help me design a radio shelter

[maddawg308]

Project for next year is to build and design a S-280 radio shelter that would be my ham shack, that could be a semi-permanent emplacement here, but could also be mounted in the future to a M923/5 series truck for bringing to shows so I could run my ham gear on site. It will also be a camper (radios and bench on one side, two bunks and storage on the other).

Was interested in hearing your opinions on what radios should be in the radio shelter, based on the needs that I would like to fill:

1. I'd prefer many of the radios to be military rack mount type, but will substitute regular military radios, or commercial radios, if no suitable rack mount mil-spec radios exist for the task (or are too expensive for most buyers)

2. RX coverage must be full spectrum, from VLF to microwave.

3. TX coverage must be most of the common ham bands, to include: 160 meters, 80 m, 40m, 20m, 15m, 12m, 10m, 6m, 2m, 70cm, and 33cm. There are a few in there that I didn't cover, but these are the ones I would like coverage on.

4. No data/RTTY is needed for the installation at this time - if I decide to do that later, I can always install a rack-mount computer PC and have the data run through that to RX/TX, to eliminate the need for a stand-alone teletype, etc.

5. Power supply? I'd like the capability to run at least one TX and one RX at one time, with 100% redundancy. Output would be 100 watts minimum average TX, but possibly up to legal max of 1KW if required.

6. Computer - I'd like to install a rack-mount PC in there, along with a suitable monitor. Some rack mount jobs are expensive, so I'd like some input of how I can make it work, without having to win the lottery.

7. Antenna types would be dependent on the capabilities of the radios, but I would like input as to what antennas you feel would be able to cover the maximum number of bands, so I don't need 100 antennas around the shelter.

8. Vintage of the radios and gear, I would like to be late 1950s to 1980s. Any newer and cost is prohibitive, or radios are too rare. Any older and the radios have issues such as lack of selectivity, drifting or RF leaking issues, obsolete parts availability, etc.

Thanks for your help and opinions.

 

[nf6x]

I have to get ready for work now, but your new project definitely interests me! I'll be thinking about it, and maybe I will be able to offer some useful suggestions.

 

[SCSG-G4]

Mike,

I think you will get better responses from the Yahoo Groups - armyradios, milpack, prc77radio, and similar focused groups. There is a LOT more radio experience there than here. Boatanchors migrated to the Yahoo Groups platform. Those folks own vehicles as accessories to their radios, This forum puts radios in our vehicles as accessories. Whole different mindset!

 

[maddawg308]

I'll poke them too, just wanted to see if anyone here, maybe OPCOM or another commo expert, could weigh in. Remember, if I don't ask, there is never an answer.

 

[RGS20inophir]

I would go with some used civy radios. They often have more features than their green counterparts, especially in the bands we operate in. I have been impressed with the FT-897D, It is **** for stout and you can build a tuner so you can load anything from a piece of wire to an insulate d tower. You would also be amazed how well a barbed wire fence can load... I have also really liked my TMD-700, if you don't need the TNC just find a TMD-710A off of fleabay. If you are looking for a **** for stout portable try the VX-7/8 series. DC to daylight RX coverage and great 6m, 220, 2m, and 70cm coverage. For the 70cm and 2m stuff, just make your own dual band Jpole and put it in a piece of PVC pipe. Can be done for a few bucks with a type N bulkhead mount on a PVC end cap.

 

[quickfarms]

Interesting project

 

[Recon Charlie Alpha]

Comm goals?

Your biggest limitation will be antenna size and placement.

Some random thoughts;

Tuners are a trade off but sometimes cant be avoided.

With an autotuner, you can make a cheep CB whip work on 6 and 10 meters.

Get an antenna analyzer, it will help a ton. You can roll your own much easier with one.

Mil radios are about twice to three times as expensive as civy ham riadios., but not always, you have to shop hard and really know what you are looking at.

