Transceiver

m ■ ■ ■ ^^ ^^ ^^ ■ w ■ ■ m" ^ Price Class: FTR-146, $150;

Build your own high-quality FM rig the easy way. $io?&HC£SlfcoDd

When Ramsey Electronics first advertised the FTR-146 2 meter transceiver kit, ihe promise of a synthesized VHF radio for $149 was just too attractive to pass up. My only fear was that a project this inexpensive might be difficult to construct—or not work very well. Fortunately, these fears proved unfounded.

Features

The FTR-146 is a six-channel diode-programmable PLL-synlhesized FM transceiver, covering 144.000 to 147 995 MHz, "Diode-programmable synthesis" means that you select six of your favome operating frequencies and program them into the radio when you build it. Programming is done by installing diodes in a binary matrix, a procedure that is much easier than it sounds. Transmit offsets for h 600 kHz, - 600 KHz, and simplex are also programmed n by installing diodes. Ramsey conveniently provides a 12-position switch with the kit, so you can add up to six additional channels by expanding upon their diode matrix.

FTR-146 RF output is rated at 4-6 watts, which is plenty of signal for base or cEose-in mobile operation. Smce the radio draws oniy 1.5 amps on transmit, nearty any inexpensive CB-type supply will provide enough power.

Although amenities like a signal strength meter, microphone, and built-in speaker aren't provided with the FTR-146 kit, il does include attractive "packet-ready" features other radios

have—like PlN-diode T/R switching and a DIN-type TNC jack on the rear panel An onboard jumper selects squelched speaker-level audio or unsquelched discriminator-level audio for your TNC, For an additional $24.95, Ramsey offers an attractive 9" x 6* x 1.5" cabinet with silk-screened front and rear panels, and matching knobs. I found plenty of room inside this enclosure to install a homebrew channel expansion board and a 3" speaker

Constructing the Kit

With any kit. the dividing line between success and frustration usually depends on two key factors: the integrity ol the circuit board, and the clarity of the instructions. A poorly designed board or a confusing manual can turn even the simplest kit into a nightmare Happily, I found the FTR-1461s CAD-designed two-sided PC board an absolute pleasure to construct- Part locations are silk-screened on the component side, and there's plenty of space for everything to fit. You won't need the dexterity of a brain surgeon to make it look professional The same CAD program that generated the board layout was used to produce striking 11" x XT* multicolored parts placement and schematic dia* grams for the manual. Credit goes to project designer Tom Hodge WA2YTM for some fine computer work,

In a simitar vein, I found the kit's documentationt written by Dan Onley K4ZRA, to be equalty impressive.

Amateur Transceiver Kit

Photo A. Completed FTR* 146, front panel, 18 73 Amateur Radio Today • December, 1991

Photo B. Completed FTR-146, rear panel has over 100 pages of information and diagrams to guide you through construction, complete with check-listed steps, mini-schematics, and parts placement figures for every stage. Even the parts list is cross-referenced to the installation steps in the manual! The instructions are not only detailed, they're educational as well, By the time I completed the project I had learned a great deal about how synthesized transceivers work.

For the most part, you won t need special tools to complete this project. However, if you make a mistake, you may need a vacuum-type desoldenng tool (or a roil of Sotderwick^) to remove parts from the radio's double-sided, plated-through, PC board. Radio Shack's desoldenng iron {#64-2060) is inexpensive at $8.49, and does this job well Also, tune-up requires nonmetailic tuning wands, including one with an insulated metal lip like the GC-8608 (Radio Shack Tuning Wand Set £642230). Finally, some of the air-wound inductors are formed on a 3/8-inch 18-TPt bolt, tf you don't have one on hand, this could mean an unscheduled trip to the hardware store.

improvements

I really enjoyed building the radio. But, before I'm accused of working for Ramsey's ad department, I'll confess to at least ONE aspect of the kit that I donTt like. The solid-copper bell wire supplied for point-to-point wiring of controls and switches was hard to handle—and easy to break. I threw it away and made a coior-coded harness from flexible stranded wire.

More significantly, 1 had to solve a couple of technical snags to get my rig on the air. Initially, the radio's squelch circuit wouldn't function properly, due to a defective IC. Ramsey helped me find the problem and promptly mailed a new chip.

Photo C The kit comes with a high-quality PC board, all components and excellent documents* tion.

