Forums :: NEW! Web Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Oct Sat 23, 2021 10:56 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 21 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 5:14 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
PCB mounted relay should reduce parts count using the same IF chain for RX and TX. Just another idea on paper. I know that good SSB filter can be built with 24MHz crystals. The high IF frequency makes construction simple. No multiple BPFs needed at the input. I was wondering if anyone here has ever built a SSB filter with 30MHz crystals? It would make this transceiver cover 3 - 27 MHz and not use any input BPF, just LPF or low pass filter is enough. The first diode mixer can be modified for higher IP3 by using a pair of four diodes and seperate LO transformers. IP3 would be > 25dBm.


Attachments:
IMG_20210711_125328.jpg
IMG_20210711_125328.jpg [ 384.71 KiB | Viewed 1203 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 5:23 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
The mixer used here boosts IP3 to +27dBm. It can be implemented in the above SSB transceiver.


Attachments:
IMG_20210721_095503.jpg
IMG_20210721_095503.jpg [ 228.17 KiB | Viewed 1200 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 5:46 am 
Member

Joined: Jan Sat 25, 2020 5:23 am
Posts: 705
Location: Colorado Springs, CO 80917
Do you ever build any part or all of any of the designs you post?


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 6:01 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
hwhall wrote:
Do you ever build any part or all of any of the designs you post?


Yes. But nothing this year due to some health issues. So a lot has accumulated. Last year was fun though. Will start building soon. The LM386, CD4066, CD4053 based SSB transceiver is still pending.


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 6:37 am 
Member

Joined: Jan Sat 25, 2020 5:23 am
Posts: 705
Location: Colorado Springs, CO 80917
Ah, I see. I've been reading the posts on several of your ideas but never thought to ask if any had been breadboarded. Your soldering iron might not be very busy but your brain is. :-)


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 6:51 am 
Member

Joined: Jun Sun 15, 2014 5:37 pm
Posts: 1389
Location: Montreal, Quebec
Once you get above a certain frequency, crystals are overtone. So I think it's a bit more involved than scaling up.

Rhode had an article included in QST in the eighties about filters using overtone crystals, but I think it was a lattice filter. I think there's been some ham work on overtone filters, maybe in QEX.

Even apart overtone crystals, don't capacitor values in ladder filters get smaller the higher the frequency? So you start with smaller va!ues, and stray capacitance then becomes more significant.
?
But there's a reason roofing filters above 30MHz have been roofing filters. And it's not because they don't want selectivity after the first mixer.


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 7:16 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
hwhall wrote:
Ah, I see. I've been reading the posts on several of your ideas but never thought to ask if any had been breadboarded. Your soldering iron might not be very busy but your brain is. :-)


I posted in January. Need to add CD4069 based BFO. The remaining two switches inside CD4066 can be used in parallel to reduce Ron. Now we just need a front end mixer, VFO, and a bidirectional IF amp to complete this transceiver.

PS: I think I need to scrap the design. It lost its charm as IC count increased.


Attachments:
IMG_20210721_113811.jpg
IMG_20210721_113811.jpg [ 450.58 KiB | Viewed 1185 times ]


Last edited by Dare4444 on Jul Wed 21, 2021 6:13 pm, edited 1 time in total.
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 21, 2021 4:18 pm 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
DSB TX. Not sure if Po will be 10W. CD4066 single switch only allows 10ma max current. The 2n2219A emitter followers should do the trick and drive IRF510 linear amp with sufficient RF power. 10W DSB is equivalent of 5W SSB and good for beginners. Sharing the circuit idea for what it's worth. Gain of LM386 should be increased to 50.


Attachments:
IMG_20210721_194015.jpg
IMG_20210721_194015.jpg [ 332.98 KiB | Viewed 1167 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Thu 22, 2021 11:25 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
Another practical circuit with J310 IF amp for 24MHz IF frequency and 2n7000 for RF/IF switching. For single band operation, an IF of 9-12 MHz is okay. Some minor tweaking may be needed to adjust IF amp gain or impedances.

