N7NEW 2 Meter VHF Portable Repeater

Used for Emergency Repeater or Event Repeater


This is a completely self contained Emergency Repeater.

145.130 (-600) PL tone 131.8 set at about 45 watts

Load it in the back of a vehicle and haul it to where ever it is needed, hook it up to a 12 volt battery, plug in the Antenna and it is on the air.

The ant mast slides into a bracket on the corner of the job box and you just tighten the thumb screw to keep it there.

If you fasten the ant mast to something else, you don't even need to unload the box out of the vehicle.

If this repeater is needed for an event or you have questions email Mike at N7NEW

Thanks to WA7HTJ, W7GLB & W7HNH for all their great help!

W7GLB Silent Key

Having a need for a portable repeater I decided to build one.

The Cle Elum & Ellensburg Ham Clubs have many events that they do communications for over the summer months.

One of which is the Cascade Crest Classic Ultra Marathon.

We tried cross-banding and it worked fine except for the normal problem of people doubling because of not being able to hear each other.

So we started thinking about a portable repeater.

I decided to use one of the SNP (shared non protected) pairs to avoid Coordination on both sides of Cascades.

The PA board in this radio puts out over a 100 watts.

We have it turned down to about 45 watts and have had it up and running almost continuous for 48 hours at a time without damage.

I installed three 2" fans on the PA cooling fins.

We built up the repeater out of...

GE MASTR II Mobile radio free from WA7HJR & W7HNH

"Wacom" WP-639 = TPRD-1554 148-174 MHz Pass-Reject Base Station Duplexer $150.00

Channel Elements: International Crystal Manufacturing Company, Inc. (ICM) $49.99 each

Controller: NHRC-4/M2 MASTR II plug in controller board $189.00

NHRC-VSQ MASTR II Internal Volume & Squelch controls $10.00

HRC Shipping +$16.00

Communications Specialists TS-64 DS Tone board $57.95

Communications Specialists Shipping $8.01

Ant Diamond CP22E $62.95

12 Volt Marine Battery $64.00

Rigid Job Box $179.99

Miscellaneous Capacitors, Components, connectors & Cable about $100.00

New 3/28/2010

Five 6-32 Ferrite Slugs for GE Mastr II PLL Exciter Conversion $17.00

One New PLL Channel Element: International Crystal Manufacturing Company, Inc. (ICM) $59.45

Total about $1014.35

The original Mastr II Mobile radio was a MX76KKS66C

We Modified the receiver Osc/mult board to make it a low band per GE specs. Then found a dead stage in the IF board. Changed that board out and the receiver sensitivity came down below .5 micro-volt.

My board = 19D423241G4 Rev F

Modify VHF oscillator/multiplier found in a GE Mastr II radio for better performance.

Background information:
The sensitivity of the stock GE Mastr II 150.8 receiver may be limited by low local oscillator injection when tuned to the amateur 2 meter band. The problem is more apparent as frequency goes down. The following modifications will improve the injection resulting in up to 4 dB more sensitivity or more. Usually the 150.8 receiver provides fairly good sensitivity in the ham band. We like to end up with about -116 dBm or .35 uV for 12 dB SINAD. When it doesn't meet this specification, 9 times out of 10, it's due to low Local Oscillator injection.

The modification:
On the later model Osc/Mult boards, (the ones with the trimmer capacitors), there are a few fixed value capacitors that you need to install or increase in value.

C 407 from a 12 to 15 pF
C 412 from a 5 to 8 pF
C 417 from (unknown value/maybe not installed) to a 3 pF
C 421 from (unknown value/maybe not installed) to a 18 pF

After getting the receiver tuned up, we worked on the PA board. It had some problems so we swapped it out for a good one. When turned up it put out 120 watts. Set the output to 40 Watts. We set the levels and called it good to go. After that I made the mods to duplex the Mastr II per MASTR 2 Infosite instructions.

The NHRC controller went in like clockwork as did the Communications Specialists TS-64 DS Tone board. Added the NHRC-VSQ MASTR II Internal Volume & Squelch control at the last. Hard wired a speaker after cutting the control head cable shorter.

W7GLB modified the Wacom Duplexer and tuned it up for me. Had to change Cable Harness to right lengths to get it to tune to 144.530/145.130.

