Author Archives: Thomas

The Muzen OTR: A handcrafted salute to Radio Caroline

Many thanks to SWLing Post contributor, John Harper (AE5X), who writes:

I thought you and your readers might be interested in this […] a cool little radio I learned about from the YouTube channel of a drone flyer I follow.
I like the craftsmanship:

Click here to view on YouTube.

Many thanks for sharing this, John!

I’ve actually been following the Muzen OTR for several months via Indiegogo thanks to my buddy and radio-enabler, David Korchin (K2WNW).

If the name Muzen sounds familiar, it’s likely because we featured the company last year in this post. After publishing the post, I was so interested in Muzen products, I reached out to a retailer who used to be a US distributor. Sadly, he no longer carried Muzen products, though he was a big fan.

The Muzen OTR is $69 US shipped. For an FM radio, Bluetooth, AUX-in speaker that’s handcrafted, with serious audio fidelity, in such a small size, I think it’s quite a good deal. On top of that 10% of the funding will go to Radio Caroline.

Even though I’m going through a serious down-sizing at the moment, John’s note prompted me to back this campaign, so I bit the bullet this morning and ordered a Muzen OTR. [In a sarcastic tone: “Thank’s a lot, John!”] Ha ha!

Click here to check out the Muzen OTR on Indiegogo.

Ultralight DX: A batch of inexpensive Sony SRF-39FPs found on eBay

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Many thanks to SWLing Post contributor, Vance Thompson, who writes:

Thought you might be interested to see that several SRF-39FP radios have been up on eBay recently at a fairly reasonable price.

I picked one up when they first were posted, but the price has gone down the last couple of days and even has a “make offer” option with free shipping.

Click here to view on eBay.

The description indicates that they are pre-owned by inmates at a Tennessee federal prison. As of this writing, there are 8 left.

The one I got was in pretty good shape cosmetically, all things considered, and works perfectly. Given that a brand new FP version of the SRF-39 is not likely to be seen again at $20, a used one such as this with a bit of history is not a bad deal for those of us that missed out when snagging one new was an option.

Although it makes me wonder what they are being swapped out for and if we might see an increase of these pre-owned ones coming up on eBay now.

Thanks for sharing, Vance! Twenty dollars (or possibly less through a Best Offer) is a fantastic deal, in my opinion, for the elusive SRF-39FP. Click here to read out previous posts about the SRF-39FP. Indeed, I’m mighty tempted to drop $20 on a spare unit myself. (Thanks for enabling me, Vance!)

It appears the seller has a stellar reputation on eBay too.

Click here to view this Sony SRF-39FP on eBay.

Click here to search eBay for other SRF-39FP listings.

A $25 upgrade for the Elecraft KX2

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Many of you know I’m quite a fan of the Elecraft KX2. I take this little transceiver along almost any time I travel. Not only is it a full-featured ham radio transceiver, but it’s also an exceptional shortwave broadcast receiver.

The KX2 is a quality US-built rig (like all of Elecraft’s gear) but I’ve never been a fan of its plastic encoder knob. It lacks a finger dimple and feels cheap compared to the rest of the radio. Don’t get me wrong: the stock encoder knob gets the job done, but it’s not nearly as nice as the one on the slightly larger Elecraft KX3.

Comparing the Elecraft KX3 (top) and KX2 (bottom) at Elecraft’s Dayton Hamvention booth.

Two weeks ago, I ran into another Elecraft KX2 owner and happened to notice that his KX2 had a solid aluminium encoder knob with a finger dimple. Turns out, he purchased the knob from a ham radio operator (W1JH) in Maine who manufactures and sells this knob on eBay.

The price was $24.95 US shipped. I didn’t hesitate to place an order.

You might think $24.95 is a lot to pay for such a small item, but third party Elecraft vendors tend to charge much more for comparable items. I’ve also considered adding a heatsink to my KX3, for example, but those can total upwards of $100!

My new encoder knob arrived in only a couple of days via the USPS–installing it was a breeze.

It took me all of thirty seconds to pull the plastic knob off of the KX2 and replace it with the new aluminium one. The seller even includes an Allen wrench to secure the new knob.

The new knob is slightly larger in outer diameter, but fits the KX2 like a glove. The slightly larger size makes the finger dimple a practical addition for smooth band-scanning.

If you own an Elecraft KX2 (or the Elecraft KX1) I highly recommend this simple encoder/VFO knob upgrade!

Click here to order on eBay.

eBay Find: Cubic Defense Applications Model 4400DF

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Many thanks to SWLing Post contributor, Dan Robinson, who shares a link to this Cubic Defense Applications Model 4400DF communications receiver on eBay.

