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Author Topic: Hughes PRC-104- new ham user  (Read 9120 times)

Posts: 22

« on: August 12, 2012, 07:41:45 AM »

Good morning gents,
 First to start off with, Im a new operator, waiting for my callsign to show in the ULS (took my exam and passed technician yesterday, missed general by two questions) Ive been doing radio work for the Navy and Marine corps for 12 years now.
Ok my question is this- I have an old Hughes PRC-104 HF field radio, works great (Ive hooked it up to our test equipment Ive got at work, passed all the maintanance checks I could find)
Are these radios good for the amatuer operator? Ive used them before, but since Im new to the amatuer world, what do you guys think?
I know most new operators start out with VHF/UHF HT's, but Im alot more comfortable with good old fashioned HF lol.

Posts: 153

« Reply #1 on: August 12, 2012, 07:55:21 AM »

Just bear in mind that the PRC104 uses a number of integrated circuits that were manufactured by Plessey Semiconductors in the UK until 1996, and they are no longer available. Even the company called Plessey Semiconductors - which is a totally different company - doesn't have the designs any more. A few of the parts are in various stockists, provided you have access to Fort Knox, because that's what you'll need to buy them! Beware any offers of those parts from the Far East.

I was the Applications Engineer for those parts......

For ham use, the real problem is that it's not easy to tune the band with that form of synthesiser.


Peter G3RZP

Posts: 3160

« Reply #2 on: August 12, 2012, 09:46:40 AM »

USA Amateur Radio Feequency Allocations

As a Technician class, HF phone usage is limited to 10 meters.
 You also have RTTY and data privileges on 10 meters.
CW usage permitted on the old Novice HF bands: 80, 40, and 15 meters.
« Last Edit: August 12, 2012, 09:50:32 AM by W9GB » Logged

Posts: 22

« Reply #3 on: August 12, 2012, 07:44:04 PM »

 If you dont mind me asking a dumb newbie question, why exactly are they difficult to tune for ham use? Granted in the military, we were given our day/night/alternate freqs, but is it because its single digit tuning? Are you refering to that?
Thanks for putting up with a relative new guy..
One a different note, does anyone make a good backpack rugged field transceiver? Ive seen the youkits TJ4a, and the elecraft line, but Im worried about moisture and wet conditions. Im hard on equipment, which is why I usually try to get mil-spec stuff (not to mention I use it at work, and know the radios inside and out.. plus having the test equipment and maintanance books on hand is a boone)
Thanks guys.

And yes, I know Im only authorized a certain frequency range in the HF spectrum with my tech license, which is why Im now studying for general. Thanks guys!!

Posts: 17476

« Reply #4 on: August 12, 2012, 09:39:38 PM »

The Santa Barbara (California) ARES group had a couple of donated PRC-104s that we used in the Field.
(They were actually demo models, and it was discovered that they weren't as waterproof as the production
model when a salesman demonstrated one by tossing it into a palace fountain.  The company shifted to
full-spec demo units after that.)

Yes, the biggest problem for ham use that I found was the tuning:  it is fine for setting a sked on a specific
frequency, but "tuning the band" listening for signals was a royal pain.  Each digit only tunes upwards, so
if you happen to tune past a signal, you can't easily go back to tune it in without incrementing the digits
all the way up to 9, 0, and back up again.  Not too bad if you are the one calling CQ and letting others
tune to your frequency, but not necessarily the other way around.  Really the only option is to tune up
the band in 1 kHz steps.  (10kHz is too wide to hear all the signals.)  That's a lot of button pushing to
span 100kHz, plus, if you go past the station, you may have to run through the 1kHz and 100Hz button
sequence and extra time or two to get them tuned in properly.

Power supply voltages were a bit difficult for mobile work - I think they take something like 18 to 32VDC?
That requires some sort of switching converter to run from a car battery.   (Using a gel cell that is
charged from the car batter, then switched in series to power the rig is one approach.)  If you have access
to the original rechargeable batteries, great, but we looked at various ways to use D-cells or lead gel batteries
and there didn't seem to be an inexpensive solution.  (The current draw on transmit is too much for D-sized
alkaline cells soldered together, and the NiCad cells of the day didn't give a lot of capacity.  NiMH or Lithium
would be better.)

We would have liked the rig to cover 160m, as it is an important backup band for emergency communications
at night during periods of low sunspots.  The PRC-104 only goes down to 2 MHz:  in an emergency you could
try running LSB there and hope you could keep enough of your modulation sidebands inside the edge that
you didn't attract unwanted attention.

The NVIS antenna kit that is often used with it isn't very efficient on 80m because it was required to work
up to 12 MHz, which limited the element lengths.  Wire dipoles for 40m and 80m (and 60m if desired) are a
much better choice:  you'll rarely if ever be using NVIS above 40m as a ham.

Other than that, it was a fun rig to play with.  I had a 6' helical mobile whip for 40m that made a convenient
"rubber ducky" for 40m and 80m, though the efficiency was, of course, terrible; and the whip antennas of any
sort weren't useful for local work beyond a few miles.   With a full-sized dipole, or an appropriate end-fed
wire, they worked pretty well.

But I certainly wouldn't want to trade in my old Argonaut 505, or my new K2, for one as a portable rig, even
for the improved dial calibration, higher output power, and built-in antenna tuner.  There are just to many times
that I want to tune though the band to find signals.  If I always hung out on the HF-PACK frequency, it might
be different.  Besides, I don't generally need a ham rig that is waterproof to 10m:  I've operated Field Day in
a rainstorm, with the Argonaut in a plastic garbage bag and the antenna tuner under a fiberglass hard hat.  I've
also hauled rigs half way around the world in my backpack, including Australia, Alaska, New Zealand and
Hawaii, and weather proofing has never been a problem that wrapping them in a plastic bag can't solve.
And, if I do need something better, I'll pack them in a large Tupperware container, as I did with my camera
that ended up floating in salt water in the bottom of a canoe with no damage.

