# Ham and Eggs - Eggtimer TRS & LCD Now in 70cm Ham Version

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#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Eggtimer Rocketry is proud to announce the availability of our premier GPS tracking product, the Eggtimer TRS GPS transmitter/altimeter and the Eggfinder LCD receiver on the 70cm Ham band. This is our first Ham-only product, with some advantages over the non-licensed 900 mHz band products...

* You get about twice the range for the same amount of output power vs 900 mHz... with 100 mW of output power you should be good to at least 50,000' (and probably significantly more, since we've hit over 30K with the 900 MHz TRS).
* Compared to higher-power 70cm GPS transmitters, the 100 mW output will give you better battery life and/or allow you to use a smaller battery and still give you good range.
* There are 300 channels available, from 420 MHz to 449.900 MHz in 100 KHz increments, to accommodate just about any local band plan.
* Your call sign is sent out along with the GPS data, for FCC Part 97 compliance.

The 70cm Ham products are $10 more than the 900 MHz version, because they include the external antenna and RP-SMA connectors on both the TRS transmitter and the LCD receiver, which collectively add about 4 dB of gain budget. The 70cm TRS sells for$100, and the matching 70cm LCD receiver sells for $65. If you buy them together, it's$160 (you get a $5 combo discount). BUT... as an introductory special through October 6th 2019, we're selling the combo for$130... that's actually less than the 900 MHz TRS/LCD combo. If you want an extra 70cm TRS transmitter, it's $80 instead of$100.

To order, send us an email, sales@eggtimerrocketry.com . We will need your FCC-issued Ham call sign, or an international equivalent.

As always, thanks for your support!

Cris Erving, Eggtimer Rocketry

#### H_Rocket

##### Death by Powerpoint
Is the data sent in APRS form so we can opt to use existing radios like the VX8-GR?

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Nope, it's still NMEA. The existing TRS hardware wouldn't be able to do the NMEA-->APRS conversion, maybe in a future product. I'm also not sure if a VX8-GR or a Kenwood D74A can decipher the Hope RF's FSK transmission... I'll have to play with it (I have the Kenwood). In either case, considering what you would get out of it for the work that you'd have to put into it, using the LCD receiver isn't really a bad option, and you can add a Bluetooth module to it and use Rocket Tracker or Rocket Locator to give you a moving map. If you add the GPS module to the LCD receiver you get single-device tracking... it will tell you which way to to and how far away it is.

#### mbeels

##### Yes balsa
TRF Supporter
This is great, just the tracker I've been looking for. I do like the combination with the GPS receiver and LCD receiver.

#### mbeels

##### Yes balsa
TRF Supporter
Chris, will you be releasing a Eggfinder Mini transmitter on the 70cm ham bands?

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
The TX and Mini are "dumb" transmitters and do not have the capability to insert your call sign into the data stream. I do plan on developing an updated TX with that capability, but probably not the Mini because of its size. Then again, any rocket that won't fit a TX is probably not going to need the extra range, either.

#### mbeels

##### Yes balsa
TRF Supporter
The TX and Mini are "dumb" transmitters and do not have the capability to insert your call sign into the data stream. I do plan on developing an updated TX with that capability, but probably not the Mini because of its size. Then again, any rocket that won't fit a TX is probably not going to need the extra range, either.
Ah, I see. I'd be interested in in Mini tx on the 70 cm band. Currently I have a 900 MHz mini in the nose cone of a minimum diameter 38mm rocket (the standard TX wouldn't fit). I wouldn't mind more range in that rocket. My larger (3" and 4") rockets don't fly nearly as high, and don't need nearly as much range. I'd rather have a TRS on the ISM bands, and a mini on the HAM bands.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Biggest issue with adding Ham to the Mini is the lack of space... I'd probably have to do some kind of daughter board for the processor and logic to maintain the form factor. With the TX, I have some space to cram more things on the same sized board. Either one is going to be 2020 project.

#### mbeels

##### Yes balsa
TRF Supporter
Biggest issue with adding Ham to the Mini is the lack of space... I'd probably have to do some kind of daughter board for the processor and logic to maintain the form factor. With the TX, I have some space to cram more things on the same sized board. Either one is going to be 2020 project.
Ok, thanks for the update. I'd be happy with a standard TX on 70cm. Keep up the good work, love the Eggtimer/finder stuff.

#### KenRico

##### 'Just the Tip'
Is the PCB of the transmitter green ?? <ducking>

Would you? Could you?
In a car?
Eat them! Eat them!
Here they are.

