TRX-1: TRX1 Tech has anyone tried? NJ 700MHZ :(

Status
Not open for further replies.

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Has anyone tried messing with the two VR's (variable resistors) inside on the
PC board? I can not get 700MHZ to work worth a darn the way it comes from the factory the Signal meter jumps around like crazy.The reception on 700 is
only mediocre with squelch down and the system set to Normal.
My settings for threshold are 01 Low and 99 high.it works sometimes at best on Phase 2 and fair on Digital phase 1.Anyone in NJ have any better settings or ideas?:mad:
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Seems I have made a little breakthrough on this thing,putting a BNC to F connector and a -6dbm attenuator they use for television (says 30-1000mhz on it).I cut a metal wire hanger,put two U-style connectors you get at Autozone on the ends and hooked that to some TV coax RG-6 quad shield into the attenuator's other end and it seems to decode about <80 percent of the time with the squelch all the way Open.My DSP is at 62.My high low threshold is 01 and 99 for that system.The problem with this is its too sensitive and not selective enough.(front end overload from a cell-tower nearby)
 

tsmooth

Member
Joined
Apr 14, 2006
Messages
81
Location
St. Tammany Parish
Seems I have made a little breakthrough on this thing,putting a BNC to F connector and a -6dbm attenuator they use for television (says 30-1000mhz on it).I cut a metal wire hanger,put two U-style connectors you get at Autozone on the ends and hooked that to some TV coax RG-6 quad shield into the attenuator's other end and it seems to decode about <80 percent of the time with the squelch all the way Open.My DSP is at 62.My high low threshold is 01 and 99 for that system.The problem with this is its too sensitive and not selective enough.(front end overload from a cell-tower nearby)
Awesome


Sent from my LGMS330 using Tapatalk
 

tsmooth

Member
Joined
Apr 14, 2006
Messages
81
Location
St. Tammany Parish
Seems I have made a little breakthrough on this thing,putting a BNC to F connector and a -6dbm attenuator they use for television (says 30-1000mhz on it).I cut a metal wire hanger,put two U-style connectors you get at Autozone on the ends and hooked that to some TV coax RG-6 quad shield into the attenuator's other end and it seems to decode about <80 percent of the time with the squelch all the way Open.My DSP is at 62.My high low threshold is 01 and 99 for that system.The problem with this is its too sensitive and not selective enough.(front end overload from a cell-tower nearby)
Can u take a picture please

Sent from my LGMS330 using Tapatalk
 

jcardani

Member
Joined
Jan 16, 2002
Messages
1,351
Location
Orlando, FL &amp; Ocean City, NJ
Hi k2ool,

There reason you are getting the signal jumping like that is due to the LSM on the simulcast sites. Try using a yagi antenna or paint can antenna that is discussed elsewhere on the forum. Or simply get closer to one of the sites. But until the scanner manufacturers realize the radios cannot properly decode LSM signals consumers will continue to have these problems. Research Max Parks's (KA1RBI) many posts about this subject. But the simplified reason is that scanners use the FM discriminator as input to the DSP/micro controller. The discriminator strips to the AM component that is required to properly decode LSM. An I/Q demodulator would need to be used instead of the discriminator, plus some other code.


Has anyone tried messing with the two VR's (variable resistors) inside on the
PC board? I can not get 700MHZ to work worth a darn the way it comes from the factory the Signal meter jumps around like crazy.The reception on 700 is
only mediocre with squelch down and the system set to Normal.
My settings for threshold are 01 Low and 99 high.it works sometimes at best on Phase 2 and fair on Digital phase 1.Anyone in NJ have any better settings or ideas?:mad:
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
fix

I know why,its because they failed somehow in the design of this thing.
The -6dbm attenuatr actually helped alot.
The Coathanger aimed vertically is giving me 99 percent decode!
Oddly its aimed AT the cell tower.
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
Attenuator

Is that 6db on top of the units builtin attenuation?

Sent from my SAMSUNG-SM-G870A using Tapatalk
Nope the built in attenuator does not work for my 700mhz issue with LSM
The television add on -6dbm filter somehow helped.....
Also setting it to custom instead of Autofill or normal.
I noticed it worked a tad with the BNC stock antenna today too,but not as good as the coat hanger mess.
 

nosoup4u

Member
Feed Provider
Joined
Jan 30, 2002
Messages
1,998
Location
High Bridge, NJ
I also want to add that I think this is more of an issue with 700mhz, than LSM. I don't get affected by LSM on the NJICS system, yet I have issues where my BCD436 and my 536 on an attic mounted antenna generally work fine. I also have the same issue on the Somerset County 700 System BEFORE I even get into Somerset and LSM should not be an issue (again its not an issue on the Unidens in the same area).
 

SCPD

QRT
Joined
Feb 24, 2001
Messages
0
Location
Virginia
trx1

Only settings are normal except for the fact that I set Autofill to Custom.
System settings are 01 and 99 on threshold.
DAC and the other one is set to 0 from -4.
The Hang-Tenna is working well.
 

nosoup4u

Member
Feed Provider
Joined
Jan 30, 2002
Messages
1,998
Location
High Bridge, NJ
Changing it to 0-99 did help, custom didn't seem to make any difference. I found often moving the radio a couple inches over makes a big difference. 700 is very touchie on this radio.

Sent from my Nexus 6 using Tapatalk
 
Status
Not open for further replies.
Top