I have been playing with a new Triquint ULNA device (TQP3M9036). It
Shows a lot of promise. It is like a MAR or MSA device in that it is
50ohm in and out. and has a claimed NF about .4db nf ( their numbers).
I have built several pramps to test them and have gotten even better
than they claim and they cover 50-1296 with ease and NF is .4ish or
below. The S11 and S22 are both great and the OIP3 is +35db also
...very nice device. It has great promise as a good terrestrial LNA.
Preamps are foolproof to build and would cost under $50 if all the best
quality parts are used.
Just for information only ...
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I’m ready on 6cm with the same dish I’m using on 3cm.
Despite the strong local 5 GHz WiFi noise, had a nice 579/569 first QSO with this setup today with HB9Q, thank you Dan !
Setup is a 3.7m dish and 60W at CP feeder.
I can be QRV on 6cm or 3cm most of the days, skeds and tests are very welcome, as usual.
qrv 70cm, 33cm, 23cm, 13cm, 9cm, 6cm and 3cm.
Hello to Lunatics.
Owners of RAS 1deg. and RAS 0.5 deg. rotators and Rot2Prog controllers
can try my free Ras Moon Tracker program.
Program was fully tested with RAS 1deg. rotator by me, because I have
it and use it.
Program can be downloaded here :
Program do not required any installation, open archive and extract
program folder to ur C:\ or any other drive.
I don't find words to say: Fausto I4EAT is passed away by Covid. A teacher and more than a brother for me. A life toghether in radio from 1972. R.I.P.
Pse say this bad new to all in your OM friends that knew him.
One reason I am putting up a shorter tower is to
shield the eme array from local noise. At 52
feet for the center of my array I could see
unobstructed horizon 360 degrees of
azimuth. That was great for gaining max Moon
time. But exposed the antennas to a wider circle of ground noise sources..
I am going back up with a shorter tower that will
place array center at 32 feet. Tree tops are
about 45-feet. With trees at 56 feet away at MR,
Moon is an elevation angle of 13 degrees when it
clears tree top (angle = arcsin(45-32)/56). At
144 the trees are not opaque to RF but will add
some attenuation to the signal. Thermal noise of
the trees is not significant at 144 due to
present total noise level. Note: VE7BQH rates
144 noise as 1600K in rural areas and 5400k in
residential areas (I interpret that to be
suburban area noise) in his antenna comparison
charts. For city noise 14,500K is used. The old
144 Tsky=290K is long gone in today's environments.
So when 144 is quiet (like the old days) I figure
1600K so adding 150K tree temperature is somewhat
significant. But at 5400K not at all. At MR the
upper yagis are looking at clear sky and only the
lower antennas looking thru trees (so drop
thermal effect from 290K to 150K). A 0.6 dBNF
preamp is about 56K. Super low-noise preamps for
144 don't really improve SNR anymore.
Guess I will know more the effect of lowering my
tower after it is up and running. But I also
will have changed cable type used for phasing
lines so it will be a combination of effects.
Not going to change antennas (M2 XP20)
. Rebuilding tower with new concrete base and
boom truck service will cost me a lot. Repair of
the one XP20 will be about $200 vs $456 for a new
antenna (I paid about $212 in 1998). 14 by 40
foot new gravel driveway to tower site for heavy
trucks to service the new tower, included (currently lawn).
One advantage of the lower tower is I can use a
man-lift for maint. My Hazer will not be re-installed.
73, Ed - KL7UW
At 02:14 PM 3/30/2021, Earl Shaffer via Moon-net wrote:
>Just to clarify a few things on this subject.
>I have done extensive testing on my gaAsfet
>preamp and measuring levels going into and out of the preamp.
>The biggest offenders are two FM BCB signals as
>well as a 162 Mhz signal. The gaAsfet preamp has unity gain
>on FM BCB due to selectivity in the LC input
>filter. There IS some gain at 162 Mhz but perhaps not enough to be
>a problem. I also added a 2 pole filter ahead of
>a preamp just as a test. This was before I added the cavity after
>the premap so perhaps I need to repeat the test
>of the filter ahead of the preamp. I think it is important to make
>test's in the correct order since it is very
>likely a combination of things. If memory serves me correctly, the offending
>signals coming out of the preamp is something
>like -50dbm. I don't know what the wideband level is but I have difficulty
>using an SDRplay at optimal sensitivity due to
>overload of the hardware from all that pulse noise in a wide bandwidth.
>What my cavity after my antenna preamp is
>solving is likely IMD in the mixer of the ORIGINAL IQ+. I want to make sure
>that is clear because I believe later versions
>of the IQ+ have a significantly strong mixer.Â The issue is the difference in
>bandwidth when dealing with pulse noise. The
>Delta44 uses 96Khz bandwidth, but the IQ+ mixer may see 5 Mhz worth
>of pulse noise which CAN overload the
>mixer.Â The mixer in your rig may or may not be
>able to handle this wide bandÂ
>pulse noise but it might be worth investigation.
>When noise overloads a mixer, I believe it can raise the noise floor to
>a degree higher than explained by on frequency
>noise alone. A simple test might be to try an RF attenuator. If reception
>improves with the attenuator, you may have
>uncovered some trouble in your system.
>Isn't really all noise pulse noise? It would be
>hard to imagine multiple sine wavesÂ at a lot of
>frequencies. By that definition
>they are no longer sign waves. I DO believe we
>can have different peak to average pulse noise ratios Â Galactic noise for
>instance would be from so many different noise
>sources, the peak to average ratio might be low while power line noise
>can have a high peak to average power ratio. I
>believe when you can not resolve the noise pulses, you simply need toÂ
>sample at a faster rate. When I evaluated my
>pulse noise at 5 Mhz bandwidth Â I concluded that much of my pulse noise
>Â was at at least 300Khz. That noise when looked
>at in a 96Khz bandwidth simply looks like an elevated noise floor due
>to pulse stretching and ringing.
