Mobile antenna adapted for base use?

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sffiremedic

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I am looking for a base station omnidirectional gain antenna for 700/800 public safety P25 with the greater need being the 700 band. I am wondering if the Tram/Browning BR-137 (claimed 6dB on 700mhz) on a Tram 1465 ground plane (radials) NMO adapter mount would work well form me, mast mounted on a different gable end. Plus I have an 800/900 12dB yagi I can utilize on the weakest tower. Larsen as a similar NMO 150/450/758 but claim less gain on 700 mhz.

Background on my location:

I have a discone antenna 18' high over one gable that does well as a broad band antenna but I need something better for several P25 systems and I do not think better cable would be enough. I have great elevation for the county to the east but with some trees blocking part of the exposure. To the west I have a bit of a hill (30') which then drops down several hundred feet to the "flats" and again trees in between. For locals, I am in Oakland off Skyline near Skyline High. With the discone I am getting some EBRCS CoCo and on conventional frequencies Coco Couny, Solano County all the way up to Dixon, some Marin County, and I have not plugged in Santa Clara, Napa or San Mateo frequencies yet.

I can just get San Francisco trunked SFFD/SFPD with the discone but quality could be better. I cannot get EBRCS NorthWest for Oakland FD/PD, I do get EMS ALCOMED 1 which I am guessing is simulcast off Mt Diablo which is line of sight from my roof. Unfortunately three I think of the four NorthWest EBRCS towers are "below me" to the west with the small hill and trees in between, the other at "Sequoia Reservoir" which may be the pumping station in Montclair higher up skyline with hills between us. However as soon as I drive two blocks and am on Skyline Bl I am pulling in NW EBRCS talk groups with a rubber duckie on my Pro-668.

So does the Triband gain antenna with ground plane mast mount sound reasonable for a gain omni gain antenna? If it did not work out I would have a decent mobile antenna for my vehicle on an NMO mag mount. Or are there 700 band cell antennas that would do a better job. I need omni directional for this situation to to multiple trunked systems.


Thanks for your advice.
 

mmckenna

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I would not trust the dB ratings from Tram. 7dB is very unlikely from that antenna, unless they are rating it by 7dBi instead of dBd. Some manufacturers/dealers like to play with the dBd vs. dBi thing to make customers believe an antenna is "better". It's shady at best. Larsen is a reputable company and they don't play those games. There isn't anything magical about the Tram antennas, they are Chinese knock offs of reputable antennas. They'll save you a few bucks, but from looking at them at trade shows and talking to their sales guy, I'd not waste my money on one. They are fine for hobby use, but not for anything else.

If you are interested in 700 and 800MHz, then stick with a dedicated 700/800MHz antenna. If you are going to mount this on your roof, go with a dedicated base antenna, also. It'll last longer.

I "inherited" a couple of radio sites at work, one of them having a similar mobile antenna base adapter set up.
Yes, they'll work, but they are not going to last as long as a dedicated base antenna. I did replace that mobile adapter and have it in one of my junk boxes.

If budget is tight, it'll work, but stick with a dedicated 700MHz antenna. The multiband antenna won't do you any favors unless you are actually going to use the VHF and UHF sides of it. Better choice is a dedicated base antenna fed with the best coaxial cable you can afford.
 

sffiremedic

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oaktown
Thank you for your reply.

So what would you recommend for an omnidirectional base antenna for 700/800mhz?
I see yagis but nothing else except cell band
mast antennas.... would they work?

This is for a hobby set up with other scanners on the discone for frequencies under 700.
 

sffiremedic

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oaktown
As luck would have it, I just picked up TWO of those Laird base antennas on Craigslist, $24 each! One has an LMR400 pigtail, the other no pigtail. Will give it a shot.
 
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