Dave, your videos have been a huge inspiration to me. I'm just getting back into ham radio after being out of it for 20 years or so. I've put a fan dipole for 20 and 10 in my attic and I just completed 70cm and 2m beams that I plan on using for satellite work. I'm working on an Arduino based AZ / EL rotator and will be posting videos of it in the future. 73's Dan
I am an amateur Amateur working 2 meters to start off. I just started working the band today- spent 3 hours driving around my area with my Icom v80. I find your channel very interesting and motivational. Keep it up. 73, Joe KC3BXZ.
For some reason, no matter what I do SWR is off the charts. I can receive 5 of 7 weather stations, just don't think I should be transmitting. ISS is passing over head in about an hour, can't wait to try anyways Any suggestion for swr?
Thanks for this video Dave. I have a sat station at my QTH. I was looking to build something for portable operation when RVing. I had an old TV antenna that I used to build the antenna. I improvised a little and reused the center insulators that were with the antenna. I tried it with a 5 watt Baofeng GT3 handheld and made contacts on AO-27 with ease. I did add the 6th element on the 70 cm antenna. I can swing the 2 meter driven element both sides of the center insulator to make it more compact for storage and the 2 meter director is easily removed and easy to reattach. Having used the driven element and director design was no issue for me. I used that design on 15 meters years ago for a 2 element yagi when I had limited antenna space. Thanks W2GDJ
That foam on the grip design is pretty smart. It also insulates it so that the cold aluminium doesn't steal the heat from your hand. It's a pain in the arse to start freezing while operating ;)
sorry! I would like to realize this antenna but I don't understand your Language very well so may you add a little drow with dimension of the antenna in meter or cm ? thank you
Recently I have been trying to raise interest in a 23cm APRS satellite network. This would benefit emergency communications by allowing hams to utilize considerably smaller, more portable, faster to deploy directional antennas paired with 1-5 watt handheld 23cm transceivers when transmitting APRS beacons to satellites. The uplink frequency would be on the 1200mhz band and the downlink would be on the standard 145.825mhz as well as 1200mhz. If this same task can be accomplished with a pocket sized SPOT GPS Satellite Tracker Transmitter that's the size of a hockey puck, runs on 2 AA batteries, puts out 0.4 watts on 1600mhz, then we should be able to do the same on 1200mhz with 1-5 watts. forums.qrz.com/index.php?threads%2F23cm-33cm-geosynchronous-aprs-digipeater-satellite-idea.536671%2F
You know what I'd like to see? You do a lot of Yagi antennas, and I think you must model these up before you build them. For example, you give an example of wanting to design for a 70cm Yagi with 4 directors spaced 5 inches apart. I'd love to see how you sit down with the computer to model something like this. I can drill holes in aluminum, but sitting down to create a design, that's something I'd appreciate a bit of insight into.
After first being licensed I spent months and months using yagi modeling software but never designed the perfect antenna nor even got one built. There are three things to consider -- purpose, cost and resources (not software). Mostly I have to consider purpose and resources. "How much boom do I have to work with?" is how I usually start. And then there are all those little things that you learn as you go. For example, yagi element lengths may be spaced anywhere from .15 to .25 of a wavelength with .225 being an optimal length. Wider spacing usually means more gain and less front-to-back ratio, and narrow spacing being the opposite. Parasitic element lengths also determine frequency. If the antenna is low in frequency and the driven element cannot be shortened anymore then the reflector and directors are made smaller. If I only need or have room for two elements then of course I'll use the widest possible spacing. When actually building antennas you learn a lot of little things that the modeling software will not teach. Like the formulas, modeling software will only get you close.
