[aprssig] 6 m APRS

Bob Mueller bob at funautical.com
Tue Mar 7 08:09:51 EST 2017

high noise floor is "normal" for 6m.  I know someone that runs a high power
(1200w) 6m repeater system.  it has ~20 repeater inputs that are voted.
His receive performance has diminished over the last few years, due to a
continually rising noise floor on 6m, and also on his link frequencies.

one method he taught me to measure the noise floor at an input site: put a
coax T on the repeater input receiver with a 50 ohm dummy load on one port,
and a service monitor on the other port.  See how many microvolts (dbm) it
takes to open the receiver on his input frequency.  Then disconnect the
dummy load and connect the antenna to that port.  Then see how many
microvolts (dbm) it takes to open the receiver.  It gives a good
performance metric for the sites.  some sites have become so noisy, he
questions whether it's worthwhile to have a receiver there.

--... ...--
Bob Mueller
bob at funautical.com

On Mon, Mar 6, 2017 at 4:54 PM, Greg D <ko6th.greg at gmail.com> wrote:

> I took a quick listen to 6m with my Yaesu FT-847 and a simple dipole
> strung across the second story eaves.  No packet heard, but I note the
> noise floor across the band is between S6 and S7, with peaks at S9.  Lots
> of digital sounding stuff, but even the "quiet" parts have a high noise
> floor.  Is this normal for this band now, or is it just my location?
> Greg  KO6TH
> Jess Haas wrote:
> I believe it is 50.62. 6 meter seems ideal for a longer range fixed
> station messaging backbone. If we got some smarter path routing involved we
> could get some real range out of the system without being reliant on the
> internet.
> If anyone is interested in setting something up in southern california I
> could setup a station(igate, digipeater whatevers needed) in culver city.
> -Jess
> On Mar 6, 2017 9:25 AM, "Earl Needham" <earl.kd5xb at gmail.com> wrote:
>> We've talked about using 6 meters for APRS in the past and I don't think
>> it ever went very far.  The reason, in my opinion, that 2 meters has worked
>> so well for APRS is that it's on a common frequency nation-state.  That,
>> plus the fact that 2 meter radios are so available.
>> IS there a common frequency for 6 meter APRS?
>> Vy 7 3
>> Earl
>> KD5XB
>> On Mar 6, 2017 9:05 AM, "Robert Bruninga" <bruninga at usna.edu> wrote:
>>> We think that 6m APRS is an ideal applicataion... especially when 100W
>>> mobile low-band surplus radios are so cheap.  A guy got 100 of them for
>>> $10
>>> each.  But then he had to modify them and add TNC's.
>>> Although this is ideal for mobile for longer distances than 2m, the
>>> problem
>>> is there will never be enough infrastrucuter for travel out of area
>>> except
>>> in local areas that embrace it.
>>> A better idea for 6m radio is for emergency APRS communications at all
>>> operatinos centers.  Hams will want to use 2m and 70c bands for voice
>>> and so
>>> we do not want APRS messaging and tactical situational awareness objects
>>> to
>>> interfere.
>>> SO best to have 6m APRS at all emergency comms sites as a 3rd band for
>>> interchange between all emergency comm sites.  The sites will of course,
>>> MONITOR 144.39 national frequency so they can see all incoming APRS
>>> tactical
>>> situation, but their messaging between emergency centers on 6m would not
>>> interfere with other voice ops on 2m and 70cm.
>>> Bob, WB4aPR
>>> -----Original Message-----
>>> From: ve2gqf at gmail.com [mailto:ve2gqf at gmail.com]
>>> Sent: Monday, March 06, 2017 10:46 AM
>>> To: WB4APR at amsat.org
>>> Subject: 6 m APRS
>>> Hi Bob,
>>> My name is Gilles, VE2GQF and live in Sherbrooke, Québec and an aprs
>>> enthousiat since the begening !
>>> We are interested to try APRS on 6 m band in Quebec province. Is it a
>>> good
>>> idea ? Is this mode on this band is always used ?  Internet seem to be
>>> have
>>> no large information about it ?
>>> I'm going to Florida in few days, is there always any 6 m APRS Igate near
>>> Washington and  Georgia - If yes I will transmet APRS 6 m beacon in my
>>> trip.
>>> Thank's for your answer and sorry if my english is not good, this is not
>>> my
>>> first langage.
>>> 73's Gilles ve2gqf
>>> ---
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