Many military radios and antenna cover 6 meters quite easily, but 6 meters range is limited ( see goals question) Still it may be your biggest bang for the military buck, as the antenna ( AS3900?) has switchable matching coils so you can go 6 meters or the mil freqs, using, say an RT524 radio
,the antenna and radio of course will have that mil look and feel while you can stil xmit on 6 meters. And the cost for anteanna and radio isnt too insane, unlike SINCGARS RT1523.


2 meter radios are reallly cheep, amps are reasonable up to 300 watts and a 1/4 wave antenna, mag mounted to your shelter ( metal exterior?) will give you excellent range, only bettered by a 2 meter Yagi.

Metal directly under a yagi has a big negative impact on performance, but a vertical loves it.

You just wont be able to do much on 160 meters other than NVIS, but there are surplus mil NVIS kits around or you can make your own. None of them are, of course, mobile.....

Some mobile HF antennas like the Hi-Q (screwdriver antenna) are pretty pricey, very compact and military looking, but have very large performance trade offs. Still, you can talk state to state, or coast to coast on a good day on 20 or 40 meters barefoot.

Also, for a mobile , stop and set it up, antenna, BuddiPole works....OK....lots of trade off there but it works, its compact and you can talk cross country ( continental US) with it

Radios

Agree with prev poster, Yaesu FT897D or 857D all mode radios pack a punch in a small package. 897D may be rack mount-able.

However, you can get racks that will mount most anything including desktop HF radios like the 897d or better still for HF, the FT950 (dc power)with built in tuner.

For a rack mount PC you can spend the bucks for a rack mount "server" or just rack mount a tower using a rack made for that.

How about keeping the rack cool? With all the gear hummming along there will be heat......and RF from the radios

If you are going to have an amp to get to legal limit (1500W) youll need shore power (or a MEP017A and a power cleaner) and a good ground system.

Also, you want to be careful running legal limit if your antennas are mounted on the shelter....., youll far exceed FCC MPE limits for RF exposure, unless the shelter is all metal exterior and well grounded....to the earth ground....you have some RF design things to think about on your set-up Also maybe some lighting and static discharge issues, depending on where you live and time of year, so a good earth ground system maybe a design consideration.

Why no data? You can communicate over a greater distance with less power using a data mode ( PSK31 or Olicia, etc,etc) than with SSB voice. CW is also an option (better than SSB voice) and you can use your PC for xmit / rec, if your CW is not quite up to speed.


Hope to see some pics as your project progresses....

 

[maddawg308]

Lots of good info, Alpha, thanks!

I hear the "civvy radios are better" opinion. And to some degree, on some bands you're right - especially 2 meters and it's surrounding regions. However, I've found military radios to be more rugged (I've beat them around moving them and they took it in stride, try that with a Yaesu), plus the overall theme of this build is such I would just prefer it. I realize I'd be losing some features that modern civilian ham radios have, like notch filters and DSP, but that's a trade off. Perhaps I can have a few more civvy radios in there for redundancy and ease of use.

No data at this point because a.I'm not too enthused with RTTY as a mode, just not my thing, and b. I cannot do CW yet. I guess I'll have to just keep studying the code for a while.

What, no mil radio recommendations?

 

[135gmc]

Recon is right - unless you're careful, you'll be inside a microwave oven. The good news is that the S280 is already designed for RF, and I think that you can add RF fingers to the door weatherstriping (like the S250). You might want to pick up some DANGER flagging tape so visitors will keep a safe distance away when you're running high power. Regarding power - you'll need a generator with some vitamins, but you could probably get by with a marine inverter for backup power.

 

[SCSG-G4]

Most HAM's I know switched to using a PC for CW about 20 years ago. They had DOS programs that would translate their typing into code on the outgoing side, and reverse the process for received signals. That's one of the main reasons that code was dropped from the General and Tech licenses.

Most Mil Radios are not going to have the power you specified - the majority runs 30-50 watts output max because they did not want to 'run over' adjacent units on the frequencies. Do you already have the racks? I still have some I took out of my S-280 that have not gone to the scrapper. Pm me if you want pictures.

