Today's Message Index:
----------------------
1. 05:19 AM - Re: handheld and intercom (Brian Lloyd)
2. 07:25 AM - Re: Strobe lamp wiring question (Robert L. Nuckolls, III)
3. 07:30 AM - Re: Re: single ground question (Robert L. Nuckolls, III)
4. 08:34 AM - Re: handheld and intercom (Steve Maher)
Message 1
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| Subject: | Re: handheld and intercom |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
Jim and Lucy wrote:
> Looking through the installation manual for a NAT
> intercom,It shows the push to talk switch grounds
> one of the pins on the intercom which grounds
> one of the pins on the radio to put it into
> the transmit mode.
> If I use a handheld radio in
> place of a panel mount radio, do these handhelds
> work the same??
Some use a separate PTT line to key the transmitter but many use the current through
the mic audio line (the line being used to power the microphone's amplifier)
to key the transmitter. In the former case you need to do nothing but hook
up the PTT line from the intercom. In the latter you will need to make an
adapter with a resistor and a capacitor but that is an inexpensive and easy task.
How the handheld radio keys its transmitter may turn out to be one of your
selection criteria.
OTOH, I think I would get a panel-mount radio. Look for a used Apollo SL-60 GPS/comm
or a GX-65 with the built-in moving map display. Both have been discontinued
by Apollo since they were acquired by Garmin but both are outstanding GPS/comm
units with the best comm radio in the industry (my opinion -- YMMV).
Evidently they are still popular as the shops are still selling them and the prices
haven't dropped too much.
I have the SL-60 and SL-30 in my Aztec. I have the GX-60 in my Comanche. I had
the SL-60 in the CJ6A I sold. I plan to put an SL-30 in The Project (my CJ6A
restoration project) to complement the Blue Mountain EFIS. I guess you could
say I found their radios to be quite to my liking. The ability of the single
comm radio to monitor the standby frequency while still operating on the active
frequency is a boon. With a single comm you can listen to the ATIS or AWOS
while still communicating with ATC.
The SL-30 nav/comm is so fantastic that it will do the job of two normal nav/coms
(like dual KX-155s) in a single 1.3" high package. Unfortunately it has become
so popular that its price is pretty high. Still, if you compare it in price
and size to a pair of standard nav/coms, it seems pretty reasonable.
(No, I don't work for Garmin/IImorrow/UPSAT. I just happen to think that they
got the engineering right in their radios and I am quite saddened to see that
Garmin is phasing out many of the aforementioned radios since they acquired the
Apollo line.)
--
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
http://www.lloyd.com St. Thomas, VI 00802
+1.340.998.9447 (voice) +1.270.912.0788 (fax)
There is a time to laud one's country and a time to protest.
A good citizen is prepared to do either as the need arises.
Message 2
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| Subject: | Re: Strobe lamp wiring question |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 02:38 PM 7/27/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: <chaztuna@adelphia.net>
>
>Bob & Listers,
> What is your opinion of the shielded strobe lamp to power supply wire
> which was supplied with my Nova strobe system? This shielded 3 lead wire
> harness is listed as 60 degree Centigrade (140 F) rated wire. The number
> E129931 is imprinted on the outer casing. Is this wire's temp rating
> adequate for use in hot climates? Is there any advantage to replacing
> this wire with MIL 27500 wire? (I have both) Is there any practical
> advantage with regards to shielding, of one of these wire types as
> opposed to the other?
>Charlie Kuss
>RV-8A cockpit wiring & systems
>Boca Raton, Fl.
While the FAA would probably roll their eyes back and swoon about this
wire in a NEW application for TSO or STC . . . this has been the wire
of choice since the 1960's when the PVC insulated, Beldfoil shielded
wire was the best-we-know-how-to-do at the time.
One one hand, you might say that here's yet another example of
antique certification and grandfathering standing in the way of
"progress". Given that this system has been installed in
tens of thousands of airplanes for over 40 years and offered
trouble-free service, it seems a bit of wasted effort and
poor return on investment to "upgrade" the installation either
by regulatory or worry-wart mandate.
