Guest Post: The Prof finds a Nova Tech Pilot II RDF receiver

Many thanks to SWLing Post contributor, The Professor, who shares the following guest post:

A 1960s Signal Sniffer

by The Professor

I just recently purchased a radio that on eBay that looks very intriguing, especially if you happen to DX AM Radio. It’s a mid-60s portable made in Japan – a Nova Tech Pilot II . However, wasn’t just a grab ën go to the beach kind of transistor set. This radio has a serious side. It’s actually an RDF – a “radio direction finder.”

I have seen these kinds of radios before, somewhere. Only the ones I’ve noticed were older and had more of a military look. Although I’ve never actually attended a hamfest, I’m sure these types of receivers might be found at a gathering like that.

But this is a smaller and frankly more stylish version of RDF. Not to go into too much detail about something I know little about, but before GPS became ubiquitous, devices like this would commonly assist in the navigation of ships and aircraft by pinpointing “beacon” transmitters at specific known locations.

As you might imagine, this type of technology was (and probably still is) a strategic tool for military purposes. In fact, one of more “infamous” incidents of using radio direction finders was when they were utilized by the Japanese in the bombing of Pearl Harbor. Their bombers just honed in on the signal of a Honolulu AM station (KGU at 760kHz) as their beacon.

So, this radio has three bands which were traditionally used by beacon transmitters. Besides the medium wave band, it also has a section of the longwave spectrum, and the VHF airband. Other models included the old marine band (around 3 to 5MHz). A later model also included the CB frequencies, and another included a VHF police band (called the Nova Tech Action!!).

So, no shortwave on this one. No FM either, but I have plenty of radios with those bands (like almost all of them). Of course, there’s not much to find on this side of the world on longwave these days, and listening to aircraft communications has its fans but it’s not something I’ve done much. But this thing has a unique toolset for medium wave DXing. And after doing a little research online I’ve discovered that the big rotating double ferrite on top is only one of the attributes it offers for AM DXing purposes.

For one, it has an RF amplifier in the front end to help pull those weak signals up out of the noise floor. For another, it has a pure RF gain function called “DF” (direction finder), which when turned on shuts down the AGC (automatic gain control) and allows you to tweak the RF gain any way you like. And it also has a very accurate tuning meter. That all sounds good to me.

So, I haven’t actually seen my Nova Tech in the flesh yet, and it will be probably a couple of weeks before I get a chance to give it a test drive. But I’m pretty confident in my purchase at this point. More than a few people have spoken glowingly of the AM DXing capabilities of this set. But one of the reasons I decided to go ahead and bid on this device was that not only did the dealer have an excellent eBay rating, but he says he also fully serviced the radio electronically and physically restored most of its original beauty. Apparently, it was cleaned up, recapped, and even a transistor was replaced. And he also aligned the AM band IF and re-peaked the antenna trim for AM and the airband.

Although this radio is still a twinkle in my eye at this point, I thought I’d mention it here in hopes some of the fine readers of this blog might have something to say about DXing with direction finding radios. And I was especially hoping that a few people might have personal experience with these 60s era Nova Tech receivers. I also noticed online that there are U.K. versions of these RDFs that were branded as “Bendix” radios.

All insights offered as comments are appreciated, and once I spend some time with this radio I’ll be sure to offer some of my own.

I always find it so much fun to await the arrival of an interesting old radio I’ve purchased on eBay, especially one that I’d never heard of before.

Thanks for sharing your find, Professor! I was not at all familiar with the Nova Tech Pilot II. I love the Transoceanicesque design! No doubt, it’ll be a handsome addition to your collection, and I’m willing to bet a MW DX machine as well!

Spread the radio love

An example of astronomical third party pricing on Amazon.com

7 Replies

I’ve been helping a friend’s daughter study for her Technician Amateur Radio License. Besides my tutoring, she’s only been studying with a free phone app thus far and essentially learning the answers to the questions. I know she really needs a book that can provide context for each question.

Since there was no need to buy a new $30 guide (that’s only valid until the end of June), I started my search on Amazon.com thinking that there may be some affordable, good condition used study guides I could snag for a decent price.