Sent in an eMail for the combo , looking forward to trying out the new items !

Kenny

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Yes, there's definitely a pun there but I was afraid of copyright infringements...

#### OverTheTop

##### Well-Known Member
TRF Supporter
Sounds like another great product Cris. Thanks .

#### scsager

##### Slightly burned-out old guy
Hi Cris, - Every time I turn around these Egg products get more interesting!

Let me make sure I'm understanding...

This is the LCD and the TRS with a 70cm radio module in place of the normal 915mhz one. You are including antennas and connectors. Are these 1/4 wave or 1/2 wave antennas?
I'm gonna' take a wild guess that the LCD will still work with the add-on GPS board- is that right?

I should include my callsign in my order email. Will you load the callsign to the radio for me, or is it end-user changeable just in case I decide to go vanity?

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Hi Cris, - Every time I turn around these Egg products get more interesting!

Let me make sure I'm understanding...

This is the LCD and the TRS with a 70cm radio module in place of the normal 915mhz one. You are including antennas and connectors. Are these 1/4 wave or 1/2 wave antennas?
I'm gonna' take a wild guess that the LCD will still work with the add-on GPS board- is that right?

I should include my callsign in my order email. Will you load the callsign to the radio for me, or is it end-user changeable just in case I decide to go vanity?
Yes, the RF module is the primary difference, but there are some firmware changes to support it too. The transmitter comes with a stubby 1/4 wave antenna (Linx ANT-433-CW-HW), the receiver with a 1/4 wave antenna (Linx ANT-433-CW-QW). All LCD accessories are supported... the LCD-GPS module, Bluetooth, etc. You add your callsign when you configure the frequency of the TRS, it goes in the Device Name field. I've updated the web site, so if you go on the Support tab for the LCD receiver or the TRS and scroll down to the Ham section you'll see a document that explains all the differences.

#### warnerr

Major upgrade! Nice Chris. If I didnt already have the 900mhz version I would jump on it- having a license is worthwhile! I would really be interested in standard ARPS packets being transmitted- only need the transmitter with that setup!0

#### Thorfire

##### Well-Known Member
Why the sma-rp when virtually all 2m/70cm handhelds use sma antennas? Doesn't that severely limit antenna selection?

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
It's because the antennas that I ship are RP-SMA, I thought about going with regular SMA but that would have been one more part to stock (and run out of). You can certainly substitute the RP-SMA for a regular SMA, TNC, BNC, or whatever, but of course it's on you to get matching antennas too. If I was going to play around with the antennas I'd probably work on the receiver... you probably don't have much room to work with in the nose cone. There are a lot more options for the receiver, something like a Diamond SRH-77CA would be fine if you go SMA.

#### Thorfire

##### Well-Known Member
It's because the antennas that I ship are RP-SMA, I thought about going with regular SMA but that would have been one more part to stock (and run out of). You can certainly substitute the RP-SMA for a regular SMA, TNC, BNC, or whatever, but of course it's on you to get matching antennas too. If I was going to play around with the antennas I'd probably work on the receiver... you probably don't have much room to work with in the nose cone. There are a lot more options for the receiver, something like a Diamond SRH-77CA would be fine if you go SMA.
We have a couple diamond, or nayoya 805 SMA-M we use with our Altus Metrums. Not much gain at 3dbi, but extremely compact.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
The Linx that comes with the receiver is 3dbi, if you need a bit more link budget and have the room in your nose cone you could use one of those instead of the stubby one that ships with the TRS. If you do that AND use the Diamond you'd pick up about 5 dB over the as-shipped antennas.

#### mbeels

##### Yes balsa
TRF Supporter
For the transmitter, you want as close to a 0dBi antenna as possible (isotropic, non-directional antenna). Any antenna with gain in one direction, is going to have a relative null in another direction. So you for sure don't want a 5/8 wave on the TX, for example. The 1/4 is a very simple antenna that is reasonably close to omni directional and can fit in a narrow cylinder. Other antenna like an eggbeater may be more omni directional, but less convenient for fitting in a rocket.

Chris' suggestion of improving the RX antenna is a good one.

