NJ VHF REPEATERS Prepared for the USAF/ALL-MARS NORTH EAST CONFERENCE SEPTEMBER 25 – 27 2015 At Fort Indiantown Gap, Pennsylvania By Bill Thiele, AFA2AY, NJ.
Download ReportTranscript NJ VHF REPEATERS Prepared for the USAF/ALL-MARS NORTH EAST CONFERENCE SEPTEMBER 25 – 27 2015 At Fort Indiantown Gap, Pennsylvania By Bill Thiele, AFA2AY, NJ.
NJ VHF REPEATERS Prepared for the USAF/ALL-MARS NORTH EAST CONFERENCE SEPTEMBER 25 – 27 2015 At Fort Indiantown Gap, Pennsylvania By Bill Thiele, AFA2AY, NJ VHF Repeater Mgr. and the TEAM Controlled Unclassified Information (CUI) (FOUO) The NJ MARS Repeater Team David DeGeorge, AFA2CD, Air Force MARS, ex NMCM Jim Demos, AAR2OA, Army MARS Mark Emanuele, AA2CD, Army MARS Harold Engleke, AFA2UM, Air Force MARS Bob Harrison, AFA2QD, Air Force MARS Joel Higgins, AFA2MR, Air Force MARS, ex NMCM Carl Lundgren, AFA4YG, Air Force MARS Bill Powell, WB1GOT, Cherryville Repeater Association David Ream, AFA2HM, Air Force MARS, ex NMCM Larrie Sutliff, NCS042, SHARES Greg Szpunar, AFA2FJ, Air Force MARS, ex NMCM Bill Thiele, AFA2AY, Air Force MARS Dave Webb, AFA2HV, Air Force MARS Jim Zipf, AAT2BM, Army MARS We thank several others for their contributions. Why VHF Repeaters? • VHF succeeds when HF propagation fails. • VHF backs up cell phone, internet and satellite systems. • Repeaters facilitate the use of small field equipment, even handhelds. • Repeaters may be creatively linked to expand coverage. • Repeaters can run analog and digital modes. • Repeater teams bring MARS members together to support the mission. Troubled Times for HF We’re here NJ Repeaters Back in the 1980s NJ AF MARS boasted on HF, “If you have one NJ station, then you have the state.” That was a stretch, but…… The repeaters were linked on a 148+ MHz dedicated frequency with directional Yagis. ! DON’T GIVE UP THE FREQUENCIES • Frequencies carry the mission. • Useful direct, for repeaters and for linking . • Simultaneously useful within a region or state. Commodore Oliver Hazard Perry Battle of Lake Erie, 1813 Classic NJX-2 at Murray Hill • Classic “hollow state” GE ProgLine repeater. • Carl Lundgren, AFA4YG, one of the early team. Carl is also classic. Nostalgia or Bad Dream? • The ProgLine performed well. • BUT, the COR was imported from Hades. • Good EMP repeater? NJX-2 “Bell Labs” Microwave Tower NJX-2 Antenna NJ MARS REPEATERS TODAY • A work in progress by the TEAM. • Coverage for most of NJ and some of Eastern PA. • Tactical coverage into Manhattan. • Creative linking is under way. • HF patch from NJX-2 is being studied by AAT2BD. Some of the TEAM at NJX-2 Bill AFA2AY AIR FORCE Jim AAT2BM ARMY Dave AFA2CD Then Larrie NMCM NCS042 SHARES Mark AAT2BD ARMY TOWER WORK AT NJX-2 LARRIE USING THE FISK DESCENDER LOOKING SW DOWN I-78 NJX-2 RUNS A RELIABLE MASTR III • Repeater courtesy of Dave Ream, AFA2HM (then NMCM) • Bill Powell, WB1GOT, tuned the cavities. • ProgLine stored under the table. • NJX-2 site continues to be somewhat noisy. NJX-2 COVERAGE PATTERN COMPUTATIONS COURTESY OF WB1GOT NJX-2W COVERAGE NJX-2W: NEW CAPABILITIES • Near “Linvale” on the western end of the Sourland Mountain. • 460 ft. site elevation plus 330 ft. of tower. • NJX-2W shares antenna at the top! • More southerly and westerly coverage. • Without the noise problems that plagued NJX-2. NJX-2W ANTENNA VIEWS VIEW NORTH VIEW EAST VIEW WEST VIEW SOUTH Views courtesy of Mark, AAT2BD NJX-2W: A REMARKABLE HAPPENING • Astounding hospitality of the Cherryville Repeater Association to share its antenna, feedline and cabinet! • Unusual engineering to let NJX-2W and Cherryville’s remote receive system work with no compromises. • Great TEAM efforts. • Cherryville is grandfathered on the tower and our presence is not visible. SOME OF THE NJX-2W TEAM Rear: Bill, WB1GOT Cherryville Mid: Jim, AAT2BM Army MARS Left: Bill, AFA2AY Air Force MARS Middle: Mark, AAT2BD Army MARS Right: Dave, AFA2CD Then NMCM Fortunate Frequencies Made it Work NJX-2W XMIT 143.450 MHz NJX-2W RX SPLITTER CRA 4.525 MHZ AWAY FROM CRA RX FQ! TO ANT. TX RX NJX-2W RX FREQ. 148.025 MHz