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UKV natjecanja => 9A microwave contest => Autor teme: 9a6c - 01. Lipanj. 2021, 13:04:28

Naslov: 9A microwave 2021
Autor: 9a6c - 01. Lipanj. 2021, 13:04:28
Pobijedili smo coronu nekoliko puta, ali kako pobijediti u ovom contestu?

Pa sam odlučio idući vikend provesti na Promini, JN83CW, na oko 1140 m asl uz 23 cm opremu malog kalibra. Nosim DB6NT tvtr i LNA i 50 W out, antena je 55 el F9FT.

Bit ću na ON4KST cijelo vrijeme i posebno me zanimaju 9A postaje.

Za sad imam 27 veza na 23 cm, ali contest počinjem od 001 :).

Tko nije na chatu može me trznuti na 095 516 76 18 za sked.

Sve u skladu s pravilima 8)

Znam da ništa od mog prvog mjesta, ali nema veze, mlad sam i za mene ima vremena.

Tešku artiljeriju za sad ostavljam kod kuće, ali bude li trebalo, zna se ;)

CU 23 cm!

GG
Naslov: Odg: 9A microwave 2021
Autor: lz2pep - 02. Lipanj. 2021, 17:33:32
Zdravo ! Dobre ste dosli na LZDX VHF/UHF Contest 5/6 June 2021
od 50 Mhz do 10 Ghz.


Addres of robot for logs will post here after contest
.
73 ! LZ2PEP , Peter                       
Naslov: Odg: 9A microwave 2021
Autor: 9a4qv - 03. Lipanj. 2021, 09:54:33
9A4QV vjerojatno samo u nedjelju na 10GHz iz JN74BX kad se vratim sa Ličko-senjske i Primorsko-goranske ture...

QV
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 06. Lipanj. 2021, 12:29:35
Čim sam upalio uređaj, svbe je bil jasno...S metar na TR751 pokazao je šum od 20 dB preko devetke...
Prije contesta uradio 9A6AR, I4UJB i Ik3GHY, a u contestu samo prvu dvojicu jer je treći bio zauzet na 3cm i gađao neki oblak na zapadu OE.

Imao sam par skedova gdje me nisu ni čuli pa nije imalo smisla noćiti na Promini.

Prilike točno prema prognostičkim kartama... sreća da avioni ipak lete.

Nadam se da su drugi bili bolje sreće.

Iza moje antenice je mrski neprijatelj >:(
POZZ

GG
Naslov: Odg: 9A microwave 2021
Autor: 9A2HM - 06. Lipanj. 2021, 13:58:00
Pozdrav ekipi.
I ja sam imao volju raditi, ali mi se prikrpao Murphy pa ništa od gušta. Nakon nekoliko godina neaktivnosti na LNA se odšarafio "N" konektor, a kako nisam mogao sam do njega, pošto Murphy ne želi pomoći nego samo odmaže, morao sam smisliti nešto drugo da napravim barem koju vezu.
Slike govore sve!
LP
K
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 06. Lipanj. 2021, 15:16:32
Ali veseli pogled na ono nešto crveno bijelo u pozadini😉

CU AAUHF!
Naslov: Odg: 9A microwave 2021
Autor: lz2pep - 08. Lipanj. 2021, 15:10:05
 http://vhfcontest.bfra.bg/cgi-bin/tools/enter/enter_log.py?fbclid=IwAR1hrFfLuRJ02v1pZj0kfOHGbIMgmO2GVTp7ZhP6tD23QDyCtm1R3qclg28

     
     Address robot for logs LZDX Contest.  Thanks for QSo,s .  73
Naslov: Odg: 9A microwave 2021
Autor: 9A5M - 08. Lipanj. 2021, 16:01:30
Evo i mog rada na 23cm
http://www.opencontest.org/edi/map/20210607164053000644VMVEAY?fbclid=IwAR1o35UZvKo9VmvMwlN7rUGmfCDcQEuj3B94uNhuUE69fqFJx7IjjPKimA4

Naslov: Odg: 9A microwave 2021
Autor: lz2pep - 08. Lipanj. 2021, 17:35:48
Zdravo Marin ...Tanks for QSO 23cm. Gongratulations for good result. I was the operator at LZ6R. Hard but good qso.  We have 2,3 too. Was able to make HA8V. Next year will be ready 5.7 Ghz
73 cu , Peter LZ2PEP.
Naslov: Odg: 9A microwave 2021
Autor: 9a6ar - 09. Lipanj. 2021, 11:39:37
Marine, čestitke za vrlo impresivan rezultat. Svim dečkima koji su učestvovali iz portabla kapa dole,
svima hvala za održane veze kao i one brojne neuspjele pokušaje.

