• Daily Deals
  • Gift Cards
  • Sell
  • Help & Contact

Bidding has ended on this item.

Ships to:
United States See exclusions
Ships to:
United States See exclusions

Details about  Hobbydyne DX Crystal Radio Kit - 2 Coil, Double Tuning, High Performance Design

See original listing
Hobbydyne DX Crystal Radio Kit - 2 Coil, Double Tuning, High Performance Design
Item Sold
Item condition:
Sep 30, 2012
Winning bid:
US $103.85
3 bids ]
$10.80 Expedited Shipping | See details
Item location:
Central Florida, United States


eBay item number:
Seller assumes all responsibility for this listing.

Item specifics

New: A brand-new, unused, unopened, undamaged item (including handmade items). See the seller's listing ... Read moreabout the condition

Hobbydyne DX Crystal Radio Kit

This auction is for a Hobbydyne™ DX State of the Art Crystal Radio kit. The kit evolved from the Hobbydyne™ line of crystal radios that were designed by Jim Frederick from the ground up as serious receivers for DX reception on the AM broadcast band. The Hobbydyne kit was offered for sale for a short time and we have a very limited number of kits remaining.

***Please note that this is a kit, not a finished radio. The first two photos show a typical completed kit for reference only. Please read entire description for complete information.***

The kit makes a two coil, double tuned crystal radio with variable coupling between the coils. A hi-tech Shottky detector diode and very high Q (Quality) coils provide exceptional performance.

What is included: This kit is supplied with everything necessary to complete the radio except for the knobs, antenna, and a set of earphones for listening. You can use standard knobs from Radio Shack, or antique National Velvet Vernier drives can be used as shown on some of the radios on Jim Frederick's hobbydyne.com web page. The first photo shows the back of a typical completed kit using a plywood base and regular knobs. The second photo shows a typical front. The knobs are not included. The third photo shows the kit as it will arrive. It will also include an assembly manual. 

The Hobbydyne™ Crystal Radio shown at the top of the Hobbydyne web page was featured in CQ Magazine, November, 2005, on pages 79 and 80. It uses the same circuit as this kit.

Once your kit is completed, you will have a very hard time finding a crystal radio that performs as well as the Hobbydyne. It is very sensitive and very selective. It is ideal for either the casual listener or an advanced hobbyist, and would make a great project for a youth to assemble with your assistance.

This Hobbydyne™ kit was designed for maximum performance at an affordable cost using all new commercially available parts. The kit uses individually tested ferrite cores with 100 strand #46 Litz wire. The use of Litz wire more than doubles the Q of the coils and the selectivity of the radio as compared to regular wire. These ferrite coils have a higher Q than most 4 to 6 inch diameter air wound coils. Their Q measures approximately 650 on a Hewlett Packard Q meter. The higher the Q the better the sensitivity and selectivity will be. The kit features variable coupling between the two coils by means of a rotating shaft and a knob on the front panel. The rotary rod assembly is completely machined, ready to accept the coil and install on the panel.

The kit also features variable capacitive coupling between the detector coil and the Shottky detector diode. This method of coupling is similar to tapping down on the coil, but with much less loss, plus continuous adjustment. It can be set for the loudest signal, the best selectivity, or anywhere in between. The kit uses a modern Aligent Schottky diode detector for maximum performance.

The kit includes a front panel made of Garolite, a very hard and strong material similar in appearance to Bakelite. Everything you need to assemble the kit (except for the knobs, earphones & antenna) is provided, including the Delrin rotating rod assembly, two ferrite cores, two tuning condensers, phone jack, capacitors, resistor, sufficient Litz wire to wind both coils, hook-up wire and all hardware. Some basic mechanical ability, drilling and soldering is required to assemble the kit.

Included is a step-by-step "heathkit" style assembly manual for the kit plus coil winding details and operating instructions.

For best performance with this kit we recommend using either a good pair of vintage earphones like the Western Electric 509 or 509W, or a pair of sound powered phones. These items are available frequently on eBay. Antique dials can also often be found on eBay, as can more modern dials. 

