Hammo Can PART III

Oh yeah, we're gonna build a 10 meter one! What's really scary is that this doesn't have SSB or CW capability.

The Why Box

10 meters behaves much like the CB radio band. They're only 1MHz away from one another yet they both are daytime skip bands. One is license free (questionable on power restriction), the other is license-bound and has an insanely higher power limit. 

Today though, I'm building The Why Box, and I'll explain why.

The Why Box is a 10 meter portable station. It has a claimed maximum power output of 8 watts and has AM and FM modulation on it. In my tests, FM has the option of 2.5, 5, and 10 watts whereas AM is only useable with 100% modulation on the low power setting of 2.5 watts. Any higher and the modulation limiter kicks in and drops modulation levels to less than 50 or 60%.

BUT NO SSB???

Yep. No SSB. Which is why it's called The Why Box. Because why would you have a 10 meter station with only AM and FM?

Because I can and I will. I'm a ham, a general class at that. I want to experiment and see if this could actually work in making a QSO. And because building these boxes is so much fun!

The Radio

The radio of my choosing is (obviously) the AnyTone Smart 10 radio. These are sold for $60 on Amazon and look just like a mini CB radio. Most folks convert these (illegally) to the CB bands or other unauthorized HF bands but I'm keeping mine stock on 10 meters.

This radio does feature the full 28.0 - 29.7MHz 10 meter band, however I'm only interested in the top band portions. Since this radio doesn't do SSB (it does CW but it's somewhat slow if you key the PTT in AM mode and lacks any logical injection point for a BFO), over half of the bands in this radio are useless.

This radio also does not come with CTCSS/DCS signaling capabilities or repeater splits, meaning that this will be simplex only. No problem, because 10 meters has plenty of room for simplex.

Speaking Simplex

There are a few things you should know when using this radio:

29.000 is the AM simplex calling frequency.

29.600 is the FM simplex calling frequency.

Bands HF through HI on this radio provide 140 channels that go from 29.0 - 29.695MHz.

The ARRL's published band plan is good, however it only limits FM simplex to one frequency. AM can operate between 29.0 to 29.200MHz - 200KHz for bandwidth. FM's simplex, if you follow the band plan, is 0KHz.

If we look at the surrounding frequencies, I don't see why you couldn't use any of the FM repeater frequencies in simplex mode. You don't have CTCSS capabilities so you can't access repeaters anyway. But if the frequency is clear? Call CQ.

The satellite sub-band of 29.3 - 29.5MHz could also be used for FM. There are literally no satellites that I know of that are still in orbit that use 10 meters. Maybe AO-7, but if I recall correctly that's just telemetry and only has about a 5 to 10 minute pass time.

For those of you wondering, yes, you can make DX contacts talking on 10 meter AM or FM. It's rare because most are using SSB. Most 10 meter simplexing is limited to local, regional, and nationwide most of the time when the band's open. This is what I'm hoping for at least, and even if I just reach Kansas or Iowa, I'll still call that a win. I remember reaching Italy on 15 meters using 10 watts SSB - amazing. In an emergency, I'll need to communicate with the four-state area anyway.

For all intents and purposes, ground wave propagation for 10 meters is limited to about 15 miles or less.

Repeaters would get me farther but alas, this radio has its limits and there aren't really any in the Midwest.

Other Radio Options

The AnyTone is built on a chassis that many mini Chinese radios follow. Below are some compatible radios that I've researched and determined that you can put in this box:

• Cobra 19 Mini (CB)
• AnyTone SMT02 (10M)
• Retevis RT98 (VHF or UHF)
• Radioddity CB27 (CB)
• Anysecu CB40M (CB)
• Anysecu CB925 (CB)
• AnyTone Smart CB (CB)
• Luiton LT310SDR (The newest micro SSB CB radio!)
• President Bill II or III (CB + WX band)

And many more in the same chassis!

Specs

The AnyTone SMT02, in my testing, has the following specs:

Some pretty impressive numbers actually. With this in mind, I'd expect the radio system to run for a few days, even on a 5Ah battery. 0.2A on receive is a very conservative number - I'd go with around 0.1 to 0.12A for a real-life estimate.

Keep in mind, AM is best used when the radio is in low power mode. This allows the radio to swing up to 100% modulation without any AMC limiting (10 watts PEP). In medium and high power, I couldn't get the radio to swing beyond 40 or 60% and it probably sounds terrible. In FM, all 3 power modes output their full-specified ratings (of course, as FM is frequency-dependent, not amplitude). Not quite the 16 watts it's rated for, but I am not complaining at all! 10 watts will do just fine. There is an adjustment potentiometer in here but I'm not opening this radio unless I have to.

A lot of people have wondered whether this will get hot enough to cook a hot dog on high power. The answer? Not really. Yes, it does get warm, but it's not warm enough to start cooking your midday lunch. However, I'd recommend you build this box like I have with a larger recess above the radio for air flow (and mic + coax storage when not in use). If desired, you COULD put a fan in but I found it to be not necessary. That might also introduce unnecessary current draw as well.

Here are some pictures of my box:

PERFECT FIT. And as a bonus I've added a US-flagged Bearcat paw to the front of this radio. 

Now if you're tight on money, you can always build just one of these boxes and swap out radios depending upon what band you want to operate on.

That's all folks, but stick around for the 50 caliber version where I attempt to stick the TK705 in it!