 Iz moje perspektive propagacije nisu još postigle svoj maximum. ODX od 627 km sam radio prije  i sa 30W i jednom Yagicom. Očekivao sam berem povećanje prosjeka (sada 410km) ali ni sa linearom se nije ništa bitno promjenilo osim što QSO-e koje sam i prije radio s mukom sada radim iz "šuba".

Ne mogu a da ne kažem što sam primjetio a nikako mi se ne sviđa a nije niti u duhu HAM SPIRITA što je postalo praksa kod timova. Timovi rade uglavnom s jednim čovjekom koji je samo na četu. I taj čet operator često, kad su operatori na stanici zauzeti, kaže "pozivaj na xxxx frkvenciji  " i ti zoveš u najboljoj namjeri a operatori na stanici rade veze okrenuti u drugom smjeru i ti si kao prvo trošio struju bez veze i gubio vrijeme. Nije u redu. Ja se radujem svakom ponovnom susretu i svakoj vezi. Kad vas čujem znam da ste živi i da nešto radite i uživate u svom hobiju.

Pozdrav svima  Dinko 9A6AR
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 09. Lipanj. 2021, 13:44:16
Pozz Dinko,

To s maltretiranju na chatu je postali odurno gubljenje vremena. Maltretiraju te likovi koji pojma nemaju i vabe te da zoveš ili slušaš za qrb ili vezu koja je out u svakom pogledu.
Na nižim bandovima još je gore.

Tebe sam u vezi čuo fondo scala, ali kad si o krenuo antenu nestalo te skroz. I tako te netko davi da ga zoveš ili slušaš, a tko zna gdje mu je antena.

Mi s ruba svemira osuđeni smo na chat. Šta da radimo, trpi i grintaj👺

Pozz svima i ako mi stigne bpf za 23 cm eto me opeT u AAUHF pa kako bude.

73

GG
Naslov: Odg: 9A microwave 2021
Autor: 9a4qv - 09. Lipanj. 2021, 16:29:37
Nije KST chat loša stvar...loše je to kako ga neki koriste...
U posljednje vrijeme taj rad na uW isto gubi na draži dosta jer 50% ljudi bulji u dva ekrana, jedan sa chatom i drugi sa sw za AS (aero scatter) i onda slijedi ono klasično bombardiranje porukama AS in 2 min...
pa mi onda lupa samo redni broj bez ičega drugog...

Ipak, naj jači su mi kolege preko sjevernih granica gdje me bombardiraju porukama tipa možemi li qso na 1296.xxx a meni lijepo piše 3cm only....

Sva sreća pa mi baterija u portablu ne traje dugo, inače bi poludio od tih bisera.... pogotovo sa Chatom na ekranu telefona  8)

QV
Naslov: Odg: 9A microwave 2021
Autor: 9a6ar - 10. Lipanj. 2021, 06:00:03
Gogo o kakvom se bpf radi?Bas me zanima moze li taj filter pomoci kod radarskog signala???
73 6AR
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 10. Lipanj. 2021, 07:20:22
U razgovoru s OK1TEH dobio sam prijedlog da nabavim bpf od PE1RKI - ima web stranicu s puno dobrih stvari - jer je takav filter i njima riješio problem. Ima dijagram gušenja iz kojeg se vidi propusni opseg i gušenje unutar propusnog opsega - a ono je jako malo, oko 0.2 dB.

Matej kaže da se Bertu može i predložiti malo drugačiji propusni opseg ako u blizini imaš neku beštiju koja ti zagorčava život. JA nemam radara blizu, ali na JN83CW ima toliko različitih signala da je to milina, pa kad se male ruke slože, i kući se otić može:-))

I oni su imali problem s radarom, a sad im nitko ne može ni blizu kad su na JO60JJ.

S dostavom izađe 120 EUR, a možeš birati kakve konektore želiš. JA sam odabrao muški i ženski N, super kvalitete, a Bert kaže da trpe mojih 350W koji još nisu u pogonu. Stavit ću ga ispred releja do antene, iako bi kao bilo bolje iza pred ulaz prijemnika. Ali gušenje je toliko sitno da mi je svejedno, transverter je DB6NT pa ću valjda nešto i čuti:-))

Idi pa vidi;-)

POZZ & CU AAUHF!