In the daytime from Central Florida this set receives about 24 stations. At night the dial is full of stations. How well it works will depend upon your antenna - the higher and longer the better.

I have been an eBay Seller since 1997 and work hard to provide an excellent eBay experience. Every effort is made to provide an honest & accurate item description and good clear photos. Most of my items are used or vintage, and may require specialized knowledge to install, setup or operate. I may not have the ability to test some items but will disclose any known issues and all items are offered as-is. If you need any additional information or have any questions please feel free to contact me at any time. 

See my other eBay items & add me to your favorites list!

Payment by Paypal is due within 48 hours of auction close. Items are shipped to the address on the Paypal transaction. Please feel free to contact me if you have any questions.

For single item purchases, you may send payment as soon as the auction ends using the "pay now" button on the auction page. For multiple purchases, I will send you an eBay Invoice with a combined shipping total.

7% Sales Tax applies for items shipped within Florida and is calculated on the total cost including shipping.

I am always happy to combine multiple items whenever possible & am also willing to use flat rate boxes or envelopes to combine any items that safely fit. I will automatically send you a combined eBay invoice for items ending at the same time. You are also welcome to contact me for a combined shipping quote at any time.

Most items are shipped within 24-48 hours of receipt of cleared payment and often even sooner. The estimated in-transit times for each carrier are shown below. In-transit time is the delivery time once the package is given to the shipping carrier and will depend on your location.
Estimated In-Transit Times:  
UPS Ground or USPS Parcel Post 2-7 Business Days
USPS Priorty Mail 2-3 Business Days
USPS First Class (max. 13oz) 2-6 Business Days
Media Mail (Books & DVD's only) 6-10 Business Days

Questions and answers about this item

No questions or answers have been posted about this item.

Place bid

Time left:
Current bid:
(Approximately ##1##)
Import charges:
Your max bid:
Your max bid:
By clicking Confirm bid, you commit to buy this item from the seller if you are the winning bidder.
By clicking Confirm bid, you are committing to buy this item from the seller if you are the winning bidder and have read and agree to the Global Shipping Program terms and conditions - opens in a new window or tab. Import charges previously quoted are subject to change if you increase you maximum bid amount.
Resume bidding, if the page does not update immediately.
Place bid
Review and confirm your bid
Bid confirmation
FREE shipping
See item description
(Approximately ##1##)
(Enter ##1## or more)
(Enter more than ##1##)
Your max bid:
Increase max bid
Place bid
Confirm bid
Increase max bid
Change bid
, you've been outbid. Don't let it get away - bid again!
, you're the highest bidder on this item. Hope you win it!
, you're the first bidder. Hope you win!
, you're currently the high bidder, but you're close to getting outbid.
, this auction is almost over and you're currently the high bidder.
, you're the high bidder, but the reserve price hasn't been met.
Please enter your bid again.
Please enter a valid number as the bid price.
Enter an amount that is equal or greater than the minimum bid required. This can be found under the bid entry box.
Maximum bids can't be lowered once they're submitted.
This seller requires the buyer to have a PayPal account to purchase this item. Get a PayPal account here .
Your bid is greater than or equal to the Buy It Now price. We recommend you purchase this item via Buy It Now. If you still wish to bid, you may do so below.
Time left:
Current bid:
(approximately ##1##)
Your maximum bid:
(approximately ##1##)
Increase your maximum bid:
By clicking 1 Click Bid, you commit to buy this item from the seller if you're the winning bidder. Learn moreabout 1-click bid - opens in a new window or tab
(approximately ##1##)
Winning bid:
Starting bid:
Congrats! The auction has ended and you're the winner.
The auction has ended, but the reserve price was not met.
Sorry, the auction has ended and you were outbid.
Good news, you're the high bidder.
Sorry, you've been outbid.
You're the high bidder, but the reserve price is not met.
Please enter a higher amount than the current bid.
Maximum bids cannot be lowered once submitted.
Please enter a valid number.