I have purchased a couple Spectras they are mdl #'s T83GXA7HA9AK & T84GXA7HA9AK, I am not familiar with all the ins & outs of the Spectras & would like to speak with someone who is a "guru" on these, they were used by a state agency & were not the federal jobs that were floating around they did have the hhch and a couple boxes I do not know what is, if anyone can
give me any help in changing these to individual use with an A7 head & what is required I would appreciate it, also these are suppose to be securenet capable can I use that mode with out the external boxes & maze of cables, thanks in advance...
Fred/W8WAR
Motorola Spectras
Moderator: Queue Moderator
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midstate33
- Posts: 5
- Joined: Fri Jun 02, 2006 11:50 am
Re: Motorola Spectras
The model numbers you have given are the exact same ones that are from the government dual radio package.
You should have YLN1120A SIU (Serial Interface Unit), the encryption unit probably has a tag HHN4034A on it.
This box has 2 funky looking keys. One on each side with a single toggle switch in the middle and a small round
connector to the right of it. There are two cables coming from the box. One goes to the radio and the other
goes to the SIU. You also should have a siren box and a couple of small switch panels. One is for the siren
control and the other is for the encryption control.
The hand held control head (HHCH) mic should have the model number YCN4012A on it. It has 3 toggle switches
that do just what the label says. If you have both radios, the toggle switch will let you flip from VHF to UHF.
The channel display will be however the SIU was programmed to display the channels. Normally it used 2
channel display numbers for the VHF and then used a letter and single number fore the UHF.
The UHF radio is probably in the 403 to 430 MHz range. They are rather hard to modify to go into the 440
ham bands. However there has been some discussion on this site about how to do that.
The VHF radio requires no mods. Just use the normal Spectra RSS, a slow computer, a RIB and the right cables
and your able to program away to your hearts content. You attach the programming cable to the right side
DB25 conncetor as you look at the front of the radio. The left DB25 is used for the control cable going to the
control group.
I have been told that you can ween the encryption boxes off the radio with the lab version RSS. You need
to use the special section of the program and change the bit flag settings to remove the encryption settings.
The encryption box needs to be connected to allow the radio to make this change. After that, you home
free to make a new cable to go between the radio and the SIU. I have made a number of these cables
over the years.
Make sure that you have a good ground on the case of the SIU. This unit is very prone to static damage.
Matter of fact I have had a number of them go bad over the years. Found out that when this happens,
you can't turn on the radio. Traced the problem to a poor circuit design by Mother M using a voltage
comparator. Also found that you could cut one pin off of one of the surface mount IC's inside the SIU
and the problem goes away. It will work normally after that. The circuit that goes bad is the monitor for
the input 12 volts to the radio. If it is too high or too low, it was designed not to allow the radio to come
on.
I would also suggest that you turn down the RF output power on the radio. They will make plenty of RF
and in most cases the radio will last much longer with the power reduced to about 60 watts. You do this
with the RSS in the service selection and adjust the TX output power. Make sure you have a watt meter
connected when you do the adjustment.
When you do get to programming the channels in the radio, you can have a scan list for each channel. The
max number of channels in each list is 16. I don't have any trouble with that many and even use the priority
selection on a couple of the lists. You will get a small hole or chop in the receive audio if you use priority
channels in the scan list. You will just have to play with it and see how the scan works for you.
I would recommend that you generate a list or use an Excel spread sheet to set up all the channels in the
radio. I have a tendency to loose my place with that many channels. I also keep a 3 ring notebook in my
truck with the channels listed for all the radios. It shows the RX channel, the RX tone squelch, the TX
channel, the TX tone and what the channel is used for. Maybe some of the new or younger people can
remember all those channels. Me, I would rather just look it up in a book when I am unsure which channel
to go to.
Have fun with the radio.
Jim
You should have YLN1120A SIU (Serial Interface Unit), the encryption unit probably has a tag HHN4034A on it.
This box has 2 funky looking keys. One on each side with a single toggle switch in the middle and a small round
connector to the right of it. There are two cables coming from the box. One goes to the radio and the other
goes to the SIU. You also should have a siren box and a couple of small switch panels. One is for the siren
control and the other is for the encryption control.
The hand held control head (HHCH) mic should have the model number YCN4012A on it. It has 3 toggle switches
that do just what the label says. If you have both radios, the toggle switch will let you flip from VHF to UHF.
The channel display will be however the SIU was programmed to display the channels. Normally it used 2
channel display numbers for the VHF and then used a letter and single number fore the UHF.
The UHF radio is probably in the 403 to 430 MHz range. They are rather hard to modify to go into the 440
ham bands. However there has been some discussion on this site about how to do that.
The VHF radio requires no mods. Just use the normal Spectra RSS, a slow computer, a RIB and the right cables
and your able to program away to your hearts content. You attach the programming cable to the right side
DB25 conncetor as you look at the front of the radio. The left DB25 is used for the control cable going to the
control group.
I have been told that you can ween the encryption boxes off the radio with the lab version RSS. You need
to use the special section of the program and change the bit flag settings to remove the encryption settings.
The encryption box needs to be connected to allow the radio to make this change. After that, you home
free to make a new cable to go between the radio and the SIU. I have made a number of these cables
over the years.
Make sure that you have a good ground on the case of the SIU. This unit is very prone to static damage.
Matter of fact I have had a number of them go bad over the years. Found out that when this happens,
you can't turn on the radio. Traced the problem to a poor circuit design by Mother M using a voltage
comparator. Also found that you could cut one pin off of one of the surface mount IC's inside the SIU
and the problem goes away. It will work normally after that. The circuit that goes bad is the monitor for
the input 12 volts to the radio. If it is too high or too low, it was designed not to allow the radio to come
on.
I would also suggest that you turn down the RF output power on the radio. They will make plenty of RF
and in most cases the radio will last much longer with the power reduced to about 60 watts. You do this
with the RSS in the service selection and adjust the TX output power. Make sure you have a watt meter
connected when you do the adjustment.
When you do get to programming the channels in the radio, you can have a scan list for each channel. The
max number of channels in each list is 16. I don't have any trouble with that many and even use the priority
selection on a couple of the lists. You will get a small hole or chop in the receive audio if you use priority
channels in the scan list. You will just have to play with it and see how the scan works for you.
I would recommend that you generate a list or use an Excel spread sheet to set up all the channels in the
radio. I have a tendency to loose my place with that many channels. I also keep a 3 ring notebook in my
truck with the channels listed for all the radios. It shows the RX channel, the RX tone squelch, the TX
channel, the TX tone and what the channel is used for. Maybe some of the new or younger people can
remember all those channels. Me, I would rather just look it up in a book when I am unsure which channel
to go to.
Have fun with the radio.
Jim
midstate33 wrote:I have purchased a couple Spectras they are mdl #'s T83GXA7HA9AK & T84GXA7HA9AK, I am not familiar with all the ins & outs of the Spectras & would like to speak with someone who is a "guru" on these, they were used by a state agency & were not the federal jobs that were floating around they did have the hhch and a couple boxes I do not know what is, if anyone can
give me any help in changing these to individual use with an A7 head & what is required I would appreciate it, also these are suppose to be securenet capable can I use that mode with out the external boxes & maze of cables, thanks in advance...
Fred/W8WAR