Jan 2006

The Spectrian 2.3GHz Amplifier was modified as per instructions from N5AC and produces 190W with 5mW of drive. It still operates from 48V, but consideration is being given to changing it to running off 26V to reduce heat generated by the DC-DC converters. Dish mount modified to enable more accurate moon tracking

Mar 2006

After publication of the WD5AGO/W1GHZ feed article a VE4MA superfeed was constructed. This used a length of 100mm ID copper tube donated by PA3CSG.

Mounted four 24V fans on back of Spectrian amp to help cooling.

Apr 2006

Apr 1: Feed and DEMI preamp mounted on dish. TX feed on dish changed from FSJ4 to LDF4. Spectrian amp mounted at dish with 48V PSU powered from 240V AC.

Apr 2: Set sked with VE6TA for 1700z. At 1640 shorted out the P channel FET in DB6NT xverter when replacing lid after setting LO frequency. Took out 3 semiconductors, took 2 hours to fix. Reset sked time to 2000. After 1st TX period no receive noise. Went to shack and ripped out Tropo xverter. Because of IF interface, had to use with IC202. But after all these problems did make QSO with VE6TA for initial #1. After sked found pin diode had blown in Xverter IF; device replaced.

Apr 5 Finished WD5AGO NE324 preamp, 0.52dB NF 20dB gain. Measured connectors/relay. By selection, managed to lower overall system NF by 0.35dB from April 2 values.  April 8. Switched on system at start of contest. Exceptionally loud signals were heard. Echoes were 2dBN. Worked OK1CA, F2TU, W5LUA and OK1KIR. CWNR ES5PC, HB9JAW. Heard nil during JA window on 2424MHz.

April 9. Signals weaker than previous day. No echoes. OK1CA down 10dB. Heard HB9SV. CWNR OE9ERC for 2 hours. Heard and worked OZ4MM (weaker). CWNR OE9ERC for 1 hour. CWNR SK0UX for 1 hour. Heard WA6PY on sked, but worked G3LTF (xband to 2320MHz) on sked

April 11: Arranged sked with OE9ERC after lack of success at weekend. Good signals. Worked OE9ERC on both CW and SSB. April 12: Nil on sked with NA4N, heard WD5AGO on sked but did not complete. April 28: Feed removed from dish.

Sep 2006

Sept 16: Put back 13cm feed for ARRL contest.  Worked OK1CA, F2TU, W5LUA, K5GW (#9), G3LTF. Signals very weak. On Sept 17 Worked K2UYH (#10), OK1KIR,  PA3CSG (#11), RW1AW (#12), OE9ERC. Signals much better than on 1st day, even though we had 2.65" of rain during the EU period (good job had installed Spectrian amp in waterproof dog kennel at the dish)!  Tweaked  AIDC3733 C band converter (previously used for AO-40) for 2424/168MHz, measured 1.8dB unit NF.

Jan 2007

Built atf36077 preamp in design by W5LUA from MUD proceedings 1994 p8 which has the input circuitry in air rather than being mounted on lossy board. NF 0.35dB gain 18dB, an useful improvement over existing preamp. 

Mar 2007

Mar 24 started with old preamp. Swapped to new preamp; sun noise went up a whole 1 dB. Worked  W5LUA on JT65C (-16db, #1). First JT65C qso on 2304? Preamp and 2nd stage on dish.

Apr 2007

Looked at my VE4MA superfeed. I noticed the screws were nowhere near the recommended starting positions,  so started tuning process again. After working KH7X on 1296MHz the previous night  I was qrv for the Dubus contest on Apr 21. Echoes were impressive, 6dB out of my noise.  Easily worked F2TU, OK1KIR, SM3AKW (#13),  KL6M (#14). Listened during the JA window, but band full of interference even with filter in front of preamp.  On April 21 near the end of a qso with G3LTF no output from spectrian amp. Opening it up found Isolator output terminal vaporised and load resistor brown. Checked antenna; swr good. So replaced isolator. Full output restored. Worked ES5PC (#15) and OZ4MM. CWNR OE9ERC, OE5JPC, LX1DB (lostout in pileup!), OH2DG, OH2AXH. Got called by K5GW but output  disapeared again, same isolator, but this time noted the heliax connector on the output was hot. Replaced connector, but unable to fix isolator...flames on the isolator output is bad news. No replacement isolators. Stole 2 x MRF286 amp from tropo system, down to 60W output, but, to my surprise still worked RW1AW and G3LTF (xband)! Heard KH7X for 60 minutes but my 60W wasnt enough to get there attention (nor was WD5AGO's 200W!). Examined Spectrian amp found substrate missing from track at output of isolator. Need to replace board.

