Indoor antenna for 700 MHz primarily

[W2IRT]

Hi all,
I have two scanners at present, a BCD996xt and a 996p2. A couple of my local agencies are on conventional VHF and UHF repeaters and I'm using a tower-mounted discone at 40' for those, with good success on my 996xt.

Where I'm having difficulties is on the statewide 770 MHz phase-2 system on my 996P2. I don't want to spend the money on a combiner, and since the 996p2 is dedicated almost exclusively to that NJ statewide "NJICS" system, I need something that performs well in that frequency range. At the moment it's connected to SpectrumForce mag mount sitting on top of my power supply inside a one-story house, roughly 10' above the outside ground level. I'm finding the signal quality varies wildly on this antenna, from 1 "bar" to full. I've tried moving the antenna around on the supply, and moving the supply around on top of the desk, but I can't seem to keep a strong signal with this. Since this is a P25 Phase Two capable system, I'm finding that with weaker signal levels comes increasingly garbled transmissions, even with the latest firmware update on the 996p2.

So I'm wondering if there's something better out there that will give me some gain on 700 MHz and as a secondary concern, might still be somewhat usable on UHF/VHF-hi if I need both radios on the local analog system.

Conversely, would I run into any significant problems if I just split the discone signal between the 996xt and 996p2? Perhaps putting in a small preamp to compensate?

Thanks in advance.

 

[doctordialtone]

would I run into any significant problems if I just split the discone signal between the 996xt and 996p2?

This is what I'd do. In my opinion you're always going to be better off with an outdoor antenna with some elevation.

 

[ka3aaa]

you can split the signal all you want but get the antenna outside and as high as possible because it will make a dramatic improvement in reception.

 

[W2IRT]

you can split the signal all you want but get the antenna outside and as high as possible because it will make a dramatic improvement in reception.

Yes, and it's as high up as I can get it. I have two towers (a 70 footer that's fully loaded with HF aluminum) and a 35 footer (with 5' mast). It has my 6m Yagi at 37' and the discone on the very top at 40-ish feet.

Short of buying a combiner, what's the best way to split the discone signal? Should I just use a BNC T or a TV splitter with BNC-F to-Type-F Male adapters? I've got a couple of 2GHz rated TV splitters here and I think I have the adapters kicking around somewhere.

 

[W2IRT]

Update: I found my adapters, used the TV type splitter, made up a couple of PL-259 to BNC-M patch cables and it looks to be running well. The splitter is down 3.5 dB per port.

I'm thinking of a preamp in there as well, but I'm wondering if anybody's aware of a preamp that has a relay to break the line on transmit? The discone is on the same mast as a 6m antenna that runs 1500W on 50 MHz and I'd like to protect the scanners' front ends when the amp keys down. So far during Es season everything's worked well and the scanners are still happy but I feel like I'm tempting fate.

 

[qcomnet]

My thought here is that you're getting too much signal from the simulcast system(s). Try attenuating the signal so your P2 doesn't hear more than one of the simulcast towers. Just a test. I'm smack in the middle between two towers in a 3 tower simulcast system. Just collapsed the stock antenna on my 996p2, layed it down and fairly certain this is my fix. (for now) Obviously I'm now not receiving all other more distant systems, but this puts me onto other avenues to remedy a disappointing experience. Good luck.
Read a good article here: The Digital Blues (or why does my local digital system sound like #$^?) | Scanner Master Blog

 

[W2IRT]

Initially I had the attenuator turned on for exactly those stated reasons but on the whole I found it better to leave it off, and quality improved.

In the end, I wound up springing for a 4-port Stridesberg combiner and replacing the RG-213 coax with LMR-400 (with 3 foot RG-8X patch cables). Still some issues on the Morris County system, and I wish I had a bit more gain on VHF-Hi and UHF. In fact, I'm definitely in the market for an antenna with a bit of gain on VHF-Hi and UHF but that still works acceptably well in the 770 and 850 MHz public safety bands.