Posts: 3289

« Reply #5 on: August 12, 2012, 11:01:28 PM »

You couldn't pay me to use a military radio as a main rig.   Even the bottom of the line ham rigs have so many features that make them easier and more comfortable to use.

Military radios are a pain in the neck to tune, typically have no AGC, have no filters, no IF shift, no auto select for USB/LSB if they even have LSB, audio quality is atrocious for both TX and Rx.  Batteries /power can be expensive or a pain in the neck.  Connectors can often run over $100.  Repairs are unlikely if anything goes wrong.  I've used them in the service and as a contractor.

If you got a radio for free great.  If you are into military radios as an interest super. I would never recommend them to a new ham as a rig.   bill

Posts: 153

« Reply #6 on: August 13, 2012, 03:55:46 AM »

I guess WB6BYU and KB4QAA have answered the questions pretty thoroughly. There's not only the PRC104 that has no spare ICs available since Plessey went out of the business - the original ITT SINGCARS and Magnavox's HaveQuick are the same. Unless somewhere the DoD have some stocks, but the equipments have all been obsoleted by now I would think.

There is a following in the UK for using the old Clansman equipment: that has the same problems with spare ICs. Not helped by the fact that when Plessey stopped their gold doped process in 1981 and there was a last time buy by the Ministry, the ICs went into one warehouse - which burned down a few years later!

Posts: 4464

« Reply #7 on: August 13, 2012, 04:05:12 AM »

I took a quick look at the docs on BAMA and as best I can tell the basic radio has an audio output level of 5 mW. No typo, five miliwatts. It uses a telephone handset for the mic and speaker. There is an optional outboard amplifier with loudspeaker. Without one the radio will need a little help as far as operator convenience goes.

Unless you don't mind holding the handset to your ear.     Tongue

The end of the world will occur on April 23, 2018 ( the day after Earth Day. Go Figure ).  If you're reading this on April 24th look for updates coming soon.  If you're reading this after June first, fuhgedaboudit.....

Posts: 22

« Reply #8 on: August 13, 2012, 06:24:36 AM »

The one I have has an LS-474 loudspeaker that came with it (They work really well, pretty loud on the 104, REALLY loud on the Harris PRC-117)
Thanks for all the input guys, I appreciate the info. Oh- my callsign showed up on the ULS this morning, so its time to play hahahaha.

Too bad my HT's rubber ducky cant hit the local repeater from the backside of Belvoir... Oh well, upgrade time!!!

Posts: 491

« Reply #9 on: August 14, 2012, 08:28:26 AM »

Congratulations and you're giong to have a blasy on ham. One the upgrade to genera, having only missed it by two questions on your first attempt, you'l do fine no the next one.

I use to use a PRC-74B, which for operations purposes shared many of the same difficulties of military manpack.  It was a blast, built like a tank (Duh! ha ha) but the main factor is that it is essentially a channelized set - no 'knob' to tune-up around, looking to see who's on the air. This makes sense for the boots-on-the-ground operator who has certain, specific frequencies to operate on , but not for 'we hams' (you included - btw!) who routinely turne through entire bands, listening for contacts.

Another factor was that may of the manpack sets from that era were set-up to work with the AN-GRA-71 'burst keyer' that sent high speed Morse burst at ~300 WPM to avoid radio direction finding.  The reasn that this was a problem was that the Morse CW sidetone on many of these sets is a very HIGH tone, so that, when slowed down, it would still be readable by ear.  Tachnology has left this behind, but I know from experience that sending/receiving CW with a 2,000Hz side tone is a pain.  The usual freq range for a side tone is between 500 - 750 Hz: whatever is comfortable for the individual.

However, you can have a LOT of fun with the PRC-104, and that's really a very good thing.  It would be fine for PSK-31 and other digital modes & portable at that, skeds on a fixe frequency or where yuo can slew-up and down that final few 1 KHz or so.  It's not nearly as conveinent, but it's entirely do-able and in fact, there are military collector's nest that operate on USB only (because many vintage radios had no LSB to avoid operator confusion) and your -104 would feel right at home. I kept skeds from all over using my PCR-74B and your -104 can do this and more, I am sure.
I can't remember whether the -104 does LSB, but if it does, there are several FIXED freq nets in this area that you can monitor now, and operate in later, when you have your general.  The Virginia phone net and several others are on 3947USB daily, on forty there is the 7272 Chew (7272LSB) during the afternoons.  No problem at all for net operations on a fixed freq.

As for the IC's, well, as a friend says: 'Ya pays yer money and ya takes yer chances'".  You might experience a catstrophic failure in 5 minutes, or it might run for the next 100 years - we really don't know. It sounds like you're a technical person, so you know how that goes.

#1 - if you have it, use it . Go forth and conquer!

73 & 'See' You On The Radio de Ray
W7ASA ..._ ._

Ps. I used to a lot of contract work on the 'backside' at Belviour too...

Posts: 491

« Reply #10 on: August 14, 2012, 11:05:31 AM »

Note to self: Never write a post to a forum when you're on pain pills... 
Sorry for all of the typos above.  Knee injury and heavy pain meds = silly writing.

SRI de Ray
W7ASA ..._ ._

Posts: 3289

« Reply #11 on: August 14, 2012, 10:01:35 PM »

Thats OK Ray, we had a "blasy" reading your post!  Smiley
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