Thanks don that would explain the trouble I had a couple years ago and we setup the radios to decode on their own .that works ok but it is slow
Thank You ,Ian Wells Kerinvale Comaudio, 361 Camboon road, Biloela.4715 Ph 0749922449 Mb 0409159932 Hm 0749922574 Fx 0749922767 www.kerinvalecomaudio.com.au -------Original Message------- From: Don Crutcher Date: 3/03/2010 4:21:09 PM To: [email protected] Subject: Re: [Repeater-Builder] Adapting ctcss decoders to maxon pm150 Hello again Ian I've also tried a decoder with a 4 MHz crystal and it still heterodyned. Get a tunable decoder and your troubles will be solved. What I found was if I turned up the TX CTCSS encode, the decoder activated and held up the receiver which held up the transmitter etc. We also had a ~ 1KHz whistle, probably the receive signals or TX were off frequency by that much. Peter VK2ZTV also has had the same problem with FM-828's Regards Don vk2zcz ----- Original Message ----- From: Ian Wells To: [email protected] Sent: Wednesday, March 03, 2010 3:12 PM Subject: Re: [Repeater-Builder] Adapting ctcss decoders to maxon pm150 >From the manual it says it uses a 4 meg crystal Thank You ,Ian Wells Kerinvale Comaudio, 361 Camboon road, Biloela.4715 Ph 0749922449 Mb 0409159932 Hm 0749922574 Fx 0749922767 www.kerinvalecomaudio.com.au -------Original Message------- From: Don Crutcher Date: 3/03/2010 3:04:49 PM To: [email protected] Subject: Re: [Repeater-Builder] Adapting ctcss decoders to maxon pm150 Hello Ian IF your repeater is a UHF and the CTCSS decoder has a 5 MHz crystal oscillator, it will mix with the transmitter and give a signal at the receiver frequency 5 MHz lower (in Australia RX 433-435 TX 438-440 MHz) This a is a common occurrence with UHF Philips FM-828's. The fix is to use a tuneable CTCSS decoder and not use the one with a crystal oscillator in it. Been there and done that. Took years to find out why we had a whistle in the receiver (heterodyne). Regards Don vk2zcz ----- Original Message ----- From: Ian Wells To: [email protected] Sent: Wednesday, March 03, 2010 2:48 PM Subject: [Repeater-Builder] Adapting ctcss decoders to maxon pm150 Hi guys .I was looking at adapting a midian tds-1 to a maxon pm150 but we end up with feedback problems when used in repeater . Can anyone suggest ideas to give rf protection to the decoder chip .I came up with shielded cable between the board and the chip And to install the chip in a metal case on near the radio .or mounting it as close to the rf motherboard as possible but I don't think It will fit under the lid .The reason we would like to use the tds-1 is that the radio has to unmute before it decodes And I would like it to decode before the signal opens the mute .This improves the speed the repeater opening up On a valid signal . Thank You ,Ian Wells Kerinvale Comaudio, 361 Camboon road, Biloela.4715 Ph 0749922449 Mb 0409159932 Hm 0749922574 Fx 0749922767 www.kerinvalecomaudio.com.au
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