Batboard

Looking to put two Spectras together, that are Securenet capable to make a repeater that will pass DES/DES-XL. Am I going down the road to failure?

We have a need for another 'channel' here, but funds are low and I have most of the equipment, but they want a 'secure' repeater to TX medical info over an ambulance net.

Can it be done? If both the receiver and transmitter of the repeater are loaded with the proper key, will it act as a tranparent repeater, or will the data get unsinc'd when it comes out the other side of the repeater?

I know it's been covered before, but all of the searches that I came up with never really said yes or no as far as if it would work or not. Thanks.

Scott,

You and ricciticcitembo (sp?) need to get together. He was building something similar to that. I believe his experience is that the audio out of the receiver is recovered audio, and then fed into the transmitter via the securenet so it's basically transparent.

But you need to get with him - he's been doing a lot of stuff lately and can surely give you good poop.


Jack

Thanks Jack, I'll send you a PM shortly...

Yeah. What Jack Said.
As long as you have the same key in both radios,
it works like a champ!

And as a further variation on this same principal,
I've successfully used a Saber as one side of
a Secure Cross-Band Repeater paired up with
a Secure Spectra.

Using a Saber is a lot of work though, I will warn you
of that. Need a heatsink, and interface just to start with.

-Also maybe ask WILL if his Extender / Repeater
module for Spectra works with the Securenet enabled.

It probably does, and it would make your life a lot
simpler since it's plug and play.

You might have to change some jumpers on the
Spectras command board though.

Coolness.
I have two Secure Spectras here, I just need a 403-433 Duplexer. The duplexer seems to be my biggest hurdle as of now. I have several very good antennas to choose from for the repeater. The feedline isn't too much of a concern until I get the duplexer...

ANYONE??? 403-433 duplexer??? Please???, but make sure it's reasonable...hehehe

How about it Will. Do you have a module for me that works with two Spectra mid power radios? PM me or e-mail me at [email protected] or [email protected] Thanks...

Scott,

Check with your comm freq coord on base. He can give you some freqs, and if this is going to be a totally non-standard repeater - why not go all the way? Get some freqs 10 or 15 meg apart instead of 5. Use antenna separation and maybe you can get by without a duplexor.

Just a thought. I haven't seen any duplexor that low in freq. on eBay or any of the boards, but maybe someone has one salted away somewhere...


Jack

If you look real hard for a few months, one may
show up on Ebay, I've seen one or two of them.
One was even listed Twice with no bids either time.
I think it was like $225 or something like that.
Too pricey for me, but it was a nice one. And then
After I got my Secure Spectra Repeater working, I
REALLY wanted a 403-433 Duplexer, and guess
what? I couldn't find ANY on Ebay. Go figure.

I'd really like a mobile duplexer for that band.

But anyhow, Since I don't have one, I did what
Jack Said and just used large channel Seperation. Like 15 Mhz.
That should work fine for Base Operation.

I haven't tried that trick in the Mobile yet, though I
didn't think it would work due to de-sense and
the likelyhood of making the repeater oscillate
from TX to RX Uncontrollably. (Not a Good thing).
And thats why I went Cross Band in the Mobile.
You'd need more separation like 30 Mhz at least,
Plus the old "Under the Vehicle" In-band antenna.

In the Mobile, I have No duplexers Yet. A VHF
one is getting ready for a pair of Sabers.

Currently my setup is like this in the Van:
I use a 403 Secure Saber As the PAC/RT unit.

This is linked by choice to any of the following
bands of Spectras- VHF, UHF range 3, and 800.

Well, I just bought a UHF duplexer...

I hope it works, it's a Sinclair MR-356. I couldn't turn it down. It is brand new still in the wrapper. It was $100.00, so I figured it was a good deal. The ad says it's 411-416 MHz, but I saw one on E-Bay that said it was 406-512. Can someone clarify whether or not it is that wide? One step closer...

If your looking for more of these 'low split' duplexers, I found the one I bought on http://www.talkfar.com The ones on E-Bay were more expensive ($150.00)...

hmmm...

Try this on for size: Disable securenet on Rx/Tx radios. Make sure you are using the un emphasized audio from the accy connector (if the option is enabled) on the spectras... That way, you don't have to worry about reloading keys on the repeater. When a radio transmits in the clear, it will be repeated in the clear. When a radio transmits encrypted, it should be repeated encrypted. After all, you are passing the straight detector audio to the transmitter, and the transmitter is not emphasyzing it...

I seem to remember this working in a commercial application somewhere...