GG
Naslov: Odg: 9A microwave 2021
Autor: 9a6ar - 10. Lipanj. 2021, 08:08:56
super!! Gogo, znam za Pe1rki, on ima i lineara, Lna itd. Ici cu i pogledati taj filter. Ako je matej zadovoljan mislim da je to dobra garancija da to nesto vrijedi.Mi uglavnom radimo od .200 do .300khz pa se taj propusni opseg moze tako i postimati .
Sada radim nesto doma prljavo do zla boga.(drvenu nadstresnicu iznad glave ).
73 6ar
Naslov: Odg: 9A microwave 2021
Autor: 9a4qv - 10. Lipanj. 2021, 08:42:43
Pozdrav,

ako je smetnja in-band onda takav pasivni filter neće pomoći u otklanjanju smetnje.
Smetnju koju proizvodi radar na Učki je in-band smetnja. To se manifestira na način da je signal prljav i širok i pokriva cca 200 kHz. Nažalost i 1296 MHz je unutar tih 200 kHz.

Ja imam sličan filter o kojem govorite i on neće riješiti problem radara. Dinko, takav filter možeš i sam napraviti, S53MV ima dobar članaka na tu temu a ima i SW alata za proračun filtra.

Smetnju koju ima Gogo ne znam kako se generira, da li je problem saturacija 23cm RX-a pa onda on generira takve probleme ili intermodulacija na objektu što je malo čudno na tako visokoj frekvenciji. Ne znam kako izgleda tvoj setup, ali smrdi mi na pretpojačalo ako postoji u tvom sistemu. Samo ga zaobiđi kada si na takvim čukama i sve će raditi OK i sa golim transverterom.

U svakom slučaju, da bi vidio da li je smetnja in-band ili generirana u RX-u potreban je spektralac na lokaciji da se to ustanovi.

QV
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 10. Lipanj. 2021, 09:16:17
Adam,

To je onaj transverteri koji je bio kod tebe na kanalu, znači DB6NT tvtr, lna i mali qro pa iza njega dg0ve na kojem piše 20w, a ti izmjerilo 50 ;D

Na lokaciji u jn73ws sve bilo ok, a u jn83cw šum konstantno 20 dB iznad devetke.

Čini mi se da je Bert spominjao i notch koji bi svakako pomogao oko neke i band smetnje, a sam filter na 23 cm svakako ne. Ipak mu je passband u MHz.

Za sad čekam i prijavit ću utiske😉

GG
Naslov: Odg: 9A microwave 2021
Autor: 9a6ar - 10. Lipanj. 2021, 12:12:29
Adame hvala za tip, vidio sam filtere od Matijaza.
Super ideja za gradnju.
73 6ar
Naslov: Odg: 9A microwave 2021
Autor: 9a4qv - 10. Lipanj. 2021, 13:31:42
Gogo,
tebi će samo brikanje LNA riješiti problem na takvim lokacijama.
Također BPF ti može pomoći plus dodatni notch na tom filteru ako znaš koji ti je najjači ometač na lokaciji.
Da pojednostaviš, makni LNA iz RX grane.

Dinko, tebi nema pomoći :-)
Snimim ti danas sa maxhold kako izgleda taj signal sa Učke.
Stara je to priča koju smo žvakali još dok smo imali ATV repeater na Učki i kad je došao radar nije bilo pomoći.
U Zagrebu su se riješili problem tako da su promijenili kanal na radaru, čini mi se po privatnom zahtjevu bivšeg predsjednika saveza. U Zagrebu je svanulo na 23cm ali se nama u Istri i sjevernom jadranu smrklo....tako to ide..
 ;D 8)

QV
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 10. Lipanj. 2021, 14:50:06
E, lako je tebi govorit, makni lna... Ionako san star i gluv, makni mi slušni aparat i di san onda?

Radije iden na brdo iznad kuće pa pomalo.

I ko će krivit one kabliće i sma konektore?

Srediću ja to nekako.

Za AA sve je spakirano😉
Naslov: Odg: 9A microwave 2021
Autor: 9a4qv - 10. Lipanj. 2021, 15:09:54
I bolje ti je na brdu pored kuće nego gore na Promini...
AA CU...
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 10. Lipanj. 2021, 15:29:10
E kad mi vrag ne da mira...

Vidićemo kako će bit u AA... Povrh kuće su crkva i groblje i normalno da nema šuma😋

Grobna tišina na 151 m asl...