Dave Tadlock You seem to have a good understanding of element spacing and Yagi design considerations but you said boom length affects SWR. Could more likely be feedpoint impedance or matching. WA5KM
Your sat videos have all been great. I don't know if it's the recording or ??? but your RX signal seemed a bit stronger with this antenna than the others. Good job on using the foam to protect the coax...reminded me of my "Home Brew J-pole" video. Hope to catch you on a satellite soon & 73! KF7TOV
Part of it is the recording. The other part is I've gotten better at tracking and tuning, hi hi. The Excalibur has the clearest signal when the antenna is pointed directly at the satellite but it is harder to aim. Thanks for watching and 73! :)
Hello Dave, where I find the antenna measures. I do not understand his words and a picture is worth a thousand words. I'm sorry my english is bad. Claudio PY2ZB
Hello dave i would like to build the antenna you presented but i do not know english well i would pray if possible a small design with the measurements possibly in cm. thank you
I think its because Dave is loading these as dipoles, and I believe he is insulating the driven elements from the boom. So, his RF is being driven onto BOTH the 2meter and the 70cm dipoles, but he is banking on the fact that the elements are simply not resonant when fed with the "wrong" frequencies. If a band pass filter were used, I bet his antennas would see significant gain, since the "wrong" antenna wouldn't be sucking RF and wasting it.
It’s better to use a vhf/uhf duplexer. That way you only use one antenna. One for transmit the other for receive. Yes you can use one feed line to both antennas as we saw but it’s not very efficient.
I live Australia and use the metric system also! But we are all connected through the interwebs and the airwaves too. Don't worry Sweden I think you are still driving on the wrong side of the road haha!
Dave, your videos have been a huge inspiration to me. I'm just getting back into ham radio after being out of it for 20 years or so. I've put a fan dipole for 20 and 10 in my attic and I just completed 70cm and 2m beams that I plan on using for satellite work. I'm working on an Arduino based AZ / EL rotator and will be posting videos of it in the future. 73's Dan
I am an amateur Amateur working 2 meters to start off. I just started working the band today- spent 3 hours driving around my area with my Icom v80. I find your channel very interesting and motivational. Keep it up. 73,
Joe KC3BXZ.
For some reason, no matter what I do SWR is off the charts. I can receive 5 of 7 weather stations, just don't think I should be transmitting. ISS is passing over head in about an hour, can't wait to try anyways
Any suggestion for swr?
Thanks for this video Dave. I have a sat station at my QTH. I was looking to build something for portable operation when RVing. I had an old TV antenna that I used to build the antenna. I improvised a little and reused the center insulators that were with the antenna. I tried it with a 5 watt Baofeng GT3 handheld and made contacts on AO-27 with ease. I did add the 6th element on the 70 cm antenna. I can swing the 2 meter driven element both sides of the center insulator to make it more compact for storage and the 2 meter director is easily removed and easy to reattach. Having used the driven element and director design was no issue for me. I used that design on 15 meters years ago for a 2 element yagi when I had limited antenna space. Thanks W2GDJ
That foam on the grip design is pretty smart. It also insulates it so that the cold aluminium doesn't steal the heat from your hand. It's a pain in the arse to start freezing while operating ;)
would love to see a video on that exact antenna BUT with the Materials Used etc
Hello Dave! I like your videos very much. Would you please enable automatic closed captions on this one. It helps me to understand better. Thanks!!
Great work Dave... As always, I enjoy your videos, hope to work you on the bands some day.
Hai Dave, Your video is very encouraging, can you share the antenna measurement as a reference.
sorry! I would like to realize this antenna but I don't understand your Language very well so may you add a little drow with dimension of the antenna in meter or cm ? thank you
A link to a diagram with the dimensions might help those who don't natively speak English. Nice work on the antenna!
Hi Dave the weather is good to try out a bottom loaded CB antenna - Fred.
Recently I have been trying to raise interest in a 23cm APRS satellite network. This would benefit emergency communications by allowing hams to utilize considerably smaller, more portable, faster to deploy directional antennas paired with 1-5 watt handheld 23cm transceivers when transmitting APRS beacons to satellites. The uplink frequency would be on the 1200mhz band and the downlink would be on the standard 145.825mhz as well as 1200mhz.
If this same task can be accomplished with a pocket sized SPOT GPS Satellite Tracker Transmitter that's the size of a hockey puck, runs on 2 AA batteries, puts out 0.4 watts on 1600mhz, then we should be able to do the same on 1200mhz with 1-5 watts. forums.qrz.com/index.php?threads%2F23cm-33cm-geosynchronous-aprs-digipeater-satellite-idea.536671%2F
You know what I'd like to see? You do a lot of Yagi antennas, and I think you must model these up before you build them. For example, you give an example of wanting to design for a 70cm Yagi with 4 directors spaced 5 inches apart.