I’ve been following this listing the past few days–the seller actually launched the item with a very low starting bid.

eBay unearths so many products that I would have never known existed. This military receiver is certainly a case in point.

As the seller states, I imagine the original price tag for this receiver was hefty–likely thousands of dollars. The front panel lacks many of the controls we’d like to see on an HF radio (bandwidth, RF gain, notch, etc.), however, I imagine there are a number of functions on the backlit screen and possibly accessible via an external monitor and/or keyboard.

I’m curious: are there any SWLing Post readers out there who can comment about the performance of this receiver? Have you ever put one on the air? Please comment!

Click here to view the Cubic Defense Applications model 4400DF on eBay.

Anil’s hack: Using a smart phone battery bank to power portable receivers

6 Replies

Many thanks to SWLing Post contributor, Anil Raj, who writes:

I wanted to share a small but useful hack with your readers.

I use a common garden variety smartphone “Powerbank” 10,000 mAH Li Ion pack to power my Sony 7600GR which is perfectly happy with the 5V which the pack supplies. [See photo above.] I see no reason why this won’t work with other radios which require a 6V supply.

As you can imagine, the setup typically lasts for many weeks of extended daily listening and recharges in a jiffy. However, one needs to sacrifice a USB cable by soldering a DC plug at the other end. Haven’t bought AA batteries in a long time…

Thank you, Anil! What a simple but useful hack. The best part is, battery packs/banks are very inexpensive these days and, I for one, have a number of USB cables I could sacrifice for the job!

TX Factor Episode 20

Doctor Vlado repairs the Panasonic RF-2200 (Part 1)

35 Replies

Last year, at Hamvention, I picked up a Panasonic RF-2200 for $70. It came with the original box, manual and was in superb cosmetic condition.

The seller told me that over the years he exclusively used the radio to listen to a local FM station.

At that price, I didn’t hesitate to make the purchase even if this would have simply been a non-functioning parts radio for my other RF-2200.

After I brought the radio home, I unpacked it and gave it a quick test.

FM worked brilliantly. Mediumwave and shortwave, however, were essentially deaf. I made the assumption that the ‘2200’s switches and pots likely needed cleaning with DeoxIT. The next day, I was leaving for a two month trip to Canada though, so I packed the RF-2200 back into its box and set it to the side of my shack table.

Fast-forward to yesterday…

While digging around my shack, I re-discovered the boxed RF-2200. Since I was planning to visit my buddy Vlado (the best radio repair guy in the world) yesterday evening, I thought I’d take the RF-2200 and do a proper contact cleaning. Several of the RF-2200’s switches and pots cannot be easily cleaned without removing the chassis.

(Click photos to enlarge.)

Vlado is familiar with the RF-2200 and since it’s not the easiest radio to work on, I asked for his expert hands on the job. Within seconds of handing him the radio, he plugged it in, tested the switches and pots, then removed the back cover (disconnecting the battery compartment leads) and then the front cover (disconnecting the speaker leads).

The magic behind the RF-2200’s classic analog dial:
Vlado offered a word of caution to anyone operating on their RF-2200: as you can see in the photo below, the dial string snakes around the front of the radio and is very close to some key components. You must exercise caution when having a soldering iron tip near the string, or using lubricants nearby.I didn’t realize this, but by the time Vlado started taking apart the RF-2200, he had already determined that even though the contacts needed cleaning, this wasn’t the source of the audio problem for the MW and SW bands.Vlado expertly pulled out the pot for the FM/AM/SW selection–not an easy task–began cleaning it, testing it and re-soldering contacts.

Vlado determined the pot was actually in good shape, thus started testing the rest of the circuit.

After a few minutes of performing tests and getting intermittent performance, he determined that at least one, if not more, of the RF-2200’s caps need to be replaced. Of course, neither one of us was terribly surprised. At this point though, it was getting late and I had an early wake up time in the morning, so I left my RF-2200 with Vlado.

Am I worried about this prognosis? No, not in the slightest…

Doctor Vlado is on the job!

Vlado will have the RF-2200 back on the air in no time, working as well as it did when it was new. He’s actually performed a similar RF-2200 repair for an SWLing Post reader and I’m willing to bet this repair job is relatively simple compared to most he encounters (including the Icom IC-7200 he recently repaired after it was hit by lightening!).

I’ll try to post a “Part 2” update with photos of the RF-2200 repair. Follow the tag: Panasonic RF-2200 Repair