GG
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 11. Lipanj. 2021, 15:04:19
Momci, javio se Matej Ok1TEH koji prati ovu našu raspravu oko mikrovalova i poslao malo duži mail s molbom da ga ovdje objavim, a mislim da ga vrijedi pročitati. Na engleskom je, ali uz malu pomoć Dr Googla mislim da će biti zanimljivo ;)

***********************************************************************************


Hi guys,
I'd like to write out few findings related to problem with 23cm QRM
from commercial or military towers and how to remove it. First you
must find out if the signal is in band or not by some spectral analyzer.



1) QRM by inband commercial signal
If the signal make problem in band, there is usually very little
what you can do.. One partial solution is to build up narrow dish
with high front to back suppression and use LNA with high IP3..



2) QRM by outband signal
If the QRM is caused by signal out of band, it's very important to
find out, how far (MHz) is the unwanted signal. At my home QTH in Prague
I had problem by DVBT2 tower operational some 300m far with few kW.
It was running DVBT some 300MHz below 1296 MHz so in this
case it was relatively easy to buy or make low ATT filter.


Making such a filter is relatively easy, we made such a filter
to suppress the mirror for the 28/1296 MHz transverter check out:
http://www.ok2kkw.com/00000104/preselector/bpf_23cm.htm
I asked to Beert, PE1RKI, because he has very well done boxes and machinery
and at least it saved lot of time. In the case it was easy because the
source of QRM was several hundreds MHz away so the
cross attenuation was only of 0,2dB.



Much worse situation happed at our contest QTH JO60JJ,
as we suffer from radar from from 14,4km far Auersberg radar
which is operating around 1259 MHz with 2,5 MW in pulse.
As the result I asked to RKI to prepare special narrow BPF version
however due to very narrow bandwidth and very high suppression
it has relatively higher cross attenuation. It's because of problem
with Q at this high frequency. Luckily we found out that such a filter
at our case was working well even when it was placed between
LNA and transverter, so the higher attenuation was still acceptable
because the whole noise figure wasn't  corrupted so much
(we use separated RX/TX path).



By the way if you have such a problem at 2m with FM BC,

check out https://www.antennas-amplifiers.com/144mhz-bandpass-filter-bpf

it's great BPF and I use it with good success..



3) QRM by usage of bad kind of LNA for contesting
For city environment with strong outband signal it's better to use
LNAs with very high IP3 like MMIC PGA103+ or some alternative.
Don't use 2 stage LNAs like VLNA from G4DDK or old LNA
with MGF1302, they are fine for EME, but not for city environment.

I had bad experience with LNAs from SSB electronics, little bit better
are HEMTs (Kuhne), better is PGA103+ but currently the best is probably LNA
from US4ICI with SKY67151, compared to PGA103 it has much lower NF
https://vhfdesign.com/lnas/lna-eme-sky67151-for-23cm-and-21cm-bands.html
Remember for 23cm tropo contests that you really don't have to use 0,1dB NF LNA,
anything below cca 0,8dB is ok (because of high thermal noise from background)



4) Operation at on4kst chat
I read your discussion, It's not easy task.



At 23cm I used to ask to more people, because I use 2 or 3 (since June)

independent antennas, so I can turn them to more stations at the same time.

Sometime it's problematic that you ask somebody for chat and you are called

at random by some other local station, so sked partner has to wait and with

nowaday smaller patience he became to be angry, that he must wait for you...



I always try to do my best and ask stations only if I checked at Airscout
that airplane is already coming. But guys please release that the situation
in Middle Europe is far different to some DX area like 9A. We oftenly work
30 stations on 23cm during first 1 hour of contest so the pileup is big
however when you wait and ask some 9A station later like around 19utc
when you have more time for skeds, at the meantime he often go QRT
or try some other band.. An another thing is QRM situation, I often ask
the sked partner to move let's say to  .310 or higher.
During some contests it's very problematic to find any free frequency
for CQ between 1296.150 to 1296.290 MHz...



In any case if you are fed-up with the too fast chat traffic, try use our VUSC

contest log because it has it's own KST chat client with very good

user text filters. If you are QRV 23cm, please write it at your name in

chat and if you are just listening, please select in KST chat that you are

"off the chat" so then is station marked with () and almost nobody will bother you.



At the end I must say that S5, 9A and YU operators are very well skilled
in CW/SSB operation so it's big pleasure to work you. And yes of course

please always send full rst+nr + loc code, the situation when
somebody send rst+nr only I don't like either hi. Last words: if you are small

stations with 10W, please realize that Airplanes are great help so even with

your small setup if you know CW, it has sense to try QSO up to 500 km,

just give it a try and please be patience hi.



