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Field Marshall Digital Tracking Receiver

thumb_Field-Marshall_logoOur Digital Field Marshall gives you the most sensitivity available in a tracking receiver.

This premium receiver offers more volume (with speakers on top and bottom), a new ultra-compact case design featuring a "Quick-Release" handle, improved LED front lighting of the control panel for night tracking, improved water resistance for use in wet weather, and the latest generation of Marshall's exclusive collapsible yagi antenna now with cable-free operation.

Also, exclusive to the Field Marshall is the addition of poyphase filters, our new noise floor reduction technology that reduces the background noise while increasing the effective range and tracking ease.

NOTE: All Field Marshall 800 receivers are now shipping with the new Half-size Loaded Yagi design as standard, making it a "pocket reciever."  A new shorter holster design is included that fits the narrow body Field Marshall when mounted with the HSL Yagi.  All Field Marshall 100 models come equiped with the original full-size Yagi.

FM100: 650£ (173 or 216) equipped w/ Full Size Yagi Antenna
FM500: 750£ (173) equipped w/ Full Size Yagi Antenna
FM800: 850£ (4 band selectable 216-219), 200KHz per band.  Equipped w/ premium Half Size HSL Yagi Antenna


Getting the best range requires having the most "useful sensitivity" in a receiver. The combination of receiver, the matching cable and the antenna designed for specifically for it consitute a complete package that must work in harmony to achieve the most sensitivity possible. The Digital Field Marshall will give the most range, especially in cities or areas of "unwanted radio noise."

Since this receiver doesn't rely on crystals to determine the frequencies it can cover, we've given it more capacity. An all-digital circuit allows the same receiver to pick up any frequency in the 216 through 219 MHz bands allowing every frequency you could possibly want or just the ones you're interested in.

Best of all, if you change your mind down the road, your same receiver can easily be converted to a different band thus protecting your investment.

A broadened, smoothed tuning mechanism means that tuning into the signal is a pleasure and much faster than before.

Tuning with the new tune knob is broad and is protected from accidental contact so it's not easily bumped off your tune setting when getting in and out of the vehicle.

Higher Sensitivity: With the new digital receiver board inside the Field Marshall, we've improved sensitivity by another 3dB, equal to that of the Stealth, currently the best in the market. This means a significant increase in reception distance for the same transmitter.

The actual sound of the receiver has been improved through the elimination of harsh harmonics and distortion, making it easier to track weak signals and far more pleasant to listen to.

Three red LEDs now illuminate the entire control panel for better clarity in the dark without compromising your night vision.

As great as it is to have a handle on long walks or when holding the receiver out the window, there's times when it's better without it. Greater portability and reduced size is achieved without the handle on a third axis.

So, how to have it both ways?

Answer: The new Quick-release handle. Now, you can choose when to use it and when to put it away in another pocket. Even though it's tight and secure with its bracket mount, it takes only seconds to remove it using the thumb wheel screw-on design.

Those who've now used it, love it.

Not only can the handle be quickly removed, it also attaches directly to the antenna. This gives you three different ways to configure your receiver.

So, now you can have it any way you'd like: use everything together in one single piece, hold the smooth and smaller case in your hand without the handle, or wear the box safely around your neck and connect the handle directly to the antenna to hold outside the window in the rain.

Hold the receiver down waist high and you have two speakers facing up at you. Hold it up high for better reception and you still have a speaker facing down at you. By incorporating three speakers, the sound on the Field Marshall has been increased in volume.

And yet it's also quiet where it needs to be: A new narrow-band filtering system is employed rejects noise better without reducing your signal, so you hear the signal more clearly with less distracting background noise, even for the weakest signals.

More importantly, it has improved the sound's omni-directionality which means the volume doesn't change as you rotate the receiver, a definite problem in other receivers that leads to erroneous perception of the signal strength in certain directions.

Nearby transmitters on other channels sometimes cause interference to your reception, but this receiver has special circuits to minimize the effect.

The improved rejection of noise near power lines means you can hear weak signals better and increase your range.

Better Range Estimation: The range settings (Medium and Near) have been adjusted so that you know it's time to start walking. You can therefore switch between these in most situations to get a better idea of how far from you the bird or dog really is.