Parts count reduced but not performance. I don't see any reason why it shouldn't work. The SBM/Product detector can have an I and Q AF port option for SDR operation.

Connect an Arduino, LCD, and Si5351 digital VFO and it's complete! Just add two 74HC4053 chips as front end mixer and SBM, both driven by the Si5351.


Attachments:
IMG_20210722_154821.jpg
IMG_20210722_154821.jpg [ 403.05 KiB | Viewed 1113 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Fri 23, 2021 5:01 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
Diode switching would be helpful here. If IF = 24MHz then it should cover 3 to 15 MHz without any problem and with a single low pass filter at RF input. Band pass filters gone! Two J310 in IF section. If anybody wants to build this then go ahead.


Attachments:
IMG_20210723_092210.jpg
IMG_20210723_092210.jpg [ 412.67 KiB | Viewed 1068 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Fri 23, 2021 5:17 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
Mixer...


Attachments:
IMG_20210723_094712.jpg
IMG_20210723_094712.jpg [ 310.12 KiB | Viewed 1068 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Sun 25, 2021 2:16 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
SDR idea with two high level diode mixers for SSB generation.

PCB relays or 3 parallel switches in CD4053 can switch AF In/Out.

Circuit complexity is reduced. No crystal filters. The two BS170 can be driven with 74F74 high speed flipflop with 4F input from Si5351 + Arduino.


It will handle both weak and strong signals well. Output BPF required. Expect RF output power of +10dBm to +16dBm after the band pass filter. It should make an excellent transceiver. I'm not sure if SSB contact with 10mW of RF power is possible.


Attachments:
IMG_20210725_064408.jpg
IMG_20210725_064408.jpg [ 521.67 KiB | Viewed 1007 times ]


Last edited by Dare4444 on Jul Sun 25, 2021 3:51 am, edited 1 time in total.
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Sun 25, 2021 3:10 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
Watch "8 milliwatts of 80 metres SSB: Can it work?" on YouTube
https://youtu.be/wAYv1SKMFrE


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Mon 26, 2021 5:46 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
Not sure of the advantages of jfet over bjts @ IF < 20MHz. Almost same gain. This ckt was tested and works well. Good for 45MHz roofing filter.


Attachments:
IMG_20210726_101335.jpg
IMG_20210726_101335.jpg [ 454.19 KiB | Viewed 947 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Mon 26, 2021 7:59 pm 
Moderator
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22501
Location: Somers, CT
I am not sure why you are using relays?? It is easier to employ solid state switching to utilize a bilateral IF for both receive and transmit. Even more so if you use DBM's for the mixers and product detectors... it becomes a matter of reversing the LO and BFO injection to go between RX and TX. I did a very simple 160 meter SSB/CW transceiver that used diode switching for most of the RF signal paths. A few NE555 devices provided the TR switching by either driving the diodes into conduction or into reverse bias.

Take a look at the QRP Plus by Index Labs ham transceiver schematic (made back in the 1980s) to get some idea how they accomplished the bilateral IF reversal.

_________________
Just because it can be done doesn't mean it should be done.


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Mon 26, 2021 9:00 pm 
Member

Joined: Jun Sun 15, 2014 5:37 pm
Posts: 1389
Location: Montreal, Quebec
Was that the160M rig that later appeared in the ARRL Handbook? I remember one, but withiut looking I'm blank about who wrote it.

I think bilateral is becoming overused. The Cosmophone was said to be bilateral, but I just saw the QST review, andthe block diagram doesn't show that. The SBE-34 was bilateral, a portion of the IF amp was in the ARRL Handbook for years. There was a clone of the SBE-34 in the ARRL SSB manual, the 1970 edition.I

The 1971 ARRL Handbook had a tube 75M SSB rig. A common IF strip, the output feeding a mixer and product detector, I don't think any switching other than B+. At the other end, a balance modulator andfirst mixer.

I think it was Vester's tiny SSB transceiver that was tye best, it's in the 1965 ARRL SSB Manual (and QST sometime in 1963). I think a diode balanced modulator in parallel with a bipolar first.mixer at one end, and a diode ring mixer at the other, for converting to signal frequency on transmit, and as a product detector on receive. Really quite simple.

