Elecraft T1 Tuner Repair

I've been kind of "radio inactive" whilst sorting out a few things over the last 3 years or so. First time operating in quite a while was back in October up in the Fish lake National forest with my sons. Just prior to leaving, I visited my buddy Chuck to run my gear through its paces. We hooked up my T1 QRP tuner (actually a max of 20 watts) to his FT-897 and my PRC74 military radio whip antenna. I keyed an AM carrier, pressed the tune switch and man--that old military whip tuned up in about 1.5 seconds. Well, that's what I thought... In actuality, I either hit it with too much RF (might have turned down the wrong power settings on the 897) or the tuner just hadn't been used in a long while... Regardless, I fried two diodes. They are barely visible on either side of the right-most torroid on the bottom of this photo. Small blue components aligned horizontally in this snap.

I looked all over and found replacement diodes at Mouser. Ironically, they are fifty cents each, and shipping is $6 (and it's no wonder--my two diodes were shipped in a mid-sized cardboard box!).

I've been stabbing away at desoldering these diodes, but no joy. I'm taking them to my buddy's. He's got a beautiful desoldering station (no joke--I seem to use it a lot). This repair should go quickly! Along wth testing my PFR, we're doing the repair in the next couple days. Hopefully my next post will be of a successful tuning sequence with my 817 and his Gap Titan antenna.

By the way: the trip to Fish Lake wasn't a total bust. That old whip is resonant on 10m (when switched to the antenna's 40m configuration), and 10m was wide open. At 5 watts with right around 1:1.5 antenna matching, I was using PSK to contact France and several US stations. It could have been worse!

73's de K7JTO

Hendricks PFR3 - Early Build Phases

If you've read my other blog posts here, you know I'm really interested in light-weight portable operations. That's what led me to buy the Yaesu FT-817, but eventually I realized that was good for park bench or quick day-trip summit work, but it just wouldn't work for a long (3+ days) backcountry hike. 

I reviewed a ton of radios annd came to the conclusion that I needed to learn CW and move to a dedicated QRP rig. After a lot of research, I was about ready to buy an Elecraft KX-1 (http://www.elecraft.com/KX1/KX1.htm). It's highly rated, well-crafted, and quite popular. Then someone turned me onto the Hendricks PFR3 (http://www.qrpkits.com/pfr3.html). The owner of the company was at a QRP meeting listening to someone discuss backcountry QRP operation. An audience member asked what the best rig for backcountry is, and the presenter said it didn't exist yet. He proceeded to list out the features of the dream rig, and Hendricks wrote it all down. He and Steve Weber design, prototyped, and started selling the rig. Not only is it better designed for the backcountry, but it's also much cheaper (the PFR3 currently sells for $240).

About 3 years ago, in 2011, I ordered my kit. I think I sorted the kit the first day I received it, but that's about it. Life got very busy for me, I went through some ups and downs, and now three years later I'm finally building it. In researching the kit, I found there's very little available on the Internet on how to build this rig. If you can't figure it out in the manual, there aren't many resources other than the group. I decided to document the build process so others might benefit.

I am about 4 hours into the build, done with the first two stages.

Basically stage 1 is the LED and power switch. The receiver, stage 2, is most of the right half of the circuit board. The build is very straightforward, except for one item: there's a torrid with a 5-turn primary winding and a 40-turn secondary winding:

I discovered in the course of winding that there is only room for a 40-turn winding, but the manual calls for 40 turns followed by 5 turns. It was all very confusing, until I emailed the PFR3 Yahoo group. A group member clarified: the 5 turns go over the 40 turns. This is probably the least clear portion of the manual.

Another point of conversation: some people have had issues with torroid wires breaking due to the jostling of backcountry travel (shaking in the pack). After discussion with list members, I decided to drop some wax under each torroid. That's what you can see in the shot above. The torroid a are installed on what will be the bottom of the board.

It's difficult to tell, but the radio is powered up and showing 30.0 on the right three digits.

My kit arrived with every component, but unfortunately I lost one of the RF chokes. A list member sent me a replacement. In the lower left of the photo you can see the stock choke--it looks like a fat resistor, just below C42. In the middle of the photo, between the blue and green caps, is the replacement choke. I love the way amateurs help each other out all the time!

Just another random shot of the main board. The kit is very well laid out and goes together quickly--most people estimate 6-8 hours to build. I'm probably 4 hours in, but a lot more considering the head scratching I went through over that torroid!

The manual lists a modification to stage two which address noise in the receiver. It requires two caps to be added--one in a through-hole, and on jumping a couple pins on another component. I was in Seattle on business so I grabbed the components at Frys and installed them with Group 2.

Next step is to dial in the receiver, then build out stage 3 (transceiver). Finally, prep the case and finalize the install.

Test Post

It's been a long while since my last post--apologies! Life has overwhelmed, but Im dusting myself off. More posts to come...

