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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Sri I made, at least a mistake, I send it again.
Very interesting answers. I come from Sats world, where the Doppler
is a serious issue and it is so quick that it is impossible to work
I will speak thinking in one carrier. Sats need to receive in only
one fix frequency (it is an active RX with a wideband), if the Sat
receives a carrier in this frequency then it will be repeated. The
signal TX from the Sat will be in one fix frequency. So people who
work Sats must correct its TX frequency (according with actual
Doppler) to reach the sat in its fix frequency, in the same way
because of the Sats will repeat this signal in a fix frequency, people
must correct its RX frequency (according with actual Doppler).
This way of dealing with Doppler is very interesting because NOBODY
KNOWS the Doppler of the other stations and nobody needs to know it,
we only need to know our own Doppler.
If we would use this agreement to EME communications we will always
speak about the frequency we hit the Moon, in other words the
frequency which the Moon hear us and repeat our signal.
The actual EME software shows us the Doppler as the sum of the Doppler
effects to reach the Moon and to receive the bounce signal, so Moon
will receive us at ½ Doppler announced, the other ½ effect will appear
after de bounce.
I will try to set a couple of examples.
1.- We will agree to hit the Moon in 1296.070. This is the frequency I
will announce in the log. In our software the dates will be:
The sign that the software shows will aplly to RX frequency and the
opposite to the TX frequency, and always ½ magnitude on each one.
Both of us must deal with Doppler, each one must do their task to hit
the moon in the agreed frequency and to receive the bounce according
our Doppler. Then we must set on our transceivers:
TX: 1296.070 -1.5KHz = 1296.0685MHz
RX: 1296.070 +1.5KHz= 1296.0715MHz
TX: 1296.070 +1.0KHz = 1299.071MHz
RX: 1296.070 -1.0KHz= 1296.069MHz
Each station who sees the post will act only according its own
Doppler. Don´t mind where is the DX station.
2.- In this case I see a signal in my receiver in 1296.070. What
kind of pair of frequencies I must set (I know nothing about the DX
station I have still decode nothing), I only know me own Doppler, and
it is +2KHz. I must hit the moon in the same frequency that my
TX: 1296.070 -1.0KHz = 1296.069MHz
RX: 1296.070 = 1296.070MHz
WE WILL NOT NEED TO KNOW NO MORE THAN OUR DATES.
I haven´t spoken about what frequencies will be the echoes (both
echoes), to make the understanding easy.
As a drawback we should change our habits, we should always use the
RIT as follow:
TX: The frequency we choose plus the opposite sign of Doppler and ½
RIT: the sign of our Doppler and ½ Doppler magnitude.
Although at first glance it seems not to be interesting in 144MHz but
we will always hit the target in whatever band, even in 144MHz.
Somebody can tell that they need a computer, to do JT65 of course, if
you do CW surely have a smart phone with the proper software to know
your own Doppler or you can print it before.
If I made some mistakes let me know.
It is my 2 cents.
Its been awhile since I have been QRV with my 2m-eme station.
Four independent problems in my transmission line during the winter
kept me off the Moon and then my HVPS acted up. Well it turned out
to be a simple problem but it didn't appear that way. My 4kV dropped
to 2.8kV without a load. I envisioned all kinds of problems but in
the end it was simply a blown HV fuse. It did not blow open but
instead went to 16meg-ohm which was enough to drop the HV with very
low current being drawn by the HV panel meter.
Having no replacement fuse, I decided to remove the HB fuse holder
from the HVPS since changing the fuse required removing the 8877 deck
from the rack to gain access thru the HVPS top plate which is
directly under the amplifier. I will order some more HV fuses from
Nebraska sales ($25/ea.) and make an inline HV fuse box which will be
much quicker access to replace a fuse. Actually, I have only blown
two of these fuses in 8-years of running.
How I blew this one is that the 6-dB attenuator that I was using to
lower drive to my transverter to keep drive below 50w to the 8877
failed in short resulting in over 100w drive to the 8877. Anode
current spiked taking out the HV fuse as it is designed to
do. Probably hit over 2kW output!
A couple other improvements will make recovery from HV events
quicker: I brought the 240vac mains fuses to the front panel of the
HVPS and increased them to 20A. And I added a vernier to the 8877
drive input cap. Looks like I got a finer tune on the input as it is
taking less drive to reach 1200w.
I will be QRV Sunday from about 1400utc to 1700utc (Moonset):
144.116, 1st for CQ and on N0UK logger. Mon> I will be trying to
work 6W/PE1L in Senegal very early in my morning. We only have about
30-min common Moon on Monday but this increases on subsequent days.