Electronics are housed in a robust case machined from a solid block of aircraft aluminum.

Purposely made for heavy use outdoors, this tracking receiver is designed to give you more years of trouble free operation through the widest range of temperatures, travel and weather than any other. Sealed connectors, mylar speakers, overlapping seams all make this receiver the most durable design now on the market.

In addition to all the performance improvements made, Marshall Radio engineers redesigned and shrunk receiver board to about 20% less total area, with everything fitting inside the case much more efficiently leaving and no wasted space. We then asked our external design team to "vacuum pack" the case down to the absolute minimum required, with no wasted airspace on the inside, no needless bulk on the outside. The result is a smaller overall receiver.

With the handle removed, the slimmed down design fits even better in your hand. Designing the outer case to be hand-held required we make additional changes, like a larger radius on all corners, and counter-sinking the earphone and power jacks to make them flush with the surface of the case, all of which just makes it feel more like an over-sized iPod in your hand.

Turns out the case is much more stout and rugged than even the previous generation Marshall receivers.

It's also designed to use six AAA batteries, cheaper to replace, and easier to change.

We kept the same, field proven, collapsible, three-element directional antenna design for maximum directionality. It's a full gain yagi when deployed, but now it collapses to an even smaller size. We reduced the size of the brackets, the sliding booms and eliminated the need for cables, cable savers and big springs found on the previous design. Also rugged solid rods are now used for the elements instead of hollow tubes.

Improving the shielding on the case also means an improvement in how the antenna works for you. It's simple now to track up to within inches of a transmitter lost in the grass with the same pin-point directionality you get at a distance. The full-size three element yagi gives the best range and directionality of any antenna, and reduces the "back lobe" which sometimes fools people into tracking 180 degrees backward, in the wrong direction.

Using newest generation electronic components and creative packaging allows us to fit a lot into a small space.

And, our committment to using aluminum alloys which have the maximum strength to weight ratios makes this receiver as light and strong as technically possible.

A key mechanical design breakthrough of all Marshall receivers is the collapsible yagi antenna. The full-sized three element antenna (shown above right) can be reduced in size by half when fully closed.

When collapsed down into its stowaway position, and put into its hoslter (included with every new receiver), the new Field Marshall makes a small and compact piece of equipment to take with you into the field.

Q & A

What are the advantages of the different frequency bands?

This is a topic of much debate among telemetry users. First and foremost, frequency bands should be selected based on what frequencies are legal for use in your country. In some countries, multiple bands are available for radio telemetry use. In those areas, the user may select the band that offers the best combination of performance, antenna size, and range. Generally speaking, a lower frequency offers better signal propagation (longer range) and better diffraction over hills and obstacles, while higher frequencies allow for smaller aerials and antennas (nice when hiking through dense woods or operating from within a vehicle). The small differences in frequency within a band have little effect on performance,  i.e. 216.005 will perform the same as 216.795.  In some areas, one band may be contain more background noise than another band. Bands with the least background noise provide the best range.

What batteries are best to use?

For general use,  Alkaline AAA batteries are the most cost effective and provide good battery life. They are commonly available as well. Lithium AAA batteries offer the best performance in cold weather, are the lightest, and last the longest (but cost significantly more). Rechargeable batteries (such as NiCad or NiMH) should not be used as they do not provide sufficient and consistent voltage to operate the receiver effectively.

Always use name brand batteries (like Energizer or Duracell) with a comprehensive warranty, in case there is ever an accident with the actual batteries inside your receiver.

Can the frequency range of my Field Marshall be reprogrammed be changed?

A lower capacity Field Marshall can be upgraded to include more channels (for example a Field Marshall 100 can be upgraded to a 800, 1000), but the band must reamain the same (i.e. a 216 MHz cannot be changed to a 173 MHz).

Can I hook it up to an cartop (Omni) antenna?

Yes, the Field Marshall easily excepts input from an external antenna, simply remove the coaxial cable from the receiver body, and plug in the coaxial cable from your external antenna. The Field Marshall uses a ‘SMB’ connector, most omni antennas use the larger ‘BNC’ connector. A simple adapter (included with the purchase of an omni from Marshall Radio) can be used to connect other manufacturers antennas to your Marshall Receiver.