Photo 0 The assembled FTR-146 transceiver board

The second snag was a bit more complex. The radio's synthesizer !C tunes in 10 kHz steps. When a +5 kHz frequency change is needed for 15 kHz channel spacing, the loading on each mixer oscillator crystal is switched by diodes to "pull" (hat oscillator in frequency (recall the +5 kHz switch on your old synthesized HT), Unfortunately. I couldn't make two of the four oscillators in my radio pull far enough to hit both frequencies I traced the problem to out-of-toterance crystals. Once again, Ramsey helped me diagnose the problem, and promptly shipped the items I needed.

Getting on the Air

Aside from the crystal problem, alignment was straightforward You'll need a frequency counter to set each oscillator on frequency, and an RF power meter to peak the transmitter. You'll also need a weak signal source to align the receiver Lacking an expensive FM service generator. 1 terminated the antenna jack with a 47 ohm resistor and used a short scrap of wire to pick up a local repeater. Any signal weak enough to produce audible background noise wilt suffice.

Dunng construction, yoult wind many of the radio's air-wound inductors by hand—a somewhat imprecise science. During tune-up, youi may need to "tweak" some of these by compressing or stretching the bindings (tweaking may be needed to bring a coil's associated trimmer capacitor in-range. or to opMmize a circuit using a fixed capacitor). Once aligned, my radio delivered 4-5 watts into a 50 ohm load and approximated the receiver sensitivity of my ICOM HT, I later measured receiver sensitivity at a respectable 0.4 pV on an FM service monitor,

The FTR-146 microphone circuit was designed to work with an iCOM-type speaker mikeT and employs ' load-sensing" to activate the transmitter (there's no separate PTT line), if you opt to use a replacement-type mobile mike, you'll need to wire the PTT switch in series with the mike cartridge in order to key the radio. When I first tested my microphone, I got reports of a ioud hum on the audio, t quickly discovered the cause to be stray RF pickup—a consequence of running tfte rig without a case into a rubber duck antenna Connecting an external antenna cured the hum.

There are as many ways to package the FTR-146 as there are ways to use it. I keep mine next to our telephone, serving as base station for our "multi-ham" household. For this task, 1 installed a three-inch speaker in the Ramsey cabinet. This provides plenty of volume to hear calls while you're in another part of the house. More extensive customizing is possible—including sophisticated channel switching schemes, and even a digital display. Toward Ihis end. manual writer Dan Onley has established a user's group and newsletter for FTR builders in order to sha-e customizing schemes and circuit upgrades.

The Bottom Line

The Ramsey FTR-146 kit is a fine value from several standpoints. First, it's instructional, After building it I find synthesized radios less mysterious, and I'm more confident when tackling repairs on other radios

Second, the FTR-146 is the right tooJ for the job. 1 don't really NEED a 50-watt radio with 100-channel scanning to hit the local repeater. The FTR-146 does this flawlessly, and people say that the Ramsey transmitter audio sounds superior lo my other rigs!

Finally, for the serious packeteer, the FTR-146 may be a sensible radio to dedicate to online data communication. Hook it onto your TNC or modem and save your other rig for voice contacts.

Evolution

By the time you read this review, an enhanced version of the FTR-146 (the FX-146) will be available for S169. According to Ramsey designer Tom Hodge, this FM transceiver is now on the bench and headed for production soon. This new radio uses a more sophisticated synthesizer chip which expands receiver coverage to 20 MHz, provides a programmable offset, and facilitates producing 220 and 440 MHz versions of the radio.. The new synthesizer also provides 5 kHz steps, eliminating the need to shift mixer frequencies. Other changes include a simplified receiver circuit using a more advanced IC, According to Hodge, receiver changes will provide tighter IF filtering, improved image 'ejection, an RSSI meter output, and enough extra boardl space to inciude a 12-channel diode matrix.

OK, so you are nervous around hot soldering irons and you have fat fingers. Should you tackie one of these kits? I say YES! Through the FTR-146, Ramsey Electronics has clearly demonstrated the ability to engineer and produce a good radio that's easy to build And. they've shown that they can support it with first-class documentation, if my experience with the FTR-146 is any indicator, construction of the FX-146 kit shouid be a snap as well! I like my radio a lot, and I suspect that Ramsey transceivers are going to be with us for a long time to come. fFl

Contact Rick Little field K13QT at 109 A McDaniel Shore Drive. Barrington NH 03625.

73 Review by Dick Goodman H AM SG

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