I'd love to see how you sit down with the computer to model something like this. I can drill holes in aluminum, but sitting down to create a design, that's something I'd appreciate a bit of insight into.
After first being licensed I spent months and months using yagi modeling software but never designed the perfect antenna nor even got one built. There are three things to consider -- purpose, cost and resources (not software). Mostly I have to consider purpose and resources. "How much boom do I have to work with?" is how I usually start. And then there are all those little things that you learn as you go. For example, yagi element lengths may be spaced anywhere from .15 to .25 of a wavelength with .225 being an optimal length. Wider spacing usually means more gain and less front-to-back ratio, and narrow spacing being the opposite. Parasitic element lengths also determine frequency. If the antenna is low in frequency and the driven element cannot be shortened anymore then the reflector and directors are made smaller. If I only need or have room for two elements then of course I'll use the widest possible spacing. When actually building antennas you learn a lot of little things that the modeling software will not teach. Like the formulas, modeling software will only get you close.
Dave Tadlock
You seem to have a good understanding of element spacing and Yagi design considerations but you said boom length affects SWR. Could more likely be feedpoint impedance or matching. WA5KM
Your sat videos have all been great. I don't know if it's the recording or ??? but your RX signal seemed a bit stronger with this antenna than the others. Good job on using the foam to protect the coax...reminded me of my "Home Brew J-pole" video. Hope to catch you on a satellite soon & 73! KF7TOV
Part of it is the recording. The other part is I've gotten better at tracking and tuning, hi hi. The Excalibur has the clearest signal when the antenna is pointed directly at the satellite but it is harder to aim. Thanks for watching and 73! :)
would the boom length matter if it was made of wood? I presume its affecting it because it is metal?
How's the SWR on 70cm? Also 2m?
Hello Dave, where I find the antenna measures. I do not understand his words and a picture is worth a thousand words. I'm sorry my english is bad. Claudio PY2ZB
you don't need an RF trap?
Is there any insulation between the boom and the parasitic elements?
Hello dave i would like to build the antenna you presented but i do not know english well i would pray if possible a small design with the measurements possibly in cm. thank you
Where can I find some plans for a 2 meter / 70 cm dual banc 5 element base antenna?
on the internet. just "google."
If you can wire 2meters and 70 cm together why does arrow sell and/or people use a "duplexes
"?
Thank you
Randall Goguen i have the same question!! Hopefully someone would answer this
I think its because Dave is loading these as dipoles, and I believe he is insulating the driven elements from the boom. So, his RF is being driven onto BOTH the 2meter and the 70cm dipoles, but he is banking on the fact that the elements are simply not resonant when fed with the "wrong" frequencies. If a band pass filter were used, I bet his antennas would see significant gain, since the "wrong" antenna wouldn't be sucking RF and wasting it.
It’s better to use a vhf/uhf duplexer. That way you only use one antenna. One for transmit the other for receive. Yes you can use one feed line to both antennas as we saw but it’s not very efficient.
I really like the feed point. nice little anteena dave 73 KC9PXZ
which measures the elements and spaces of yagi 2 vhf uhf 5 TKS 73
The 2 m and 70 cm antenna sb at 90 d from each other kg6mn
Can I you please give me the materials needed and plans for this?
Very good video and information! Thank's a lot! 73! de UT1ZZ
good job KF5AXY 73s
Good job
WAHYUDI SOEKISNO
JZ13AAP
sir can't see your swr reading...
nice antenna, but isn't it a pain in the arse to use the imperial units.
I live in Sweden and here we use the metric system. :)
I live Australia and use the metric system also! But we are all connected through the interwebs and the airwaves too. Don't worry Sweden I think you are still driving on the wrong side of the road haha!
Or maybe we have been driving on the right side of the road scince 1967. ;)
i think metric is a pain in the arse! 😉
I guess its all what you are used to
Your videos are great, except that they are too long.