73, Ed - KL7UW
"Kits made by KL7UW"
Dubus Mag business:
My Teledyne (MTI5015D) TWT has a Double Ridged WRD-750 output flange. I
would like to transition this to a WR90 or WR75 guide if possible. If you
have such a transition, know of a surplus emporium, or have suggestions as
to fabricating such a device I would appreciate a reply.
I'm assembling a terrestrial 1296 system with WA2ODO 0.33 dBNF preamp
and 50w PA to be housed in a Hoffman-style box at tower top. Today,
I measured the isolation of my coax relay to be 45-dB by transmitting
42 dBm (15w) and measuring -3 dBm on the Rx port with my
HP432A. Since my PA output will be 47-dBm (50w) this means the
preamp will be exposed to +2 dBm.
I wonder if I should be concerned or is that low enough to not harm
the preamp? I really do not want the added complication of two
relays to achieve more isolation. Preamp will be powered-off in Tx
and relays and PA keyed by a sequencer.
Relay is a Tohtsu CX520 which is rated by RFParts at 1000-MHz at
250w/47-dB/iso=0.2 dB insertion loss. Note the NO port is
dc-grounded. PA has a keying line to bias it into cutoff in Rx.
Line loss + insertion loss = 0.5 dB such that Tr = 65K (Nr = 0.88
dB). Sky noise (on horizon) plus antenna temp est. at 225K so
resultant system noise temp = 290K and SSB MDS about -140 dBm.
73, Ed - KL7UW
"Kits made by KL7UW"
Dubus Mag business:
I have for sale my:
TAPR Hermes single board SDR transceiver, with N8UR breakout board for J16 and G8ONH 'refclock' autoswitching board for 10MHz external clock management and de-glitching. The Hermes is mounted in a Hammond enclosure.
One built set of Alex transmit and receive filters (controlled directly from Hermes) in Hammond box with cables.
Munin 100W PA kit - complete with drilled/tapped heatsink, copper spreader and all components, as supplied by Don Waddel. Hammond box available to complete the matching set.
Prepared to consider sensible offers for any of the units, either as one complete lot, or separately. Will ship worldwide, at cost. Can ship with US at reduced cost for quick sale
Please e-mail me directly (off list) at g4hup-at- btinternet-dot-com for further info and questions. Photos of the units are available on request.
Thanks & 73,
Despite the minus 25-30 Degree C weather I activated the station for the 432 contest.
Activity is lower than previous years and an elevated K index disturbed conditions.
The following stations were worked this weekend;
N4GJV, ES5PC, VK3UM, JA6AHB, I1NDP, OK1CA, UA3PTW, SP6JLW, LZ1DX, NC1I, DL9KR, SP7DCS.
Huge signals this weekend from DL9KR, NC1I, UA3PTW, OK1CA, and VK3UM despite the disturbances, and apogee conditions.
I called W1AW/4 and received QRZ's, and heard the following with no opportunity to call, DL7APV, DF3RU, PA3?, and IK2OLO?.
Overall a fun weekend and nice to hear some of the big signals make it back from the moon.
I also managed to work WA4NJP as W1AW/4 prior to the contest period.
I hope to make it on for the 13 cm contest next month.
73's to all and thanks to the stations who got on.
After posting I am circular on 10 GHz I have received a question, Why?
Geometrical is the same at 10 GHz as on other bands. Normally 45 deg / 3 dB to the east coast of the US and approaching 90 deg west of that. With increasing activity from different parts of the world simultaneously gives circular polarization an advantage. 6 cm is circular, why not 3 cm EME activity?
In 1990 I went to the EME Conference in Trenton, NJ with a very nice 10 GHz copy of the W2IMU horn for .6 dishes, and everybody was impressed. There were not many stations on the band at that time and most of them were linear. Except my good friend SM4DHN, who made his own version and has been circular since then. The same issue came up in Prague in 2002 and it was decided that use of circular pol. was recommended. 24 years and not much has changed...
Today there are several good designs of feedhorns for CP, and mine is one of SM6FHZ's. I also think there are CP horns available commercially.
Anyway, today I worked OK1CA, OH2DG, SM4DHN and DL0SHF on 3 cm. I also heard Toly, UA4HTS several times. I measured 16 dB of Sun noise and 2,3 dB moon noise with my 4m dish. Power output to the CP horn is 15-18 watts through a very short cable.
73 de Ben, SM6CKU