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New Blog Home

To reflect my new call sign (K7JTO), I have moved my radio blog to http://k7jto.blogspot.com. All future posts will take place there - please update and follow me there!

Check out my YouTube Account

I’ve set up a YouTube account where I’ll be posting video recordings of radio-related activities. As I learn more about HF radio and about QRP operation, I’ll post what I’ve learned.

http://www.youtube.com/user/KF7DVJ

Also, I’ve posted my first video on YouTube – it’s about my ultra-mobile bicycle emergency communications rig. http://www.youtube.com/watch?v=VKfxzOKIMaY

Ultra Mobile

Today was Centerville’s Independence Day parade, and I was able to be net control for the parade. Lots of fun! This article is more about my mobile emcomm unit than about the parade, though.

Wanting to test out my emergency communications, I chose to do the parade using my FT-817 QRP (low-power) radio. The 817 is essentially a hand-held radio in a larger box—it’s an all-band radio (HF, VHF, UHF) with a max output power of 5 watts in any mode.

Yaesu FT-817

I’ve had my 817 for about two months now and have really enjoyed using it, although I’ve had less than exceptional success using the HF bands for voice (I have succeeded to have digital conversations using PSK-31 and my laptop, though). It’s all about the antenna and the timing—more on that in another article.

My 817 has a couple of modifications, including:

• One Big Punch speech compressor, to increase readability on voice/SSB transmissions.
•   2700 mAH battery for much longer battery life (factory default is a paltry 1800 mAH)
• One Fast Charger reduces charging time from 18 hours to just over 2 hours.

The battery has been helpful. In fact, today I did an entire parade (7:00 AM till 10:15 AM) on my 2700 mAH battery. Didn’t even have to connect!

Portable Antenna

My stated goal was to perform net control duties using a low-power VHF rig. I also wanted to test my field setup, which includes a home-brew J-pole antenna for 2 m made of simple, cheap ladder line. It worked stupendously!

My antenna is about 57” long, made of ladder-line. I connect to it with a 6’ piece of coax with alligator clips. I’ve stripped away a fair amount of the insulation, giving plenty of room for tuning this antenna. It’s ultra-light, and it’s--surprisingly enough--a gain antenna! With a simple male-to-male coax adapter, I connected a 10’ coax line to the short line coming off the antenna. The antenna is slightly directional, but for the most part works efficiently in 360 degrees. It worked amazingly well for the parade; never an issue and the 817’s SWR meter never registered! I did decide to hook the hot portion of the coax line to the shortest section of the antenna; don’t know if it made a measurable difference or not.

My antenna mast was a simple 10’ piece of 3/4” PVC pipe. The only modification I’d like to do here is cut it into sections to fit into my bike trailer or my go kit.

Go-Kit

I have wrapped up construction on my go-kit (see my blog posting on the kit), and it’s really ready for use. I’m playing with what I keep in the kit, but today I had:

• FT-817
• Ladder-line J-pole
• 6’ coax with alligator clips
• 10’ coax
• Various wire antennas
• LED flashlight
• 12v AA/AAA battery charger
• Various wires and plugs
• Manuals
• Two sealed lead acid batteries
• Papers

The beauty of this go-kit is how well it fits into my bike trailer. Which puts the ‘ultra’ in ultra-mobile!

Set Up

I was the first person around, so for a while I was just sitting on the stairs with my radio on my go-kit lid. Finally the announcer arrived and soon we were ready to go. Pretty easy – you can see the power cable coming up between my 817 and my HT. Note that it’s not plugged into anything. I did the entire parade w/o additional power. Although each one of my solar-charged SLAs will run the 817 for 24+ hours (with two in my go-kit and the ability to add two more, that means I can operate up to 4 days without a power source).

Getting Around

In the event of a disaster, I don’t know if my vehicles will be available or not. But we own around 10 bikes, and a little “Bob Yak” bike trailer as well. So for the parade (not wanting to mess with parking), I loaded up the bike trailer and headed down!

 

Like I said, I’m planning to cut the antenna down to fit in the trailer or in the go-kit itself, but haven’t done it yet.

So there you go – a parade in a box. Just add some marching bands, a whole smattering of politicians, and a lot of sun!

PSK-31

So about 2 months ago I got to visit my buddy WB6YOK and watch him operate PSK-31. This is a really cool digital mode – while we were operating, we watched two guys in Cuba and Panama chat.

Over the weekend, I got to operate K7P, the special event station for the 150th anniversary of the Pony Express. I did a lot of PSK-31 then. And surprise – my SignaLink USB sound card arrived today and I’m on the air as myself finally! Hooked it up and made 10 contacts this evening—including Australia (near Melbourne).

Lots to learn, but I’m still just having a blast!

BTW: kept chasing FK8GX around – he’s transmitting from New Caledonia, a Pacific Island between Australia and Fiji. I heard him loud and clear, but he never could hear me. My cheap dipole just isn’t putting out the signal like I need it to.