The ultimate HF/VHF backpack rig!
The PRC-138 is probably the most sophisticated HF/VHF man pack rig that will ever fall into the hands of a civilian. Why? The successor (PRC-150) has built in encryption that is strong enough to be considered a Munition by the government. As such, PRC-150 rigs will probably go to the crusher when they quit working or are replaced. Sad..
Anyway, the PRC-138 encryption was an option and easily removed -- so these units are available as surplus.
And, what a unit it is! The PRC-138 has:
- ALE - Automatic Link Establishment, Mil Std 188-141A
- Frequency Hopping
- Digital Voice Capability
- Mil Std 110A and RTTY Data Modem
- Internal Antenna Tuning Unit
- Operates from 1.6 mHz to 60 mHz
All this in a lightweight package that runs on batteries and fits in a backpack! It's truly a tour-de-force, an engineering marvel.
From the Harris marketing literature, here's what it looks like:
ALE - Automatic Link Establishment
ALE can automatically establish communications with other stations on the best available authorized frequency. The ALE system chooses the best available channel based on Link Quality assessments -- which take into account station facilities (antennas, power levels, etc.) as well as propagation. Very cool stuff, great for MARS and EMCOMM.
Frequency Hopping on HF ham bands? I think the current restriction is that you need to be running 10 watts or less. But, look it up for yourself -- it's in the FCC regs. Frequency Hopping would allow you to pick a center channel frequency and the hopping algorithm will select a set of nearby frequencies for you. Then you and your similarly equipped mates can chat to your heart's content and very few people will be able to eavesdrop on the conversation. They probably won't even know you're there!
Digital Voice on the ham bands? I dunno; look up the Rules and Regs. Digital voice would allow you to converse in near total privacy! Share your Top Secret fishing hole information! Go wild!
Mil Std 110A Data Modem
Mil Std 110A data mode isn't used much on the ham bands which is a pity -- it's an extremely robust HF radio data protocol. It is, however, used extensively by the military and by MARS. And the PRC-138 has it built in! No need for an external modem.
Internal Antenna Tuning Unit
The internal antenna coupler has matched everything I've thrown at it -- even on ALE and in Frequency Hopping modes. And, it's in-line all the time so it will tune a whip or a coax fed dipole or whatever. Put up your antenna and forget about it. The internal coupler just deals with it, you don't have to even think about it.
Enough of this chatter. Here's mine:
Clockwise from the left:
- The Harris backpack
- The (unobtanium) Harris data cable
- A NOS set of Saft (non-rechargeable) batteries
- An extra battery box (one is attached to the radio in this pic)
- An H-250 military handset
- The (unobtanium) Harris Intermediate Maintenance Manual (about 2" thick)
- The (unobtanium) Harris Operator Manual (about 1.5" thick)
- And, finally, in the center is the PRC-138 itself.
Here's the whole enchilada with the rig itself in the backpack:
Here's the Harris backpack:
Here's the Harris data cable. Try to find one of these on the open market!
Below is a picture of the Saft batteries. These are labeled:
- BATTERY, NON-RECHARGEABLE
- LITHIUM SULFER DIOXIDE
They're NOS (still in the factory plastic wrapper) and typically last me through a weekend. A rechargeable battery pack would be a smart move - I just havent' gotten around to it yet.
Here's the extra battery box. I had planned to build a 120VAC supply into this like I did for my PRC-2000.
Here's the H-250 handset:
Here's the essentially unobtanium Harris Intermediate Maintenance Manual:
Here's the essentially unobtanium Harris Operations Manual:
Here's the left side of the PRC-138 Face:
Here's the right side of the PRC-138 Face:
Here's the view from the top:
And here's the ever so important result of the internal self test:
So, there you have it! A PRC-138 with backpack, data cable, a set of NOS batteries, a spare battery box, an H-250 handset and the actual Harris Maintenance and Operation manuals. You will be hard pressed to find a nicer setup. The only item not included is a whip antenna. I don't have one; I've always used this rig on antennas thrown into a tree or my main station antennas.
The PRC-138. It's the ultimate backpack rig but I sold it in 2012...