 

[swbradley1]

I have purchased rack mount computers off of flea bay pretty cheap. If you don't need 32 processors and 64Gb of RAM I doubt you'll spend much. I just threw one away this year. Yes, it still worked along with a $50k network switch that worked as well. Crap builds up and I wanted it all out of my home office.

 

[swbradley1]

Just found several RM PCs on flea bay $79 and up it looks like.

 

[Recon Charlie Alpha]

Sorry, your right I didn’t provide any mil recommendations, lost my mind...here are some.

To digress a moment, that ham radios are tender in nature is a misnomer. I use my FT857D as a manpack radio for “mountain topping” and while the radio shell itself was not ruggedized, doing so was pretty easy……..I also use my FTM10SR and VX7R hts, both ruggedized straight from the factory…….…but, the idea here is to build out with mil radios………., I get that and think it would be a very cool build out!

Now, back to our program.......

The radios used at the squad level, as “manpacks”, like the PRC-25, PRC-77, and PRC-1177 are all low power units and only have a freq range around 6 meters (30 to 90 mghz).

Mobile is probably where you want to start looking. Right around 1980 there was a changeover to freq hopping radios, so the pre-hoppers are around, available and still in use by other countrys.

PRC-104 (2 thru 30 mghz) manpack but mobile config is PRC-104= RT-1209/ URC, AM6874/PRC-104 amp coupler, AM7152 audio amp, power conditioner, squelch circuit.

PRC-117 ( RF3090) w/50watt amp, freq ranges are 30-90mghz, 118-174 mghz, 225-420 mghz

PRC-2000 ( versatile manpack radio, often vehicle mounted) all HF freqs, but only 20 watts, 400 watts with a BA1358 amp, 100 watts with the BA1385 amp

GRC-106 (RT-662 w/AM-3349 amp) 400 watts

GRC-193 consisting of CU-2064 antenna coupler, AM5545A power amp,AM-6879/urc amp converter, RTC1209/urc receiver / transmitter

Then there are the rack mount radios ( most are made by Harris)

RF-4000 series = RF-4040 transciever ( 2 to 30 mghz), RF4030 400 watt amp, RF-4031 antenna coupler ( highly recommended!!) If you can get your hands on one , this is what you are looking for hands down. It tunes up on a flippin coat hanger, no joke…..

RF-5022 w/125 watt amp ( Harris RF-5000 series)

RT7000 that is 125watts out of the box and has an option to go up to 5KW. ( illegal for civvy use)

You could use a ham amp with the RT7000 as the freqs (1.6 thru 30 mghz) line up well and I think ACOM has a rack mount version.

“Pacer Bounce” URC-119 rack mounted system (1.6 thru 30 mghz) 100/500/1kw configs. 500 watt config consisting of RT-1466 transciever, cu-2310 antenna coupler, AM-7223 amp.

W7RCA clear............

 

[Recon Charlie Alpha]

doh!

 

[tennmogger]

Probably the best buy in full coverage HF radio right now is British Clansman RT-320, aka, PRC-320. Rx and Tx from 2 MHz to 30 MHz, USB only but there are conversions available to add LSB (for 75 and 40m). Lots of accessories available too. This is not a rack radio but could be bracketed to rack mount. Output is 3W or 30W. Consider a solid state amp like RM Italy HLA-300 to make a great combination good for up to 300W, if you really need that power... The Prc-320 also does AM so you can 'listen' on CB. Antenna tuner is internal but manual.

I really like PRC-174 (Israeli). It covers 2 to 30, LSB and USB, and AM, and CW narrow and wide. Has built in autotuner for antenna. 20 w out, ditto HLA-300 amp.

Bob WB4ETT

 

[uscgmatt]

I am trying to do what you are Mike but backwards. I'm in the process of mounting a 40 foot crank up tower, and an mep-002a to a m200a1 trailer. When thats done its time for an
s-280 to build.

