HP-1: Frequency coverage VHF Low

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jonwienke

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There isn't one. Frequency coverage is determined by components buried in epoxy, and trying to remove it will destroy the scanner. You need to buy a scanner tha covers that range, like the BCD436HP.
 

n3617400

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There isn't one. Frequency coverage is determined by components buried in epoxy, and trying to remove it will destroy the scanner. You need to buy a scanner tha covers that range, like the BCD436HP.

Frequency coverage is determined by firmware.
 

Ubbe

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Whistler opened up the 68-88MHz band in their firmware for the TRX scanners but the front-end filtering attenuate too much in the upper band and 88MHz are almost dead having a reach of max 1km.

When Uniden market a scanner for EU they open up their 25-50MHz filter to 25-88MHz and that's so close to the FM broadcast band that a FM trap filter is mandatory to get any kind of use of the 68-88MHz band.

Maybe John Doe could try and expand the 50MHz limit to 88MHz in the HP1s firmware to see if it will calculate the frequencies correctly to the oscillators, if the decoding of the FW have reached that point.

/Ubbe
 

jonwienke

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No. The hardware configuration is different. The components used to determine frequency range are buried in blobs of epoxy on the circuit board. Cutting through the epoxy will disable the radio.
 

mancow

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If you get the epoxy up to a certain temp you can peel it off like silicone. I of course can't recall what it was now. I want to say 120c but could very well be wrong. I used a hot air station and it worked fine but you have to be sure it's done thoroughly and consistently or you will rip components off the board.

Even if it's removed it doesn't guarantee anything. You would still need to be able to actually tune there and that's software.
 

Ubbe

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There's several instructions on youtube on how to remove that kind of epoxy, some actually without destroying anything.

/Ubbe
 

jonwienke

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So if you can remove the epoxy without damaging anything, reconfigure the components under the epoxy, and manage to install a modified firmware not available to the public, then you can open up the frequency range of the scanner. But that isn't something that anyone here can do, or there would be YouTube videos describing how to do it.
 

Ubbe

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I have to do that front-end modification at some point of time to the TRX-2 but will probably only be by removing a capacitor or a coil or two.
John Doe have disassembled the HP1 code and can probably move the upper range of low-VHF to 88MHz.

I wish that manufacturers wouldn't encrypt their firmware to make it more possible for us to tinker with it. TYT made a mistake and left the encryption key in the FW file that made it possible to do all these wonderful hacks to the MD380 that we can enjoy now and that the chinese developer would never do due to cost and lack of imagination.

The same thing happend to the CD/DVD copy protection key that where supposed to be a secret held within the manufactures but was by mistake included with a developer package to the public. There where never any hacker who cracked the key, it where left in the open for anyone to find. And now we can share copies of CD/DVD's among friends, that for some reason are completly legal in my country.

Sometimes it just neccesary to find out the addresses of all ports and memories by disassembly and then make a totally new firmware from scratch.

/Ubbe
 
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