YMMV. I think you should be good with a discone in the attic unless you want to pull in very distant sites. But I would suggest you go in your attic and search around for that “sweet spot” before permanently mounting the antenna. I took the discone, scanner and short piece of coax and moved around the attic to find the best location within the attic before mounting it. I found that even a few inches made a difference. Good luck.
 

ka3aaa

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I think i seen someone that makes a tri band dipole around 48 inches tall. mount that on you balcony and put a flag on it, you didnt put up an antenna you put up a flag pole.
 

iMONITOR

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This antenna should perform well in your situation for 700-800MHz. It doesn't even resemble an antenna to most people and you could probably find a place to mount it outside without upsetting the HOA goons! Tell them it's an outdoor air freshener to help the environment! :ROFLMAO:

85694
 

prcguy

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And their only about $14 with shipping!

This antenna should perform well in your situation for 700-800MHz. It doesn't even resemble an antenna to most people and you could probably find a place to mount it outside without upsetting the HOA goons! Tell them it's an outdoor air freshener to help the environment! :ROFLMAO:

View attachment 85694
 

JimD56

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I love the flag idea. That got me thinking I might even put a flag pole in the front yard with the terrawave on top. I have a 2400sqft single-story house. No balcony. HOA says the flagpole cant even exceed 20 feet, which will barely clear the roof peak of my single story.
I ordered the discone and diplexer today. Going with the Tram 1410 for VHF/UHF 108-460 and swapping out the scanner all band antenna for an 80cm whip off of the already 86cm ground plane NMO kit for 800mhz and see how that goes. Saw that 800mhz setup in a youtube video and I have all the parts. Stay tuned I'll update how it goes next week sometime.
 

tunnelmot

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On topic: I would think that an in-attic all band discone *should* work ok from the situation you described (barring any radiant barrier type insulation). You seem fairly close to your 800meg sources so I actually think your VHF and to a lesser degree UHF rx may be more of an issue depending on your distance from those sites. Let us know how your setup works either way.

Off topic: My brother who lives in Ft.Laud/W.Palm area wanted me to set him up with some monitoring gear. After looking through the database I didn't think there was much to monitor as far as Public Safety due to the dreaded E.
 

JimD56

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The only "E" is all of Miami and Fort Lauderdale is SWAT Entry and NARC Ops only. Plenty of PD and FD to listen too, BUT All of Broward will be transitioning to a new P25 II System that will have some "multicast". SDS Series is the way to go.
 

dave3825

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It doesn't even resemble an antenna to most people and you could probably find a place to mount it outside without upsetting the HOA goons
If you could rearrange the mounting bracket, it looks like it could be mounted like a half inch above your toilet waste vent pipe. If anyone questions it, you could tell them is a waste vent cap

85800
 

JimD56

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Antennas in the attic are done, and I have zero issues, definitely better reception using just the wavelength strength indicator on SDR# sharp.
1) Tram 1410 Discone for 108-460mhz on a 10-foot mast
2) Laird Mobile tuned 800-900mhz on a ground plane mount then on a 5-foot mast.
Using a Comet Duplexer CF-413B separating the 2 antennas, then a single RG-6 coax 35-foot feed into an Electroline powered 8 way VHF/UHF 5mhz-1.5ghz antenna splitter/amplifier. Thanks for the advice from all. Forgot to take a pic and its too damn hot to go back up there.
 

thinbluebbq

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Antennas in the attic are done, and I have zero issues, definitely better reception using just the wavelength strength indicator on SDR# sharp.
1) Tram 1410 Discone for 108-460mhz on a 10-foot mast
2) Laird Mobile tuned 800-900mhz on a ground plane mount then on a 5-foot mast.
Using a Comet Duplexer CF-413B separating the 2 antennas, then a single RG-6 coax 35-foot feed into an Electroline powered 8 way VHF/UHF 5mhz-1.5ghz antenna splitter/amplifier. Thanks for the advice from all. Forgot to take a pic and its too damn hot to go back up there.
Thanks for the explanation on your setup. I have the antennas to do the same thing. My one question is about the Electroline. Is that at your desk/listening post? Are you finding it boosts the signals on UHF and VHF but doesn't overload signals? I was just planning to use the Comet but I would consider adding one in if it seems effective.
 

WB9YBM

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An antenna engineer I once worked with at Motorola told me the best antenna is one that operates on a single band; multi-band antennas are a compromise. How much of a compromise, he didn't say; I guess that depends on the quality of the components used, and the talents of the designer.
 
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