What would cause this?

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Tryton

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Hello all, I just updated my Uniden 996XT with the new firmware. I have tried every setting under the sun. Here is whats going on.. While watching the err rate as well as the P25 err rate on freescan, I will get a few transmissions crystal clear. then the next minute, the err rate is high and I get garbled comms.. I have switched antennas from the radio shack rubber ducky to the stock one fully extended, which seems to be better. but it's still happening.. any clues? I am trying to monitor the Pinellas county fl P25 system here. Thank for any help or incite you can give me..
 

Tryton

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Well it seems I have found the issue.. "Multipath Distortion" My clue is when I put the stock antenna on, I was getting a better receive. I cut a small piece of wire, stuck it in the back, and low and behold, I was getting good copy! So it seems I can either stice a paperclip in the scanner to monitor, or maybe buy a 800mhz yagi and point the sucker right at the closest tower. if you have any suggestions PLEASE let me know.. I'm not sure that Yagi I linked to would be right.. thanks all

Tryton
 
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kruser

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Hey Tryton,

I've tried the settings you found and they did not work quite as good as what I'm using now which is 119/8.

I spent several hours tonight playing with the settings in the hidden menu. I found that the older firmware for both the 396 and 996XT models works better then the newest firmware for my trouble system.
The same 119/8 manual settings are the best but on the older firmware.
The new firmware, I'll see error rates in the 90's. The older firmware hits the 40's tops.

I dug through my notes and found that I first complained about the removal of the true manual P25 settings that could be set per site back in 2009! I really wish this new firmware did have a manual setting like the T models did as I know it would help for me.
I think in your case, you will do fine with a Yagi as it sounds like you get a great signal with a paperclip! You just need to minimize or eliminate the multipath and you should be all set. Doing that is much easier if you sit more between the towers unlike my location where I'm a fair distance from all the towers. The thing that may still get you is if the towers are directly inline with your location and your Yagi aims at one tower with the other tower directly behind the Yagi. I'm not sure if a higher gain (more elements) Yagi would help in that situation or not but I think it would as it would pull in more signal off the front with the greater amount of elements. I wonder if you could mount a plate off the rear so signals from the back of the yagi do not get into it? You should be able to find a performance plot of a Yagi and you can see the side and rear lobes that still allow signal in that I'm talking about.
On the other hand, if your aim to the nearest tower makes the other tower more off to the side of the Yagi, it should work just fine.

A lot of people have had great success using a Yagi to minimize multipath so I'd say to go for it if you have the space to mount one.

Separate it by several feet from your other antennas also.

Good Luck!
 

kruser

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One other thing, you may want to search around the forums here. For some reason I think I recall many having negative comments about The Antenna Farm that your link pointed too.
The antenna itself was fine but check out the company!

Things like slow shipping maybe or saying an item is in stock while it is not. I hope I'm wrong on this but that name sure rings a bell!
 

Tryton

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Thanks so much for the input and heads up Kruser! I'm going to make a little video after I get out of work today showing the improvement..
 

hiegtx

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One other thing, you may want to search around the forums here. For some reason I think I recall many having negative comments about The Antenna Farm that your link pointed too.
The antenna itself was fine but check out the company!

Things like slow shipping maybe or saying an item is in stock while it is not. I hope I'm wrong on this but that name sure rings a bell!
Did a quick search for this company in the forums, and you're correct, the reviews are definitely mixed: See this thread from the antenna forum, or this one from farther back. Limited responses on Reseller Ratings as well. Two good, two 'in the tank'.
 

Tryton

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I live in the black dot, these are all the sites around me..would a yagi help me in the situation? if so what gain should I be looking for? Thanks again!
 

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ak4fn

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Just a thought, have you tried to make a reflector to make your antenna directional, like people make for routers. I would definitively give it a try to see if you could block the other strong tower signal that you have to the south of you. Here is a google search on wifi reflector You will have to play with the size and the distance that it is away from your antenna. Looks cheap enough to try.
 

Tryton

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Looks good for what it was designed for, but I need to pull in the one tower.. so for me I think a high gain antenna is what I need.. But thanks for the cool info!
 

Astrak

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I was using a Wilson 800mhz yagi when I had my Phoenix PD feed that worked pretty good. I was a good distance from any tower. You can find them at cell phone shops or on eBay.
 

Tryton

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Thanks all, I am going to try this.. it's really my last chance (Short of moving). Hopefully this does the trick.. has anyone else solved this problem with a Yagi?
 

kb2vxa

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Hold on fellas, the Yagi idea sent everybody in the wrong direction. The clue is the paperclip antenna, it's as omnidirectional as the others so multipath isn't the problem. I've heard of buggy firmware upgrades and it looks like this is one of them. Since there was no problem until it was installed going retro will fix it, then wait until the bugs are worked out and try again or just leave well enough alone, forget about the upgrade.

Just a personal thought, I don't understand why you ignored the first rule of maintenance. If it ain't broke don't try to fix it.
 

Tryton

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Hold on fellas, the Yagi idea sent everybody in the wrong direction. The clue is the paperclip antenna, it's as omnidirectional as the others so multipath isn't the problem. I've heard of buggy firmware upgrades and it looks like this is one of them. Since there was no problem until it was installed going retro will fix it, then wait until the bugs are worked out and try again or just leave well enough alone, forget about the upgrade.

Just a personal thought, I don't understand why you ignored the first rule of maintenance. If it ain't broke don't try to fix it.
Unfortunately, is was worse before the upgrade.. I am now using the stock antenna instead of the rs 800mhz and seeing MUCH butter results. but I still do get garbled transmissions and error rates in the 30's.
 
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