Can this receiver pick up my existing transmitters?

Yes, as long as the frequency range of your transmitters lies within the coverage of your Field Marshall receiver.

We have a problem in our area in that people think you're carrying a gun.

The Field Marshall comes standard with a quick release handle. Removing the handle and grasping the receiver case directly helps prevent the receiver from being mistaken for a weapon. However, the sight of a stranger walking through a neighborhood or farmyard holding and sweeping a beeping device with antennas is sure to arouse concerns if you do not explain to spectators what you are doing.

I don't see any place on the website to order replacement parts.

A small packet of common parts, like an axtra cable, thumbscrews, etc are provided with your new receiver. Also, replacement parts are just a phone call away, and we'll send out what you need.

What are the regulations for using the 433MHz band in the United States and Canada?

The use of the 433 (or UHF) band in the USA & Canada requires the user to apply for a Ham Radio License (easily attainable by paying a small fee and passing a written test). Once done, the user is now a legal ‘station’ and is able to use the quiet UHF band and at much higher power levels. To legally use telemetry on this band, your transmitter must broadcast your station ID (Ham Radio Call Sign) once every ten minutes in Morse Code (a feature exclusive to Marshall transmitters). You simply provide us with your Call Sign and we'll include it in each of your UHF transmitters.

How do you handle repairs when the receiver is out of Warranty?

If you receiver requires repair outside of the warranty period, it can be returned to Marshall Radio (or through your local distributor) for repairs at reasonable cost to you. You will be notified with the results of our testing and evaluation as to your options and their costs.


Customers Say


Nick_Kester2"I hunt with Goshawks and found the new digital Field Marshall incredibily effective, it makes finding a hawk in deep cover, hiding after catching a Woodcock (if I'm lucky) a breeze. The directionality of the new receiver is amazing and allows me to get to the bird faster than ever before. This takes a lot of stress out of flying and I'd recommend it to any Austringer.

-  Nick Kester, at the Falconry Fair 2010



alberto"The new Field Marshall is a remarkable receiver with features that translate into tangible advantages in the field. It is so well shielded and filtered that, not only is range vastly improved, but localizing a signal is so fast you can literally run right to it. This difference is not lost on those of us that have arrived moments before a stalking coyote or eagle!

"In recent years, I have flown well-hacked gyrfalcons that share a rather cosmopolitan view of the sky. This past season, a talented young female, “Sonde” took it upon herself to ring long-billed curlews up to the space station. Fortuitously, I had the new Field Marshall to find her quickly when she drifted back to earth miles downwind.

"Having used or tested most other receivers, even in places as sketchy as the tropics, I think there is nothing that touches this one. The beautiful little unit is also rugged, so it is a no-brainer to always have it along. It is simply an awesome unit."
- Alberto Palleroni


daver"I was thinking about writing you to say how much I love my new receiver! The FM 1000 really is an amazing piece of technology and a real quality unit...You should be charging more!

"There are a number of features I like such as the smaller size, quick release handle and improved antenna. But, what I really like is that it's just easier to track a bird. The combination of a very directional unit plus almost no background noise makes this by far the best system I have used and I find that I can track a bird much faster than before. I am happy to say that I haven't had to track my new hybrid much this season but I use it to find him quickly on a duck in the bushes which is important because the red-tails seemed to be more aggressive than ever before. I have also used it to track the birds of my friends and we used it in Wyoming when I was at Steve's in the fall.

"I am very glad I changed my two transmitter frequencies so they each have the same last three numbers. I just switch from 216 to 218 without having to punch in the numbers each time. Thanks very much for helping me with that when Marci and I came by for a visit!"
- Dave Rimlinger, CA

tonyjames"We all know that to get the full benefit of our telemetry system we need to thoroughly test it, to become well acquainted with it, so that we understand the full meaning of that reassuring bleep. And yet, if I'm honest, I've never really done so.

"Whenever I've needed telemetry, which thankfully hasn't been too often, it's generally worked well enough to find a missing hawk --- although the reunion would have been swifter and more certain had I taken the time to practice my tracking skills, and had I possessed the new Marshall receiver.