I was wrong.

Check out the screenshot below from this page:

And if $2,000 US (plus $3.95 shipping!) wasn’t too high…$4,093 (plus $3.95 shipping!) for a used “Acceptable” condition Technician License Study Guide?!? What a deal! Is there a limit on how many I can buy? 🙂

I’ve heard that some sellers add high prices to items that they want to put on “hold.” I did some searching this afternoon and saw discussions by sellers admitting that this technique saves them time from relisting an item that might need more research. More than one admitted that “And hey, if someone buys it for that price, all the better!”

Personally, I think this practice should be banned by Amazon. I checked out one of the stores from a seller in the list above and almost all of their listings have astronomical prices.

What do you think? Am I the only one noticing this trend?

Spread the radio love

Guest Post: Review of the TYT SF-401 Plus Frequency Counter/Tone Meter

2 Replies

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), for sharing the following guest post:

TYT Frequency Counter/Tone Meter Review

by Mario Filippi (N2HUN)
All photos courtesy of author

Most hobbyists own some type of transceiver whether it is a handheld, mobile, or base station. Some examples are amateur radio HF/VHF/UHF transceivers, Citizen’s Band radios, FRS (Family Radio Service) and GMRS (General Mobile Radio Service) handhelds.

A useful tool for the shack or the field is a frequency counter/tone meter since it can measure frequencies and analog/digital tones from transmitters/transceivers. At times ascertaining that a UUT (Unit Under Test) such as a 2 meter handheld is transmitting accurately may be indicated due to problems communicating with other stations. In addition, if the UUT transmits a sub-audible tone (either analog or digital) to access a repeater, a frequency counter/tone meter can detect the presence and verify accuracy of the CTCSS/digital tone.

Author’s TYT SF-401Plus, includes instructions, antenna, rechargeable battery and charger/cable. Covers 27 MHz – 3 GHz

Frequency/tone meters can be purchased for less than twenty US dollars but normally do not include a rechargeable battery and BNC connector for attaching an external antenna. Having had experience with these types, the time finally came for an upgrade.

After shopping around a decision was made to purchase the Tytera TYT SF-401 Plus. This model includes an instruction sheet, antenna, internal rechargeable battery, USB charger and cable. It represents a significant improvement over my previous, inexpensive meter, as the TYT has a BNC connector to attach a larger antenna and has four control buttons on the front panel. It also has, via a system menu, options to adjust the frequency/tone offset, dimmer levels, three or four decimal display and auto power off. All these valuable features warrant a higher cost, which was about $50, but well worth it. This price fits the budget of most hobbyists. However, higher end frequency/tone meters are available and cost several hundred dollars for those requiring that level of quality.

Out of the box the TYT SF-401 Plus, when checked against an IFR FM/AM-500A communications service monitor, was right on the money as far as accuracy. Note that the IFR-500A was calibrated against a high precision internal 10 MHz crystal in an “oven” and this is my gold standard reference for frequency accuracy in my shack.

TYT accuracy checked against an IFR FM/AM-500A communications service monitor transmitting a 146.52 MHz/131.8 Hz tone. Note frequency readout to four decimal places.

Now, it was time to check typical radios around the shack using the TYT. The first radio tested for frequency accuracy was a BTECH GMRS-V1 HT which I use to communicate with the home QTH while running errands around town. See photo for results. The BTECH and TYT agreed perfectly. Note that the TYT’s display includes a battery status indicator on top left and a timer use indicator, which resets every time the TYT is turned on. If you are going to measure digital signals (not included in this review) there is an option in the Setup Menu for that. With the BTECH handheld running 2 watts the TYT could detect its’ frequency at roughly four feet away.

Confirming BTECH transmit frequency against the TYT. Output is 2 watts. TYT multicolor display is super.

For VHF/UHF operating, especially when afield with other hams or groups such as CERT (Community Emergency Response Teams), problems can ensue if one does not have the correct frequency or tone programmed, so having the TYT in your shirt pocket to confirm these parameters when trouble occurs can be a quick way to get to the problem. See photo of an Icom IC-2300H 2 meter transceiver checked against the TYT for proper offset and tone. The Icom was putting out 65 watts and a repeater with an offset of -1.3 MHz and 88.5 Hz tone was checked.