A simimlar layout in a rig in Ham Radio in 1973, using LM373s.

Bilateral means extra transistors, though maybe less tuned circuits. And unless diode mixers are used, not so easy to make bilateral mixers.

But for some reason bilateral has come back. It fits the minimalist mentality, try to simplify as much as possible. Except sometimes adding parts makes other things simple.

I mentioned previously that in the late eighties or early nineties, Wes Hayward had a 14MHz ssb rig in QST, and he used separate IF strips, complete with a KVG filter in each. Redundant, but other than the filters, barely more expensive than a shared IF strip.


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Mon 26, 2021 9:30 pm 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
Peter Bertini wrote:
I am not sure why you are using relays??


In the first one I did but not in the SE612 one where the chip has been used as DSB generator + product detector. The switches can be replaced by 2n7000 mosfets. They have good isolation.


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Tue 27, 2021 12:17 am 
Moderator
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 22501
Location: Somers, CT
mblack wrote:
Was that the160M rig that later appeared in the ARRL Handbook? I remember one, but withiut looking I'm blank about who wrote it.


I think it was Vester's tiny SSB transceiver that was tye best, it's in the 1965 ARRL SSB Manual (and QST sometime in 1963). I think a diode balanced modulator in parallel with a bipolar first.mixer at one end, and a diode ring mixer at the other, for converting to signal frequency on transmit, and as a product detector on receive. Really quite simple.

A simimlar layout in a rig in Ham Radio in 1973, using LM373s.

Bilateral means extra transistors, though maybe less tuned circuits. And unless diode mixers are used, not so easy to make bilateral mixers.

But for some reason bilateral has come back. It fits the minimalist mentality, try to simplify as much as possible. Except sometimes adding parts makes other things simple.

I mentioned previously that in the late eighties or early nineties, Wes Hayward had a 14MHz ssb rig in QST, and he used separate IF strips, complete with a KVG filter in each. Redundant, but other than the filters, barely more expensive than a shared IF strip.


Michae; Doug DeMaw expressed some interest in the rig for QST. For some reason I never followed through, but I did a cursory article for HR for the IF. Ben Vester's 20 meter QRP rig was a classic. Last I looked he was still licensed.

_________________
Just because it can be done doesn't mean it should be done.


Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 28, 2021 1:19 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
BFO oscillator should ideally have a -3dB pad and not just a 51ohm resistor to reduce drive level to 5mW to the balanced modulator + product detector. Four IN4148 diodes are used for switching the IF path. A single 17-21MHz LPF at the input is all that is needed. Just another idea for a SSB TRX covering the 80/40/30/20 meter ham bands.

Si5351 is the VFO and BFO to select frequency and LSB/USB operation. The flip flop used in the first mixer should supress the carrier well. The IF amp uses two transistors with 50ohm Z in and out and about 10dB gain each.

My first diode switched transceiver design. It is simple enough to be homebrewed.


Attachments:
IMG_20210728_054451.jpg
IMG_20210728_054451.jpg [ 304.61 KiB | Viewed 837 times ]
images - 2021-07-28T060918.809.jpeg
images - 2021-07-28T060918.809.jpeg [ 37.82 KiB | Viewed 835 times ]
IMG_20210728_061126.jpg
IMG_20210728_061126.jpg [ 39.96 KiB | Viewed 835 times ]
Top
 Profile  
 
 Post subject: Re: SSB transceiver idea
PostPosted: Jul Wed 28, 2021 3:41 am 
Member

Joined: Mar Thu 01, 2018 1:30 am
Posts: 733
IF amp updated for 50ohm impedance


Attachments:
IMG_20210728_081003.jpg
IMG_20210728_081003.jpg [ 371.07 KiB | Viewed 824 times ]
Top
 Profile  
 
Post New Topic Post Reply  [ 21 posts ]  Go to page 1, 2  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: ACORNVALVE and 5 guests



Search for:
Jump to:  


































Privacy Policy :: Powered by phpBB