"In November 2007 I had the misfortune to lose my falcon to a tragic accident when out hawking. Nothing could have influenced what happened that day, but because I tend to fly just one falcon, the loss was devastating. My season was over, but I needed to look to the future.

"The need for good telemetry is at its most obvious for the falconer who puts all his eggs in one basket, and having found myself without a hawk, I resolved to develop some level of competence with telemetry in preparation for the new season.

"A month after that loss, I had the pleasure of getting to know Robert Bagley during the week of the IAF/ANFA AGM in Sezanne, France. Of course we discussed telemetry experiences, both good and bad, and I learned a lot about the development and evolution of Marshall telemetry equipment. Robert's obvious pride at Marshall's development of the most advanced and reliable telemetry system available convinced me that I should invest in some of Marshall's latest equipment. As it transpired, the investment turned out to be much less than expected, as for the price of a handful of raffle tickets I became the proud owner of the receiver and a PowerMax transmitter, donated at that meeting by Marshall Radio. Oh the irony --- the best telemetry in the world, and no falcon!

"Still, determined to look for the positive, I set about comparing my new prize with the setup that had served me well enough over the preceding years. No doubt unfairly, I set about the comparative tests in the naive belief that my existing equipment fulfilled my requirements admirably, and could not be bettered. I expected there to be little discernible difference between the two outfits.

"But, quite simply, there was no comparison. The new Marshall equipment outperformed my old set in every department. In signal detection, both in range and clarity, in directionality, and functionality. The design and build quality are testament to a commitment to improve, in an age when the global trend is to 'dumb down.' I don't imagine the word 'compromise' figured in its development.

"Next season, as I again go through the process of making a game hawk, I hope not to call on my telemetry to save the day --- but if I need to, I'm now more confident than ever that I have the best equipment available to ensure a safe return."
- Tony James, UK

dougp"I've consistently used the new Field Marshall receiver this past season as my primary receiver. It's a significant refinement from the original, which was a breakthrough receiver/antenna combination in its own right.

"Even without considering the improvements in gain and noise reduction, the new Field Marshall is a big improvement over the original in three ways:

  1. You finally took my advice and made the pistol grip a modular element attached with a beautifully machined bayonet fitting. Excellent execution of this concept, beautifully machined;
  2. The new receiver housing is significantly more compact than the original, and therefore easier to hold;
  3. The new folding antenna retains all of the positive, instant deployment of the original, but is much simpler and more robust, as well as being narrower in folded mode and therefore more compact. The machining on this antenna, and the mechanical design with the helical springs is just beautiful. Very elegant design. Excellent!

"I've had quite a few opportunities to recommend the new Field Marshall receiver to a number of customers and friends, without reservation. Its stout design and construction, compact size, and sensitive gain make it the compelling choice. I suspect new technology will soon displace current dominant RF technology in falconry and sporting dog telemetry. Until this happens, the new Field Marshall will be the last word and only choice for falconry or hunting with sporting dogs."
- Doug Pineo

stanislav"I have been using the Marshall receivers 8th years now. Started with Dave Jamieson's Stealth in Nevada deserts. Then after three seasons went back to Czech Republic and start use it here in small hillside with many small villages and towns around. So I had to learn new tracking tactics.
I and mine few freinds tested four different receivers from europe and US and one made here in CZ. The Marshall was on top.

"Now I sold mine two years old FM-10 receiver and and start use the new Field Marshall firs season. In the start it was hard as I was knowing the old receivers sensitivity well. After few chases the receiver start be mine new friend.

"Has very good sensitivity, is more directional, small to carry in mine hawking vest, has nice professional dezine. And it is not like a toy receiver that does not get good direction when you need it because it points to the falcon like no other receiver I have ever tried, straight to the falcon with no mistake.

"I think it is the best in all the world, not just the Czech Republic."
- Stanislav Menclik

HSL Yagi


What is the HSL Yagi?

It is a new design that reduces the overall size and weight of the yagi antenna by half. Since it uses small loading coils to do this, it's called the "Half-Size Loaded" Yagi, or, HSL for short.

It's now standard equipment for the FM800 receiver. It will be a $100 Upgrade option for the FM100 beginning December 1, 2010.