TYT confirming unusual offset (-1.3 MHz) and tone for a repeater. Icom IC-2300H was at high (65W) setting and connected to an outdoor discone antenna.

According to the instructions included with the TYT SF-401 Plus, the operating range is from 27 MHz – 3000 MHz with a note stating “27 MHz – 100 MHz it can not be guaranteed and the corresponding normal emission appliance” which I interpret as accuracy is not guaranteed in this frequency range. Well, I checked the TYT against the IFR FM/AM-500A service monitor transmitting an AM signal on CB Channel 19, 27.185 MHz, and the TYT measured it exactly. One other important note is that according to the instructions, the tone decoder operates in the 136 MHz – 174 MHz and 400 MHz – 520 MHz frequency range. So that may limit its use in certain areas of the spectrum. One other item if interest is that the TYT has a 10 dB attenuator when dealing with high power signals.

All in all, I’m very happy with this purchase, and find the TYT SF-401 Plus useful for “first pass” troubleshooting and helpful when aligning older rigs which due to age are off frequency /tone. It definitely has a use in this shack.

Wow–what a bargain tool for the radio shack! Thank you for sharing your review, Mario. Once again, however, you have tempted me with a purchase! I remember when frequency counters would set you back a couple hundred bucks–it’s insane to think that you can grab one for $40-50 US shipped.

SF-401 Plus Retailers:

Note that the TYT SF 401 Plus is also marketed as the Surecom SF401 Plus:

Spread the radio love

Special two hour DRM broadcast today at 12:00 UTC

6 Replies

According to the DRM Consortium, there will be a special two hour DRM broadcast today (April 18) starting at 12:00 UTC:

Special DRM transmission tomorrow 18th April from Spaceline during DRM GA at 1200-1400UTC on 11600kHz. From Kostinbrod, Bulgaria with antenna directed at 260 degrees. The content will be from Mighty KBC.

Note that this broadcast starts less than two hours from time of posting. Please comment if you log this broadcast!

Spread the radio love

RootIO and a new community radio initiative in Uganda

FTIOM & UBMP, April 22-28

A taste of Gary DeBock’s Cook Islands (Aitutaki) Ultralight DXpedition

5 Replies

Many thanks to SWLing Post contributor, Gary DeBock, who shares the following notes from his Cook Islands Ultralight DXpedition:

Cook Islands (Aitutaki) Ultralight DXpedition from April 8-13

A gorgeous environment, with thrilling long range DX! Ruth and I took this trip as the 38th anniversary of out first meeting at Victoria Peak in Hong Kong (April 10, 1980).

DXing highlights were the reception of 693-Bangladesh, 918-Cambodia and 1431-Mongolia on the 7.5 inch loopstick C.Crane Skywave SSB Ultralight and 5 inch “Frequent Flyer” FSL antenna (designed to provide inductive coupling gain equal to that of a 4 foot air core box loop, but in a much more compact size).

693-Bangladesh 1652 UTC April 10 (mention of Bangladesh at 8 second point; thanks to Chuck Hutton for listening):

Download: 693-Bangladesh-1652z041018CCSWANR

918-Cambodia 1659 UTC April 12 (Khmer female speech, National Anthem with “Cuckoo Clock” time pips at 1:41; thanks to Hiroyuki Okamura for listening):

Download: 918-Cambodia-1659z041218CCSWANR

1431-Mongolia 1631 UTC April 11 (BBC Korean service interval signal at 46 seconds; thanks to Hiroyuki Okamura for listening):

Download: 1431-Mongolia-1631z041118CCSW

Location: Tamanu Beach Resort ocean shore, Aitutaki, Cook Islands (in the South Pacific)

Amazing catches, Gary–thank you for sharing! It seems your modified CC Skywave SSB is serving you well. Looks like you were chasing amazing DX from an amazing part of our planet!

Spread the radio love