Re: [Repeater-Builder] TKR-820 Reciever Issues
Did you calculate the correct LO frequency? Also you may try reversing the high byte and low byte figures of the receive frequency. On 11/21/07, John Barrett <[EMAIL PROTECTED]> wrote: > > This one is for folks that know the Kenwood TKR-820 repeater J Or how to > modify a VCO frequency range J > > > > I have a known working on 451.125/456.125 TKR-820 UHF repeater that I'm > attempting to move down to 441.350/446.350… I've got the chip reprogrammed > and the transmit VCO had no problems retuning to the target frequency ( > 441.350). The receive VCO is another story… The manual says that PLL/VCO > lock happens when the voltage from the PLL's integrator is between 4 and 5 > volts, with a target of 4.5 volts. After adjusting the VCO's variable > capacitor (the only adjustment available), the best I can get is 2.5volts, > and I'm getting a slow sawtooth on the integrator output from the > PLL. This is surprising to me since it seems the RX and TX use identical PLL > and VCO modules, and the RX VCO only has to tune down to 446.350… 5mhz > higher than the TX. In any case.. the 2.5v control voltage is obviously > incorrect since I cannot key the repeater with my HT at that adjustment. > > > > I have pulled the CTCSS configuration chip as recommended in one set of > retuning instructions so I should be able to key the repeater without a PL > (the repeater controller will be handling that in any case, so that chip > will likely never be reinstalled). > > > > Any ideas what I might be doing wrong, or any tricks on how to get > everything tuned up ?? > >
RE: [Repeater-Builder] TKR-820 Reciever Issues
Byte swapped version of the chip was unable to get the test point voltages above 150mV on either TX or RX, so I presume I have the byte order correct :-) Data for the chip was generated with KPG21D (the programming software for this repeater) and validated with the formula from a 3rd party document detailing the frequency to hex code calculation. The binary data saved by KPG21D was edited with a hex editor to extract the 128 bytes needed for the frequency eeprom. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of DCFluX Sent: Wednesday, November 21, 2007 5:29 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] TKR-820 Reciever Issues Did you calculate the correct LO frequency? Also you may try reversing the high byte and low byte figures of the receive frequency. On 11/21/07, John Barrett <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> net > wrote: This one is for folks that know the Kenwood TKR-820 repeater :-) Or how to modify a VCO frequency range :-) I have a known working on 451.125/456.125 TKR-820 UHF repeater that I'm attempting to move down to 441.350/446.350. I've got the chip reprogrammed and the transmit VCO had no problems retuning to the target frequency (441.350). The receive VCO is another story. The manual says that PLL/VCO lock happens when the voltage from the PLL's integrator is between 4 and 5 volts, with a target of 4.5 volts. After adjusting the VCO's variable capacitor (the only adjustment available), the best I can get is 2.5 volts, and I'm getting a slow sawtooth on the integrator output from the PLL. This is surprising to me since it seems the RX and TX use identical PLL and VCO modules, and the RX VCO only has to tune down to 446.350. 5mhz higher than the TX. In any case.. the 2.5v control voltage is obviously incorrect since I cannot key the repeater with my HT at that adjustment. I have pulled the CTCSS configuration chip as recommended in one set of retuning instructions so I should be able to key the repeater without a PL (the repeater controller will be handling that in any case, so that chip will likely never be reinstalled). Any ideas what I might be doing wrong, or any tricks on how to get everything tuned up ??
Re: [Repeater-Builder] TKR-820 Reciever Issues
If you are up to removing the eeprom from the front panel (soldered in) and mail it to me I will put it in my kpt20 and verify operation - I have never run into trouble with a UHF repeater. Some of the TKR720's were borderline, but the TKR820's were OK. You don't have a T band unit or something out of the ordinary do you? Steve NU5D John Barrett wrote: > > Byte swapped version of the chip was unable to get the test point > voltages above 150mV on either TX or RX, so I presume I have the byte > order correct J > > > > Data for the chip was generated with KPG21D (the programming software > for this repeater) and validated with the formula from a 3^rd party > document detailing the frequency to hex code calculation. The binary > data saved by KPG21D was edited with a hex editor to extract the 128 > bytes needed for the frequency eeprom. >
RE: [Repeater-Builder] TKR-820 Reciever Issues
I've got the chip pulled, and a socket installed, but I'd prefer to wait on sending a chip out until my replacement programmer gets here and I can validate the chip myself.. if I'm lucky it will be here tomorrow. The unit was previously programmed for 451.125/456.125.. I'm moving it down 10mhz to 441.350/446.350. the data in the chip is CC 84 3C 83 if you want to compare that to what your programmer would put in. _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Steve S. Bosshard (NU5D) Sent: Wednesday, November 21, 2007 6:33 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] TKR-820 Reciever Issues If you are up to removing the eeprom from the front panel (soldered in) and mail it to me I will put it in my kpt20 and verify operation - I have never run into trouble with a UHF repeater. Some of the TKR720's were borderline, but the TKR820's were OK. You don't have a T band unit or something out of the ordinary do you? Steve NU5D John Barrett wrote: > > Byte swapped version of the chip was unable to get the test point > voltages above 150mV on either TX or RX, so I presume I have the byte > order correct J > > > > Data for the chip was generated with KPG21D (the programming software > for this repeater) and validated with the formula from a 3^rd party > document detailing the frequency to hex code calculation. The binary > data saved by KPG21D was edited with a hex editor to extract the 128 > bytes needed for the frequency eeprom. >
RE: [Repeater-Builder] TKR-820 Reciever Issues
Seller claimed the repeater was removed from operation, and it was labeled 451/456 - so it should be the right one to tune down The 1st 4 bytes are CC 84 3C 83 if you can compare that to the data your programmer would write.. The target frequencies are 441.350 TX and 456.350 RX I've already removed the chip and installed a socket . I'll consider sending the chip if no other viable solution comes up. I don't know what T band is, unless that's the 470-500 version of the repeater. How would I tell ?? I don't see any particular markings on the chassis or boards that would tell me what exactly I have.. The only thing that might be relevant is a sticker on the RX VCO marked "COM15" _ From: Repeater-Builder@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Steve S. Bosshard (NU5D) Sent: Wednesday, November 21, 2007 6:33 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] TKR-820 Reciever Issues If you are up to removing the eeprom from the front panel (soldered in) and mail it to me I will put it in my kpt20 and verify operation - I have never run into trouble with a UHF repeater. Some of the TKR720's were borderline, but the TKR820's were OK. You don't have a T band unit or something out of the ordinary do you? Steve NU5D John Barrett wrote: > > Byte swapped version of the chip was unable to get the test point > voltages above 150mV on either TX or RX, so I presume I have the byte > order correct J > > > > Data for the chip was generated with KPG21D (the programming software > for this repeater) and validated with the formula from a 3^rd party > document detailing the frequency to hex code calculation. The binary > data saved by KPG21D was edited with a hex editor to extract the 128 > bytes needed for the frequency eeprom. >
