[amsat-bb] Re: EggBeater

[Mark Spencer]

Several years ago I had reasonable success with a UHF colinear mobile antenna mag mounted onto the metal flashing of my house connected via a short piece of low loss cable to an ARR Gasfet pre amp.    (I used a mag mount intended for 800 mhz applications that had low loss cable with an N connector.)   At times though you won't be able to hear the satellites very well but you should be able to hear enough to make some contacts.  

I ended up connecting a 2 m to 70 cm duplexer between the antenna and the preamp and connected the 2 m port of the duplexer to a dummy load to cure a desense issue on some frequencies.     I was able to make a number of contacts on AO51, SO50, FO29 and AO27.

I've also tried listening to FO29 using a dual band ground plane anteena fed via approx 70 feet of 9913 and with my FT736 and the pre amp in my mirage power amplifer I can reliably hear the beacon from horizon to horizon but the signals are quite weak.   Without the preamp the signals are hard to copy. The ARR pre amp works a bit better but is not T/R switched.   I suspect directly connecting a good preamp to the ground plane antenna would make a significant improvement.



Regards
Mark VE7AFZ


----- Original Message ----
From: Bruce Robertson <ve9qrp at gmail.com>
To: Steve Bluemel <stevebluemel at gmail.com>
Cc: amsat-bb at amsat.org
Sent: Thursday, April 16, 2009 6:31:35 AM
Subject: [amsat-bb] Re: EggBeater

On Wed, Apr 15, 2009 at 2:36 PM, Rick - WA4NVM <wa4nvm at comcast.net> wrote:
>
> Steve,
>
> Good luck with your testing.  The ISS and A0-51 haven't been on for you
> to try with your setup.  Try S0-50 and A0-27 at this time.
>
> Look for you on the birds,
> Rick- WA4NVM

Thanks for sharing your experiments with us, Steve.

In my experience, with a omni antenna and no preamp, these two 70cm
satellites are very difficult to hear if there is any significant
amount of cable between the antenna and the radio. On the other hand I
find that a low-noise preamp *at the antenna* with a well-built omni
antenna should hear at least parts of their passes. If you're unsure
that your egg-beater is working properly, consider using a simple 1/4
wave vertical with legs of about 6" at 70cm. Put this as close to the
preamp as possible: I constructed mine out of the connector that mates
with the preamp's connector!

Again in my experience, an easier introductory experiment is to copy
the birds with CW telemetry, especially LO-19 (sometimes LU-19). If
your radio has CW reception in 70cm, you might want to give this a try
without the preamp. SatPC32 has the frequency for this bird stored in
it from the get-go. You needn't have  Doppler tuning in place; just
look at the corrected frequency and tune around that. Don't make your
CW filter too tight: 500 Hz is better than 200 if you're hunting for a
moving signal.

Indeed, the FM signals of SO-50 and AO-27 can also be copied in CW
mode, and will be more easily heard with a typical radio than the same
signal in FM mode. Of course, you can't understand the modulated
information, but it is a good baseline to ensure that other aspects of
your station are working well, and allows you to focus on the issue of
antenna gain. Similarly, the beacon on VO-52, though usually an
unmodulated CW signal, provides a pretty nice baseline for 2m
reception.


73, Bruce
VE9QRP

>> Well, Im sorry to say that my Egg Beater experiment has yet to yield any
>> good results. I have attempted passes on IIS, AO-51, and SO-50 and not
>> heard
>> a single contact. Im a trying some reconfiguring and will keep at it. I
>> will
>> post pictures of my progress soon and would appreciate any observations
>> you
>> might have.
>>
>> I'll tell you, the Pre-amp thread could not have been more timely. I just
>> ordered one from ARR. If im lucky....and im always lucky, this will make
>> some difference.
>>
>> In the mean time, I will listen for you all with the Elk and HT!
>>
>> Cheers!
>>
>> Steve KI6OQU
>> _______________________________________________
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> _______________________________________________
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