 

[maddawg308]

Recon Charlie Alpha - thanks for the input. Some of those milpack radios are very expensive for what you get, and most are not rack mounted. But there are a few good ones in there. The GRC-106 is probably one of the better ones that I would use, for 2-30 MHz TX and RX. However, it's USB and I'll need to probably utilize a SB converter to use it on LSB. But that's an option.

For VLF receiving, I'd prefer the Collin-designed R-389.

For HF receiving, I'd prefer to install my R-390A that I already own. There is no RX better on Earth, IMHO, than the -390A

GRR-23 receiver - 116-150 MHz
GRR-24 receiver - 225-400 MHz

The GRT-21 and -22 transmitters to match the above series receivers would not be suitable since they are AM only over the above bands of 116-150 to 225-400 MHz.

RT-524 - RX and TX for 30-75 MHz covering the 6-meter band.

 

[uscgmatt]

GRR-23 receiver - 116-150 MHz
GRR-24 receiver - 225-400 MHz

The GRT-21 and -22 transmitters to match the above series receivers would not be suitable since they are AM only over the above bands of 116-150 to 225-400 MHz.

The only problem with these is they are crystal units, you need a crystal for every freq you want. I have a complete vhf and uhf set plus the 50w amps. All they are doing is giving my house ballast. The crystals have to be custom made, or you can get a tuning unit to replace the crystal setup from Columbia electronics for a low 1295.00ea, and you only need 4 .

 

[OKCM38CDN]

While I was in the Air Force, I was in the 3rd Combat Comm group and took my personal radios with me on deployments... I carried a Kenwood TS-440S/AT and a Cushcraft R7 vertical antenna... Operated as KG4HM in 1992 and made over 1250 Q's with that set up running 100W...

The radio is a fixed / mobie rig with a built in antenna tuner, will do 1.8 to 30Mhz if you clip diode 80 on the control board (I did this to operate MARS). The antenna is a 7 band verticle with 3 ft whips for counterpoise... operates all ham bands from 40 to 10 meters includig WARC... worked great for me at 12 feet off the ground...

The radio also has connections for a PC if you want to go that way, I use a PC for logging and other modes than RTTY,; low power PSK31 is a great mode when camping and such...

I have two RT-68 radios and a PRC-10 with the AN-598 amp but those rigs are heavy and are not as versitle as the civilian rigs... use mobiles and mount them under a shelf on the work bench... rack mounted equipment is great, but when it comes time to clean the rack, good luck... When I came home from the first gulf war, we had to clean (use high pressure air) the shelters 3 times just to get to the point of being able to vacumme the dust to see the racks...

With Rack mounted equipment you are going to need dedicated fans to keep the racks cool and all the dust will settle in the racks. So be prepaed to take every thijng out to clean it regularly...

This is my opinion, I like what you are doing and have thought about it my self... Also if you do have a proper S-280 shelter you can tow it using a M-720 mobilizer and get away with more... a M-35 will tow the shelter with no problems, then you could load a MEP-003 in the truck and have plenty of power for anything...

Hope it works out for you...

Hal, KB1ZQ
TSgt USAF (Ret)

 

[Aswayze]

I have a commo shelter that I put together to use at East Wind. Nothing as fancy as what you guys are wanting to do, just a simple VRC-12 and VRC-64 setup with retrans and a spot to stick the SB-22. I’ve got the trusty old SIAC V2LC (monochrome of course) in there and will be adding in a UCG-74 teletypewriter as well. The big reason I wanted to set all this up was to save myself set up time at my event. I waste an inordinate amount of time setting up the comms system and having everything needed to run the a company sized unit stuffed into a box means that I can focus on making a better experience for attendees instead of running all over the place stringing wire for the first day. I only use 6 meter and wire line stuff for East Wind so using all .mil stuff is easier.

My shelter was pretty empty when I got it so I ended up having to fab up most of the inside stuff. I made the quarter bins out of some 3/16 aluminum plate and used unistrut to lay out the front frame with again 3/16 aluminum for table and shelf tops. There are HUNDREDS of rivets to drive if you do it this way…


Anyhow, here’s a few pics. Nothing like what you guys want to do but it might give you a few ideas.