I am a newbie to the Spectra Series, but I am wanting to install a remote-mount VHF/UHF set of A7 Spectras in my explorer. After careful consideration, these are what would fit my 2000 Explorer XLT best since no one makes a console. (You can buy a console for a buick, but not an explorer, go figure.) Here is the intended application...
VHF will be for Public Safety monitoring (150-160 range), 2-Meter Ham, and Railroad Monitoring in thr 160-162 range. TX Range will be mostly the 144-152 range. Will a 146-174 Split radio do this split well with decent reception over the entire 144-162 range?
UHF will be for Public Safety monitoing mostly, some 70cm ham, and some business use in the 460's. I'm not too familiar with Spectra Splits, but I think a 438-482 split is what I need?
The next question is, does anyone have any pictures of the back of the A7 control heads showing the mounting hole locations? I'm going to have to fabricate a bracket myself to hold the two heads.
Many thanks for the help!
Spectra Newbie Questions
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SYNTORX71MAN
- Posts: 520
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Re: Spectra Newbie Questions
I might be wrong, but I think the A-9 and A-7 series use the same bracket... 
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Josh
- Posts: 1931
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Re: Spectra Newbie Questions
Yes, you're wrong. Entirely different control heads.SYNTORX71MAN wrote:I might be wrong, but I think the A-9 and A-7 series use the same bracket...
How are you mounting the radios? Right in the console, dash-mount, or remotely mounted somewhere else?
Re: Spectra Newbie Questions
I'm going to remote-mount them directly over the upper pocket in my center console, with the bracket mounted to the dash right under the A/C controls.
Jake
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SYNTORX71MAN
- Posts: 520
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Re: Spectra Newbie Questions
Well I know the heads are different.....LMAO...I just thought the width between the wingnuts were the same...Thanks for the enlightenment....LOL 
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Josh
- Posts: 1931
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- What radios do you own?: APX4K, XTL5K, NX5200, NX700HK
Re: Spectra Newbie Questions
ahh, well... it uses a different bracket, too.. with the A7 type head in the remote-mounting back-plate, the space between is narrower than an A9 head, whose bracket connects on each side of the head.SYNTORX71MAN wrote:Well I know the heads are different.....LMAO...I just thought the width between the wingnuts were the same...Thanks for the enlightenment....LOL
Re: Spectra Newbie Questions
Just so you know:
Spectras, great radios in their time, are not (and never were) designed for monitoring of a wide array of channels. For two reasons:
First: the scan list or lists (depending on whether the radios are "zonable") are limited, consistent with the public safety mission for which these radios were designed.
Second: there is what some people consider a "glitch" in the Spectra scan routine, which was never fixed before the Spectra was superceded by the MCS2000. If you program a priority channel in the scan list, and if that channel has co-channel activity, on detection of the co-channel activity, the radio will park itself on that channel, but (since it fails valid tone) without opening audio. (The fix, in later radios, is "channel marking," which temporarily deletes the priority channel scan check once valid freq and either no tone or invalid tone has been detected, until the radio later detects no activity on the freq.)
Presuming your mid-power Spectras have been modified for trunk-mount, the A5 and A7 control heads (which are much smaller than the A9 head) use the same trunnion mount. This is a rather simply metal piece, which you can make yourself if need be, though most radio shops have boxes full of them that are, by now, mostly surplus. However, the control head mounting cable is thick, so be sure you are going to have a useable route between the control head and the radio deck.
You will want to install your radios so that the radio decks have continuous access to 12VDC, even with the key off. This will preserve selected channel state, scan state, squelch state and dim state. You then wire an ignition-switched 12VDC source to control heads, which causes the radios to turn on and off with the key.
Also, Spectras use external speakers, which in the trunk mount configuration, connect to a flying plug near the control head end of the head-to-radio cable. Be sure you have enough room in the passenger footwell for the speakers.
Good luck.
Spectras, great radios in their time, are not (and never were) designed for monitoring of a wide array of channels. For two reasons:
First: the scan list or lists (depending on whether the radios are "zonable") are limited, consistent with the public safety mission for which these radios were designed.
Second: there is what some people consider a "glitch" in the Spectra scan routine, which was never fixed before the Spectra was superceded by the MCS2000. If you program a priority channel in the scan list, and if that channel has co-channel activity, on detection of the co-channel activity, the radio will park itself on that channel, but (since it fails valid tone) without opening audio. (The fix, in later radios, is "channel marking," which temporarily deletes the priority channel scan check once valid freq and either no tone or invalid tone has been detected, until the radio later detects no activity on the freq.)
Presuming your mid-power Spectras have been modified for trunk-mount, the A5 and A7 control heads (which are much smaller than the A9 head) use the same trunnion mount. This is a rather simply metal piece, which you can make yourself if need be, though most radio shops have boxes full of them that are, by now, mostly surplus. However, the control head mounting cable is thick, so be sure you are going to have a useable route between the control head and the radio deck.
You will want to install your radios so that the radio decks have continuous access to 12VDC, even with the key off. This will preserve selected channel state, scan state, squelch state and dim state. You then wire an ignition-switched 12VDC source to control heads, which causes the radios to turn on and off with the key.
Also, Spectras use external speakers, which in the trunk mount configuration, connect to a flying plug near the control head end of the head-to-radio cable. Be sure you have enough room in the passenger footwell for the speakers.
Good luck.
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RadioSouth
- Batboard $upporter
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- Joined: Mon Sep 03, 2001 4:00 pm
Re: Spectra Newbie Questions
Take a look at the main BatLabs site, they have installation diagrams. Far as your UHF Spectra the 438-470 is a motorcycle 15 w. split so to cover what you'd want the 450-482 split is what you'd need which might need some tweeking to get it below 445. Also due to the age of this series have the electrolytic capacitors changed prior to install as if there not yet leaking they will be. Board member Will fixed me up real well on both capacitors and getting my UHF to lock below 445. You'd probably want Zone capable radios so you can get 16 channels per zone to scan otherwise you can only scan 16 per radio. I've had the VHF in the truck a few months now and am fixing to get the UHF in soon. Great radios albeit the mentioned scan issue.