[MAMS] 902 activity

[Dr. Gerald N. Johnson]

A simple way to achieve optimum alignment is with a weak signal and the 
receiver on FM. The signal should be so weak there is only partial 
quieting. then tweak the preamp for maximum quieting. That also achieves 
best NF. If you get too much quieting, you can reduce the test signal 
some more. A Simpson or Triplett VOM on the speaker wires on AC is a 
good indicator of quieting. No modulation on the signal, just a carrier.

73, Jerry, K0CQ

On 1/29/2012 4:49 PM, Zack Widup wrote:
> Great! I have one of those "Dayton Special" Yagi antennas but it
> expectedly does not perform as well as my looper on a longer boom.
>
> I think I need to tweak my 902 preamp. It's a WD5AGO circuit using the
> ATF36077 followed by MGA61563. I have heard that, lacking a NF meter,
> I can tweak it by adjusting for a peak in signal, then just backing
> off slightly.Not sure which way I should back it off for best NF -
> above or below the peak. There is only one adjustment on this amp -
> the inductor in the input circuit. WD5AGO says it's supposed to have a
> gain on the order of 35 dB and NF of 0.3 dB. I'm working on a similar
> circuit for 1296 (only the input inductor is different).
>
> I got an amp for 2304 that's supposed to put out 25 watts. Haven't
> fired it up yet; maybe in the next week so I can use it in MAD.
>
> 73, Zack W9SZ
>
>
> On 1/29/12, Dave Calvert<kb0pe at yahoo.com>  wrote:
>> Hello to the group,
>> After a great time at our WinterFest in Collinsville, IL. this Saturday I
>> ran into Marcel - N9NJY/ EM58bL
>> and he has worked Zack on 902 for his first contact ever!  Marcel has a DEMI
>> box with 30 watts and he
>> bought two of the cheap end mounted 902 Mhz yagi's at this past Dayton
>> hamfest.  He made a power
>> combiner so that the two yagi's are up around 130 ft. on his tower.  We made
>> a sked for this morning and
>> we worked each other on 902.100 using USB!  He was 5X5 at my end so we tried
>> 1296 but he
>> discovered high VSWR on his line plus I didn't hear anything so hopefully he
>> will find the problem and be
>> ready for the next MAD weekend, this 4 th of FEB.  The two combined
>> yagi's seem to be performing OK but
>> the band conditions are way down.....
>>
>> I will be getting my ROVER Antenna rack on my Mercury Mountaineer this
>> weekend and plan to drive up
>> to EM49ua and see what can be worked next weekend on the uW bands!  2m
>> Liaison 144.260, 902,
>> 1296, 3456 and 5.7.  anyone like a sked, let me know.
>> 73,
>> Dave
>> ______________________________________________________________
>> MAMS mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/mams
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:MAMS at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> MAMS mailing list
> Home: http://mailman.qth.net/mailman/listinfo/mams
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:MAMS at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>