How does this new yagi compare to the regular size Marshall yagi?

For the three key areas that an engineer designs for, the forward gain, the front-to-back ratio and the directionality, it has the same performance as our full-size yagi antenna. And our full-size yagi is virtually optimal in terms of the achievable performance in gain and front-to-back-ratio.




How did you shorten the antenna without losing performance?

The elements have been reduced by 30% in length, but each one now has a tiny structural loading coil designed and produced here at Marshall Radio to accurately maintain the "electrical length" of each one.



What's a loading coil, and how do they work on a receiving antenna?

Here's an explanation from a recent interview with Dave Marshall: "There are ways of shortening a regular size yagi and maintaining its performance by keeping it electrically at a half wave length. You fool the electrons in to thinking it's a half wave length and they still manage to time their travel across the elements correctly so it's perfectly resonant like the pendulum of a clock that's got to keep in tune with the transmitting frequency as it goes back and forth. We alter the path of the electrons, and there are various ways of doing that using principles of self magnetic induction which slow the electrons down on their path and various other techniques. This is called "loading" the antenna, and it's a combination of adjusting the diameters of the elements and adding certain fixed components in that tend to create a spiral path for the electric current to travel down. As it does so it creates very rapidly changing magnetic fields, that if you get it just right, they kind of speed the electrons on their way just at the right moment and then at the other moment they slow them down, like putting the brake on.

Holding_without_handle_view_-_300wThat part is the little lumpy but really cool looking thing you see now on each of the elements that a normal full size yagi doesn't have. It took a lot of time to design that in such a way that it'd have the right performance and allow the elements to be shortened just the right amount, be structurally sound and rugged and the biggest parameter of all that you have to be careful about is that it's easy when you shorten these antenna element lengths to lose a lot of the efficiency in the antenna itself through certain kinds of electrical losses that occur. The nature of a shortened antenna element is that it involves much higher currents flowing along with much lower voltages. And the result is that these higher currents tend to be dissipated in resistive loss or well just loss as they travel along the elements, and especially this little helical loading element that we created. So it's very important to design that with just the right shape, the right material on the inside, and the right type of metal. All these factors come together to make it a "low-loss loading component." And if you don't do it right, your shortened the antenna will be much worse than the full size antenna.


It's that challenge that probably makes it so that loaded yagi are not so commonly seen, as you look around. Even with HAMs (Amatuer Radio enthusiasts), when you look at their yagi antennas and you see these big lumped elements, those are usually not loading coils, they are called traps. They have a different function which is to make the antenna elements assume various different lengths depending on what frequency of energy is fed into it.

I find it interesting that inductively loading yagi antennas I don't see that in the published antenna work very frequently or in practice as I drive around cities, I see all kinds of yagi antennas, but I rarely see this. You see in in the vertical roof top antennas. But is is a challenge to do it just right, and not make it actually worse."

(To read the complete interview, click here)




General: Dual conversion, superheterodyne, synthesized receiver

Dimensions: Height 2 inches, width 3 inches, Length 14 inches

Weight: 2 pounds

Frequency Range:

1 MHz within either of the following ranges:

150.790152.490 MHz

173.300173.999 MHz

1 or 4 MHz within one of the following ranges:

216.000219.999 MHz

232.300237.999 MHz

432.000 435.999 MHz

Fine Tuning: +/- 1.3 KHz continuously variable w/ analog control

Center Frequency Variation relative to Specified Frequency: Less than +/- .5 KHz.

Long Term Frequency Drift: .2 KHz

Power Supply: 12-14 VDC through external power jack. 9V (internal, using six AAA batteries)

RF Impedance: 50 ohms

Sensitivity: Typical minimum discernable input level: -150 dBm. Input level for 10 dB S+N+D/N –131 dB maximum. Noise Figure: 2.5 dB typical with 50 ohm source.

Image Rejection: > 45 dB

Spurious Emissions: < .2 nW



Beam Width: 38 Degree 3dB Down Point

Gain: 6 dBd

Front to Back Ratio: 14 dB

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Model Frequency Band
Price with discount 650.00£
Sales price 650.00£
Sales price without tax 650.00£