NJ VHF REPEATERS

Prepared for theUSAF/ALL-MARS NORTH EAST CONFERENCE

SEPTEMBER 25 – 27 2015At Fort Indiantown Gap, Pennsylvania

By Bill Thiele, AFA2AY, NJ VHF Repeater Mgr. and the TEAM Controlled Unclassified Information (CUI)

(FOUO)

The NJ MARS Repeater TeamDavid DeGeorge, AFA2CD, Air Force MARS, ex NMCMJim Demos, AAR2OA, Army MARSMark Emanuele, AA2CD, Army MARSHarold Engleke, AFA2UM, Air Force MARSBob Harrison, AFA2QD, Air Force MARSJoel Higgins, AFA2MR, Air Force MARS, ex NMCMCarl Lundgren, AFA4YG, Air Force MARSBill Powell, WB1GOT, Cherryville Repeater AssociationDavid Ream, AFA2HM, Air Force MARS, ex NMCMLarrie Sutliff, NCS042, SHARESGreg Szpunar, AFA2FJ, Air Force MARS, ex NMCMBill Thiele, AFA2AY, Air Force MARSDave Webb, AFA2HV, Air Force MARSJim 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

Mark AAT2BDARMY

Dave AFA2CD

ThenNMCM

Jim AAT2BM

ARMY

Larrie NCS042SHARES

Bill AFA2AY

AIR FORCE

TOWER WORK AT NJX-2LARRIE USING THE FISK DESCENDER

LOOKING SWDOWN 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 COMPUTATIONSCOURTESY 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.

VIEW SOUTHVIEW WEST

VIEW NORTH

VIEW EAST

Views courtesy of Mark, AAT2BD

NJX-2W ANTENNA VIEWS

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 TEAMRear:Bill, WB1GOTCherryville

Mid:Jim, AAT2BMArmy MARS

Left:Bill, AFA2AYAir Force MARS

Middle:Mark, AAT2BDArmy MARS

Right:Dave, AFA2CDThen NMCM

Fortunate Frequencies Made it Work NJX-2W XMIT 143.450 MHz

NJX-2W RX FREQ. 148.025 MHzCHERRYVILLE RX 147.975 MHZTUNE PASS CAVITIES 148.000 MHZ,WHICH IS ONLY 25 KHZ AWAY FROM EITHER!(PASS MODE CAVITIES ARE RATHER BROAD.)

4.525 MHZ AWAY FROM CRA RX FQ!

NJX-2W

CRA

RX SPLITTER RX

TX TO ANT.

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.

NEW CAVITIES & PS

BRIDGECOM AND TINYDUPLEXER

MASTR II CRA REMOTE UNIT

TEAM WORKINGIN 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!

(LinkingLater)

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

RCV 143.775 MHzXmit 148.050 MHzTone 156.7 HZ

RCV 143.450 MHzXmit 148.025 MHzTone 156.7 HZ

Example: Link at CLOVER

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 NJX-2W, 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.

NJX-2

NJX-2W

CLOVER LINK HARDWARE

NJX-2W NJX-2

VOXBOX

IC-2300H IC-2300H

VOXBOX

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.