On Wed, 09 Dec 2009 17:23:19 -0800, Jeff Liebermann
wrote:

Here's what CDF (Cal Fire) requires to share their vault:
http://webmain02.fire.ca.gov/pubs/issuance/8000/rvsapp.pdf
I've seen worse.

Ah, I found one that's worse:
http://www.elsinorepeak.com/documents.html
Ummm... don't let the new site owner see these.

Mo
http://www.repeater-builder.com/antenna/site-stuff/radiositerules.html
ALL LMR and PAGING TRANSMITTERS not equipped with a Pass-Notch
duplexer, will have an additional pass cavity installed to prevent
spurious emissions and minimize ambient RF noise to the other
equipment installed at this, and adjacent sites. An isolator
is also required between the transmitter and the cavity.
There are to be no PA decks, isolators or circulators looking
directly into an antenna, even a temporarily unused one.

I forgot to mention my pet peeve. Please label everything. Extra
credit for a block diagram showing where the wires and cables are
suppose to go. Here's mine:
http://www.LearnByDestroying.com/k6bj/K6BJ%20Repeater/slides/Documentation.html
Ummm... Bad example. Do like I say, not like I do.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

Thanks to those who have responded already. I was hoping for some
elegant solution I had not thought of, but so far nothing has come to
light. Also I was hoping there would be some way to implement this
wihthout relays.... but maybe not.

Regarding the comment about breaking out the Rx line to a separate
output... that might be possible but its solid state switching and would
be somewhat tricky to implement right after this solid state PA module
output.

One reason I hate the thought of adding antenna relays to switch the Rx
around the isolator is that this is a busy packet node and I don't like
the reliability issues a couple of added relays might add to a presently
solid state switched radio.. . although I could do this if forced to.

Another option is to buy a second radio, and use it for the receive
channel. Your existing transceiver would be used solely as a
transmitter, and could thus be hard-wired to an isolator.

You'd need to run the receiver on a different antenna, or have some
form of switchable protection circuit to keep it from having its
brains blown out by the transmitter.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Another option is to buy a second radio, and use it for the receive
channel. Your existing transceiver would be used solely as a
transmitter, and could thus be hard-wired to an isolator.

You'd need to run the receiver on a different antenna, or have some
form of switchable protection circuit to keep it from having its
brains blown out by the transmitter.



Of all the possibilites, I like this one the best... for reliability
and simplicity. We actually are antenna rich at this site. We also have a
small surplus of 2M transceivers, of which the receivers would probably
work just fine for packet.

If we can not negotiate an exemption from the management, I think this
is my first choice.

Thanks to all.

Ed




..

On Dec 9, 1:07*pm, Ed wrote:
* We have 2M packet node transceivers at a new government radio site. * The
new site owner requires isolators be installed on all transmitters. *As you
might surmise, it doesn't seem possible to do so on a simplex one RF port
radio such an Alinco DR-135.

* Anyone out there with some realistic suggestions on how we might manage
to do this?

* Ed * K7AAT

As described elsewhere, by using RF bypass relays for receive, the
isolator can be installed as designed, with one port terminated.
(This rig still requires bandpass filtering to keep intermod products
from being generated in the front end of your receiver and being re-
radiated. Such EMI can be very nasty.)

Sal

As described elsewhere, by using RF bypass relays for receive, the
isolator can be installed as designed, with one port terminated.
(This rig still requires bandpass filtering to keep intermod products
from being generated in the front end of your receiver and being re-
radiated. Such EMI can be very nasty.)

Sal


While I hate the thought of such chattering relays and the inherant
possiblity of degraded reliability on a busy packet node station, I must
admit this is a very logical method. Taken under consideration.
Thanks, Sal.

Ed K7AAT




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