>I think a person would be hard pressed to use a
>pair of maximum gain yagis on EME in the city. What is needed is
>low sidelobes and to be satisfied with not
>hearing anything at low elevations such as 10 degrees. One might get away
>with a pair of long low sidelobe vertical yagis
>side by side, but I think city dwellers should be using 4 low sidelobe yagis
>even if they have to be short. Another trick
>often used is to place the array as low as practical. A low yagi will have aÂ
>high radiation angle and that will result is far
>less low angle signal pickup.Â One trick I often use for lower angle moon
>elevations is to park the array in the first
>elevation null. In that case it is 25 degrees elevation. The main lobe is then
>above the horizon Â while the first sidelobe is
>then below the horizon. There is some signal loss, but I get good signals
>this way down to about 15 degrees elevation. 10
>degrees is usable if it is a good 4 yagi station I am shooting for.
>If this causes me to not be heard, I simply
>lower the elevation during TX. I used this approachÂ a lot during the ARRl EME
>contest.Â I'm pretty happy with my score
>especially considering my city location. There are some good low rear mountedÂ
>rotatable polarization Â arrays out there. I'm
>not about to give up on 2 meter EME in the city. My incremental changes HAVE
>been yielding positive results. I like the challenge.
>On Tue, Mar 30, 2021 at 2:22 AM Oliver Dunker
>Great to hear that you are onto something regarding your heavy noise problems!
>When it comes to Preamps/LNAs there still is
>that misunderstanding "the lower the NF the
>better" and "take the most modern
>transistor"..In the lab that looks fantastic,but
>there are several problems:All of these
>transistors are designed for ghz commercial
>applications.Not at all for VHF.When you force
>them into 2m work,thats a problem by itself.Then
>also shooting for lowest noise factor makes real real bad IMD figures!
>Ok,there are somewhat OK designs,but also real
>bad ones.Like that very popular german brand
>that uses a stoneage JA... design that was
>critical from the beginning.What happens is,when
>you force them to lowest noise you completly loose any kind of selectivity!
>Now combine that with a city enviroment and that
>preamp will be saturated 24 hours a day.A wide
>sweep at a city based 2m antenna will show
>shocking results there.Like fm radio stations or
>pagers that are so vvery strong they might light a bike bulb at your coax end.
>Such a preamp will do nothing against
>this,quiete often even amplify such signals.At
>least air airband and pagers,while fm radio gets through 1:1,which is real bad.
>I remember that DJ9BV showed us what actually
>happens then with a GaasFET frontend:
>One might expect to find birdys or such,but that
>is not the case.What really happens is a user
>undetected,somewhat white noise level.Or wide
>noise level?you know what i mean,lol
>The usual filtering after the LNA,for best NF
>cant help there at all.One can say its already too late.
>You can get around this,thats what we did,by
>using super low loss matching in front of that
>transistor.Like cavitys for example.The matching
>is the filtering there,thats the problem.Or at
>least very hi class parts in L+C..Shure that ... brand never did that.
>I know why i have 2 Landwehrs,he had ervything
>in silver,and expensive Cs,whole LNA designed
>with IMD in mind from the beginning and not "the latest transistor"..etc..
>Ok,so what to do today?
>Well thats real easy,since electronics have moved forward so rapidly.
>Just take a look at the IMD figures of devices
>like the PGA103 and you will be shocked.Made for
>full duplex in mobile phones its unreal what
>they can take!I even tried those in the city
>with no front end filter at all (except the ant) and it worked!
>Simply because they can take it,theres no magic noise raising!
>But if you go ahead and build something like
>YU1CF,a PGA103 with a very hi Q,super low loss
>filter,you havve a real winning combination!
>Oy yeah:And we also learned from DJ9BV what
>happens if you(fE) shoot with your GaasFET LNA on a radio or xverter that
>already HAS a GaasFET frontend:Talk about
>killing IMD totally!Your neighbours hairdryer
>might be enough to kill such a system.
>But i see people doing that,over and over.
>I disabled/bridged my IC275H frontend,that does
>the Landwehr preamp.More than enough gain.
>I like what you wrote abot array directivity on
>other than design qrg,very true!A 2m beam will
>be more like a 4 leaf clover there,so fE fm or
>pager noise might be much worse than one expects!
>The SDRs.Well i think that direct sampling and
>all the other things are great.But to really
>work in a tough enviroment we need at least 10
>years more tech there(or money?).Just look at
>the IMD figures of that IC 9700...oh boy,a
>TS790,IC970,IC 275 etc runs rings around that
>thing,very easily!And thats 1980s tech...
>best 73s and stay healthy!
>Olli DM2TT ex DJ2TX
>Moon-Net posting and subscription instructions
>Earl Shaffer,Â WB9UWA
>My EME array photos
>Detailed array photos
>Moon-Net posting and subscription instructions
>are at http://www.nlsa.com/nets/moon-net-help.html
73, Ed - KL7UW
Dubus-NA Business mail:
I have 1 pc of Qorvo TGA2227-SM EVAL PCBs. The are 2 connectors on the
board… 2.92mm fm each. tested and working. Mid band nf is 2dB or better
on each. Data sheet below. Great instrument preamp $190 shipped CONUS… .
outside US additional.
No paypal, check or MO OK, outside US Western Union or bank transfer
Ft. Mill, SC, USA_._,_