Just my thoughts
-Head

That is kind of what I was thinking. I only had one customer when I was with M that had a DVPXLII system and I remember that the Spectra-Dekstrac control station hardly ever worked right in Secure mode, locked up sometimes in regualr mode and was plan X'd about 3 times. And the recovered audio on a mobile was never that good, at least I thought. They were just giddy to have something no one else could hear them on when they wanted it that way. It was a Police Dept.
I was thinking that the Secured audio would pass as long as it wasnt monkeyed with in the rx-tx stages of the repeater. But, I know the one we had supposedly had to be a Secure Repeater. Luckily my techs serviced this account and I hardly ever went there. They had the best stuff you could get but acted like if their scanner or or tone remoted-to-the CCII-consle CB base was out, it was the end of the world, you can only imagine how it was if something else was wrong.

I am not sure how it would work, just taking the recovered audio and rebroadcasting it. What I have found is go into the secure board and pull the data just before it goes into the hybrid. By then it has already been cleaned up and reclocked. Believe it or not I have found Micor and Syntor mobiles to work great. mearly take the recovered data just before the hybrid and insert into the modulator, directly not through any audio filtering. Sometimes you need a resitor or so to get the levels right. I have built about a dozen secure Micor repeaters using the receivers from old secure Micor mobiles, using the secure board from a Syntor or SyntorX mobile for decoding and reclocking. Then just insert the data where the DPL enters the modulator.

OK then Radioman2002, The way you have done
it is superior to the Spectra since those older
radios can operate Full Duplex.

-Only one radio is required, not two

-Only one Secure board is needed.

Although you would really only need one Secure
Spectra (The Receiver) to do the re-clocking and
buffering. The TX radio doesn't need a Secure
Board if you are going to just Inject the reclocked Data from the RX radio.

I have been meaning to try this, and I will soon.

The main reason that I did not do this in the first
place is because I was in some kinda rush to
make it work, and It is simply easier to use
recovered audio (both radios need key loaded).
Also NO Modifications need be done to the Spectras.
This could be an issue if the radio is a new Astro
and is Still under warranty for example.

But aside from that, All I would need to do is pass the Still Encrypted Signal from the RX radio out of it's 15 pin rear connector. This Signal can be undoubtedly found right on the Header Connector
where the Internal Secure Board Plugs in. I just need to try it. The sticking point for me is going to
be that shielded jumper wire thats going to have to be soldered from the front to the back of the radio. Doh. I can see no other way. A jumper on the command board isn't going to do it.
A long wire will though...


The Spectra already has a place to inject Raw Data on the 15 pin plug on the rear, so that is fine like it is.

Of course the other and least expensive method
of simply not using ANY secure boards at all in the repeater, and simply rebroadcast the unfiltered
audio/data. I have not tried this with the Spectras or Sabers yet.

So far I know for sure that two Secure equiped Spectras works good using recovered audio.

I would suspect an improvement to very good, with the use of re-clocked data instead of recovered audio like I am now using. As soon as I get a little time on my hands, I'll do it.

Keep the details coming.....great project!

ricciticcitembo wrote:But aside from that, All I would need to do is pass the Still Encrypted Signal from the RX radio out of it's 15 pin rear connector. This Signal can be undoubtedly found right on the Header Connector
where the Internal Secure Board Plugs in. I just need to try it. The sticking point for me is going to
be that shielded jumper wire thats going to have to be soldered from the front to the back of the radio. Doh. I can see no other way. A jumper on the command board isn't going to do it.
A long wire will though...

So, where is the best place to pull the reclocked signal from? Would it be fine to run it straight to pin 15 like it is, or will I be needing a resistor? I don't have a service manual, so if you could help out on this one, that'd be great.

Also, how many watts were you running with your setup? Is it 100% duty? Right now, the one I'm going to use as the TX is putting out 30 watts. I want to bring the power down to make the repeater 100% duty. How far down should I go to make it 100%?

Thanks guys

Sorry for the delay, but the repeater is finished - Special thanks to jcobb, ricciticcitembo and firemedic for their support in this project.

Okay, I built my own repeater module, well, not my own design, but I built it just the same. The audio levels are adjustable through the volume of the RX radio. It passes clear and secure signals. Secure operation right now is about 3 miles away from the repeater and clear is about 5. It will be much further once it goes onto the tower, right now we're just testing it out with the antenna about 25 ft up (about 45 ft above most surrounding areas).

I have a couple of pictures of it during construction, but today I found that somehow, coffee has magically gotten into the inside and all over the front of my camera??? Sooo, the finished project won't be seen for sometime, but you can get the picture (no pun intended). Also, geocities sucks, so if you want to see the pictures that I do have, I'll have to email them to you.

Now, I just have to train everyone not to take the batteries off of the Sabers...