New Improvements 3/28/2010

Remember, this is on the 2M ham band, (low end)... changed the slug in the VCO coil to ferrite. It was aluminum and placing a ferrite slug in the coil form will lower the resonance, allowing better PLL lock, especially in cold weather.

After testing the repeater out for some months at various events, I found that the PLL board would not lock every time. Ordered up a ferrite slug for the VCO coil (Repeater Builder) and replaced the aluminum one with the new ferrite slug. Also sent in a new Icom (International Crystal Manufacturing) for crystal cut & temp comp for the PLL board. Installed both and tuned up the VCO coil 3/28/2010 with Bob’s help. Set VCO voltage to about 5.64 Volts.

Where to buy the ferrite coils... 6-32 Ferrite Slug for GE MII PLL Conversion

Report 7/19/2010

Have had the Repeater on the air here at the home QTH for 3 months using it locally. 

Have not had one problem with it since changing the VCO coil to ferrite. 

It has worked flawlessly.

Report 8/30/2010

Used the Repeater for the Cascade Crest Classic 100 mile ultra over the weekend.

Turned it on 8/27/2010 Friday night at about 9:30 PM and it ran continuous until 

8/29/201 Sunday 4:00 PM without a glitch. I am real happy with it.

By the way a new course record was made this year... 18 1/2 hours for the winner.

Report August 25-26 2012

Used the repeater for the 2012 Cascade Classic 100 mile Ultra Run.

It was on the air from Friday late afternoon until late Sunday afternoon.

It worked flawlessly.

Report 12/5/2012

Used the repeater for Bothell HAM-CERT-Fire-Police-EOC-Schools-retirement homes exercise for 2012.

Repeater was up and running on battery power with no problems for this emergency exercise.

Here are a couple of pictures taken at the drill & one showing the way the repeater was set up but from earlier practice drill. (both at Fire Station #44)

Bothell Command Van 1a.jpg (142523 bytes)    Bothell Command Van 3a.jpg (146716 bytes)    Practice during Bothel Emerg Net-2a.jpg (252224 bytes)

Below is a picture showing VCO Voltage TP

100_0932-b.jpg (291606 bytes)

Pictures of Repeater

100_0720-a.jpg (343125 bytes)


100_0721-a.jpg (354251 bytes)


100_0722-a.jpg (378241 bytes)


100_0724-a.jpg (332819 bytes)


Picture showing NHRC Controller board & Volume/Squelch board

100_0726-a.jpg (430376 bytes)


Picture showing Communications Specialists TS-64 DS Tone board mounting.

100_0729-a.jpg (384766 bytes)

Pin out for TS-64

TS-64 Colors



Maiden Voyage to be August 29/30 2009.

Will let you know how it held up.


August 31 2009... Well the repeater did a great job. It had only 2 glitches. One was Saturday Night about 9:30 PM and the other was Sunday morning about 10:00 AM.

Both times it was the same problem and only lasted about 2 minutes each. The phase locked loop quit locking for a couple of min. The first time it started working again before I got the lid off the radio. The second time I had time to adjust it a smidgen. It did not fail again after that. Will be checking that out further right away.

Here are some pictures of it's maiden voyage on the 2009 Cascade Crest Classic.

We were located near the center of the 100 mile course on Amabilis MT. at about 4500'

Amabilis Repeater Site-3-a.jpg (396770 bytes)



Amabilis Repeater Site-2-a.jpg (391812 bytes)



Event Rptr in operation-2-a.jpg (475799 bytes)


Amabilis Site-KB7QPY-4-a.jpg (417705 bytes)


Event Reapeater Transport-a.jpg (423889 bytes)


Amabilis as viewed from Thorp Mt. Thanks Glenn !

Amabilis from Thorp Mt..jpg (421259 bytes)


Cascade Crest Classic Aid Station Sites as viewed from Amabilis Mt Repeater site.

Thorp Mt-a.jpg (443954 bytes)


French Cabin Creek-a.jpg (401949 bytes)


Silver Creek-a.jpg (426812 bytes)


Back to HTRC Link Page                   Back to Ham Radio Page

Back to Home Page