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

SCPD · Mar 13, 2017

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?

SCPD · Mar 15, 2017

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 · Mar 15, 2017

k2ool said:
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

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tsmooth · Mar 15, 2017

k2ool said:
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

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tsmooth · Mar 15, 2017

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tsmooth · Mar 15, 2017

Im getting excellent decode with this paperclip but not so good when driving

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jcardani · Mar 15, 2017

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.

k2ool said:
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?

SCPD · Mar 15, 2017

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 · Mar 16, 2017

Pic of the hang-tenna

Hang-Tenna!

tsmooth · Mar 16, 2017

k2ool said:
Hang-Tenna!

Ok kool

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SCPD · Mar 16, 2017

TV antennuator F connector to BNC

Tv attenuator to F connector BNC ,yes all that to decode 700mhz.:roll:

tsmooth · Mar 16, 2017

k2ool said:
Tv attenuator to F connector BNC ,yes all that to decode 700mhz.:roll:

At least its working for u. Its ashame that we have to make an adjustment just to make these scanners work

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SCPD · Mar 16, 2017

TRX1

Now its supposed to be a portable....

tsmooth · Mar 17, 2017

k2ool said:
Now its supposed to be a portable....

Right i should have just purchased a mobile.

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TAbirdman · Mar 17, 2017

k2ool said:
Tv attenuator to F connector BNC ,yes all that to decode 700mhz.:roll:

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

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SCPD · Mar 17, 2017

Attenuator

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

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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 · Mar 18, 2017

Can you post your table settings? I would like to see if that makes a difference on my end.

nosoup4u · Mar 18, 2017

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 · Mar 19, 2017

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 · Mar 20, 2017

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.

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

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