CHERRYVILLE RX 147.975 MHZ TUNE PASS CAVITIES 148.000 MHZ, WHICH IS ONLY 25 KHZ AWAY FROM EITHER! (PASS MODE CAVITIES ARE RATHER BROAD.) NJX-2W: TIGHT CABINET SPACE • BRIDGECOM REPEATER FIT NICELY. • 4.575 MHZ SPLIT AND ONLY 50 W ALLOWED USE OF TINY 6 CAVITY DUPLEXER. (THAT WORKS GREAT.) • EVEN MADE ROOM FOR NEW RACKMOUNTED ASTRON POWER SUPPLY. • AND FOR BIG NEW PASS CAVITIES. BRIDGECOM AND TINY DUPLEXER MASTR II CRA REMOTE UNIT NEW CAVITIES & PS TEAM WORKING IN CRAMPED CABINET NJX-2S COVERAGE NJX-2S EXPANDS COVERAGE SOUTH • Dave Ream, AFA2HM (formerly of NMCM), has transferred his Navy-Marine Corps repeater intact into the Air Force MARS system, with its frequencies. • Had NMCM continued, he would have offered the same use of his repeater. That’s what team cooperation is about. • Dave has also been a benefactor for NJX-2 and for NJX-2W. • NJX-2S is in Runnemede, NJ. Site altitude is 132 ft. He has a Stationmaster antenna on his 60 ft. tower and delivers an effective radiated power of about 290 Watts. • NJX-2S is now delivering coverage to some who can’t access NJX-2W, including the SMD, Bob Harrison. • Linking NJX-2, NJX-2W and NJX-2S is a high priority, to be discussed in a few minutes. NJX-2S ERICKSON 5XHMCS & STATIONMASTER ANT FUTURE NJX-2N COVERAGE? NJX-2N: UNDER STUDY • Mark Emanuele, AAT2BD, is project manager for this. • Catfish tower has clear paths for long distances. • Linking within NJ and surrounding states may be practical. • Area VHF linking may become more important with the decline of HF propagation. View from Catfish Tower NJ MARS REPEATERS LINKING • NJX-2W is between NJX-2 and NJX-2S, so it is key. • Unfortunately NJX-2W cannot host another antenna for linking, or a data line. • That means linking must happen on the repeater frequencies themselves. • All the repeater frequencies are different and wide spaced, so that should be possible. • MARS is not constrained, like ham, radio to close spacings, like 600 kHz. NJX-2S has over 2 MHz and NJX-2 and NJX-2W have over 4 MHz of shift! (Linking Later) Intermediate Link Station Approach A link station may be located at a favorable intermediate point between the two repeaters to be linked. Directional antennas vertically separated, plus wide repeater shifts in MARS, help to reduce desensing and other problems. Simplified Link Station Diagram Example: Link at CLOVER RCV 143.450 MHz Xmit 148.025 MHz Tone 156.7 HZ RCV 143.775 MHz Xmit 148.050 MHz Tone 156.7 HZ Some Link Questions Pre-answered • No. It’s not that simple. Grounds, RF quirks and audio quality need attention. For example, the VOX boards are shielded in a metal box accessed only via feed through capacitors. This is a work in progress. • The two radios are ICOM 2300H. • Actual audio is used for T/R to avoid the cumulative squelch tail delays if the radio’s squelch was used. • The strongest station will call up the repeater. That will usually be the link. • Yes. We will hear the ID of every repeater in the link. That tells us which repeaters are functioning as linked. The Link at Clover Hill • 2 four element Yagis in phase face NJX-2. Two more face NJX2W, with vertical spacing. • Solar panel and batteries provide back up. • Plan to replicate the prototype link board with IC-2300H xcvrs for the NJX-2W/NJX-2S link. • Several enhancements may be added if needed. • The previous digipeater CLOVER performed well. The CLOVER link uses its antennas. CLOVER LINK HARDWARE VOX BOX IC-2300H NJX-2W VOX BOX IC-2300H NJX-2 CONCLUSIONS • That HF propagation will remain poor for some years increases the importance of VHF to our mission. • VHF can support even hand held field communications. • Don’t give up VHF frequencies. We need them. They may be reused over and over. If NJX-2N happens, then it may use the frequency pair of NJX-2S. • VHF repeaters can be linked in new ways to cover larger areas. We need to learn how to do that well. • VHF repeaters are TEAM building opportunities. In NJ Army MARS, Navy-Marine Corps MARS, Air Force MARS, SHARES and the Cherryville Repeater Association have worked well together.