73
Matej, OK1TEH

********************

Najbolje od svega mi je što je teško naći slobodnu frekvenciju  i da postoji pile up na 23 cm, e da mi je to doživit...

Naprid naši!

73 GG
Naslov: Odg: 9A microwave 2021
Autor: 9a4qv - 12. Lipanj. 2021, 19:46:41
Hello Matej,

just for the curiosity, I left the SA on max hold for a 15 min to plot the spectrum.
What you can see is the spectrum of the FPS-117 Long range radar system capable of plotting the targets at 470km!
L-band or NATO standard D-band 1215-1400 MHz (18 channels).
Av.power is 4.5kW max power 24.6kW with the 44 active Rows (antenna with amplifier).

This plot was created with a 10el.cheap yagi indoor using the 4mtrs RG-223 coaxial cable and HP8559A SA to be on the safe side.
The NF of the SA is really high, no external preamp used. Radar distance cca 30km.
Center frequency 1296MHz, span 200MHz, ref level -10dBm.

So, who is that fancy guy that can solve this problem using a passive fiter technics? Just show us that guy  ;D

In band signal from the radar is -50dBm at 1296 MHz....
Naslov: Odg: 9A microwave 2021
Autor: AD6IW - 13. Lipanj. 2021, 06:32:19
There is relative easy way to cancel radar or other sources of interference, without using any filter.
Using phase canceling method, separate antenna pick up interfering signal, and combine that signal after amplitude and phase adjustments in main receiver.
Signals with same amplitude but opposite phase will cancel each other.
In reality it would be possible to reject interference up to 40 - 45dB. Another advantage of this approach is that interference or jamming signal could be at same frequency of weak signal.
 73 Goran AD6IW
Naslov: Odg: 9A microwave 2021
Autor: 9A2M - 13. Lipanj. 2021, 13:41:03
To dečki, drago mi je da se ovaj forum vraća opet u život. Tehnika, propagacije... a ne svađanja i trolanja.
AD6IW posebno mi je drago da si i ti opet ovdje aktivan.
Naslov: Odg: 9A microwave 2021
Autor: 9a6c - 13. Lipanj. 2021, 17:12:39
Malo smo off topic, ali rekao bih da je problem sve vremenski pa možda i nismo😔
Naslov: Odg: 9A microwave 2021
Autor: s55m - 15. Lipanj. 2021, 13:39:44
To sa brisanjem radara sa signalom u protufazi je tocno, ali ako radar vrti antenu, tesko ce ga biti uloviti po amplitudi i fazi...
Naslov: Odg: 9A microwave 2021
Autor: s55m - 15. Lipanj. 2021, 13:57:43
Hello Matej,

just for the curiosity, I left the SA on max hold for a 15 min to plot the spectrum.
What you can see is the spectrum of the FPS-117 Long range radar system capable of plotting the targets at 470km!
L-band or NATO standard D-band 1215-1400 MHz (18 channels).
Av.power is 4.5kW max power 24.6kW with the 44 active Rows (antenna with amplifier).

This plot was created with a 10el.cheap yagi indoor using the 4mtrs RG-223 coaxial cable and HP8559A SA to be on the safe side.
The NF of the SA is really high, no external preamp used. Radar distance cca 30km.
Center frequency 1296MHz, span 200MHz, ref level -10dBm.

So, who is that fancy guy that can solve this problem using a passive fiter technics? Just show us that guy  ;D

In band signal from the radar is -50dBm at 1296 MHz....

I fight with 180cm dish and discard any attempt of qso over the radar path. Had a lot of burned front-ends (23cm 13cm 9cm 6cm) on JN76PB because of weather radar on Lisca. But is it truth, that it was 50m away :). Even so close (radar is working on 5.61GHz), i was able to use 6cm band without problems.
Naslov: Odg: 9A microwave 2021
Autor: AD6IW - 15. Lipanj. 2021, 16:20:12
Citat:
To sa brisanjem radara sa signalom u protufazi je tocno, ali ako radar vrti antenu, tesko ce ga biti uloviti po amplitudi i fazi...
Main lobe of radar will be rejected up 40-45dB, sto je bitno. Za potpuno ponistavanje signala treba signal processing.
Citat:
Had a lot of burned front-ends (23cm 13cm 9cm 6cm) on JN76PB because of weather radar on Lisca.
Stavi limiter ispred LNA