On Aug 9, 6:03 pm, **THE-RFI-EMI-GUY** wrote:
Martin; Are the 7400's capable of GMRS repeater operation? If so, where
did you buy them?





Martin wrote:
Hopefully someone who reads this group will be familiar with these
radios, Motorola T7400 FRS/GMRS. The alt.radio.family newsgroup has
degenerated to an unintellible level.

My friend and I have a set of these, which work extremely well as
general-purpose handhelds (much better range than our IC-Q7s, and only
cost $20 a pair after rebate). We'd like to use the T7400s for bike-
to-bike communications on motorcycle trips. Our plan is to mount
small speakers inside the helmets, and a microphone element in the
lower face guard, to reduce wind noise. There would be a PTT switch,
most likely mounted near one of the handgrips.

What we can't seem to find are the required tech specs on the speaker
and microphone elements, or a wiring diagram for the single plug that
connects everything to the radio. I'm aware that some radios short
the mic element with a resistor to actuate PTT, but need a lot more
specifics for this model.

thanks and regards,

Martin

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P- Hide quoted text -

- Show quoted text -

Hi Joe,

As far as I know, the 7400 radios do not have any frequency-offset
capablity, but I suppose it's possible that there are undocumented
features. For example, if you engage the "QT" function from the menu,
it layers a tone squelch over the standard CTCSS (actually uses the
tone to precede the first transmission), which virtually guarantees
that no other extraneous sources will activate the receiver.

I bought them at Fry's Electronics in Dallas, TX. They were $20 per
pair, after a $10 rebate. The maker claims 8 miles optimum range, but
we tested them and got 10 miles. Here is a link to my review, which
also gives the locations and terrain details:
http://groups.google.com/group/alt.r...d2bbab8ffcd1fd

These are the only blister-pack radios I have ever tested that beat
the manufacturer's range claims. And they did so using rechargeable
NiMH batteries, which have a slightly-lower terminal voltage than the
alkalines often used to generate the claims. Part of the performance
is no doubt due to physical reasons - the chassis is probably twice
the size of most FRS radios, and it uses four AA batteries instead of
the now-typical AAAs. I'd say these radios are far more likely than
most to actually deliver their rated output power. And perhaps they
have a good receiver section as well, plus enough chassis mass for the
antenna to work properly. For whatever reason, the peformance was
outstanding for something that retailed for $10 per unit.

best regards,

Martin