May 2007

Disaster struck. May 2nd dish hit by 81mph winds.Sheared the two bolts holding actuator to post, releasing actuator. Dish swung over smacking dish into concrete supports bending rim and popping panels. May 5 spent day straightening out dish with steel angle, 3 C Clamps and a bench vice. Added 2 muffler clamps to stop clamp slipping again:- 

Obtained replacement input and output combiner boards for spectrian amp after being advised to replace both at once as they are a matched pair. Replaced output combiner amp produced 120W. Next replaced input board amp produced the usual 160W; advice was correct. Had always wondered why output power decreased if amp was overdriven; found 26.5V from output of dc to dec converter module drops to 17V if RF modules take too much current. Could get more power if run RF stages directly off 28V, (some have got 250W off 28V) but decided to leave amp alone as 160W is enough...to prove the point on May 19 worked TF/DL1YMK (#16) on sked

Jun 2007

Modified DB6NT Transverter to provide a receive only output to feed SDR. To reduce the 144MHz level on transmit coming out of this "receive" port an extra relay was fitted that terminates the port in 50 ohms on transmit which allows only -85dBm on TX to appear at output port.

Aug 2007

Aug 4 Worked VK7MO (#2) on JT65C (-19dB) on 2301.965MHz sked. Also copied his cw signals, even with dish pointing through the garden fence but he couldnt hear me. Aug 11 worked LX1DB (#17) on cw sked. Converted my other spectrian to work off 28V. Takes 55A to give 200W output for 7mW input. Biggest issue was circuit breaker would trip if key kept down. Found breaker trips at 37.5A so have now bypassed breaker; no more issues. Managed to impliment remote monitoring for the Spectrian Amplifier

Mar 2008

Mar 22. Installed G4DDK ATF36077 preamp on dish. Much more compact than old preamps and increased sun noise measurement.

Apr 2008

In DUBUS contest on 4/12 worked VK4AFL (#18 DXCC#15) , W5LUA, VE6TA, F2TU, HB9SV(#19, DXCC#16 ), G3LTF(xband), G3LQR(xband #20), HB9Q(#21), OZ4MM, OK1KIR, SD3F (ex SM3AKW), ES5PC, K2UYH, WA6PY (#22) CWNR VK3NX. The only escapee xband was f5jwf, no other signals were heard on 2320MHz, despite having an SDRIQ on each band (thanks G4DZU!).

May 2008

During the increased activity on the band coincident with the DL1YMK expedition to Uruguay, worked IW2FZR (#23, DXCC #17), DL4MEA (#24, DXCC #18), WD5AGO (#25, state #5) and the expedition station itself DL1YMK/CX (#26, DXCC #19)

Jun 2008

Jun 28. Completed a sked with G4CCH (#27) , but not without difficulties. S9 noise level on 2320MHz, S1 noise level on 2304. S2 noise level on both bands when preamp terminated. Turned off every wireless device in the house but no help. One hour later noise the same on both bands. Learnt from W5LUA that it was a south american Siriues Sat radio Transmissions. Luckily the noise reducer on the newly acquired sdr1000 rx dug the signals out of the qrm (knew i bought it 4 days before for some reason!). Worked VE6TA on QRM free 2304MHz with no  problems. Jun  29: No 2320 QRM. Worked SM2CEW (#28) on sked. Worked G4CCH again, with no QRM  much easier. Worked G4CCH (#3 on JT65C) (-19dB), despite my drifting LO.

 Current Equipment: 

RX/TX: 2304/2320MHZ: G4DDK ATF36077 Preamp (0.35dB NF) mounted on feed via isolation relay. DB6NT 2304/144MHz Xverter + Spectrian PA (180W) mounted near dish  + FT847

RX: 2424MHZ: ATF36077 Preamp (0.35dB NF) + AIDC3733 Converter (1.8dB) + FT847 on 168MHz

ANTENNA: 10' C band TVRO dish. F/D = 0.4. Home made VE4MA "super" feed.

Initial QSOS: 

CW

Also heard but not worked:   NA4N, OH2DG, OH2AXH

JT65C

GREEN = QSL RECEIVED

YELLOW = QSL SENT

Thanks to W5LUA, G4DDK for advice and PA3CSG for supplying the vital copper tube!

This page last updated Jul 4 2008