An Interesting, SECURE, Comm's Device, for your CN-AoO

Also look for NNTN5539A, that's the antenna for the i325 and fits the i315 & i355.
Like Bruce I had to buy a lot of 10 NNTN5539A. Paid $120 shipped for the lot so the price has gone up.

I find the range is increased enough to warrent the cost tho.

BTW, the NNTN7510A is for the i365, it's slightly shorter then the 5539.
I did put the 5539's on three of the i365's I have and they seemed to benefite more then the i355's. Go figure!

I have a couple the the NNTN5539A antennas left if you need them. My cost ($12) + shipping. PM me if interested.

The BDA's for cell phone use (Bi-directional Amplifier) will not work for the Direct Talk... because wrong frequency range.
Nextel iDEN network was in the upper 800 mhz but the Direct Talk wasin the low 900 mhz and the BDA's don't go that high.

 

If that is the case what we need is a screw in adapter to replace the stock antenna.

 

No, when the iDEN unit is in Direct Talk the external antenna port on the units is "live". Many people have been using external mounted antennas on the iDEN units in Direct Talk with success.

The guy who goes by Jackson Pointe has done some extensive testing of the Nextel iDEN units in Direct Talk mode. He's made a series of videos for YouTube. One video demonstrates the use of a 6db gain antenna with a range of 14 miles. Also see this thread:
Possible SHTF Comms Handheld - i355 - Survivalist Forum
He's been attempting to create a repeater but hasn't been successful yet.

I think the issue with a BDA is the amp it's self. Don't know if it's sensing circuits or a LPF but they do not work on the 900 mhz IMS band.
That being said, if someone can get one to work, many people, my self included would be real interested...

 

Were you using a spectrum analyzer centerd on 915? Or were you looking for power out at the external antenna port?

If you're right and the external antenna port is disconnected in DT, I'm wondering if a little jumper in place of a pin diode could take care of that.

I'll have to break out my test gear and check this out. I've been assuming that the antenna port was live... but you know where that will get ya.

 

I just received the DRIVE TIME KIT from cellphone accesories.com and it was not as described at all... It was a wilson triband antenna 800/900/1900 with a magnetic mount and a Wilson universal FME adapter the basicaly sticks to the back of the phone. Monday I will call and see what happened. Im not too disappointed as this really wasnt the best solution anyway.

 

Well it was worth a shot... Anyway My next test is going to be with the
NNTN4998. It has 2 connectors coming out of the unit one is a standard DB15pin connector. The other is a mini-UHF antenna connector that I hope to connect to an amp. I am sure it is going to be similar to the Wilson universal RF connector. (I know may not perform as well as an antenna mod) I do like the quality of the nntn4998 even as a holder alone. it is meant to be used in conjunction with the car kit (NNTN4892) Both of the part #'s I have listed above should also prove useful even for parts alone.

I know many Hams have been looking for an AMP to hook up to these radios. I am going to try the PA8-1AA-M By TPL Communications

It is factory adjusted to 806-870mhz but I am hoping I can change that. I will post more info once I get the thing in the shack. My goals are reliability, durability, low cost and its got to be easy enough for me to do. If I can help with the repeater project I am willing to try I don't have any fancy test equipment though.

 

I've wondered about using the type of amp you posted. My concern is will it be able to switch fast enough to handle the "hand shake" signaling when you first key the iDen unit?

The upper freq limit of this amp is 870 mhz... I've used TPL amps in the past in 150 mhz and 450 mhz range, they usually had compression mica caps for adjusting the tuning range. I don't think an 800 mhz amp will have such, probably just moving some of the "book" mica caps to a new position on the strip line would do the trick or lowering the value of a selected few to raise the freq. It will be a bit of trial and error work for sure.

There's also the question of the antenna port actually being live on the i355 when in DT mode as Bruce pointed out.

But please don't let me dicourage you! Go for it... if you have the time and money... I have other irons in the fire at the moment... if you can extend the range of these radios I'm very inertested.

 

Anybody know how to completely disable the cell network on these?

So far every i355 I've gotten will attempt to connect to the phone network on startup. I have configured the phones to boot to MotoTalk, but it doesn't get to MotoTalk until the network times out or I press the hang up button to abort.

I have tried full resets of the phones so I could start with a clean slate, btw the default PIN is all zeroes, but can't find a way to disable the phone network. I'm not so much worried about the extra step, but I am worried that the phones might continue to try to connect and not only use use power but provide a way to detect my position defeating the frequency hopping ability of MotoTalk.

 

I don't remember off the top of my head but there are youtube videos on how to set them to go directly into DT, I think the guys name is Jackson Pointe.

On youtube as The Care of Man (SHTF)

Or HominisCura

Rancher

 

If you go to 5:45 in this video this is exactly what mine is doing


My questions are:

• Can this first step of trying lo locate a phone service potentially compromise you?
• Is there any way to disable the phone network so that it never even attempts to locate a carrier?

I've watched a ton of videos, performed several searches, and done a brute force and ignorance exploration of all the phone menus.

 

Thanks and most appreciated. That puts my mind at ease to know what I'm seeing is normal and isn't going to compromise me.

That's exactly what mine have been doing, so all is normal and that puts this issue to bed.

Be prepared for additional stupid questions...

 

No such thing as a stupid question, just an unasked one. If in doubt, ask.

 

So far every i355 I've bought came with weak or crap batteries.What are you guys using for replacements?