If you have whippier wire and want to "upgrade", I can't
tell you with confidence that you've done a better thing than
to simply install the kit that comes with the strobe. When it
comes to shielding effectiveness, it's hard to beat the 100%
coverage offered by the Beldfoil product . . . problem is that
for most installations, strobe wires don't get bundled with
wires tied to potential victim systems. Yeah, the PVC that we
so highly prized 50 years ago is now a pariah in the eyes of
those-who-know-more-about-airplanes-than-we-do. So we could
debate the various pro/con artifacts of the old/new installation
ad-nauseam without adding much to the pool of useful, simple-ideas.
How's that for definitive advice? If it were my airplane, I'd
put the factory supplied kit in and save the "new" wire for
other tasks. Some wild-eyed ol' gray-beard in Wichita was once
heard to opine, "Sometimes the best way to drive a nail
is with a hammer." A hammer has low parts count and no batteries
to run down. They have a successful track record that goes
back thousands of years. Unlike nail guns, they're great multi-
tasking tools. Best yet, when you're too tired to drive the nail
straight, it's your signal to take a break. Really great tools
them hammers.
Bob . . .
---
Message 3
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| Subject: | Re: single ground question |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 02:12 AM 7/25/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: CardinalNSB@aol.com
>
>I think that I understand that a single ground for the avionics and
>electrical instruments is best.
>
>Does the cabin and instrument lighting need the signel ground also?
>
>I remember a comment by Bob that it would be best to run the bus avionics
>directly to the battery, as a sort of electronic shock
>absorber. Assuming that
>it is impossible to run the positive bus lead directly to the battery, would
>there be any point in running just the negative lead directly to the
>battery? I think my ai will sign this off as a minor mod, since "its
>only the
>ground"....
I didn't say anything like that. Chapter 5 of the 'Connection
can be downloaded here:
http://aeroelectric.com/articles/Rev9/ch5-9.pdf
. . . this chapter speaks to grounding issues. There are ground
systems suggested in Figure Z-15 of Appendix Z which can also be
downloaded at:
http://aeroelectric.com/articles/Rev10/z10.pdf
I'll suggest you review these documents and come back to the
list if there are any clarification or additional information
is needed.
Bob . . .
---
Message 4
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| Subject: | Re: handheld and intercom |
--> AeroElectric-List message posted by: Steve Maher <lilabner_45@yahoo.com>
Some handhelds do, some don't.
I had a JRC JHP-520 handheld navcomm, and found that the owner's manual
stated in big black letters, DO NOT GROUND THE PTT LINE TO TRANSMIT. In
that radio, it says you have to connect the PTT line to another line on
the plug, to transmit.
I now have a Vertex (formerly Yaesu) VXA-210 handheld navcomm. Its
manual doesn't say much about what to do with the PTT line, so I called
their service department and talked to one of their techs who seemed
quite knowledgeable. He checked the schematics and told me that
grounding the PTT line to transmit, is definitely the correct way to
go.
Whatever radio you're contemplating, if I were you I'd call the company
first and ask them about the PTT line. Personally I like the ground-it
types, since they conform to what most intercoms do.
Steve Maher
San Diego, CA
--- Jim and Lucy <jpollard@mnsi.net> wrote:
> --> AeroElectric-List message posted by: Jim and Lucy
> <jpollard@mnsi.net>
>
> Looking through the installation manual for a NAT
> intercom,It shows the push to talk switch grounds
> one of the pins on the intercom which grounds
> one of the pins on the radio to put it into
> the transmit mode.
> If I use a handheld radio in
> place of a panel mount radio, do these handhelds
> work the same?? Is the airframe ground the same
> as the handheld ground to activate the transmitter?
> If the handheld was operating off internal batteries
> I don't see how it could be.
> I have not picked out a handheld radio yet but that
> is the way I would like to go.
>
>
> thanks
>
>
> Jim Pollard
> ch601hds
> wireing and plumbing
>
>
>
>
> http://www.matronics.com/FAQ/AeroElectric-List.htm
>
>
>
>
>
>
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