Manager


Manager - NA4M
Manager Notes
Reviews Home

Reviews For: Small Wonder Labs Retro 75 AM Xceiver

Category: QRP Radios (5 watts or less)

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : Small Wonder Labs Retro 75 AM Xceiver
Reviews: 6MSRP: $69 (board & parts only)
Description:
AM Transceiver Kit, Board size 3.5” x 5.27” Xtal Transmit 3.885 MHz optional second channel. Tunable Receiver- 50 kHz, 4 kHz receiver crystal filter. Transmitter output power: 2.5W carrier/ 8W peak
Product is not in production
More Info: http://www.smallwonderlabs.com/
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0065
N3IBX Rating: 2014-07-03
Fun to play with in the "PW" mode! Time Owned: 0 to 3 months.
I just purchased my first "Retro 75" after listening to them on the air for a little over a year now. I just have a barebones kit without a lot of options which should suit my needs.
The receiver in it is surprisingly good for what it is and will swing about 60kc. Transmit audio isn't necessarily hi-fi, but it gets the message through.

All in all,a good little kit for you to play around with on 75M AM and have some fun with.
Look at it as a modern day AN/GRC-9!
W1RKW Rating: 2012-02-17
Nice Compact AM XCVR Time Owned: more than 12 months.
I built my Retro75 a year ago. As built it works good. I've made contacts with it all over the north east.


This little radio is perfect for experimenting. I've modified my Retro75 to have a wider frequency response and increase the modulation index. Also modified the receiver for increase gain.

The Retro Helper is a add-on VFO. This accessory is well worth the few dollars.

One does not need to modify it however, it works well as is. And is excellent for portable use on battery power.

I've since built the Retro40 as well. I recommend both.
WA0TPN Rating: 2011-11-24
Pure fun! Time Owned: more than 12 months.
I built the Retro-75 a year ago. The output power is 3 watts. The receiver is outstanding...better than any of the modern or vintage radios in the shack. Making QRP contacts is easy with good results.

This morning, I built and installed the VFO for the transmitter (the Retro Helper) so that the Retro-75 transmits on whatever frequency is dialed in for receive. The VFO works great.

Next will be the purchase the Retro-40 kit and Retro-Helper to explore QRP AM on 40-meters.

Thank you, Dave, for designing such fun radios, with outstanding performance, to keep the hobby interesting!

----------------------
Earlier 5-star review posted by WA0TPN on 2010-11-28

My newly minted Retro-75 made its first QSOs a couple of minutes ago to two fellows 194 miles away in Minnesota (from Iowa) on 3.885 mhz at 2:00 pm on Sunday afternoon! It is quite a thrill to answer a CQ with 3 watts on AM and have the station respond to your call sign! Although QSB was affecting both of our signals, it was easy to communicate.

The Retro-75 kit is a pleasure to build and is a great 2-day project. Previous kit building experience is helpful only because no step-by-step instructions are provided. Not all of the component locations are marked on the circuit board so it is essential that the diagram on page 11 of the instructions showing the component location be carefully examined as each component is installed. I installed all of the resistors first, then the capacitors, then all of the other components, and saved winding the 5 toriods until last. Any building sequence will work as well as another.

Receiver alignment requires peaking the two IF transformers. I discovered that using a guitar tuner to generate a steady tone through the microphone of another HF rig made the receiver alignment easy. A Sinadder Linear 5 was connected to the speaker jack to peak the audio signal while receiving the steady tone although peaking for maximum sound by ear will also work fairly well without using any test equipment.

Calibrating the receiver frequency dial setting to match the crystal controlled transmit frequency took a bit of trail and error. The instructions provide receiver voltages to match the local oscillator to the desired receiver frequency location on the tuning dial. I found that 2.675 volts was needed to calibrate to 3885 kHz instead of the 2.72 volts suggested in the instructions. Initially the receiver was receiving an AM signal 50 kHz below 3885 kHz and it took some time to find what frequency was being received. Once the amount of frequency mismatch was known, it was easy to recompute the target voltage needed to calibrate the receiver to 3885 kHz for a mid-range tuning dial setting. Then, the C3 trimmer capacitor was carefully adjusted while listening to a station transmitting on 3885 kHz to set the tuning dial precisely. It is possible that my digital voltmeter is not reading the correct voltage so differences may be relative to meter tolerances. Nonetheless, an hour or so was required to calibrate the receiver tuning dial with transmit frequency. This is about a 5-minute procedure if the receive frequency is known.