#### Thorfire

##### Well-Known Member
The Linx that comes with the receiver is 3dbi, if you need a bit more link budget and have the room in your nose cone you could use one of those instead of the stubby one that ships with the TRS. If you do that AND use the Diamond you'd pick up about 5 dB over the as-shipped antennas.
We have a spare Nagoya 771 'put your eye out' whip we may use on the receiver. If we want serious gain we'll hook up my kid's homebrew 5 element yagi or the seven element arrow. They work great for fox hunting trackers too ;-)

#### John Kemker

##### Well-Known Member
TRF Supporter
I'm sending one of those "put your eye out" whips to my eldest daughter in Tacoma to go with the DMR HT that I'm shipping her. Just got to thinking I need to take it out of the box and try it on my NanoVNA before I ship it to her to find out just how good it is. Remember, it's a dual-band antenna, which means that it's a compromise on one or both bands. 2m & 70cm.

. . .

Okay, just swept it. Looks like best SWR for 70cm is at 434.480MHz of 1.356:1. Looks better on 2m than it does on 70cm. Personally, I'd be tempted to use a handheld circular-polarized Yagi or helix on 70cm for location. At those frequencies, it's easy to put together. For ID, just turn the carrier on and off once every ten minutes in a controlled pattern, say short and long pulses. You know, like "didahdah dididididit dahdit dahdit didididit" [grin]

73 de W5NNH

Edit: Removed the gain information, as the reported information was useless with the methodology I was using.

Last edited:

#### Thorfire

##### Well-Known Member
Just a note. The nomenclature on the board indicates two 10 uF capacitors, the directions and parts list only indicate one. Some photos in the directions still show the transistors from the original board; different package, so I verified the new parts with the spec sheet. It's now mounted in our two stage for next weekend Having two bands for two stages makes life easier! Can't wait for a smaller 70cm tracker.

#### Thorfire

##### Well-Known Member
I'm sending one of those "put your eye out" whips to my eldest daughter in Tacoma to go with the DMR HT that I'm shipping her. Just got to thinking I need to take it out of the box and try it on my NanoVNA before I ship it to her to find out just how good it is. Remember, it's a dual-band antenna, which means that it's a compromise on one or both bands. 2m & 70cm.

. . .

Okay, just swept it. Looks like best SWR for 70cm is at 434.480MHz of 1.356:1. Looks better on 2m than it does on 70cm. Personally, I'd be tempted to use a handheld circular-polarized Yagi or helix on 70cm for location. At those frequencies, it's easy to put together. For ID, just turn the carrier on and off once every ten minutes in a controlled pattern, say short and long pulses. You know, like "didahdah dididididit dahdit dahdit didididit" [grin]

73 de W5NNH

Edit: Removed the gain information, as the reported information was useless with the methodology I was using.
Check the cheap Chinese radios!!!! We received a 'new in box' Baofeng DM1702GPS from a brick & mortar ham dealer that was the non GPS model, scratched like dragged behind a car display, and set up with Chinese language screens.... Surprised them as much as us.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
Just a note. The nomenclature on the board indicates two 10 uF capacitors, the directions and parts list only indicate one. Some photos in the directions still show the transistors from the original board; different package, so I verified the new parts with the spec sheet. It's now mounted in our two stage for next weekend Having two bands for two stages makes life easier! Can't wait for a smaller 70cm tracker. View attachment 396939
Nice soldering job! I'll check the docs and parts list... there have always been two 10 uF caps on the "B" version board.

#### Thorfire

##### Well-Known Member
Nice soldering job! I'll check the docs and parts list... there have always been two 10 uF caps on the "B" version board.
A syringe of solder paste, a $38 eBay hot air soldering station, a$12 board holder, and a microscope ;-)

#### John Kemker

##### Well-Known Member
TRF Supporter
Check the cheap Chinese radios!!!! We received a 'new in box' Baofeng DM1702GPS from a brick & mortar ham dealer that was the non GPS model, scratched like dragged behind a car display, and set up with Chinese language screens.... Surprised them as much as us.
Nah. Sent her my old AnyTone AT-D868UV. I bought an '878 when they came out because I wanted the Bluetooth and built-in APRS functionality. She gets the DMR/GPS w/o BT or APRS. I'd already used it, so just cleared the Georgia/Atlanta codeplug and gave her some resources to create a codeplug for her local area.

#### ether

##### Well-Known Member
TRF Supporter
Nope, it's still NMEA. The existing TRS hardware wouldn't be able to do the NMEA-->APRS conversion, maybe in a future product. I'm also not sure if a VX8-GR or a Kenwood D74A can decipher the Hope RF's FSK transmission... I'll have to play with it (I have the Kenwood).
Cris - have you tried to see if TH-d74a can decipher the transmission? if it does not work, any plans to update the regular TX to do 70cm with APRS, having the GPS datalogging would be great, especially for those that may already have HAM radios that can display APRS packets