I elected to install crystals for 3.885 and 3.870 mhz although I am hearing a lot of QSO's on 3.880 mhz as well. I want to see if 3.870 may be better for QSO's in the upper Midwest (Iowa). If 3.870 proves not to be popular in the Midwest, I will install the 3.880 mhz crystal in its place.

The received signals sound better than the same signals from the Icom 756Pro using the same antenna and speaker system. In fact, the Retro-75 receiver has a lot of audio output and fills the room with a very pleasant AM quality sound at low audio gain settings.

The transmitter requires no alignment. My transmitter outputs exactly 3 watts of carrier power as measured with the WM-2 QRP watt meter and more than 7 watts of peak audio using the D-104 microphone.

Great QRP fun, get one!
N8SDD Rating: 2011-03-30
Good shtuph! Time Owned: 3 to 6 months.
Yeah, I got one, and it has turned out to be the most used Receiver in the shack. I mostly do AM in the window and have little interest in anything else and this little dude has awesome receive! Up where I live there are a lot of Am enthusiasts. We have been operating the AM window, in my recollection, for nigh on 15 years....unfortunately, the Magnolia guys have been working 3.878 for quite sometime as well......this little guy has filtering that makes listening on 3.880 a joy! Am currently working on a way to mute it so I can use it as a main receiver. I love my NC-183d....but the Retro 75 over shadows it.....No AGC, but I can live with throttling the nearby guys.....so long as it keeps filtering out the side band splatter. You homebrew guys who operate the AM window.....You should pick one up.

And so speaketh the word of our Lord.....ME! ;)
KG8LB Rating: 2011-01-11
What fun ! Time Owned: 0 to 3 months.
Got this kit back in November. It took but a few hours to wire up the board but the case was on back order. We resisted the temptation to try out the board and waited instead for the case to arrive.
The case arrived first Friday in January and we finally finished the project. The power up and alignment went just as described. We aligned/peaked the receiver to an on-air signal provided by my buddy Sam/AA8WL from about 3 miles away. So far , so good. Right after that was done I heard Joe/W8DCQ calling CQ from about 20 miles away. I gave him a call and got a good signal report right off the bat .We were then joined by another friend, Mike/KD8CVY from Midland, MI about 100 miles away. (This was at 4:00 PM) Our station is just North of Detroit, MI. At this point I was quite impressed with the performance of the receiver. The receiver is very stable , has a low noise floor. The sensitivity and selectivity are quite good as well. The 3 pole crystal filter is just about perfect for this application.
It was dinner time now so we reluctantly pulled away from the new toy.
Returned after dinner. Now it is 6:30 and prime time in the 75 meter AM window. The little receiver was doing a fine job hearing W7IUC in Southeast Tennessee (About 600 miles distant at prime time with 2 watts) )as well as WB3ETN in PA and another station in Durham NC. On a whim I tossed my call in with the little 2 watt TX. The TN station came right back. Carried on a fine QSO with all three. WB3ETN commented that he had bought a Retro 75 kit but never put it together. I am betting he will now.

The receiver has plenty of audio and I am using it to drive a 10 inch National speaker. The kit comes with crystals for 3880 and 3885, mine transmits about 200 cycles higher than the crystal marked freq.

The total assembly time should run 4 to 8 hours for most folks and the instructions are quite good. The components are of good quality.
I am a metal model maker by trade and usually take care of fabricating my enclosures for all home brew projects. In this case I took the easy way and ordered the optional enclosure kit. It turns out the enclosure kit was a bargain in my opinion. Many folks have balked a bit at the enclosure price but the enclosure kit has EVERYTHING needed to finish off the transceiver.
The switches, connectors, pots and knobs along with a supply of wire and the power plug are all included. The pre-painted and silkscreened case is a quality US made product of no less than Ten-Tec and offers a perfect, professional looking finished product.

All in all a very fine kit, based on a solid design platform. I am now waiting for the 40 meter version.

http://www.smallwonderlabs.com/Retro-75.htm
KB1NLW Rating: 2010-05-16
Great Kit Time Owned: 0 to 3 months.
Dave has done it again with a first rate design.

It is a QRP, AM design so only expect local contacts.

The Kit only includes the parts on the circuit card, so you need to order two potentiometers, switches, microphone, speaker, connectors and case. (I expect and hope Dave adds these as an option).